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1

Study of Aerosol Indirect Effects in China  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security AdministrationcontrollerNanocrystalline Gallium Oxide Thin Films.AdministrationAerosol Indirect

2

Parameterizations of Cloud Microphysics and Indirect Aerosol Effects  

SciTech Connect (OSTI)

1. OVERVIEW Aerosols and especially their effect on clouds are one of the key components of the climate system and the hydrological cycle [Ramanathan et al., 2001]. Yet, the aerosol effect on clouds remains largely unknown and the processes involved not well understood. A recent report published by the National Academy of Science states "The greatest uncertainty about the aerosol climate forcing - indeed, the largest of all the uncertainties about global climate forcing - is probably the indirect effect of aerosols on clouds [NRC, 2001]." The aerosol effect on clouds is often categorized into the traditional "first indirect (i.e., Twomey)" effect on the cloud droplet sizes for a constant liquid water path [Twomey, 1977] and the "semi-direct" effect on cloud coverage [e.g., Ackerman et al., 2000]. Enhanced aerosol concentrations can also suppress warm rain processes by producing a narrow droplet spectrum that inhibits collision and coalescence processes [e.g., Squires and Twomey, 1961; Warner and Twomey, 1967; Warner, 1968; Rosenfeld, 1999]. The aerosol effect on precipitation processes, also known as the second type of aerosol indirect effect [Albrecht, 1989], is even more complex, especially for mixed-phase convective clouds. Table 1 summarizes the key observational studies identifying the microphysical properties, cloud characteristics, thermodynamics and dynamics associated with cloud systems from high-aerosol continental environments. For example, atmospheric aerosol concentrations can influence cloud droplet size distributions, warm-rain process, cold-rain process, cloud-top height, the depth of the mixed phase region, and occurrence of lightning. In addition, high aerosol concentrations in urban environments could affect precipitation variability by providing an enhanced source of cloud condensation nuclei (CCN). Hypotheses have been developed to explain the effect of urban regions on convection and precipitation [van den Heever and Cotton, 2007 and Shepherd, 2005]. Recently, a detailed spectral-bin microphysical scheme was implemented into the Goddard Cumulus Ensemble (GCE) model. Atmospheric aerosols are also described using number density size-distribution functions. A spectral-bin microphysical model is very expensive from a computational point of view and has only been implemented into the 2D version of the GCE at the present time. The model is tested by studying the evolution of deep tropical clouds in the west Pacific warm pool region and summertime convection over a mid-latitude continent with different concentrations of CCN: a low "clean" concentration and a high "dirty" concentration. The impact of atmospheric aerosol concentration on cloud and precipitation will be investigated. 2. MODEL DESCRIPTION AND CASE STUDIES 2.1 GCE MODEL The model used in this study is the 2D version of the GCE model. Modeled flow is anelastic. Second- or higher-order advection schemes can produce negative values in the solution. Thus, a Multi-dimensional Positive Definite Advection Transport Algorithm (MPDATA) has been implemented into the model. All scalar variables (potential temperature, water vapor, turbulent coefficient and all five hydrometeor classes) use forward time differencing and the MPDATA for advection. Dynamic variables, u, v and w, use a second-order accurate advection scheme and a leapfrog time integration (kinetic energy semi-conserving method). Short-wave (solar) and long-wave radiation as well as a subgrid-scale TKE turbulence scheme are also included in the model. Details of the model can be found in Tao and Simpson (1993) and Tao et al. (2003). 2.2 Microphysics (Bin Model) The formulation of the explicit spectral-bin microphysical processes is based on solving stochastic kinetic equations for the size distribution functions of water droplets (cloud droplets and raindrops), and six types of ice particles: pristine ice crystals (columnar and plate-like), snow (dendrites and aggregates), graupel and frozen drops/hail. Each type is described by a special size distribution function containing 33 categories (bin

Tao, Wei-Kuo [NASA/GSFC] [NASA/GSFC

2014-05-19T23:59:59.000Z

3

Observations of the first aerosol indirect effect in shallow cumuli  

SciTech Connect (OSTI)

Data from the Cumulus Humilis Aerosol Processing Study (CHAPS) are used to estimate the impact of both aerosol indirect effects and cloud dynamics on the microphysical and optical properties of shallow cumuli observed in the vicinity of Oklahoma City, Oklahoma. Not surprisingly, we find that the amount of light scattered by the clouds is dominated by their liquid water content (LWC), which in turn is driven by cloud dynamics. However, removing the effect of cloud dynamics by examining the scattering normalized by LWC shows a strong sensitivity of scattering to pollutant loading. These results suggest that even moderately sized cities, like Oklahoma City, can have a measureable impact on the optical properties of shallow cumuli.

Berg, Larry K.; Berkowitz, Carl M.; Barnard, James C.; Senum, Gunar; Springston, Stephen R.

2011-02-08T23:59:59.000Z

4

FY 2011 Third Quarter Report Estimate of Historical Aerosol Direct and Indirect Effects  

SciTech Connect (OSTI)

The global and annual mean aerosol direct and indirect effects estimated from Community Earth System Model (CESM) simulations are -0.06 W m-2 and -1.39 W m-2, respectively.

Koch, D

2011-06-22T23:59:59.000Z

5

aerosol indirect effects: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of direct reciprocal and indirect effects in a host-parasite network Shai Pilosof Fortuna, Miguel A. First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19...

6

aerosol indirect effect: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of direct reciprocal and indirect effects in a host-parasite network Shai Pilosof Fortuna, Miguel A. First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19...

7

FY 2011 4th Quarter Metric: Estimate of Future Aerosol Direct and Indirect Effects  

SciTech Connect (OSTI)

The global and annual mean aerosol direct and indirect effects, relative to 1850 conditions, estimated from CESM simulations are 0.02 W m-2 and -0.39 W m-2, respectively, for emissions in year 2100 under the IPCC RCP8.5 scenario. The indirect effect is much smaller than that for 2000 emissions because of much smaller SO2 emissions in 2100; the direct effects are small due to compensation between warming by black carbon and cooling by sulfate.

Koch, D

2011-09-21T23:59:59.000Z

8

Aerosol indirect effects -- general circulation model intercomparison and evaluation with satellite data  

SciTech Connect (OSTI)

Aerosol indirect effects continue to constitute one of the most important uncertainties for anthropogenic climate perturbations. Within the international AEROCOM initiative, the representation of aerosol-cloud-radiation interactions in ten different general circulation models (GCMs) is evaluated using three satellite datasets. The focus is on stratiform liquid water clouds since most GCMs do not include ice nucleation effects, and none of the model explicitly parameterizes aerosol effects on convective clouds. We compute statistical relationships between aerosol optical depth (Ta) and various cloud and radiation quantities in a manner that is consistent between the models and the satellite data. It is found that the model-simulated influence of aerosols on cloud droplet number concentration (Nd) compares relatively well to the satellite data at least over the ocean. The relationship between Ta and liquid water path is simulated much too strongly by the models. It is shown that this is partly related to the representation of the second aerosol indirect effect in terms of autoconversion. A positive relationship between total cloud fraction (fcld) and Ta as found in the satellite data is simulated by the majority of the models, albeit less strongly than that in the satellite data in most of them. In a discussion of the hypotheses proposed in the literature to explain the satellite-derived strong fcld - Ta relationship, our results indicate that none can be identified as unique explanation. Relationships similar to the ones found in satellite data between Ta and cloud top temperature or outgoing long-wave radiation (OLR) are simulated by only a few GCMs. The GCMs that simulate a negative OLR - Ta relationship show a strong positive correlation between Ta and fcld The short-wave total aerosol radiative forcing as simulated by the GCMs is strongly influenced by the simulated anthropogenic fraction of Ta, and parameterisation assumptions such as a lower bound on Nd. Nevertheless, the strengths of the statistical relationships are good predictors for the aerosol forcings in the models. An estimate of the total short-wave aerosol forcing inferred from the combination of these predictors for the modelled forcings with the satellite-derived statistical relationships yields a global annual mean value of -1.5+-0.5 Wm-2. An alternative estimate obtained by scaling the simulated clear- and cloudy-sky forcings with estimates of anthropogenic Ta and satellite-retrieved Nd - Ta regression slopes, respectively, yields a global annual mean clear-sky (aerosol direct effect) estimate of -0.4+-0.2 Wm-2 and a cloudy-sky (aerosol indirect effect) estimate of -0.7+-0.5 Wm-2, with a total estimate of -1.2+-0.4 Wm-2.

Quaas, Johannes; Ming, Yi; Menon, Surabi; Takemura, Toshihiko; Wang, Minghuai; Penner, Joyce E.; Gettelman, Andrew; Lohmann, Ulrike; Bellouin, Nicolas; Boucher, Olivier; Sayer, Andrew M.; Thomas, Gareth E.; McComiskey, Allison; Feingold, Graham; Hoose, Corinna; Kristjansson, Jon Egill; Liu, Xiaohong; Balkanski, Yves; Donner, Leo J.; Ginoux, Paul A.; Stier, Philip; Feichter, Johann; Sednev, Igor; Bauer, Susanne E.; Koch, Dorothy; Grainger, Roy G.; Kirkevag, Alf; Iversen, Trond; Seland, Oyvind; Easter, Richard; Ghan, Steven J.; Rasch, Philip J.; Morrison, Hugh; Lamarque, Jean-Francois; Iacono, Michael J.; Kinne, Stefan; Schulz, Michael

2009-04-10T23:59:59.000Z

9

Evaluating WRF-Chem aerosol indirect effects in Southeast Pacific marine stratocumulus during VOCALS-REx  

SciTech Connect (OSTI)

We evaluate a regional-scale simulation with the WRF-Chem model for the VAMOS (Variability of the American Monsoon Systems) Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx), which sampled the Southeast Pacific's persistent stratocumulus deck. Evaluation of VOCALS-REx ship-based and aircraft observations focuses on analyzing how aerosol loading affects marine boundary layer (MBL) dynamics and cloud microphysics. We compare local time series and campaign averaged longitudinal gradients, and highlight differences in model simulations with (W) and without wet (NW) deposition processes. The higher aerosol loadings in the NW case produce considerable changes in MBL dynamics and cloud microphysics, in accordance with the established conceptual model of aerosol indirect effects. These include increase in cloud albedo, increase in MBL and cloud heights, drizzle suppression, increase in liquid water content, and increase in cloud lifetime. Moreover, better statistical representation of aerosol mass and number concentration improves model fidelity in reproducing observed spatial and temporal variability in cloud properties, including top and base height, droplet concentration, water content, rain rate, optical depth (COD) and liquid water path (LWP). Together, these help to quantify confidence in WRF-Chem's modeled aerosol-cloud interactions, while identifying structural and parametric uncertainties including: irreversibility in rain wet removal; overestimation of marine DMS and sea salt emissions and accelerated aqueous sulfate conversion. Our findings suggest that WRF-Chem simulates marine cloud-aerosol interactions at a level sufficient for applications in forecasting weather and air quality and studying aerosol climate forcing, including the reliability required for policy analysis and geo-engineering applications.

Saide, Pablo; Spak, S. N.; Carmichael, Gregory; Mena-Carrasco, M. A.; Yang, Qing; Howell, S. G.; Leon, Dolislager; Snider, Jefferson R.; Bandy, Alan R.; Collett, Jeffrey L.; Benedict, K. B.; de Szoeke, S.; Hawkins, Lisa; Allen, Grant; Crawford, I.; Crosier, J.; Springston, S. R.

2012-03-30T23:59:59.000Z

10

Study of Mechanisms of Aerosol Indirect Effects on Glaciated Clouds: Progress during the Project Final Technical Report  

SciTech Connect (OSTI)

This 3-year project has studied how aerosol pollution influences glaciated clouds. The tool applied has been an 'aerosol-cloud model'. It is a type of Cloud-System Resolving Model (CSRM) modified to include 2-moment bulk microphysics and 7 aerosol species, as described by Phillips et al. (2009, 2013). The study has been done by, first, improving the model and then performing sensitivity studies with validated simulations of a couple of observed cases from ARM. These are namely the Tropical Warm Pool International Cloud Experiment (TWP-ICE) over the tropical west Pacific and the Cloud and Land Surface Interaction Campaign (CLASIC) over Oklahoma. During the project, sensitivity tests with the model showed that in continental clouds, extra liquid aerosols (soluble aerosol material) from pollution inhibited warm rain processes for precipitation production. This promoted homogeneous freezing of cloud droplets and aerosols. Mass and number concentrations of cloud-ice particles were boosted. The mean sizes of cloud-ice particles were reduced by the pollution. Hence, the lifetime of glaciated clouds, especially ice-only clouds, was augmented due to inhibition of sedimentation and ice-ice aggregation. Latent heat released from extra homogeneous freezing invigorated convective updrafts, and raised their maximum cloud-tops, when aerosol pollution was included. In the particular cases simulated in the project, the aerosol indirect effect of glaciated clouds was twice than of (warm) water clouds. This was because glaciated clouds are higher in the troposphere than water clouds and have the first interaction with incoming solar radiation. Ice-only clouds caused solar cooling by becoming more extensive as a result of aerosol pollution. This 'lifetime indirect effect' of ice-only clouds was due to higher numbers of homogeneously nucleated ice crystals causing a reduction in their mean size, slowing the ice-crystal process of snow production and slowing sedimentation. In addition to the known indirect effects (glaciation, riming and thermodynamic), new indirect effects were discovered and quantified due to responses of sedimentation, aggregation and coalescence in glaciated clouds to changing aerosol conditions. In summary, the change in horizontal extent of the glaciated clouds ('lifetime indirect effects'), especially of ice-only clouds, was seen to be of higher importance in regulating aerosol indirect effects than changes in cloud properties ('cloud albedo indirect effects').

None

2013-10-18T23:59:59.000Z

11

Modeling the Direct and Indirect Effects of Atmospheric Aerosols on Tropical Cyclones  

E-Print Network [OSTI]

í are conducted under the three aerosol scenarios: 1) the clean case with an aerosol number concentration of 200 cm-1, 2) the polluted case with a number concentration of 1000 cm-1, and 3) the aerosol radiative effects (AR) case with same aerosol concentration...

Lee, Keun-Hee

2012-02-14T23:59:59.000Z

12

Atmospheric Radiation Measurement (ARM) Data from Shouxian, China for the Study of Aerosol Indirect Effects in China  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

In a complex ARM Mobile Facility (AMF) deployment, monitoring data was collected at four locations in China during 2008. The various sites are located in regions with different climate regimes and with high aerosol loadings of different optical, physical, and chemical properties. Measurements obtained at all the AMF sites during the 8-month deployment in China will help scientists to validate satellite-based findings, understand the mechanisms of the aerosol indirect effects in the region, and examine the roles of aerosols in affecting regional climate and atmospheric circulation, with a special focus on the impact of the East Asian monsoon system. As with other collections from the ARM Mobile Facility, the datasets are available from the ARM Archive. The ARM Archive physically resides at the Oak Ridge National Laboratory.

13

Investigation of Aerosol Indirect Effects using a Cumulus Microphysics Parameterization in a Regional Climate Model  

SciTech Connect (OSTI)

A new Zhang and McFarlane (ZM) cumulus scheme includes a two-moment cloud microphysics parameterization for convective clouds. This allows aerosol effects to be investigated more comprehensively by linking aerosols with microphysical processes in both stratiform clouds that are explicitly resolved and convective clouds that are parameterized in climate models. This new scheme is implemented in the Weather Research and Forecasting (WRF) model, which is coupled with the physics and aerosol packages from the Community Atmospheric Model version 5 (CAM5). A test case of July 2008 during the East Asian summer monsoon is selected to evaluate the performance of the new ZM scheme and to investigate aerosol effects on monsoon precipitation. The precipitation and radiative fluxes simulated by the new ZM scheme show a better agreement with observations compared to simulations with the original ZM scheme that does not include convective cloud microphysics and aerosol convective cloud interactions. Detailed analysis suggests that an increase in detrained cloud water and ice mass by the new ZM scheme is responsible for this improvement. To investigate precipitation response to increased anthropogenic aerosols, a sensitivity experiment is performed that mimics a clean environment by reducing the primary aerosols and anthropogenic emissions to 30% of that used in the control simulation of a polluted environment. The simulated surface precipitation is reduced by 9.8% from clean to polluted environment and the reduction is less significant when microphysics processes are excluded from the cumulus clouds. Ensemble experiments with ten members under each condition (i.e., clean and polluted) indicate similar response of the monsoon precipitation to increasing aerosols.

Lim, Kyo-Sun; Fan, Jiwen; Leung, Lai-Yung R.; Ma, Po-Lun; Singh, Balwinder; Zhao, Chun; Zhang, Yang; Zhang, Guang; Song, Xiaoliang

2014-01-29T23:59:59.000Z

14

The Indirect and Semi-Direct Aerosol Campaign  

ScienceCinema (OSTI)

Research projects like the Indirect and Semi-Direct Aerosol Campaign, or ISDAC, increase our knowledge of atmospheric aerosol particles and cloud physics.

Ghan, Steve

2014-06-12T23:59:59.000Z

15

The Indirect and Semi-Direct Aerosol Campaign  

SciTech Connect (OSTI)

Research projects like the Indirect and Semi-Direct Aerosol Campaign, or ISDAC, increase our knowledge of atmospheric aerosol particles and cloud physics.

Ghan, Steve

2014-03-24T23:59:59.000Z

16

Effect of Subgrid Cloud Variability on Parameterization of Indirect Aerosol Effect in Large-Scale Models  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed NewcatalystNeutronEnvironmentZIRKLE FRUITYearEffect of

17

Black carbon radiative heating effects on cloud microphysics and implications for the aerosol indirect  

E-Print Network [OSTI]

thought. 1. Introduction Black Carbon (BC) has important effects on climate, owing to its ability of Technology, Pasadena, California, 91125, USA Abstract. This work examines the effect of black carbon (BC) radiative heating on cloud droplet formation. Changes in cloud droplet concentration and cloud albedo due

Nenes, Athanasios

18

Quantifying the Uncertainties of Aerosol Indirect Effects and Impacts on Decadal-Scale Climate Variability in NCAR CAM5 and CESM1  

SciTech Connect (OSTI)

The main goal of this project is to systematically quantify the major uncertainties of aerosol indirect effects due to the treatment of moist turbulent processes that drive aerosol activation, cloud macrophysics and microphysics in response to anthropogenic aerosol perturbations using the CAM5/CESM1. To achieve this goal, the P.I. hired a postdoctoral research scientist (Dr. Anna Fitch) who started her work from the Nov.1st.2012. In order to achieve the project goal, the first task that the Postdoc. and the P.I. did was to quantify the role of subgrid vertical velocity variance on the activation and nucleation of cloud liquid droplets and ice crystals and its impact on the aerosol indirect effect in CAM5. First, we analyzed various LES cases (from dry stable to cloud-topped PBL) to check whether this isotropic turbulence assumption used in CAM5 is really valid. It turned out that this isotropic turbulence assumption is not universally valid. Consequently, from the analysis of LES, we derived an empirical formulation relaxing the isotropic turbulence assumption used for the CAM5 aerosol activation and ice nucleation, and implemented the empirical formulation into CAM5/CESM1, and tested in the single-column and global simulation modes, and examined how it changed aerosol indirect effects in the CAM5/CESM1. These results were reported in the poster section in the 18th Annual CESM workshop held in Breckenridge, CO during Jun.17-20.2013. While we derived an empirical formulation from the analysis of couple of LES from the first task, the general applicability of that empirical formulation was questionable, because it was obtained from the limited number of LES simulations. The second task we did was to derive a more fundamental analytical formulation relating vertical velocity variance to TKE using other information starting from basic physical principles. This was a somewhat challenging subject, but if this could be done in a successful way, it could be directly implemented into the CAM5 as a practical parameterization, and substantially contributes to achieving the project goal. Through an intensive research for about one year, we found appropriate mathematical formulation and tried to implement it into the CAM5 PBL and activation routine as a practical parameterized numerical code. During these processes, however, the Postdoc applied for another position in Sweden, Europe, and accepted a job offer there, and left NCAR in August 2014. In Sweden, Dr. Anna Fitch is still working on this subject in a part time, planning to finalize the research and to write the paper in a near future.

Park, Sungsu

2014-12-12T23:59:59.000Z

19

Indirect and Semi-Direct Aerosol Campaign  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

October? 2. To what extent do the different properties of the Arctic aerosol during April produce differences in clouds? * Do the more polluted conditions during April in the...

20

Aerosol Indirect Effect on the Grid-scale Clouds in the Two-way Coupled WRF-CMAQ: Model Description, Development, Evaluation and Regional Analysis  

SciTech Connect (OSTI)

This study implemented first, second and glaciations aerosol indirect effects (AIE) on resolved clouds in the two-way coupled WRF-CMAQ modeling system by including parameterizations for both cloud drop and ice number concentrations on the basis of CMAQpredicted aerosol distributions and WRF meteorological conditions. The performance of the newly-developed WRF-CMAQ model, with alternate CAM and RRTMG radiation schemes, was evaluated with the observations from the CERES satellite and surface monitoring networks (AQS, IMPROVE, CASTNet, STN, and PRISM) over the continental U.S. (CONUS) (12-km resolution) and eastern Texas (4-km resolution) during August and September of 2006. The results at the AQS surface sites show that in August, the NMB values for PM2.5 over the eastern/western U.S (EUS/WUS) and western U.S. (WUS) are 5.3% (?0.1%) and 0.4% (-5.2%) for WRF-CMAQ/CAM (WRF-CMAQ/RRTMG), respectively. The evaluation of PM2.5 chemical composition reveals that in August, WRF-CMAQ/CAM (WRF-CMAQ/RRTMG) consistently underestimated the observed SO4 2? by -23.0% (-27.7%), -12.5% (-18.9%) and -7.9% (-14.8%) over the EUS at the CASTNet, IMPROVE and STN sites, respectively. Both models (WRF-CMAQ/CAM, WRF-CMAQ/RRTMG) overestimated the observed mean OC, EC and TC concentrations over the EUS in August at the IMPROVE sites. Both models generally underestimated the cloud field (SWCF) over the CONUS in August due to the fact that the AIE on the subgrid convective clouds was not considered when the model simulations were run at the 12 km resolution. This is in agreement with the fact that both models captured SWCF and LWCF very well for the 4-km simulation over the eastern Texas when all clouds were resolved by the finer domain. Both models generally overestimated the observed precipitation by more than 40% mainly because of significant overestimation in the southern part of the CONUS in August. The simulations of WRF-CMAQ/CAM and WRF-CMAQ/RRTMG show dramatic improvements for SWCF, LWCF, COD, cloud fractions and precipitation over the ocean relative to those of WRF default cases in August. The model performance in September is similar to that in August except for greater overestimation of PM2.5 due to the overestimations of SO4 2-, NH4 +, NO3 -, and TC over the EUS, less underestimation of clouds (SWCF) over the land areas due to about 10% lower SWCF values and less convective clouds in September.

Yu, Shaocai; Mathur, Rohit; Pleim, Jonathan; Wong, David; Gilliam, R.; Alapaty, Kiran; Zhao, Chun; Liu, Xiaohong

2014-10-24T23:59:59.000Z

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Science Overview Document Indirect and Semi-Direct Aerosol Campaign (ISDAC) April 2008  

SciTech Connect (OSTI)

The ARM Climate Research Facilityís (ACRF) Aerial Vehicle Program (AVP) will deploy an intensive cloud and aerosol observing system to the ARM North Slope of Alaska (NSA) locale for a five week Indirect and Semi-Direct Aerosol Campaign (ISDAC) during period 29 March through 30 April 2008. The deployment period is within the International Polar Year, thus contributing to and benefiting from the many ancillary observing systems collecting data synergistically. We will deploy the Canadian National Research Council Convair 580 aircraft to measure temperature, humidity, total particle number, aerosol size distribution, single particle composition, concentrations of cloud condensation nuclei and ice nuclei, optical scattering and absorption, updraft velocity, cloud liquid water and ice contents, cloud droplet and crystal size distributions, cloud particle shape, and cloud extinction. In addition to these aircraft measurements, ISDAC will deploy two instruments at the ARM site in Barrow: a spectroradiometer to retrieve cloud optical depth and effective radius, and a tandem differential mobility analyzer to measure the aerosol size distribution and hygroscopicity. By using many of the same instruments used during Mixed-Phase Arctic Cloud Experiment (M-PACE), conducted in October 2004, we will be able to contrast the arctic aerosol and cloud properties during the fall and spring transitions. The aerosol measurements can be used in cloud models driven by objectively analyzed boundary conditions to test whether the cloud models can simulate the aerosol influence on the clouds. The influence of aerosol and boundary conditions on the simulated clouds can be separated by running the cloud models with all four combinations of M-PACE and ISDAC aerosol and boundary conditions: M-PACE aerosol and boundary conditions, M-PACE aerosol and ISDAC boundary conditions, ISDAC aerosol and M-PACE boundary conditions, and ISDAC aerosol and boundary conditions. ISDAC and M-PACE boundary conditions are likely to be very different because of the much more extensive ocean water during M-PACE. The uniformity of the surface conditions during ISDAC greatly simplifies the objective analysis (surface fluxes and precipitation are very weak), so that it can largely rely on the European Centre for Medium-Range Weather Forecasts analysis. The aerosol measurements can also be used as input to the cloud models and to evaluate the aerosol retrievals. By running the cloud models with and without solar absorption by the aerosols, we can determine the semidirect effect of the aerosol on the clouds.

SJ Ghan; B Schmid; JM Hubbe; CJ Flynn; A Laskin; AA Zelenyuk; DJ Czizco; CN Long; G McFarquhar; J Verlinde; J Harrington; JW Strapp; P Liu; A Korolev; A McDonald; M Wolde; A Fridlind; T Garrett; G Mace; G Kok; S Brooks; D Collins; D Lubin; P Lawson; M Dubey; C Mazzoleni; M Shupe; S Xie; DD Turner; Q Min; EJ Mlawer; D Mitchell

2007-11-01T23:59:59.000Z

22

CARES: Carbonaceous Aerosol and Radiative Effects Study Science Plan  

SciTech Connect (OSTI)

Carbonaceous aerosol components, which include black carbon (BC), urban primary organic aerosols (POA), biomass burning aerosols, and secondary organic aerosols (SOA) from both urban and biogenic precursors, have been previously shown to play a major role in the direct and indirect radiative forcing of climate. The primary objective of the CARES 2010 intensive field study is to investigate the evolution of carbonaceous aerosols of different types and their effects on optical and cloud formation properties.

Zaveri, RA; Shaw, WJ; Cziczo, DJ

2010-05-27T23:59:59.000Z

23

Indirect radiative forcing by ion-mediated nucleation of aerosol  

SciTech Connect (OSTI)

A clear understanding of particle formation mechanisms is critical for assessing aerosol indirect radiative forcing and associated climate feedback processes. Recent studies reveal the importance of ion-mediated nucleation (IMN) in generating new particles and cloud condensation nuclei (CCN) in the atmosphere. Here we implement for the first time a physically based treatment of IMN into the Community Atmosphere Model version 5. Our simulations show that, compared to globally averaged results based on binary homogeneous nucleation (BHN), the presence of ionization (i.e., IMN) halves H2SO4 column burden, but increases the column integrated nucleation rate by around one order of magnitude, total particle number burden by a factor of ~ 3, CCN burden by ~ 10% (at 0.2% supersaturation) to 65% (at 1.0% supersaturation), and cloud droplet number burden by ~ 18%. Compared to BHN, IMN increases cloud liquid water path by 7.5%, decreases precipitation by 1.1%, and increases total cloud cover by 1.9%. This leads to an increase of total shortwave cloud radiative forcing by 3.67 W/m2 (more negative) and longwave cloud forcing by 1.78 W/m2 (more positive), resulting in a -1.9 W/m2 net change in cloud radiative forcing associated with IMN. The significant impacts of ionization on global aerosol formation, CCN abundance, and cloud radiative forcing may provide an important physical mechanism linking the global energy balance to various processes affecting atmospheric ionization, which should be properly represented in climate models.

Yu, Fangqun; Luo, Gan; Liu, Xiaohong; Easter, Richard C.; Ma, Xiaoyan; Ghan, Steven J.

2012-12-03T23:59:59.000Z

24

Constraining the influence of natural variability to improve estimates of global aerosol indirect effects in a nudged version of the Community Atmosphere Model 5  

E-Print Network [OSTI]

Zhao (2006), A simulated climatology of Asian dust aerosolN) PI (F) ? PI (F) ? X ? 2000 (PD Climatology) ? ? 2000 (PD Climatology) ? PD (F) X a All simulations used the same

Kooperman, Gabriel J; Pritchard, Michael S; Ghan, Steven J; Wang, Minghuai; Somerville, Richard C. J; Russell, Lynn M

2012-01-01T23:59:59.000Z

25

aerosolized pentamidine effect: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ON CCN CONCENTRATION AND AEROSOL FIRST INDIRECT RADIATIVE composition, aerosol size distribution is the more dominant parameter on CCN activation Feingold, GRL 2003;...

26

Total aerosol effect: forcing or radiative flux perturbation?  

SciTech Connect (OSTI)

Uncertainties in aerosol forcings, especially those associated with clouds, contribute to a large extent to uncertainties in the total anthropogenic forcing. The interaction of aerosols with clouds and radiation introduces feedbacks which can affect the rate of rain formation. Traditionally these feedbacks were not included in estimates of total aerosol forcing. Here we argue that they should be included because these feedbacks act quickly compared with the time scale of global warming. We show that for different forcing agents (aerosols and greenhouse gases) the radiative forcings as traditionally defined agree rather well with estimates from a method, here referred to as radiative flux perturbations (RFP), that takes these fast feedbacks and interactions into account. Thus we propose replacing the direct and indirect aerosol forcing in the IPCC forcing chart with RFP estimates. This implies that it is better to evaluate the total anthropogenic aerosol effect as a whole.

Lohmann, Ulrike; Storelvmo, Trude; Jones, Andy; Rotstayn, Leon; Menon, Surabi; Quaas, Johannes; Ekman, Annica; Koch, Dorothy; Ruedy, Reto

2009-09-25T23:59:59.000Z

27

Indirect and Semi-Direct Aerosol Campaign: The Impact of Arctic...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Aerosol Campaign: The Impact of Arctic Aerosols on Clouds . Abstract: A comprehensive dataset of microphysical and radiative properties of aerosols and clouds in the arctic...

28

A numerical study of the effect of different aerosol types on East Asian summer clouds and precipitation  

SciTech Connect (OSTI)

The impact of anthropogenic aerosol on the East Asian summer monsoon (EASM) is investigated with NCAR CAM5, a state-of-the-art climate model with aerosolís direct and indirect effects. Results indicate that anthropogenic aerosol tends to cause a weakened EASM with a southward shift of precipitation in East Asia mostly by its radiative effect. Anthropogenic aerosol induced surface cooling stabilizes the boundary layer, suppresses the convection and latent heat release in northern China, and reduces the tropospheric temperature over land and land-sea thermal contrast, thus leading to a weakened EASM. Meanwhile, acting as cloud condensation nuclei (CCN), anthropogenic aerosol can significantly increase the cloud droplet number concentration but decrease the cloud droplet effective radius over Indochina and Indian Peninsulas as well as over southwestern and northern China, inhibiting the precipitation in these regions. Thus, anthropogenic aerosol tends to reduce Southeast and South Asian summer monsoon precipitation by its indirect effect.

Jiang, Yiquan; Liu, Xiaohong; Yang, Xiuqun; Wang, Minghuai

2013-05-01T23:59:59.000Z

29

Direct and semi-direct aerosol effects of Southern African1 biomass burning aerosol2  

E-Print Network [OSTI]

1 Direct and semi-direct aerosol effects of Southern African1 biomass burning aerosol2 Naoko effects of biomass burning aerosols from Southern African fires9 during July-October are investigated region the overall TOA radiative effect from the23 biomass burning aerosols is almost zero due

Wood, Robert

30

ENCAPSULATION EFFECTS ON CARBONACEOUS AEROSOL LIGHT ABSORPTION  

E-Print Network [OSTI]

ENCAPSULATION EFFECTS ON CARBONACEOUS AEROSOL LIGHT ABSORPTION Arthur Sedlacek, Brookhaven National of aerosol absorption on direct radiative forcing is still an active area of research, in part, because. This poster presents data on black carbon (BC) light absorption measured by Photothermal Interferometry

31

Constraining cloud lifetime effects of aerosols using A-Train satellite observations  

SciTech Connect (OSTI)

Aerosol indirect effects have remained the largest uncertainty in estimates of the radiative forcing of past and future climate change. Observational constraints on cloud lifetime effects are particularly challenging since it is difficult to separate aerosol effects from meteorological influences. Here we use three global climate models, including a multi-scale aerosol-climate model PNNL-MMF, to show that the dependence of the probability of precipitation on aerosol loading, termed the precipitation frequency susceptibility (S{sub pop}), is a good measure of the liquid water path response to aerosol perturbation ({lambda}), as both Spop and {lambda} strongly depend on the magnitude of autoconversion, a model representation of precipitation formation via collisions among cloud droplets. This provides a method to use satellite observations to constrain cloud lifetime effects in global climate models. S{sub pop} in marine clouds estimated from CloudSat, MODIS and AMSR-E observations is substantially lower than that from global climate models and suggests a liquid water path increase of less than 5% from doubled cloud condensation nuclei concentrations. This implies a substantially smaller impact on shortwave cloud radiative forcing (SWCF) over ocean due to aerosol indirect effects than simulated by current global climate models (a reduction by one-third for one of the conventional aerosol-climate models). Further work is needed to quantify the uncertainties in satellite-derived estimates of S{sub pop} and to examine S{sub pop} in high-resolution models.

Wang, Minghuai; Ghan, Steven J.; Liu, Xiaohong; Ecuyer, Tristan L.; Zhang, Kai; Morrison, H.; Ovchinnikov, Mikhail; Easter, Richard C.; Marchand, Roger; Chand, Duli; Qian, Yun; Penner, Joyce E.

2012-08-15T23:59:59.000Z

32

Assessing the effects of anthropogenic aerosols on Pacific storm track using a multiscale global  

E-Print Network [OSTI]

, the aerosols have an indirect effect by serving as cloud condensation nuclei, and their interaction latent heating (6), leading to an enhanced pre- cipitation efficiency (7­12), invigorated convection Satellite Cloud Climatology Project and high-resolution infrared sounder. In addition, a trend of increasing

33

Direct and semidirect aerosol effects of southern African biomass burning aerosol  

E-Print Network [OSTI]

Direct and semidirect aerosol effects of southern African biomass burning aerosol Naoko Sakaeda,1 2011; published 21 June 2011. [1] Direct and semidirect radiative effects of biomass burning aerosols static stability. Over the entire region the overall TOA radiative effect from the biomass burning

Wood, Robert

34

A New Assessment of the Aerosol First Indirect Effect  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLasDelivered¬ČPNGExperience hands-onASTROPHYSICSHe ő≤-Research andAFishing forAAEIA'sNew

35

Technical Note: Estimating Aerosol Effects on Cloud Radiative Forcing  

SciTech Connect (OSTI)

Estimating anthropogenic aerosol effects on the planetary energy balance through the aerosol influence on clouds using the difference in cloud radiative forcing from simulations with and without anthropogenic emissions produces estimates that are positively biased. A more representative method is suggested using the difference in cloud radiative forcing calculated with aerosol radiative effects neglected. The method also yields an aerosol radiative forcing decomposition that includes a term quantifying the impact of changes in surface albedo. The method requires only two additional diagnostic calculations: the whole-sky and clear-sky top-of-atmosphere radiative flux with aerosol radiative effects neglected.

Ghan, Steven J.

2013-10-09T23:59:59.000Z

36

Improving Bulk Microphysics Parameterizations in Simulations of Aerosol Effects  

SciTech Connect (OSTI)

To improve the microphysical parameterizations for simulations of the aerosol indirect effect (AIE) in regional and global climate models, a double-moment bulk microphysical scheme presently implemented in the Weather Research and Forecasting (WRF) model is modified and the results are compared against atmospheric observations and simulations produced by a spectral bin microphysical scheme (SBM). Rather than using prescribed aerosols as in the original bulk scheme (Bulk-OR), a prognostic doublemoment aerosol representation is introduced to predict both the aerosol number concentration and mass mixing ratio (Bulk-2M). The impacts of the parameterizations of diffusional growth and autoconversion and the selection of the embryonic raindrop radius on the performance of the bulk microphysical scheme are also evaluated. Sensitivity modeling experiments are performed for two distinct cloud regimes, maritime warm stratocumulus clouds (SC) over southeast Pacific Ocean from the VOCALS project and continental deep convective clouds (DCC) in the southeast of China from the Department of Energy/ARM Mobile Facility (DOE/AMF) - China field campaign. The results from Bulk-2M exhibit a much better agreement in the cloud number concentration and effective droplet radius in both the SC and DCC cases with those from SBM and field measurements than those from Bulk-OR. In the SC case particularly, Bulk-2M reproduces the observed drizzle precipitation, which is largely inhibited in Bulk-OR. Bulk-2M predicts enhanced precipitation and invigorated convection with increased aerosol loading in the DCC case, consistent with the SBM simulation, while Bulk-OR predicts the opposite behaviors. Sensitivity experiments using four different types of autoconversion schemes reveal that the autoconversion parameterization is crucial in determining the raindrop number, mass concentration, and drizzle formation for warm 2 stratocumulus clouds. An embryonic raindrop size of 40 ?m is determined as a more realistic setting in the autoconversion parameterization. The saturation adjustment employed in calculating condensation/evaporation in the bulk scheme is identified as the main factor responsible for the large discrepancies in predicting cloud water in the SC case, suggesting that an explicit calculation of diffusion growth with predicted supersaturation is necessary for further improvements of the bulk microphysics scheme. Lastly, a larger rain evaporation rate below cloud is found in the bulk scheme in comparison to the SBM simulation, which could contribute to a lower surface precipitation in the bulk scheme.

Wang, Yuan; Fan, Jiwen; Zhang, Renyi; Leung, Lai-Yung R.; Franklin, Charmaine N.

2013-06-05T23:59:59.000Z

37

Direct and semidirect aerosol effects of Southern African biomass burning aerosol  

SciTech Connect (OSTI)

The direct and semi-direct radiative effects of biomass burning aerosols from Southern African fires during July-October are investigated using 20 year runs of the Community Atmospheric Model (CAM) coupled to a slab ocean model. The aerosol optical depth is constrained using observations in clear skies from MODIS and for aerosol layers above clouds from CALIPSO. Over the ocean, where the absorbing biomass burning aerosol layers are primarily located above cloud, negative top of atmosphere (TOA) semi-direct radiative effects associated with increased low cloud cover dominate over a weaker positive all-sky direct radiative effect (DRE). In contrast, over the land where the aerosols are often below or within cloud layers, reductions in cloud liquid water path (LWP) lead to a positive semi-direct radiative effect that dominates over a near-zero DRE. Over the ocean, the cloud response can be understood as a response to increased lower tropospheric stability (LTS) which is caused both by aerosol absorptive warming in overlying layers and surface cooling in response to direct aerosol forcing. The ocean cloud changes are robust to changes in the cloud parameterization (removal of the hard-wired dependence of clouds on LTS), suggesting that they are physically realistic. Over land where cloud cover changes are minimal, decreased LWP is consistent with weaker convection driven by increased static stability. Over the entire region the overall TOA radiative effect from the biomass burning aerosols is almost zero due to opposing effects over the land and ocean. However, the surface forcing is strongly negative requiring a reduction in precipitation. This is primarily realized through reductions in convective precipitation on both the southern and northern flanks of the convective precipitation region spanning the equatorial rainforest and the ITCZ in the southern Sahel. The changes are consistent with the low-level aerosol forced cooling pattern. The results highlight the importance of semi-direct radiative effects and precipitation responses for determining the climatic effects of aerosols in the African region.

Sakaeda, Naoko; Wood, Robert; Rasch, Philip J.

2011-06-21T23:59:59.000Z

38

AEROSOL, CLOUDS, AND CLIMATE CHANGE  

SciTech Connect (OSTI)

Earth's climate is thought to be quite sensitive to changes in radiative fluxes that are quite small in absolute magnitude, a few watts per square meter, and in relation to these fluxes in the natural climate. Atmospheric aerosol particles exert influence on climate directly, by scattering and absorbing radiation, and indirectly by modifying the microphysical properties of clouds and in turn their radiative effects and hydrology. The forcing of climate change by these indirect effects is thought to be quite substantial relative to forcing by incremental concentrations of greenhouse gases, but highly uncertain. Quantification of aerosol indirect forcing by satellite- or ground-based remote sensing has proved quite difficult in view of inherent large variation in the pertinent observables such as cloud optical depth, which is controlled mainly by liquid water path and only secondarily by aerosols. Limited work has shown instances of large magnitude of aerosol indirect forcing, with local instantaneous forcing upwards of 50 W m{sup 66}-2. Ultimately it will be necessary to represent aerosol indirect effects in climate models to accurately identify the anthropogenic forcing at present and over secular time and to assess the influence of this forcing in the context of other forcings of climate change. While the elements of aerosol processes that must be represented in models describing the evolution and properties of aerosol particles that serve as cloud condensation particles are known, many important components of these processes remain to be understood and to be represented in models, and the models evaluated against observation, before such model-based representations can confidently be used to represent aerosol indirect effects in climate models.

SCHWARTZ, S.E.

2005-09-01T23:59:59.000Z

39

Potential Direct and Indirect Effects of Global Cellulosic Biofuel Production on Greenhouse  

E-Print Network [OSTI]

Potential Direct and Indirect Effects of Global Cellulosic Biofuel Production on Greenhouse Gas on recycled paper #12;1 Potential Direct and Indirect Effects of Global Cellulosic Biofuel Production. Melillo*, John M. Reilly§ , and Sergey Paltsev§ Abstract The production of cellulosic biofuels may have

40

Effects of aerosols on deep convective cumulus clouds  

E-Print Network [OSTI]

This work investigates the effects of anthropogenic aerosols on deep convective clouds and the associated radiative forcing in the Houston area. The Goddard Cumulus Ensemble model (GCE) coupled with a spectral-bin microphysics is employed...

Fan, Jiwen

2009-05-15T23:59:59.000Z

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Conceptualizing and testing random indirect effects and moderated mediation in multilevel models: New procedures and recommendations  

E-Print Network [OSTI]

The authors propose new procedures for evaluating direct, indirect, and total effects in multilevel models when all relevant variables are measured at Level 1 and all effects are random. Formulas are provided for the mean ...

Bauer, D. J.; Preacher, K. J.; Gil, Karen M.

2006-01-01T23:59:59.000Z

42

SPSS and SAS procedures for estimating indirect effects in simple mediation models  

E-Print Network [OSTI]

Researchers often conduct mediation analysis in order to indirectly assess the effect of a proposed cause on some outcome through a proposed mediator. The utility of mediation analysis stems from its ability to go beyond ...

Preacher, K. J.; Hayes, A. F.

2004-01-01T23:59:59.000Z

43

Light Absorption by Secondary Organic Aerosol from ?-Pinene: Effects of Oxidants, Seed Aerosol Acidity, and Relative Humidity  

SciTech Connect (OSTI)

It is well known that light absorption from dust and black carbon aerosols has a warming effect on climate while light scattering from sulfate, nitrate, and sea salt aerosols has a cooling effect. However, there are large uncertainties associated with light absorption and scattering by different types of organic aerosols, especially in the near-UV and UV spectral regions. In this paper, we present the results from a systematic laboratory study focused on measuring light absorption by secondary organic aerosols (SOA) generated from ozonolysis or NO3 oxidation of ?-pinene in the presence of neutral and acidic sulfate seed aerosols. Light absorption was monitored using photoacoustic spectrometers at four different wavelengths: 355, 405, 532 and 870 nm. Light absorption at 355 and 405 nm was observed by SOA generated from oxidation of ?-pinene in the presence of acidic sulfate seed aerosols, under dry conditions. No absorption was observed when the relative humidity was elevated to greater than 27%, or in the presence of neutral sulfate seed aerosols. The light-absorbing compounds are speculated to be aldol condensation oligomers with organosulfate and organic nitrate groups. The results of this study also indicate that organic nitrates from ?-pinene SOA formed in the presence of neutral sulfate seed aerosols do not appear to absorb near-UV and UV radiation.

Song, Chen; Gyawali, Madhu S.; Zaveri, Rahul A.; Shilling, John E.; Arnott, W. Patrick

2013-10-25T23:59:59.000Z

44

Model analysis of the anthropogenic aerosol effect on clouds over East Asia  

SciTech Connect (OSTI)

A coupled meteorology and aerosol/chemistry model WRF-Chem (Weather Research and Forecast model coupled with Chemistry) was used to conduct a pair of simulations with present-day (PD) and preindustrial (PI) emissions over East Asia to examine the aerosol indirect effect on clouds. As a result of an increase in aerosols in January, the cloud droplet number increased by 650 cm{sup -3} over the ocean and East China, 400 cm{sup -3} over Central and Southwest China, and less than 200 cm{sup -3} over North China. The cloud liquid water path (LWP) increased by 40-60 g m{sup -2} over the ocean and Southeast China and 30 g m{sup -2} over Central China; the LWP increased less than 5 g m{sup -2} or decreased by 5 g m{sup -2} over North China. The effective radius (Re) decreased by more than 4 {mu}m over Southwest, Central, and Southeast China and 2 {mu}m over North China. In July, variations in cloud properties were more uniform; the cloud droplet number increased by approximately 250-400 cm{sup -3}, the LWP increased by approximately 30-50 g m{sup -2}, and Re decreased by approximately 3 {mu}m over most regions of China. In response to cloud property changes from PI to PD, shortwave (SW) cloud radiative forcing strengthened by 30 W m{sup -2} over the ocean and 10 W m{sup -2} over Southeast China, and it weakened slightly by approximately 2-10 W m{sup -2} over Central and Southwest China in January. In July, SW cloud radiative forcing strengthened by 15 W m{sup -2} over Southeast and North China and weakened by 10 W m{sup -2} over Central China. The different responses of SW cloud radiative forcing in different regions was related to cloud feedbacks and natural variability.

Gao, Yi; Zhang, Meigen; Liu, Xiaohong; Zhao, Chun

2012-01-16T23:59:59.000Z

45

Global Indirect Effects of U.S. Corn Ethanol Production: A Review of the Evidence  

E-Print Network [OSTI]

Global Indirect Effects of U.S. Corn Ethanol Production: A Review of the Evidence Energy security) requires 36 billion gallons of ethanol by 2022 to replace about 20 percent of U.S. gasoline consumption. Since 2001 ethanol produc- tion, mainly from corn, has increased dramatically at an annual average

Grissino-Mayer, Henri D.

46

Dust Aerosol Impact on North Africa Climate: A GCM Investigation of Aerosol-Cloud-Radiation Interactions Using A-Train Satellite Data  

SciTech Connect (OSTI)

The climatic effects of dust aerosols in North Africa have been investigated using the atmospheric general circulation model (AGCM) developed at the University of California, Los Angeles (UCLA). The model includes an efficient and physically based radiation parameterization scheme developed specifically for application to clouds and aerosols. Parameterization of the effective ice particle size in association with the aerosol indirect effect based on cloud and aerosol data retrieved from A-Train satellite observations have been employed in the climate model simulations. Offline simulations reveal that the direct solar, IR, and net forcings by dust aerosols generally increase with increasing aerosol optical depth (AOD). When the dust semi-direct effect is included with the presence of ice clouds, positive IR radiative forcing is enhanced, since ice clouds trap substantial IR radiation, while the positive solar forcing with dust aerosols alone has been changed to negative values due to the strong reflection of solar radiation by clouds, indicating that cloud forcing could exceed aerosol forcing. With the aerosol indirect effect, the net cloud forcing is generally reduced for ice water path (IWP) larger than 20 g m-2. The magnitude of the reduction increases with IWP. AGCM simulations show that the reduced ice crystal mean effective size due to the aerosol first indirect effect result in less OLR and net solar flux at the top of the atmosphere over the cloudy area of the North Africa region because ice clouds with smaller size trap more IR radiation and reflect more solar radiation. The precipitation in the same area, however, increases due to the aerosol indirect effect on ice clouds, corresponding to the enhanced convection as indicated by reduced OLR. The increased precipitation seems to be associated with enhanced ice water contents in this region. The 200 mb radiative heating rate shows more cooling with the aerosol indirect effect since greater cooling is produced at the cloud top with smaller ice crystal size. The 500 mb omega indicates strong upward motion, which, together with the increased cooling effect, results in the increased ice water contents. Adding the aerosol direct effect into the model simulation reduces the precipitation in the normal rainfall band over North Africa, where precipitation is shifted to the south and the northeast produced by the absorption of sunlight and the subsequent heating of the air column by dust particles. As a result, rainfall is drawn further inland to the northeast. This study represents the first attempt to quantify the climate impact of aerosol indirect effect using a GCM in connection with A-train satellite data. The parameterization for the aerosol first indirect effect developed in this study can be readily incorporated for application to any other GCMs.

Gu, Y.; Liou, K. N.; Jiang, Jonathan; Su, Hui; Liu, Xiaohong

2012-02-15T23:59:59.000Z

47

Effects of operating conditions on a heat transfer fluid aerosol  

E-Print Network [OSTI]

of heat transfer fluid aerosols from process leaks. To simulate industrial leaks, aerosol formation from a plain orifice into ambient air is studied by measuring liquid drop sizes and size distributions at various distances from an orifice. Measurements...

Sukmarg, Passaporn

2000-01-01T23:59:59.000Z

48

aerosols radioactifs artificiels: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ON CCN CONCENTRATION AND AEROSOL FIRST INDIRECT RADIATIVE composition, aerosol size distribution is the more dominant parameter on CCN activation Feingold, GRL 2003;...

49

AEROSOL DIRECT RADIATIVE EFFECTS OVER THE NORTHWEST ATLANTIC, NORTHWEST PACIFIC, AND NORTH INDIAN OCEANS  

E-Print Network [OSTI]

AEROSOL DIRECT RADIATIVE EFFECTS OVER THE NORTHWEST ATLANTIC, NORTHWEST PACIFIC, AND NORTH INDIAN OCEANS: ESTIMATES BASED ON IN-SITU CHEMICAL AND OPTICAL MEASUREMENTS AND CHEMICAL TRANSPORT MODELING, for United States Government purposes. #12;AEROSOL DIRECT RADIATIVE EFFECTS OVER THE NORTHWEST ATLANTIC

50

Direct and semi-direct radiative effects of anthropogenic aerosols in the Western United States: Seasonal  

E-Print Network [OSTI]

a regional climate model (RCM) in conjunction with the aerosol fields from a GEOS-Chem chemical- transport emissions and the seasonal low-level winds. The RCM-simulated anthropogenic aerosol radiative effects vary, respectively, following the seasonal AOD. In Arizona-New Mexico (AZNM), the effect of anthropogenic sulfates

Liou, K. N.

51

Dispersion of Cloud Droplet Size Distributions, Cloud Parameterizations and Indirect Aerosol Effects  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed Newcatalyst phasesDataTranslocation ofthe APSDiscoverDisorder-InducedDisordering

52

Observations and Modeling of Shallow Convective Clouds: Implications for the Indirect Aerosol Effects  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLasDelivered¬ČPNG IHDR¬Ä√ćSolar Energy SystemsFebruary 7-8,March 8,8)Normal 27 1 54In

53

Analysis of Aerosol Indirect Effects in California Coastal Stratus and Fog  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAbout theOFFICEAmes Laboratory Site| Department ofAn|Oil andU.S.methods

54

Surface-Based Remote Sensing of the Aerosol Indirect Effect at Southern Great Plains  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security AdministrationcontrollerNanocrystalline GalliumSuppression of conductivitySurface based

55

Quantifying the Aerosol Indirect Effect Using Ground-Based Remote Sensors and Models  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 - SeptemberMicroneedlesAdvancedJanuaryNETL-2010/????QualityQuality

56

Carbonaceous Aerosols and Radiative Effects Study (CARES), g1-aircraft, sedlacek sp2  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

The primary objective of the Carbonaceous Aerosol and Radiative Effects Study (CARES) in 2010 was to investigate the evolution of carbonaceous aerosols of different types and their optical and hygroscopic properties in central California, with a focus on the Sacramento urban plume.

Sedlacek, Art

57

Assessing the Effects of Anthropogenic Aerosols on Pacific Storm Track Using a Multiscale Global Climate Model  

SciTech Connect (OSTI)

Atmospheric aerosols impact weather and global general circulation by modifying cloud and precipitation processes, but the magnitude of cloud adjustment by aerosols remains poorly quantified and represents the largest uncertainty in estimated forcing of climate change. Here we assess the impacts of anthropogenic aerosols on the Pacific storm track using a multi-scale global aerosol-climate model (GCM). Simulations of two aerosol scenarios corresponding to the present day and pre-industrial conditions reveal long-range transport of anthropogenic aerosols across the north Pacific and large resulting changes in the aerosol optical depth, cloud droplet number concentration, and cloud and ice water paths. Shortwave and longwave cloud radiative forcing at the top of atmosphere are changed by - 2.5 and + 1.3 W m-2, respectively, by emission changes from pre-industrial to present day, and an increased cloud-top height indicates invigorated mid-latitude cyclones. The overall increased precipitation and poleward heat transport reflect intensification of the Pacific storm track by anthropogenic aerosols. Hence, this work provides for the first time a global perspective of the impacts of Asian pollution outflows from GCMs. Furthermore, our results suggest that the multi-scale modeling framework is essential in producing the aerosol invigoration effect of deep convective clouds on the global scale.

Wang, Yuan; Wang, Minghuai; Zhang, Renyi; Ghan, Steven J.; Lin, Yun; Hu, Jiaxi; Pan, Bowen; Levy, Misti; Jiang, Jonathan; Molina, Mario J.

2014-05-13T23:59:59.000Z

58

Radiative Effects of Dust Aerosols, Natural Cirrus Clouds and Contrails: Broadband Optical Properties and Sensitivity Studies  

E-Print Network [OSTI]

This dissertation aims to study the broadband optical properties and radiative effects of dust aerosols and ice clouds. It covers three main topics: the uncertainty of dust optical properties and radiative effects from the dust particle shape...

Yi, Bingqi

2013-07-09T23:59:59.000Z

59

Direct and indirect effects of southern flounder predation on a spot population: Experimental and model analyses  

SciTech Connect (OSTI)

We have previously shown that southern flounder (Paralichthys lethostigma Jordan and Gilbert) influence the survival and size-distribution of spot (Leiostomus xanthurus Lafayette) and other small estuarine fishes in experimental ponds. In this paper, we seek to determine whether these of effects can be accounted for by direct size-dependent predation or if there is also evidence for indirect behavioral effects on spot foraging which might alter their survival or population size structure. In our experiment, spot were allowed to grow in the presence and absence of southern flounder in an experimental estuarine pond for 101 days. Each treatment was replicated three times. We also apply a recently published simulation model of the flounder-spot interaction to this experiment to independently test the model and to estimate the direct effects of flounder predation on spot survival and size structure.

Crowder, L.B.; Wright, R.A.; Martin, T.H.; Rice, J.A. (North Carolina State Univ., Raleigh, NC (United States). Dept. of Zoology); Rose, K.A. (Oak Ridge National Lab., TN (United States))

1992-01-01T23:59:59.000Z

60

Direct and indirect effects of southern flounder predation on a spot population: Experimental and model analyses  

SciTech Connect (OSTI)

We have previously shown that southern flounder (Paralichthys lethostigma Jordan and Gilbert) influence the survival and size-distribution of spot (Leiostomus xanthurus Lafayette) and other small estuarine fishes in experimental ponds. In this paper, we seek to determine whether these of effects can be accounted for by direct size-dependent predation or if there is also evidence for indirect behavioral effects on spot foraging which might alter their survival or population size structure. In our experiment, spot were allowed to grow in the presence and absence of southern flounder in an experimental estuarine pond for 101 days. Each treatment was replicated three times. We also apply a recently published simulation model of the flounder-spot interaction to this experiment to independently test the model and to estimate the direct effects of flounder predation on spot survival and size structure.

Crowder, L.B.; Wright, R.A.; Martin, T.H.; Rice, J.A. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Zoology; Rose, K.A. [Oak Ridge National Lab., TN (United States)

1992-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Microphysical Effects Determine Macrophysical Response for Aerosol Impacts on Deep Convective Clouds  

SciTech Connect (OSTI)

Deep convective clouds (DCCs) play a crucial role in the general circulation and energy and hydrological cycle of our climate system. Anthropogenic and natural aerosol particles can influence DCCs through changes in cloud properties, precipitation regimes, and radiation balance. Modeling studies have reported both invigoration and suppression of DCCs by aerosols, but none has fully quantified aerosol impacts on convection life cycle and radiative forcing. By conducting multiple month-long cloud-resolving simulations with spectral-bin cloud microphysics that capture the observed macro- and micro-physical properties of summer convective clouds in the tropics and mid-latitudes, this study provides the first comprehensive look at how aerosols affect cloud cover, cloud top height (CTH), and radiative forcing. Observations validate these simulation results. We find that microphysical aerosol effects contribute predominantly to increased cloud cover and CTH by inducing larger amount of smaller but longer lasting ice particles in the stratiform/anvils of DCCs with dynamical aerosol effects contributing at most ~ 1/4 of the total increase of cloud cover. The overall effect is a radiative warming in the atmosphere (3 to 5 W m-2) with strong surface cooling (-5 to -8 W m-2). Herein we clearly identified mechanisms more important than and additional to the invigoration effects hypothesized previously that explain the consistent signatures of increased cloud tops area and height by aerosols in DCCs revealed by observations.

Fan, Jiwen; Leung, Lai-Yung R.; Rosenfeld, Daniel; Chen, Qian; Li, Zhanqing; Zhang, Jinqiang; Yan, Hongru

2013-11-26T23:59:59.000Z

62

Effects of Sea-Salt Aerosols on Precipitation in Simulations of Shallow Cumulus  

E-Print Network [OSTI]

A suite of large-eddy simulations with size-resolving microphysical processes was performed in order to assess effects of sea-salt aerosols on precipitation process in trade cumulus. Simulations based on observations from ...

Kogan, Yefim L.; Mechem, David B.; Choi, Kityan

2012-02-01T23:59:59.000Z

63

Contrasting the direct radiative effect and direct radiative forcing of aerosols  

E-Print Network [OSTI]

The direct radiative effect (DRE) of aerosols, which is the instantaneous radiative impact of all atmospheric particles on the Earth's energy balance, is sometimes confused with the direct radiative forcing (DRF), which ...

Heald, Colette L.

64

Indirection and computer security.  

SciTech Connect (OSTI)

The discipline of computer science is built on indirection. David Wheeler famously said, 'All problems in computer science can be solved by another layer of indirection. But that usually will create another problem'. We propose that every computer security vulnerability is yet another problem created by the indirections in system designs and that focusing on the indirections involved is a better way to design, evaluate, and compare security solutions. We are not proposing that indirection be avoided when solving problems, but that understanding the relationships between indirections and vulnerabilities is key to securing computer systems. Using this perspective, we analyze common vulnerabilities that plague our computer systems, consider the effectiveness of currently available security solutions, and propose several new security solutions.

Berg, Michael J.

2011-09-01T23:59:59.000Z

65

Global Distribution and Climate Forcing of Marine Organic Aerosol - Part 2: Effects on Cloud Properties and Radiative Forcing  

SciTech Connect (OSTI)

A series of simulations with the Community Atmosphere Model version 5 (CAM5) with a 7-mode Modal Aerosol Model were conducted to assess the changes in cloud microphysical properties and radiative forcing resulting from marine organic aerosols. Model simulations show that the anthropogenic aerosol indirect forcing (AIF) predicted by CAM5 is decreased in absolute magnitude by up to 0.09 Wm{sup -2} (7 %) when marine organic aerosols are included. Changes in the AIF from marine organic aerosols are associated with small global increases in low-level incloud droplet number concentration and liquid water path of 1.3 cm{sup -3} (1.5 %) and 0.22 gm{sup -2} (0.5 %), respectively. Areas especially sensitive to changes in cloud properties due to marine organic aerosol include the Southern Ocean, North Pacific Ocean, and North Atlantic Ocean, all of which are characterized by high marine organic emission rates. As climate models are particularly sensitive to the background aerosol concentration, this small but non-negligible change in the AIF due to marine organic aerosols provides a notable link for ocean-ecosystem marine low-level cloud interactions and may be a candidate for consideration in future earth system models.

Gantt, Brett; Xu, Jun; Meskhidze, N.; Zhang, Yang; Nenes, Athanasios; Ghan, Steven J.; Liu, Xiaohong; Easter, Richard C.; Zaveri, Rahul A.

2012-07-25T23:59:59.000Z

66

CARES: Carbonaceous Aerosol and Radiative Effects Study Operations Plan  

SciTech Connect (OSTI)

The CARES field campaign is motivated by the scientific issues described in the CARES Science Plan. The primary objectives of this field campaign are to investigate the evolution and aging of carbonaceous aerosols and their climate-affecting properties in the urban plume of Sacramento, California, a mid-size, mid-latitude city that is located upwind of a biogenic volatile organic compound (VOC) emission region. Our basic observational strategy is to make comprehensive gas, aerosol, and meteorological measurements upwind, within, and downwind of the urban area with the DOE G-1 aircraft and at strategically located ground sites so as to study the evolution of urban aerosols as they age and mix with biogenic SOA precursors. The NASA B-200 aircraft, equipped with the High Spectral Resolution Lidar (HSRL), digital camera, and the Research Scanning Polarimeter (RSP), will be flown in coordination with the G-1 to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties, and to provide the vertical context for the G-1 and ground in situ measurements.

Zaveri, RA; Shaw, WJ; Cziczo, DJ

2010-07-12T23:59:59.000Z

67

Investigation of multiple scattering effects in aerosols. Final report, Sep 1978 - Dec 1979  

SciTech Connect (OSTI)

The results are presented of investigations on the various aspects of multiple scattering effects on visible and infrared laser beams transversing dense fog oil aerosols contained in a chamber (4' x 4' x 9'). The report briefly describes: (1) the experimental details and measurements (2) analytical representation of the aerosol size distribution data by two analytical models (the regularized power law distribution and the inverse modified gamma distribution) (3) retrieval of aerosol size distributions from multispectral optical depth measurements by two methods (the two and three parameter fast table search methods and the nonlinear least squares method) (4) modeling of the effects of aerosol microphysical (coagulation and evaporation) and dynamical processes (gravitational settling) on the temporal behavior of aerosol size distribution, and hence on the extinction of four laser beams with wavelengths 0.44, 0.6328, 1.15, and 3.39 micrometers and (5) the exact and approximate formulations for four methods for computing the effects of multiple scattering on the transmittance of laser beams in dense aerosols, all of which are based on the solution of the radiative transfer equation under the small angle approximation.

Deepak, A.

1980-05-01T23:59:59.000Z

68

aerosol source-receptor relationships: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ON CCN CONCENTRATION AND AEROSOL FIRST INDIRECT RADIATIVE composition, aerosol size distribution is the more dominant parameter on CCN activation Feingold, GRL 2003;...

69

The dependence of ice microphysics on aerosol concentration in arctic mixed-phase stratus clouds during ISDAC and M-PACE  

SciTech Connect (OSTI)

Cloud and aerosol data acquired by the National Research Council of Canada (NRC) Convair-580 aircraft in, above, and below single-layer arctic stratocumulus cloud during the Indirect and Semi-Direct Aerosol Campaign (ISDAC) in April 2008 were used to test three aerosol indirect effects hypothesized to act in mixed-phase clouds: the riming indirect effect, the glaciation indirect effect, and the cold second indirect effect. The data showed a correlation of R= 0.75 between liquid drop number concentration, Nliq, inside cloud and ambient aerosol number concentration NPCASP below cloud. This, combined with increasing liquid water content LWC with height above cloud base and the nearly constant profile of Nliq, suggested that liquid drops were nucleated from aerosol at cloud base. No strong evidence of a riming indirect effect was observed, but a strong correlation of R = 0.69 between ice crystal number concentration Ni and NPCASP above cloud was noted. Increases in ice nuclei (IN) concentration with NPCASP above cloud combined with the subadiabatic LWC profiles suggest possible mixing of IN from cloud top consistent with the glaciation indirect effect. The higher Nice and lower effective radius rel for the more polluted ISDAC cases compared to data collected in cleaner single-layer stratocumulus conditions during the Mixed-Phase Arctic Cloud Experiment is consistent with the operation of the cold second indirect effect. However, more data in a wider variety of meteorological and surface conditions, with greater variations in aerosol forcing, are required to identify the dominant aerosol forcing mechanisms in mixed-phase arctic clouds.

Jackson, Robert C.; McFarquhar, Greg; Korolev, Alexei; Earle, Michael; Liu, Peter S.; Lawson, R. P.; Brooks, Sarah D.; Wolde, Mengistu; Laskin, Alexander; Freer, Matthew

2012-08-14T23:59:59.000Z

70

Evaluate and characterize mechanisms controlling transport, fate, and effects of army smokes in the aerosol wind tunnel: Transport, transformations, fate, and terrestrial ecological effects of hexachloroethane obscurant smokes  

SciTech Connect (OSTI)

The terrestrial transport, chemical fate, and ecological effects of hexachloroethane (HC) smoke were evaluated under controlled wind tunnel conditions. The primary objectives of this research program are to characterize and assess the impacts of smoke and obscurants on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of soils representative of these training sites; and (3) soil microbiological and invertebrate communities. Impacts and dose/responses were evaluated based on exposure scenarios, including exposure duration, exposure rate, and sequential cumulative dosing. Key to understanding the environmental impacts of HC smoke/obscurants is establishing the importance of environmental parameters such as relative humidity and wind speed on airborne aerosol characteristics and deposition to receptor surfaces. Direct and indirect biotic effects were evaluated using five plant species and two soil types. HC aerosols were generated in a controlled atmosphere wind tunnel by combustion of hexachloroethane mixtures prepared to simulate normal pot burn rates and conditions. The aerosol was characterized and used to expose plant, soil, and other test systems. Particle sizes of airborne HC ranged from 1.3 to 2.1 {mu}m mass median aerodynamic diameter (MMAD), and particle size was affected by relative humidity over a range of 20% to 85%. Air concentrations employed ranged from 130 to 680 mg/m{sup 3}, depending on exposure scenario. Chlorocarbon concentrations within smokes, deposition rates for plant and soil surfaces, and persistence were determined. The fate of principal inorganic species (Zn, Al, and Cl) in a range of soils was assessed.

Cataldo, D.A.; Ligotke, M.W.; Bolton, H. Jr.; Fellows, R.J.; Van Voris, P.; McVeety, B.D.; Li, Shu-mei W.; McFadden, K.M.

1989-09-01T23:59:59.000Z

71

Enhancement factors for resuspended aerosol radioactivity: Effects of topsoil disturbance  

SciTech Connect (OSTI)

The enhancement factor for airborne radionuclides resuspended by wind is defined as the ratio of the activity density (Bq g{sup {minus}1}) in the aerosol to the activity density in the underlying surface of contaminated soil. Enhancement factors are useful for assessment of worst-case exposure scenarios and transport conditions, and are one of the criteria for setting environmental standards for radioactivity in soil. This paper presents results of experimental studies where resuspension of {sup 239}Pu was measured when air concentrations were equilibrated to the soil surface. Enhancement factors were observed for several types of man-made disturbances (bulldozer-blading, soil raking, vacuum-cleaning) and natural disturbances (springtime thaw, soil-drying, wildfire). For some cases, enhancement factors are compared over range of geographical locations (Bikini Atoll, California, Nevada, and South Carolina). The particle-size distributions of aerosol activity are compared to particle-size distributions of the underlying soil.

Shinn, J.H.

1991-11-01T23:59:59.000Z

72

Cloud/Aerosol Parameterizations: Application and Improvement of General Circulation Models  

SciTech Connect (OSTI)

One of the biggest uncertainties associated with climate models and climate forcing is the treatment of aerosols and their effects on clouds. The effect of aerosols on clouds can be divided into two components: The first indirect effect is the forcing associated with increases in droplet concentrations; the second indirect effect is the forcing associated with changes in liquid water path, cloud morphology, and cloud lifetime. Both are highly uncertain. This project applied a cloud-resolving model to understand the response of clouds under a variety of conditions to changes in aerosols. These responses are categorized according to the large-scale meteorological conditions that lead to the response. Meteorological conditions were sampled from various fields, which, together with a global aerosol model determination of the change in aerosols from present day to pre-industrial conditions, was used to determine a first order estimate of the response of global cloud fields to changes in aerosols. The response of the clouds in the NCAR CAM3 GCM coupled to our global aerosol model were tested by examining whether the response is similar to that of the cloud resolving model and methods for improving the representation of clouds and cloud/aerosol interactions were examined.

Penner, Joyce

2012-06-30T23:59:59.000Z

73

ARM - Publications: Science Team Meeting Documents: Effects of Aerosol Size  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD) by Microtops AtmosphericApplication andAn AssessmentARMArctic FacilityRetrievalsAerosol

74

Importance of Iron Mineralogy to Aerosol Solubility: Potential Effects of  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinementEtching. |EndecahemeEMSLImagingOregonAerosol Source on

75

Effects of Aerosols on Autumn Precipitation over Mid-Eastern China  

SciTech Connect (OSTI)

Long-term observational data indicated a decreasing trend for the amount of autumn precipitation (i.e. 54.3 mm per decade) over Mid-Eastern China, especially after 1980s (~ 5.6% per decade). To examine the cause of the decreasing trend, the mechanisms associated with the change of autumn precipitation were investigated from the perspective of water vapor transportation, atmospheric stability and cloud microphysics. Results show that the decrease of convective available potential energy (i.e. 12.81 J kg-1/ decade) and change of cloud microphysics, which were closely related to the increase of aerosol loading during the past twenty years, were the two primary factors responsible for the decrease of autumn precipitation. Ours results showed that increased aerosol could enhance the atmospheric stability thus weaken the convection. Meanwhile, more aerosols also led to a significant decline of raindrop concentration and to a delay of raindrop formation because of smaller size of cloud droplets. Thus, increased aerosols produced by air pollution could be one of the major reasons for the decrease of autumn precipitation. Furthermore, we found that the aerosol effects on precipitation in autumn was more significant than in other seasons, partly due to the relatively more stable synoptic system in autumn. The impact of large-scale circulation dominated in autumn and the dynamic influence on precipitation was more important than the thermodynamic activity.

Chen, Siyu; Huang, J.; Qian, Yun; Ge, Jinming; Su, Jing

2014-09-20T23:59:59.000Z

76

The effects of emission of anthropogenic chemical species on chemical and physical properties of aerosols  

SciTech Connect (OSTI)

Numerical studies have been carried out to examine the effects of chemically reactive trace gases emitted into the atmosphere on the evolution of chemical species concentrations, on the chemical composition and size distribution of airborne particles, and on optical properties of aerosols. Argonne`s chemistry module has been modified by refining the treatment of gas-to-particle conversion. The changes in size distribution and chemical composition of aerosols are calculated with consideration of heteramolecular diffusion and coagulation. Results of the 24 h real-time simulation indicate that the maximum oxidation rate of sulfur dioxide is about 0.4% h{sup {minus}1}; that the total aerosol volume increases with the increase in relative humidity by as much as 36% (due mainly to the collection of sulfuric acid embryos by preexisting particles); and that the surface area, a measure of optical depth, increases with the increase in relative humidity by as much as 27%.

Lee, In Young

1994-07-01T23:59:59.000Z

77

Significant aerosol direct radiative effects during a pollution episode in northern China  

E-Print Network [OSTI]

Significant aerosol direct radiative effects during a pollution episode in northern China J. Liu,1 during a heavy pollution episode that occurred in October 2004 over northern China are explored , resulting in solar heating of the atmosphere on the order of 300 Wmņ2 . Solar radiation reflected

Li, Zhanqing

78

Representing Cloud Processing of Aerosol in Numerical Models  

SciTech Connect (OSTI)

The satellite imagery in Figure 1 provides dramatic examples of how aerosol influences the cloud field. Aerosol from ship exhaust can serve as nucleation centers in otherwise cloud-free regions, forming ship tracks (top image), or can enhance the reflectance/albedo in already cloudy regions. This image is a demonstration of the first indirect effect, in which changes in aerosol modulate cloud droplet radius and concentration, which influences albedo. It is thought that, through the effects it has on precipitation (drizzle), aerosol can also affect the structure and persistence of planetary boundary layer (PBL) clouds. Regions of cellular convection, or open pockets of cloudiness (bottom image) are thought to be remnants of strongly drizzling PBL clouds. Pockets of Open Cloudiness (POCs) (Stevens et al. 2005) or Albrecht's ''rifts'' are low cloud fraction regions characterized by anomalously low aerosol concentrations, implying they result from precipitation. These features may in fact be a demonstration of the second indirect effect. To accurately represent these clouds in numerical models, we have to treat the coupled cloud-aerosol system. We present the following series of mesoscale and large eddy simulation (LES) experiments to evaluate the important aspects of treating the coupled cloud-aerosol problem. 1. Drizzling and nondrizzling simulations demonstrate the effect of drizzle on a mesoscale forecast off the California coast. 2. LES experiments with explicit (bin) microphysics gauge the relative importance of the shape of the aerosol spectrum on the 3D dynamics and cloud structure. 3. Idealized mesoscale model simulations evaluate the relative roles of various processes, sources, and sinks.

Mechem, D.B.; Kogan, Y.L.

2005-03-18T23:59:59.000Z

79

Modeling Study of the Effect of Anthropogenic Aerosols on Late Spring Drought in South China  

SciTech Connect (OSTI)

In this study, the mechanisms underlying the decadal variability of late spring precipitation in south China are investigated using the latest version 1 of Community Earth System Model (CESM1). We aim to unravel the effects of different climate forcing agents, such as aerosols and greenhouse gases (GHGs), on the decadal variation of precipitation with transient experiments from pre-industry (for year 1850) to present-day (for year 2000). Our results reveal that: (1) CESM1 can reproduce the climatological features of atmospheric circulation and precipitation for the late spring in south China; (2) Only simulations including the forcing of anthropogenic aerosols can reproduce the observed decreasing trend of late spring precipitation from 1950-2000 in south China; (3) Aerosols affect the decadal change of precipitation mainly by altering the large scale atmospheric circulation, and to a less extent by increasing the lower-tropospheric stability to inhibit the convective precipitation; and (4) In comparison, other climate forcing agents, such as GHGs, have much smaller effects on the decadal change of spring precipitation in south China. Key words: precipitation, aerosols, climate change, south China, Community Earth System Model

Hu, Ning; Liu, Xiaohong

2013-10-01T23:59:59.000Z

80

Modeling aerosols and their interactions with shallow cumuli during the 2007 CHAPS field study  

SciTech Connect (OSTI)

The Weather Research and Forecasting model coupled with chemistry (WRF-Chem) is used to simulate relationships between aerosols and clouds in the vicinity of Oklahoma City during the June 2007 Cumulus Humilis Aerosol Processing Study (CHAPS). The regional scale simulation completed using 2 km horizontal grid spacing evaluates four important relationships between aerosols and shallow cumulus clouds observed during CHAPS. First, the model reproduces the trends of higher nitrate volume fractions in cloud droplet residuals compared to interstitial non-activated aerosols, as measured using the Aerosol Mass Spectrometer. Comparing simulations with cloud chemistry turned on and off, we show that nitric acid vapor uptake by cloud droplets explains the higher nitrate content of cloud droplet residuals. Second, as documented using an offline code, both aerosol water and other inorganics (OIN), which are related to dust and crustal emissions, significantly affect predicted aerosol optical properties. Reducing the OIN content of wet aerosols by 50% significantly improves agreement of model predictions with measurements of aerosol optical properties. Third, the simulated hygroscopicity of aerosols is too high as compared to their hygroscopicity derived from cloud condensation nuclei and particle size distribution measurements, indicating uncertainties associated with simulating size-dependent chemical composition and treatment of aerosol mixing state within the model. Fourth, the model reasonably represents the observations of the first aerosol indirect effect where pollutants in the vicinity of Oklahoma City increase cloud droplet number concentrations and decrease the droplet effective radius. While previous studies have often focused on cloud-aerosol interactions in stratiform and deep convective clouds, this study highlights the ability of regional-scale models to represent some of the important aspects of cloud-aerosol interactions associated with fields of short-lived shallow cumuli.

Shrivastava, ManishKumar B.; Berg, Larry K.; Fast, Jerome D.; Easter, Richard C.; Laskin, Alexander; Chapman, Elaine G.; Gustafson, William I.; Liu, Ying; Berkowitz, Carl M.

2013-02-07T23:59:59.000Z

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Investigations of cloud altering effects of atmospheric aerosols using a new mixed Eulerian-Lagrangian aerosol model  

E-Print Network [OSTI]

Industry, urban development, and other anthropogenic influences have substantially altered the composition and size-distribution of atmospheric aerosol particles over the last century. This, in turn, has altered cloud ...

Steele, Henry Donnan, 1974-

2004-01-01T23:59:59.000Z

82

Aerosols, Clouds, and Climate Change Stephen E. Schwartz  

E-Print Network [OSTI]

in atmospheric carbon dioxide associated with fossil fuel combustion. Briefly the options are mitigation work has shown instances of large magnitude of aerosol indirect forcing, with local instantaneous

Schwartz, Stephen E.

83

Nonlinear Effects of Coexisting Surface and Atmospheric Forcing of Anthropogenic Absorbing Aerosols: Impact on the South Asian Monsoon Onset  

E-Print Network [OSTI]

The direct radiative effect of absorbing aerosols consists of absorption-induced atmospheric heating together with scattering- and absorption-induced surface cooling. It is thus important to understand whether some of the ...

Lee, Shao-Yi

84

Indirect and Semi-Direct Aerosol Campaign  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinementEtching.348ASSEMBLY [ICO] Name LastNews Archive

85

Indirect and Semi-Direct Aerosol Campaign  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinementEtching.348ASSEMBLY [ICO] Name LastNews ArchiveCampaign

86

A geostatistical data fusion technique for merging remote sensing and groundbased observations of aerosol optical thickness  

E-Print Network [OSTI]

A geostatistical data fusion technique for merging remote sensing and groundbased observations. Braverman, and C. E. Miller (2010), A geostatistical data fusion technique for merging remote sensing cloud properties (the aerosol indirect effect), producing a net cooling of the Earth surface, and can

Michalak, Anna M.

87

The Two-Column Aerosol Project (TCAP) Science Plan  

SciTech Connect (OSTI)

The Two-Column Aerosol Project (TCAP) field campaign will provide a detailed set of observations with which to (1) perform radiative and cloud condensation nuclei (CCN) closure studies, (2) evaluate a new retrieval algorithm for aerosol optical depth (AOD) in the presence of clouds using passive remote sensing, (3) extend a previously developed technique to investigate aerosol indirect effects, and (4) evaluate the performance of a detailed regional-scale model and a more parameterized global-scale model in simulating particle activation and AOD associated with the aging of anthropogenic aerosols. To meet these science objectives, the Atmospheric Radiation Measurement (ARM) Climate Research Facility will deploy the ARM Mobile Facility (AMF) and the Mobile Aerosol Observing System (MAOS) on Cape Cod, Massachusetts, for a 12-month period starting in the summer of 2012 in order to quantify aerosol properties, radiation, and cloud characteristics at a location subject to both clear and cloudy conditions, and clean and polluted conditions. These observations will be supplemented by two aircraft intensive observation periods (IOPs), one in the summer and a second in the winter. Each IOP will deploy one, and possibly two, aircraft depending on available resources. The first aircraft will be equipped with a suite of in situ instrumentation to provide measurements of aerosol optical properties, particle composition and direct-beam irradiance. The second aircraft will fly directly over the first and use a multi-wavelength high spectral resolution lidar (HSRL) and scanning polarimeter to provide continuous optical and cloud properties in the column below.

Berkowitz, CM; Berg, LK; Cziczo, DJ; Flynn, CJ; Kassianov, EI; Fast, JD; Rasch, PJ; Shilling, JE; Zaveri, RA; Zelenyuk, A; Ferrare, RA; Hostetler, CA; Cairns, B; Russell, PB; Ervens, B

2011-07-27T23:59:59.000Z

88

The inertial and electrical effects on aerosol sampling, charging, and size distribution  

SciTech Connect (OSTI)

An experimental study was conducted to investigate the effect of particle inertia on deposition behavior near the filter cassette sampler. Field sampling cassettes were tested in a subsonic wind tunnel for 0.2, 0.5 and 0.68 m/s wind speeds to simulate indoor air environment. Fluorescein aerosols of 2 and 5 {mu}m were generated from Berglund-Liu vibrating orifice generator as test material. Sampling tests were conducted in a subsonic wind tunnel with variables of particle size, wind speed, suction velocity and orientation of sampler examined to evaluate the combined effects. Sampling efficiencies were also examined. Electrostatic force is usually used as an effective method for removing, classifying and separating aerosols according to the electrical mobilities of the particulates. On the other hand, the aerosol charging theories possess differences in the ultrafine size range and need experimental verification. The present TSI's electrostatic aerosol analyzer has particle loss problem and cannot be used as a reliable tool in achieving efficient charging. A new unipolar charger with associated electronic circuits was designed, constructed and tested. The performance of the charger is tested in terms of particle loss, uncharged particles, and the collection efficiency of the precipitator. The results were compared with other investigator's data. The log-Beta distribution function is considered to be more versatile in representing size distribution. This study discussed the method in determining the size parameters under different conditions. Also the mutability of size distribution was evaluated when particles undergo coagulation or classification processes. Comparison of evolution between log-Beta and lognormal distributions were made.

Wang, Chuenchung.

1991-01-01T23:59:59.000Z

89

Direct and indirect effects of alpha-particle irradiations of human prostate tumor cells  

E-Print Network [OSTI]

The objective of this project is to establish a model system to study the direct effect, the bystander effect and the combinational effect of alpha-particle irradiations of human prostate tumor cells, toward the goal of ...

Wang, Rong, Ph. D. Massachusetts Institute of Technology

2005-01-01T23:59:59.000Z

90

An optimal fitting approach to improve the GISS ModelE aerosol optical property parameterization using AERONET data  

E-Print Network [OSTI]

and absorbing solar radiation and the indirect effect by interacting with water vapor to affect cloud formation and lifetime. Absorbing aerosols also have the semidirect effect by heating the atmosphere layer, reducing; Intergovernmental Panel on Climate Change, 2001]. [3] Globalscale models, which simulate the emission, transport

91

aerosol radiative effects: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

space-borne sensors use information from the ultraviolet (UV) to the visible and thermal infrared Christopher, Sundar A. 25 Black carbon radiative heating effects on cloud...

92

Climatic effects of different aerosol types in China simulated  

E-Print Network [OSTI]

of Earthís surface solar radiation in China during 30 recenttering and absorption of solar radiation (direct effect) andsulfates mainly reflect solar radiation and induce negative

Y. GU

2006-01-01T23:59:59.000Z

93

Evaluate and characterize mechanisms controlling transport, fate and effects of army smokes in an aerosol wind tunnel: Transport, transformations, fate and terrestrial ecological effects of fog oil obscurant smokes: Final report  

SciTech Connect (OSTI)

The terrestrial transport, chemical fate, and ecological effects of fog oil (FO) smoke obscurants were evaluated under controlled wind tunnel conditions. The primary objectives of this research program are to characterize and assess the impacts of smoke and obscurants on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of soils representative of these training sites; and (3) soil microbiological and invertebrate communities. Impacts and dose/responses were evaluated based on an exposure scenario, including exposure duration, exposure rate, and sequential cumulative dosing. Key to understanding the environmental impacts of fog oil smoke/obscurants is establishing the importance of environmental parameters, such as relative humidity and wind speed on airborne aerosol characteristics and deposition to receptor surfaces. Direct and indirect biotic effects were evaluated using five plant species and three soil types. 29 refs., 35 figs., 32 tabs.

Cataldo, D.A.; Van Voris, P.; Ligotke, M.W.; Fellows, R.J.; McVeety, B.D.; Li, Shu-mei W.; Bolton, H. Jr.; Fredrickson, J.K.

1989-01-01T23:59:59.000Z

94

The importance of aerosol composition and mixing state on predicted CCN concentration and the variation of the importance with atmospheric processing of aerosol  

SciTech Connect (OSTI)

The influences of atmospheric aerosols on cloud properties (i.e., aerosol indirect effects) strongly depend on the aerosol CCN concentrations, which can be effectively predicted from detailed aerosol size distribution, mixing state, and chemical composition using KŲhler theory. However, atmospheric aerosols are complex and heterogeneous mixtures of a large number of species that cannot be individually simulated in global or regional models due to computational constraints. Furthermore, the thermodynamic properties or even the molecular identities of many organic species present in ambient aerosols are often not known to predict their cloud-activation behavior using KŲhler theory. As a result, simplified presentations of aerosol composition and mixing state are necessary for large-scale models. In this study, aerosol microphysics, CCN concentrations, and chemical composition measured at the T0 urban super-site in Mexico City during MILAGRO are analyzed. During the campaign in March 2006, aerosol size distribution and composition often showed strong diurnal variation as a result of both primary emissions and aging of aerosols through coagulation and local photochemical production of secondary aerosol species. The submicron aerosol composition was ~1/2 organic species. Closure analysis is first carried out by comparing CCN concentrations calculated from the measured aerosol size distribution, mixing state, and chemical composition using extended KŲhler theory to concurrent CCN measurements at five supersaturations ranging from 0.11% to 0.35%. The closure agreement and its diurnal variation are studied. CCN concentrations are also derived using various simplifications of the measured aerosol mixing state and chemical composition. The biases associated with these simplifications are compared for different supersaturations, and the variation of the biases is examined as a function of aerosol age. The results show that the simplification of internally mixed, size-independent particle composition leads to substantial overestimation of CCN concentration for freshly emitted aerosols in early morning, but can reasonably predict the CCN concentration after the aerosols underwent atmospheric processing for several hours. This analysis employing various simplifications provides insights into the essential information of particle chemical composition that needs to be represented in models to adequately predict CCN concentration and cloud microphysics.

Wang, J.; Cubison, M.; Aiken, A.; Jimenez, J.; Collins, D.; Gaffney, J.; Marley, N.

2010-03-15T23:59:59.000Z

95

Effect of Humidity on the Composition of Isoprene Photooxidation Secondary Organic Aerosol  

SciTech Connect (OSTI)

The effect of relative humidity (RH) on the composition and concentrations of gas-phase products and secondary organic aerosol (SOA) generated from the photooxidation of isoprene under high-NOx conditions was investigated. The yields of most gas-phase products were the same regardless of initial water vapor concentration with exception of hydroxyacetone and glycolaldehyde, which were considerably affected by RH. A significant change was observed in the SOA composition, with many unique condensed-phase products formed under humid (90% RH) vs. dry (<2% RH) conditions, without any observable effect on the rate and extent of the SOA mass growth.

Nguyen, Tran B.; Roach, Patrick J.; Laskin, Julia; Laskin, Alexander; Nizkorodov, Serguei

2011-07-18T23:59:59.000Z

96

Nonequilibrium Atmospheric Secondary Organic Aerosol Formation...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Aerosol Formation and Growth. Abstract: Airborne particles play a critical role in air quality, human health effects, visibility and climate. Secondary organic aerosols (SOA)...

97

Effects of aerosol organics on cloud condensation nucleus (CCN)  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed NewcatalystNeutronEnvironmentZIRKLE FRUITYearEffect0/2002catalysts:|Effects

98

Cloud Scavenging Effects on Aerosol Radiative and Cloud-nucleating Properties - Final Technical Report  

SciTech Connect (OSTI)

The optical properties of aerosol particles are the controlling factors in determining direct aerosol radiative forcing. These optical properties depend on the chemical composition and size distribution of the aerosol particles, which can change due to various processes during the particlesí lifetime in the atmosphere. Over the course of this project we have studied how cloud processing of atmospheric aerosol changes the aerosol optical properties. A counterflow virtual impactor was used to separate cloud drops from interstitial aerosol and parallel aerosol systems were used to measure the optical properties of the interstitial and cloud-scavenged aerosol. Specifically, aerosol light scattering, back-scattering and absorption were measured and used to derive radiatively significant parameters such as aerosol single scattering albedo and backscatter fraction for cloud-scavenged and interstitial aerosol. This data allows us to demonstrate that the radiative properties of cloud-processed aerosol can be quite different than pre-cloud aerosol. These differences can be used to improve the parameterization of aerosol forcing in climate models.

Ogren, John A.; Sheridan, Patrick S.; Andrews, Elisabeth

2009-03-05T23:59:59.000Z

99

Effects of aerosol and horizontal inhomogeneity on the broadband albedo of marine stratus: Numerical simulations  

SciTech Connect (OSTI)

Recent estimates of the effect of increasing of anthropogenic sulfate aerosol on the radiative forcing of the atmosphere have indicated that its impact may be comparable in magnitude to the effect from increases in CO{sub 2}. Much of this impact is expected from the effects of the aerosol on cloud microphysics and the subsequent impact on cloud albedo. A solar broadband version of a 2D radiative transfer model was used to quantify the impact of enhanced aerosol concentrations and horizontal inhomogeneity on the solar broadband albedo of marine stratus. The results of the radiative transfer calculations indicated that in unbroken marine stratus clouds the net horizontal transport of photons over a domain of a few kilometers was nearly zero, and the domain-average broadband albedo computed in a 2D cross section was nearly identical to the domain average calculated from a series of independent pixel approximation (IPA) calculations of the same cross section. However, the horizontal inhomogeneity does affect the cloud albedo compared to plane-parallel approximation (PPA) computations due to the nonlinear relationship between albedo and optical depth. The reduction in cloud albedo could be related to the variability of the distribution of log (cloud optical depth). These results extend the finding of Cahalan et al. to broadband solar albedos in a more realistic cloud model and suggest that accurate computation of domain-averaged broadband albedos in unbroken (or nearly unbroken) marine stratus can be made using IPA calculations with 1D radiative transfer models. Computations of the mean albedo over portions of the 3D RAMS domain show the relative increase in cloud albedo due to a 67% increase in the boundary-layer average CCN concentration was between 6% and 9%. The effects of cloud inhomogeneity on the broadband albedo as measured from the PPA bias ranged from 3% to 5%. 25 refs., 8 figs., 4 tabs.

Duda, D.P.; Stephens, G.L.; Stevens, B.; Cotton, W.R. [Colorado State Univ., Fort Collins, CO (United States)] [Colorado State Univ., Fort Collins, CO (United States)

1996-12-15T23:59:59.000Z

100

Aerosol Radiative Effects in the Tropical Western Pacific  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAbout the BuildingInnovation 2011 Simulation Studies ofBusinessEffects in

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

3D EFFECTS ON SPECTRALLY INVARIANT BEHAVIOR NEAR CLOUD EDGES: IMPLICATIONS FOR RETRIEVING AEROSOL AND CLOUD PROPERTIES IN  

E-Print Network [OSTI]

3D EFFECTS ON SPECTRALLY INVARIANT BEHAVIOR NEAR CLOUD EDGES: IMPLICATIONS FOR RETRIEVING AEROSOL between cloudy and clear air is always ambiguous, and because effects of the 3D nature of clouds will demonstrate how 3D effects may modulate the spectrally invariant relationships. We will also show the extent

102

Climate effects of seasonally varying Biomass Burning emitted Carbonaceous Aerosols (BBCA)  

E-Print Network [OSTI]

The climate impact of the seasonality of Biomass Burning emitted Carbonaceous Aerosols (BBCA) is studied using an aerosol-climate model coupled with a slab ocean model in a set of 60-year long simulations, driven by BBCA ...

Jeong, Gill-Ran

103

CHASER: An Innovative Satellite Mission Concept to Measure the Effects of Aerosols on Clouds and Climate  

E-Print Network [OSTI]

The formation of cloud droplets on aerosol particles, technically known as the activation of cloud condensation nuclei (CCN), is the fundamental process driving the interactions of aerosols with clouds and precipitation. ...

Rosenfeld, Daniel

104

The effects of volcanic aerosols on mid-latitude ozone recovery  

E-Print Network [OSTI]

In this paper, comparisons between the derived Chemistry Climate Model Initiative aerosol data set to balloon sonde measurements of aerosols made in Laramie, Wyoming are made between 1979- 2012. Using the derived CCMI ...

Haskins, Jessica D

2014-01-01T23:59:59.000Z

105

Aerosol effects on the photochemistry in Mexico City during MCMA-2006/MILAGRO campaign  

E-Print Network [OSTI]

In the present study, the impact of aerosols on the photochemistry in Mexico City is evaluated using the WRF-CHEM model for the period from 24 to 29 March during the MCMA-2006/MILAGRO campaign. An aerosol radiative module ...

Li, Guohui

106

aerosols | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

aerosols aerosols Leads No leads are available at this time. Magnesium behavior and structural defects in Mg+ ion implanted silicon carbide. Abstract: As a candidate material for...

107

Simultaneous Retrieval of Effective Refractive Index and Density from Size Distribution and Light Scattering Data: Weakly-Absorbing Aerosol  

SciTech Connect (OSTI)

We propose here a novel approach for retrieving in parallel the effective density and real refractive index of weakly absorbing aerosol from optical and size distribution measurements. Here we define ďweakly absorbingĒ as aerosol single-scattering albedos that exceed 0.95 at 0.5 um.The required optical measurements are the scattering coefficient and the hemispheric backscatter fraction, obtained in this work from an integrating nephelometer. The required size spectra come from a Scanning Mobility Particle Sizer and an Aerodynamic Particle Sizer. The performance of this approach is first evaluated using a sensitivity study with synthetically generated but measurement-related inputs. The sensitivity study reveals that the proposed approach is robust to random noise; additionally the uncertainties of the retrieval are almost linearly proportional to the measurement errors, and these uncertainties are smaller for the real refractive index than for the effective density. Next, actual measurements are used to evaluate our approach. These measurements include the optical, microphysical, and chemical properties of weakly absorbing aerosol which are representative of a variety of coastal summertime conditions observed during the Two-Column Aerosol Project (TCAP; http://campaign.arm.gov/tcap/). The evaluation includes calculating the root mean square error (RMSE) between the aerosol characteristics retrieved by our approach, and the same quantities calculated using the conventional volume mixing rule for chemical constituents. For dry conditions (defined in this work as relative humidity less than 55%) and sub-micron particles, a very good (RMSE~3%) and reasonable (RMSE~28%) agreement is obtained for the retrieved real refractive index (1.49Ī0.02) and effective density (1.68Ī0.21), respectively. Our approach permits discrimination between the retrieved aerosol characteristics of sub-micron and sub-10micron particles. The evaluation results also reveal that the retrieved density and refractive index tend to decrease with an increase of the relative humidity.

Kassianov, Evgueni I.; Barnard, James C.; Pekour, Mikhail S.; Berg, Larry K.; Shilling, John E.; Flynn, Connor J.; Mei, Fan; Jefferson, Anne

2014-10-01T23:59:59.000Z

108

Investigation of warm-cloud microphysics using a multi-component cloud model: Interactive effects of the aerosol spectrum. Master's thesis  

SciTech Connect (OSTI)

Clouds, especially low, warm, boundary-layer clouds, play an important role in regulating the earth's climate due to their significant contribution to the global albedo. The radiative effects of individual clouds are controlled largely by cloud microstructure, which is itself sensitive to the concentration and spectral distribution of the atmospheric aerosol. Increases in aerosol particle concentrations from anthropogenic activity could result in increased cloud albedo and global cloudiness, increasing the amount of reflected solar radiation. However, the effects of increased aerosol particle concentrations could be offset by the presence of giant or ultragiant aerosol particles. A one-dimensional, multi-component microphysical cloud model has been used to demonstrate the effects of aerosol particle spectral variations on the microstructure of warm clouds. Simulations performed with this model demonstrate that the introduction of increased concentrations of giant aerosol particles has a destabilizing effect on the cloud microstructure. Also, it is shown that warm-cloud microphysical processes modify the aerosol particle spectrum, favoring the generation of the largest sized particles via the collision-coalescence process. These simulations provide further evidence that the effect of aerosol particles on cloud microstructure must be addressed when considering global climate forecasts.

Zahn, S.G.

1993-12-01T23:59:59.000Z

109

Direct/Indirect Costs  

Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

This chapter provides recommended categories for direct and indirect elements developed by the Committee for Cost Methods Development (CCMD) and describes various estimating techniques for direct and indirect costs.

1997-03-28T23:59:59.000Z

110

Distinguishing Aerosol Impacts on Climate Over the Past Century  

SciTech Connect (OSTI)

Aerosol direct (DE), indirect (IE), and black carbon-snow albedo (BAE) effects on climate between 1890 and 1995 are compared using equilibrium aerosol-climate simulations in the Goddard Institute for Space Studies General Circulation Model coupled to a mixed layer ocean. Pairs of control(1890)-perturbation(1995) with successive aerosol effects allow isolation of each effect. The experiments are conducted both with and without concurrent changes in greenhouse gases (GHG's). A new scheme allowing dependence of snow albedo on black carbon snow concentration is introduced. The fixed GHG experiments global surface air temperature (SAT) changed -0.2, -1.0 and +0.2 C from the DE, IE, and BAE. Ice and snow cover increased 1.0% from the IE and decreased 0.3% from the BAE. These changes were a factor of 4 larger in the Arctic. Global cloud cover increased by 0.5% from the IE. Net aerosol cooling effects are about half as large as the GHG warming, and their combined climate effects are smaller than the sum of their individual effects. Increasing GHG's did not affect the IE impact on cloud cover, however they decreased aerosol effects on SAT by 20% and on snow/ice cover by 50%; they also obscure the BAE on snow/ice cover. Arctic snow, ice, cloud, and shortwave forcing changes occur mostly during summer-fall, but SAT, sea level pressure, and long-wave forcing changes occur during winter. An explanation is that aerosols impact the cryosphere during the warm-season but the associated SAT effect is delayed until winter.

Koch, Dorothy; Menon, Surabi; Del Genio, Anthony; Ruedy, Reto; Alienov, Igor; Schmidt, Gavin A.

2008-08-22T23:59:59.000Z

111

The effect of marine isoprene emissions on secondary organic aerosol and ozone formation in the coastal United States  

E-Print Network [OSTI]

The effect of marine isoprene emissions on secondary organic aerosol and ozone formation) in the coastal areas of the continental United States is studied using the U.S. Environmental Protection Agency regional-scale Community Multiscale Air Quality (CMAQ) modeling system. Marine isoprene emission rates

Zhang, Yang

112

Ganges Valley Aerosol Experiment: Science and Operations Plan  

SciTech Connect (OSTI)

The Ganges Valley region is one of the largest and most rapidly developing sections of the Indian subcontinent. The Ganges River, which provides the region with water needed for sustaining life, is fed primarily by snow and rainfall associated with Indian summer monsoons. Impacts of changes in precipitation patterns, temperature, and the flow of the snow-fed rivers can be immense. Recent satellite-based measurements have indicated that the upper Ganges Valley has some of the highest persistently observed aerosol optical depth values. The aerosol layer covers a vast region, extending across the Indo-Gangetic Plain to the Bay of Bengal during the winter and early spring of each year. The persistent winter fog in the region is already a cause of much concern, and several studies have been proposed to understand the economic, scientific, and societal dimensions of this problem. During the INDian Ocean EXperiment (INDOEX) field studies, aerosols from this region were shown to affect cloud formation and monsoon activity over the Indian Ocean. This is one of the few regions showing a trend toward increasing surface dimming and enhanced mid-tropospheric warming. Increasing air pollution over this region could modify the radiative balance through direct, indirect, and semi-indirect effects associated with aerosols. The consequences of aerosols and associated pollution for surface insolation over the Ganges Valley and monsoons, in particular, are not well understood. The proposed field study is designed for use of (1) the ARM Mobile Facility (AMF) to measure relevant radiative, cloud, convection, and aerosol optical characteristics over mainland India during an extended period of 9Ė12 months and (2) the G-1 aircraft and surface sites to measure relevant aerosol chemical, physical, and optical characteristics in the Ganges Valley during a period of 6Ė12 weeks. The aerosols in this region have complex sources, including burning of coal, biomass, and biofuels; automobile emissions; and dust. The extended AMF deployment will enable measurements under different regimes of the climate and aerosol abundanceóin the wet monsoon period with low aerosol loading; in the dry, hot summer with aerosols dispersed throughout the atmospheric column; and in the cool, dry winter with aerosols confined mostly to the boundary later and mid-troposphere. Each regime, in addition, has its own distinct radiative and atmospheric dynamic drivers. The aircraft operational phase will assist in characterizing the aerosols at times when they have been observed to be at the highest concentrations. A number of agencies in India will collaborate with the proposed field study and provide support in terms of planning, aircraft measurements, and surface sites. The high concentration of aerosols in the upper Ganges Valley, together with hypotheses involving several possible mechanisms with direct impacts on the hydrologic cycle of the region, gives us a unique opportunity to generate data sets that will be useful both in understanding the processes at work and in providing answers regarding the effects of aerosols on climate in a region where the perturbation is the highest.

Kotamarthi, VR

2010-06-21T23:59:59.000Z

113

Single particle characterization, source apportionment, and aging effects of ambient aerosols in Southern California  

E-Print Network [OSTI]

of scale, in Air Pollution and Health in Rapidly Developingfor particulate air pollution health standards, Aerosolfor particulate air pollution health standards, Aerosol

Shields, Laura Grace

2008-01-01T23:59:59.000Z

114

Chapter 3: Evaluating the impacts of carbonaceous aerosols on clouds and climate  

SciTech Connect (OSTI)

Any attempt to reconcile observed surface temperature changes within the last 150 years to changes simulated by climate models that include various atmospheric forcings is sensitive to the changes attributed to aerosols and aerosol-cloud-climate interactions, which are the main contributors that may well balance the positive forcings associated with greenhouse gases, absorbing aerosols, ozone related changes, etc. These aerosol effects on climate, from various modeling studies discussed in Menon (2004), range from +0.8 to -2.4 W m{sup -2}, with an implied value of -1.0 W m{sup -2} (range from -0.5 to -4.5 W m{sup -2}) for the aerosol indirect effects. Quantifying the contribution of aerosols and aerosol-cloud interactions remain complicated for several reasons some of which are related to aerosol distributions and some to the processes used to represent their effects on clouds. Aerosol effects on low lying marine stratocumulus clouds that cover much of the Earth's surface (about 70%) have been the focus of most of prior aerosol-cloud interaction effect simulations. Since cumulus clouds (shallow and deep convective) are short lived and cover about 15 to 20% of the Earth's surface, they are not usually considered as radiatively important. However, the large amount of latent heat released from convective towers, and corresponding changes in precipitation, especially in biomass regions due to convective heating effects (Graf et al. 2004), suggest that these cloud systems and aerosol effects on them, must be examined more closely. The radiative heating effects for mature deep convective systems can account for 10-30% of maximum latent heating effects and thus cannot be ignored (Jensen and Del Genio 2003). The first study that isolated the sensitivity of cumulus clouds to aerosols was from Nober et al. (2003) who found a reduction in precipitation in biomass burning regions and shifts in circulation patterns. Aerosol effects on convection have been included in other models as well (cf. Jacobson, 2002) but the relative impacts on convective and stratiform processes were not separated. Other changes to atmospheric stability and thermodynamical quantities due to aerosol absorption are also known to be important in modifying cloud macro/micro properties. Linkages between convection and boreal biomass burning can also impact the upper troposphere and lower stratosphere, radiation and cloud microphysical properties via transport of tropospheric aerosols to the lower stratosphere during extreme convection (Fromm and Servranckx 2003). Relevant questions regarding the impact of biomass aerosols on convective cloud properties include the effects of vertical transport of aerosols, spatial and temporal distribution of rainfall, vertical shift in latent heat release, phase shift of precipitation, circulation and their impacts on radiation. Over land surfaces, a decrease in surface shortwave radiation ({approx} 3-6 W m{sup -2} per decade) has been observed between 1960 to 1990, whereas, increases of 0.4 K in land temperature during the same period that occurred have resulted in speculations that evaporation and precipitation should also have decreased (Wild et al. 2004). However, precipitation records for the same period over land do not indicate any significant trend (Beck et al. 2005). The changes in precipitation are thought to be related to increased moisture advection from the oceans (Wild et al. 2004), which may well have some contributions from aerosol-radiation-convection coupling that could modify circulation patterns and hence moisture advection in specific regions. Other important aspects of aerosol effects, besides the direct, semi-direct, microphysical and thermodynamical impacts include alteration of surface albedos, especially snow and ice covered surfaces, due to absorbing aerosols. These effects are uncertain (Jacobson, 2004) but may produce as much as 0.3 W m{sup -2} forcing in the Northern hemisphere that could contribute to melting of ice and permafrost and change in the length of the season (e.g. early arrival of Spring

Menon, Surabi; Del Genio, Anthony D.

2007-09-03T23:59:59.000Z

115

The effect of aerosol vertical profiles on satellite-estimated surface particle sulfate concentrations  

SciTech Connect (OSTI)

The aerosol vertical distribution is an important factor in determining the relationship between satellite retrieved aerosol optical depth (AOD) and ground-level fine particle pollution concentrations. We evaluate how aerosol profiles measured by ground-based lidar and simulated by models can help improve the association between AOD retrieved by the Multi-angle Imaging Spectroradiometer (MISR) and fine particle sulfate (SO4) concentrations using matched data at two lidar sites. At the Goddard Space Flight Center (GSFC) site, both lidar and model aerosol profiles marginally improve the association between SO4 concentrations and MISR fractional AODs, as the correlation coefficient between cross-validation (CV) and observed SO4 concentrations changes from 0.87 for the no-scaling model to 0.88 for models scaled with aerosol vertical profiles. At the GSFC site, a large amount of urban aerosols resides in the well-mixed boundary layer so the column fractional AODs are already excellent indicators of ground-level particle pollution. In contrast, at the Atmospheric Radiation Measurement Program (ARM) site with relatively low aerosol loadings, scaling substantially improves model performance. The correlation coefficient between CV and observed SO4 concentrations is increased from 0.58 for the no-scaling model to 0.76 in the GEOS-Chem scaling model, and the model bias is reduced from 17% to 9%. In summary, despite the inaccuracy due to the coarse horizontal resolution and the challenges of simulating turbulent mixing in the boundary layer, GEOS-Chem simulated aerosol profiles can still improve methods for estimating surface aerosol (SO4) mass from satellite-based AODs, particularly in rural areas where aerosols in the free troposphere and any long-range transport of aerosols can significantly contribute to the column AOD.

Liu, Yang; Wang, Zifeng; Wang, Jun; Ferrare, Richard A.; Newsom, Rob K.; Welton, Ellsworth J.

2011-02-15T23:59:59.000Z

116

E-Print Network 3.0 - aerosol chemical vapor Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

chemical and microphysical properties influence aerosol optical properties and radiative effects... distribution of aerosol extensive and intensive properties will aid ......

117

Effective Henry's Law Partitioning and the Salting Constant of Glyoxal in Aerosols Containing Sulfate  

E-Print Network [OSTI]

-resolved measurements of gas-phase and particle-phase concentrations in sulfate- containing aerosols. Two complementary utilizing filter sampling of chamber aerosols followed by HPLC-MS/MS analysis and (2) positive matrix and irreversible condensed-phase reactions of these compounds yield products of lower volatility; e.g. acetal

118

Point and column aerosol radiative closure during ACE 1: Effects of particle shape and size  

E-Print Network [OSTI]

impact the earth's climate and photo- chemistry by directly scattering and absorbing solar radia- tion these impacts [e.g., Intergovernmental Panel on Climate Change, 2001]. Because of the short temporal and spatial scales of aerosol heterogeneity, numerical models of aerosol optical behavior are required to make

119

Residence times of fine tropospheric aerosols as determined by {sup 210}Pb progeny.  

SciTech Connect (OSTI)

Fine tropospheric aerosols can play important roles in the radiative balance of the atmosphere. The fine aerosols can act directly to cool the atmosphere by scattering incoming solar radiation, as well as indirectly by serving as cloud condensation nuclei. Fine aerosols, particularly carbonaceous soots, can also warm the atmosphere by absorbing incoming solar radiation. In addition, aerosols smaller than 2.5 {micro}m have recently been implicated in the health effects of air pollution. Aerosol-active radioisotopes are ideal tracers for the study of atmospheric transport processes. The source terms of these radioisotopes are relatively well known, and they are removed from the atmosphere only by radioactive decay or by wet or dry deposition of the host aerosol. The progeny of the primordial radionuclide {sup 238}U are of particular importance to atmospheric studies. Uranium-238 is common throughout Earth's crust and decays to the inert gas {sup 222}Rn, which escapes into the atmosphere. Radon-222 decays by the series of alpha and beta emissions shown in Figure 1 to the long-lived {sup 210}Pb. Once formed, {sup 210}Pb becomes attached to aerosol particles with average attachment times of 40 s to 3 min.

Marley, N. A.; Gaffney, J. S.; Drayton, P. J.; Cunningham, M. M.; Mielcarek, C.; Ravelo, R.; Wagner, C.

1999-10-05T23:59:59.000Z

120

The effectiveness of an indirect control message in decreasing the depreciative behavior of remote camping location users  

E-Print Network [OSTI]

in the number of visitors utilizing these resources and the ever expanding variety of activities in which people participate when they visit a particular natural resource setting. According to vernon D. Dame (Dame 1977), past chief of Interpretation..., a 12% increase over the previous year (Clark et al. 1972). Less tangible, but equally important are the indirect costs of depreciative behaviors (Clark et al. 1971). Cole 10 (1982) concluded that most site impacts do not appear to sharply reduce...

Barget, Robert George

1984-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Aerosol engineering: design and stability of aerosol reactors  

SciTech Connect (OSTI)

A theoretical study of the performance of aerosol reactors is presented. The goals of this study are (1) to identify the appropriate reactor types (batch, CSTR, and tubular) for production of aerosol with specific properties (for example, uniform size particles, high aerosol surface area, etc.) and (2) to investigate the effect of various process parameters on product aerosol characteristics and on the stability of operation of aerosol reactors. In all the reactors considered, the aerosol dynamics were detemined by chemical reaction, nucleation, and aerosol growth in the free molecule regime in the absence of coagulation at isothermal conditions. Formulation of the aerosol dynamics in terms of moments of the aerosol size distribution facilitated the numerical solution of the resulting systems of ordinary or partial differential equations. The stability characteristics of a continuous stirred tank aerosol reactor (CSTAR) were investigated since experimental data in the literature indicate that under certain conditions this reactor exhibits oscillatory behavior with respect to product aerosol concentration and size distribution.

Pratsinis, S.E.

1985-01-01T23:59:59.000Z

122

Oxidation of ambient biogenic secondary organic aerosol by hydroxyl radicals: Effects on cloud condensation nuclei activity  

E-Print Network [OSTI]

Changes in the hygroscopicity of ambient biogenic secondary organic aerosols (SOA) due to controlled OH oxidation were investigated at a remote forested site at Whistler Mountain, British Columbia during July of 2010. ...

Wong, J. P. S.

123

Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES)  

E-Print Network [OSTI]

Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic) emissions in the production and transformation of atmospheric aerosol and the resulting ...

Cziczo, Daniel James

124

Climatic effects of 1950Ė2050 changes in US anthropogenic aerosols Ė Part 2: Climate response  

E-Print Network [OSTI]

We investigate the climate response to changing US anthropogenic aerosol sources over the 1950Ė2050 period by using the NASA GISS general circulation model (GCM) and comparing to observed US temperature trends. Time-dependent ...

Leibensperger, Eric Michael

125

Effect of Terrestrial and Marine Organic Aerosol on Regional and Global Climate: Model Development, Application, and Verification with Satellite Data  

SciTech Connect (OSTI)

In this DOE project the improvements to parameterization of marine primary organic matter (POM) emissions, hygroscopic properties of marine POM, marine isoprene derived secondary organic aerosol (SOA) emissions, surfactant effects, new cloud droplet activation parameterization have been implemented into Community Atmosphere Model (CAM 5.0), with a seven mode aerosol module from the Pacific Northwest National Laboratory (PNNL)√?¬?√?¬Ę√?¬?√?¬?√?¬?√?¬?s Modal Aerosol Model (MAM7). The effects of marine aerosols derived from sea spray and ocean emitted biogenic volatile organic compounds (BVOCs) on microphysical properties of clouds were explored by conducting 10 year CAM5.0-MAM7 model simulations at a grid resolution 1.9√?¬?√?¬?√?¬?√?¬į√?¬?√?¬?√?¬?√?¬?2.5√?¬?√?¬?√?¬?√?¬į with 30 vertical layers. Model-predicted relationship between ocean physical and biological systems and the abundance of CCN in remote marine atmosphere was compared to data from the A-Train satellites (MODIS, CALIPSO, AMSR-E). Model simulations show that on average, primary and secondary organic aerosol emissions from the ocean can yield up to 20% increase in Cloud Condensation Nuclei (CCN) at 0.2% Supersaturation, and up to 5% increases in droplet number concentration of global maritime shallow clouds. Marine organics were treated as internally or externally mixed with sea salt. Changes associated with cloud properties reduced (absolute value) the model-predicted short wave cloud forcing from -1.35 Wm-2 to -0.25 Wm-2. By using different emission scenarios, and droplet activation parameterizations, this study suggests that addition of marine primary aerosols and biologically generated reactive gases makes an important difference in radiative forcing assessments. All baseline and sensitivity simulations for 2001 and 2050 using global-through-urban WRF/Chem (GU-WRF) were completed. The main objective of these simulations was to evaluate the capability of GU-WRF for an accurate representation of the global atmosphere by exploring the most accurate configuration of physics options in GWRF for global scale modeling in 2001 at a horizontal grid resolution of 1√?¬?√?¬?√?¬?√?¬į x 1√?¬?√?¬?√?¬?√?¬į. GU-WRF model output was evaluated using observational datasets from a variety of sources including surface based observations (NCDC and BSRN), model reanalysis (NCEP/ NCAR Reanalysis and CMAP), and remotely-sensed data (TRMM) to evaluate the ability of GU-WRF to simulate atmospheric variables at the surface as well as aloft. Explicit treatment of nanoparticles produced from new particle formation in GU-WRF/Chem-MADRID was achieved by expanding particle size sections from 8 to 12 to cover particles with the size range of 1.16 nm to 11.6 √?¬?√?¬?√?¬?√?¬Ķm. Simulations with two different nucleation parameterizations were conducted for August 2002 over a global domain at a 4√?¬?√?¬?√?¬?√?¬ļ by 5√?¬?√?¬?√?¬?√?¬ļ horizontal resolution. The results are evaluated against field measurement data from the 2002 Aerosol Nucleation and Real Time Characterization Experiment (ANARChE) in Atlanta, Georgia, as well as satellite and reanalysis data. We have also explored the relationship between √?¬?√?¬Ę√?¬?√?¬?√?¬?√?¬?clean marine√?¬?√?¬Ę√?¬?√?¬?√?¬?√?¬Ě aerosol optical properties and ocean surface wind speed using remotely sensed data from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board the CALIPSO satellite and the Advanced Microwave Scanning Radiometer (AMSR-E) on board the AQUA satellite. Detailed data analyses

Meskhidze, Nicholas; Zhang, Yang; Kamykowski, Daniel

2012-03-28T23:59:59.000Z

126

Development of an atmospheric aerosol model for studies of global budgets and effects of airborne particulate material  

SciTech Connect (OSTI)

A microphysics-removal Atmospheric Aerosol Model (AAM) is developed for use in General Circulation Models (GCM) to study global budgets and effects of particulate material. In this model the particle population is assumed to be composed of a set of log-normal modes whose time evolution due to microphysical processes is described via prognostic equations for an appropriate number of moments of the particle size distribution. This newly devised technique, by making use of a small number of prognostic equations for the aerosol variables and utilizing optimized numerical procedures, renders the model computationally efficient, hence particularly suitable for use in complex 3D GCMs. Detailed parameterizations of particle coagulation, sedimentation, dry deposition, and wet removal are incorporated into the AAM.

Giorgi, F.

1986-01-01T23:59:59.000Z

127

EMSL - aerosols  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

aerosols en Magnesium behavior and structural defects in Mg+ ion implanted silicon carbide. http:www.emsl.pnl.govemslwebpublicationsmagnesium-behavior-and-structural-defects-m...

128

Aerosols and clouds in chemical transport models and climate models.  

SciTech Connect (OSTI)

Clouds exert major influences on both shortwave and longwave radiation as well as on the hydrological cycle. Accurate representation of clouds in climate models is a major unsolved problem because of high sensitivity of radiation and hydrology to cloud properties and processes, incomplete understanding of these processes, and the wide range of length scales over which these processes occur. Small changes in the amount, altitude, physical thickness, and/or microphysical properties of clouds due to human influences can exert changes in Earth's radiation budget that are comparable to the radiative forcing by anthropogenic greenhouse gases, thus either partly offsetting or enhancing the warming due to these gases. Because clouds form on aerosol particles, changes in the amount and/or composition of aerosols affect clouds in a variety of ways. The forcing of the radiation balance due to aerosol-cloud interactions (indirect aerosol effect) has large uncertainties because a variety of important processes are not well understood precluding their accurate representation in models.

Lohmann,U.; Schwartz, S. E.

2008-03-02T23:59:59.000Z

129

Effects of aerosol species on atmospheric visibility in Kaohsiung City, Taiwan  

SciTech Connect (OSTI)

Visibility data collected from Kaohsiung City, Taiwan, for the past two decades indicated that the air pollutants have significantly degraded visibility in recent years. During the study period, the seasonal mean visibilities in spring, summer, fall, and winter were only 5.4, 9.1, 8.2, and 3.4 km, respectively. To ascertain how urban aerosols influence the visibility, we conducted concurrent visibility monitoring and aerosol sampling in 1999 to identify the principal causes of visibility impairments in the region. In this study, ambient aerosols were sampled and analyzed for 11 constituents, including water-soluble ions and carbon materials, to investigate the chemical composition of Kaohsiung aerosols. Stepwise regression method was used to correlate the impact of aerosol species on visibility impairments. Both seasonal and diurnal variation patterns were found from the monitoring of visibility. Results showed that light scattering was attributed primarily to aerosols with sizes that range from 0.26 to 0.90 {mu}m, corresponding with the wavelength region of visible light, which accounted for {approximately} 72% of the light scattering coefficient. Sulfate was a dominant component that affected both the light scattering coefficient and the visibility in the region. On average, (NH{sub 4}){sup 2}SO{sub 4}, NH{sub 4}NO{sub 3}, total carbon, and fine particulate matter (PM2.5)-remainder contributed 53%, 17%, 16%, and 14% to total light scattering, respectively. An empirical regression model of visibility based on sulfate, elemental carbon, and humidity was developed, and the comparison indicated that visibility in an urban area could be properly simulated by the equation derived herein. 35 refs., 10 figs., 4 tabs.

Chang-Gai Lee; Chung-Shin Yuan; Jui-Cheng Chang; Ching Yuan [National Sun Yat-Sen University (Taiwan)

2005-07-01T23:59:59.000Z

130

Variability of Aerosol Optical Properties from Long-term  

E-Print Network [OSTI]

%) controlled measurements: sp ­ Aerosol total light scattering coefficient at 450, 550, and 700 nm wavelengths automated generation and review of quality control plots · Weekly editing of data by station scientist]. Indirect Forcing Direct Forcing Carbon Dioxide Forcing Total Forcing Importance of Aerosols #12;Direct

Delene, David J.

131

Atmospheric multiple scattering of fluorescence light from extensive air showers and effect of the aerosol size on the reconstruction of energy and depth of maximum  

E-Print Network [OSTI]

The reconstruction of the energy and the depth of maximum $X_{\\rm max}$ of an extensive air shower depends on the multiple scattering of fluorescence photons in the atmosphere. In this work, we explain how atmospheric aerosols, and especially their size, scatter the fluorescence photons during their propagation. Using a Monte Carlo simulation for the scattering of light, the dependence on the aerosol conditions of the multiple scattered light contribution to the recorded signal is fully parameterised. A clear dependence on the aerosol size is proposed for the first time. Finally, using this new parameterisation, the effect of atmospheric aerosols on the energy and on the $X_{\\rm max}$ reconstructions is presented for a vertical extensive air shower observed by a ground-based detector at $30~$km: for typical aerosol conditions, multiple scattering leads to a systematic over-estimation of $5\\pm1.5\\%$ for the energy and $4.0\\pm 1.5~$g/cm$^2$ for the $X_{\\rm max}$, where the uncertainties refer to a variation of the aerosol size.

K. Louedec; J. Colombi

2014-03-17T23:59:59.000Z

132

Aerosol Effects on Cirrus through Ice Nucleation in the Community Atmosphere Model CAM5 with a Statistical Cirrus Scheme  

SciTech Connect (OSTI)

A statistical cirrus cloud scheme that tracks ice saturation ratio in the clear-sky and cloudy portion of a grid box separately has been implemented into NCAR CAM5 to provide a consistent treatment of ice nucleation and cloud formation. Simulated ice supersaturation and ice crystal number concentrations strongly depend on the number concentrations of heterogeneous ice nuclei (IN), subgrid temperature formulas and the number concentration of sulfate particles participating in homogeneous freezing, while simulated ice water content is insensitive to these perturbations. 1% to 10% dust particles serving as heterogeneous IN is 20 found to produce ice supersaturaiton in better agreement with observations. Introducing a subgrid temperature perturbation based on long-term aircraft observations of meso-scale motion produces a better hemispheric contrast in ice supersaturation compared to observations. Heterogeneous IN from dust particles significantly alter the net radiative fluxes at the top of atmosphere (TOA) (-0.24 to -1.59 W m-2) with a significant clear-sky longwave component (0.01 to -0.55 W m-2). Different cirrus treatments significantly perturb the net TOA anthropogenic aerosol forcing from -1.21 W m-2 to -1.54 W m-2, with a standard deviation of 0.10 W m-2. Aerosol effects on cirrus clouds exert an even larger impact on the atmospheric component of the radiative fluxes (two or three times the changes in the TOA radiative fluxes) and therefore on the hydrology cycle through the fast atmosphere response. This points to the urgent need to quantify aerosol effects on cirrus clouds through ice nucleation and how these further affect the hydrological cycle.

Wang, Minghuai; Liu, Xiaohong; Zhang, Kai; Comstock, Jennifer M.

2014-09-01T23:59:59.000Z

133

The effect of stratification on gravitational coagulation and settling of aerosols  

SciTech Connect (OSTI)

The differential equations describing the gravitational collision and coalescence of aerosol particles have been solved numerically, using an explicit two-step marching procedure, for the simple case of a single-component aerosol settling in a quiescent environment. The initial particle size distribution is arbitrary and is allowed to change in time due to coagulation and loss due to precipitation. These equations are solved at discrete heights, with the aerosol assumed to be homogeneous (well-mixed) in each height interval. The term describing precipitation allows for the transfer of mass from one height to the next lower and, so on, to the ground. This allows one-dimensional spatial stratification to develop when larger particles, that continue to grow due to coagulation, settle faster than the smaller particles. Numerical studies show that stratification in particle size and concentration can be significant in some cases. Stratification rates increase as the initial concentration of particles increases and as the range of initial particle sizes increases. Comparison of results from a well-mixed model and a height dependent model shows that significant differences in the predicted fallout rates can occur. 22 refs., 5 figs.

Mondy, L.A. (Sandia National Labs., Albuquerque, NM (USA)); Griffiths, S.K. (Sandia National Labs., Livermore, CA (USA))

1990-03-01T23:59:59.000Z

134

Atmospheric Aerosol Systems | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Science Themes Atmospheric Aerosol Systems Overview Atmospheric Aerosol Systems Biosystem Dynamics & Design Energy Materials & Processes Terrestrial & Subsurface Ecosystems...

135

Constraining the influence of natural variability to improve estimates of global aerosol indirect effects in a nudged version of the Community Atmosphere Model 5  

E-Print Network [OSTI]

the northern hemisphere Pacific Ocean and along the westernacross the northern Pacific Ocean, coincident with regionsthe Northern Hemisphere Pacific Ocean and off the northwest

Kooperman, Gabriel J; Pritchard, Michael S; Ghan, Steven J; Wang, Minghuai; Somerville, Richard C. J; Russell, Lynn M

2012-01-01T23:59:59.000Z

136

Constraining the influence of natural variability to improve estimates of global aerosol indirect effects in a nudged version of the Community Atmosphere Model 5  

E-Print Network [OSTI]

by direct emission inventories; sea salt and dust enter the32 ] Direct emission inventories represent the only sourcesemissions from prescribed inventories and parameterized

Kooperman, Gabriel J; Pritchard, Michael S; Ghan, Steven J; Wang, Minghuai; Somerville, Richard C. J; Russell, Lynn M

2012-01-01T23:59:59.000Z

137

Atmospheric Radiation Measurement (ARM) Data from Cape Cod, Massachusetts for the Two-Column Aerosol Project (TCAP)  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

The Two-Column Aerosol Project (TCAP) was designed to provide a detailed set of observations with which to (1) perform radiative and cloud condensation nuclei (CCN) closure studies, (2) evaluate a new retrieval algorithm for aerosol optical depth (AOD) in the presence of clouds using passive remote sensing, (3) extend a previously developed technique to investigate aerosol indirect effects, and (4) evaluate the performance of a detailed regional-scale model and a more parameterized global-scale model in simulating particle activation and AOD associated with the aging of anthropogenic aerosols. To meet these science objectives, the ARM Mobile Facility and the Mobile Aerosol Observing System were deployed on Cape Cod, Massachusetts, for a 12-month period starting in the summer of 2012 in order to quantify aerosol properties, radiation, and cloud characteristics at a location subject to both clear and cloudy conditions, and clean and polluted conditions. These observations were supplemented by two aircraft intensive observation periods, one in the summer and a second in the winter.

138

Development of an atmospheric aerosol model for studies of global budgets and effects of airborne particulate material  

SciTech Connect (OSTI)

A microphysics-removal atmospheric aerosol model (AAM) is developed for use in general circulation models (GCMs) to study global budgets and effects of particulate material. In this model the particle population is composed of a set of log-normal modes whose time evolution due to microphysical processes is described via prognostic equations for an appropriate number of moments of the particle-size distribution. Detailed parameterizations of particle coagulation, sedimentation, dry deposition, and wet removal are developed and implemented into the AAM. The AAM is incorporated into a GCM and is applied to two types of studies: (1) characteristics of the particle wet and dry removal processes, and (2) climatic impact of massive particulate injections following a global nuclear war, with emphasis on the sensitivity of the simulated effects to the inclusion of particle microphysics. Results are discussed.

Giorgi, F.

1986-01-01T23:59:59.000Z

139

Effects of sulfate aerosol on the central Pennsylvania surface shortwave radiation budget. Master's thesis  

SciTech Connect (OSTI)

Surface radiation measurements are taken simultaneously with measurements of meteorological variables including temperature, pressure, relative humidity, and visibility to evaluate the impact of sulfate haze on the surface radiation budget. A relationship is sought between flux losses due only to aerosol and relative humidity, visibility or both, with the goal of facilitating parameterization of sulfate hazes by climate modelers. At the same time, a rotating shadowband radiometer (RSR) is compared with a more costly sun photometer to determine the feasibility of substituting the former for the latter in future research. It is found that depletion of surface radiation due to aerosol is typically ten to twenty percent of initial insolation, and that the losses can be correlated with zenith angle, relative humidity and optical depth. In the case of flux loss as a function of optical depth, the two are related in a nearly linear fashion. It is also discovered that the RSR has a predictable error owing to a wider field of view than the sun photometer, and can be used as a replacement for the former by correcting for the error.

Guimond, P.W.

1994-12-01T23:59:59.000Z

140

The Effect of Solvent on the Analysis of Secondary Organic Aerosol Using Electrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

Solvent-analyte reactions in organic aerosol (OA) extracts prepared for analysis by electrospray ionization mass spectrometry (ESI-MS) were examined. Secondary organic aerosol (SOA) produced by ozonation of d-limonene as well as several test organic chemicals with functional groups typical for OA constituents were dissolved and stored in methanol, d3-methanol, acetonitrile, and d3-acetonitrile to investigate the extent and relative rates of reactions between analyte and solvent. High resolution ESI-MS showed that reactions of carbonyls with methanol produce significant amounts of hemiacetals and acetals on time scales ranging from several minutes to several days, with the reaction rates increasing in acidified solutions. Carboxylic acid groups were observed to react with methanol resulting in the formation of esters. In contrast, acetonitrile extracts showed no evidence of reactions with analyte molecules, suggesting that acetonitrile is the preferred solvent for SOA extraction. The use of solvent-analyte reactivity as an analytical chemistry tool for the improved characterization of functional groups in complex organic mixtures was also demonstrated. Direct comparison between ESI mass spectra of the same SOA samples extracted in reactive (methanol) versus non-reactive (acetonitrile) solvents was used to estimate the relative fractions of ketones (?38%), aldehydes (?6%), and carboxylic acids (?55%) in d-limonene SOA.

Bateman, Adam P.; Walser, Maggie L.; Dessiaterik, Yury; Laskin, Julia; Laskin, Alexander; Nizkorodov, Serguei

2008-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

AEROSOL DIRECT RADIATIVE EFFECTS OVER THE NORTHWEST ATLANTIC, NORTHWEST PACIFIC, AND NORTH INDIAN OCEANS: ESTIMATES BASED ON IN-SITU CHEMICAL AND  

E-Print Network [OSTI]

AEROSOL DIRECT RADIATIVE EFFECTS OVER THE NORTHWEST ATLANTIC, NORTHWEST PACIFIC, AND NORTH INDIAN OCEANS: ESTIMATES BASED ON IN-SITU CHEMICAL AND OPTICAL MEASUREMENTS AND CHEMICAL TRANSPORT MODELING radiation, changing cloud properties and altering precipitation. The largest uncertainty in the radiative

142

Researchers Model Impact of Aerosols Over California  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Impact of Aerosols Over California Research may clarify the effectiveness of regional pollution controls May 28, 2013 | Tags: Climate Research, Hopper Contact: Linda Vu,...

143

ARM - Indirect and Semi-Direct Aerosol Campaign (ISDAC)  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcal Documentation(AVIRIS) ProductsAirborneOctober 11, 2011 [FacilityIndiaGVAX NewsCalculators Outreach Home

144

E-Print Network 3.0 - aerosol load study Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

conditions... reserved. Keywords: India; Aerosol loading; Aerosol forcing; MODIS; TOMS; Remote sensing 1. Introduction... heating effect on the earth surface and in turn...

145

Aerosol Characterization Data from the Asian Pacific Regional Aerosol Characterization Project (ACE-Asia)  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

The Aerosol Characterization Experiments (ACE) were designed to increase understanding of how atmospheric aerosol particles affect the Earth's climate system. These experiments integrated in-situ measurements, satellite observations, and models to reduce the uncertainty in calculations of the climate forcing due to aerosol particles and improve the ability of models to predict the influences of aerosols on the Earth's radiation balance. ACE-Asia was the fourth in a series of experiments organized by the International Global Atmospheric Chemistry (IGAC) Program (A Core Project of the International Geosphere Biosphere Program). The Intensive Field Phase for ACE-Asia took place during the spring of 2001 (mid-March through early May) off the coast of China, Japan and Korea. ACE-Asia pursued three specific objectives: 1) Determine the physical, chemical, and radiative properties of the major aerosol types in the Eastern Asia and Northwest Pacific region and investigate the relationships among these properties. 2) Quantify the physical and chemical processes controlling the evolution of the major aerosol types and in particular their physical, chemical, and radiative properties. 3) Develop procedures to extrapolate aerosol properties and processes from local to regional and global scales, and assess the regional direct and indirect radiative forcing by aerosols in the Eastern Asia and Northwest Pacific region [Edited and shortened version of summary at http://data.eol.ucar.edu/codiac/projs?ACE-ASIA]. The Ace-Asia collection contains 174 datasets.

146

Factors influencing the microphysics and radiative properties of liquid-dominated Arctic clouds: insight from observations of aerosol and clouds during ISDAC  

SciTech Connect (OSTI)

Aircraft measurements during the Indirect and Semi-Direct Aerosol Campaign (ISDAC) in April 2008 are used to investigate aerosol indirect effects in Arctic clouds. Two aerosol-cloud regimes are considered in this analysis: single-layer stratocumulus cloud with below-cloud aerosol concentrations (N{sub a}) below 300 cm{sup -3} on April 8 and April 26-27 (clean cases); and inhomogeneous layered cloud with N{sub a} > 500 cm{sup -3} below cloud base on April 19-20, concurrent with a biomass burning episode (polluted cases). Vertical profiles through cloud in each regime are used to determine average cloud microphysical and optical properties. Positive correlations between the cloud droplet effective radius (Re) and cloud optical depth ({tau}) are observed for both clean and polluted cases, which are characteristic of optically-thin, non-precipitating clouds. Average Re values for each case are {approx} 6.2 {mu}m, despite significantly higher droplet number concentrations (Nd) in the polluted cases. The apparent independence of Re and Nd simplifies the description of indirect effects, such that {tau} and the cloud albedo (A) can be described by relatively simple functions of the cloud liquid water path. Adiabatic cloud parcel model simulations show that the marked differences in Na between the regimes account largely for differences in droplet activation, but that the properties of precursor aerosol also play a role, particularly for polluted cases where competition for vapour amongst the more numerous particles limits activation to larger and/or more hygroscopic particles. The similarity of Re for clean and polluted cases is attributed to compensating droplet growth processes for different initial droplet size distributions.

Earle, Michael; Liu, Peter S.; Strapp, J. Walter; Zelenyuk, Alla; Imre, D.; McFarquhar, Greg; Shantz, Nicole C.; Leaitch, W. R.

2011-11-04T23:59:59.000Z

147

E-Print Network 3.0 - aerosol particles originating Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

the U.S. Department of Energy under Contract No. DE-AC02-98CH10886. Summary: incoming solar radiation, either directly or indirectly as cloud particles, aerosols exert a cooling...

148

he Impact of Primary Marine Aerosol on Atmospheric Chemistry, Radiation and Climate: A CCSM Model Development Study  

SciTech Connect (OSTI)

This project examined the potential large-scale influence of marine aerosol cycling on atmospheric chemistry, physics and radiative transfer. Measurements indicate that the size-dependent generation of marine aerosols by wind waves at the ocean surface and the subsequent production and cycling of halogen-radicals are important but poorly constrained processes that influence climate regionally and globally. A reliable capacity to examine the role of marine aerosol in the global-scale atmospheric system requires that the important size-resolved chemical processes be treated explicitly. But the treatment of multiphase chemistry across the breadth of chemical scenarios encountered throughout the atmosphere is sensitive to the initial conditions and the precision of the solution method. This study examined this sensitivity, constrained it using high-resolution laboratory and field measurements, and deployed it in a coupled chemical-microphysical 3-D atmosphere model. First, laboratory measurements of fresh, unreacted marine aerosol were used to formulate a sea-state based marine aerosol source parameterization that captured the initial organic, inorganic, and physical conditions of the aerosol population. Second, a multiphase chemical mechanism, solved using the Max Planck Institute for Chemistry‚??s MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere) system, was benchmarked across a broad set of observed chemical and physical conditions in the marine atmosphere. Using these results, the mechanism was systematically reduced to maximize computational speed. Finally, the mechanism was coupled to the 3-mode modal aerosol version of the NCAR Community Atmosphere Model (CAM v3.6.33). Decadal-scale simulations with CAM v.3.6.33, were run both with and without reactive-halogen chemistry and with and without explicit treatment of particulate organic carbon in the marine aerosol source function. Simulated results were interpreted (1) to evaluate influences of marine aerosol production on the microphysical properties of aerosol populations and clouds over the ocean and the corresponding direct and indirect effects on radiative transfer; (2) atmospheric burdens of reactive halogen species and their impacts on O3, NOx, OH, DMS, and particulate non-sea-salt SO42-; and (3) the global production and influences of marine-derived particulate organic carbon. The model reproduced major characteristics of the marine aerosol system and demonstrated the potential sensitivity of global, decadal-scale climate metrics to multiphase marine-derived components of Earth‚??s troposphere. Due to the combined computational burden of the coupled system, the currently available computational resources were the limiting factor preventing the adequate statistical analysis of the overall impact that multiphase chemistry might have on climate-scale radiative transfer and climate.

Keene, William C. [University of Virginia] [University of Virginia; Long, Michael S. [University of Virginia] [University of Virginia

2013-05-20T23:59:59.000Z

149

Effect of coal type, residence time, and combustion configuration on the submicron aerosol composition and size distribution from pulverized coal combustion  

SciTech Connect (OSTI)

Pulverized samples of Utah bituminous, Beulah (North Dakota) low Na lignite, Deulah high Na lignite and Texas (San Miguel) lignite coals were burned at a rate of 2.5 kg/hr in a laboratory furnace under various (overall fuel lean) combustion conditions. Particle size distributions (PSD) and size segregated particle filter samples were taken at various positions within the convection section. Temperature and gas concentrations were measured throughout. The evolution of the submicron PSD within the convection section for the four coals was similar, although the location of the initial particle mode at the convection section inlet varied with coal type. While stage combustion of the Utah bituminous coal had a variable effect on the volume of submicron aerosol produced, staged combustion of two of the three lignites (Beulah low Na and Texas) caused a definite increase in the submicron aerosol volume. Chemical analysis of the size segregated particle samples show the trace elements, As, Pb, Zn, and the major elements, Na and K to be enriched in the submicron aerosol. Auger depth profiles show these small particles to be comprised of a core enriched in Fe, Si, Ca and Mg and surface layers enriched in Na and K. These results point to a mechanism of homogeneous nucleation of low vapor pressure species followed by successive layering of progressively more volatile species. Volatile species are enriched in the submicron aerosol due to the large surface areas provided. Modeling efforts show that while coagulation may be the dominant mechanism to describe the aerosol evolving within the convection section, it cannot be used solely to predict the PSD. Another mechanism, presumably surface area dependent growth (condensation) must be included.

Linak, W.P.

1985-01-01T23:59:59.000Z

150

Organic Aerosols in the Earth's J O O S T D E G O U W *  

E-Print Network [OSTI]

, and indirectly through their role as cloud-condensation nuclei. A large fraction (50%) of the submicron aerosol(primaryorganicaerosolorPOA) are distinguished from secondary organic aerosol (SOA) formed in the atmosphere from gas-phase precursors. Both POA scales of minutes: particle-into-liquid sampling combined with total organic carbon analysis for measure

Jimenez, Jose-Luis

151

Effects of mineral aerosols on the summertime climate of southwest Asia: Incorporating subgrid variability in a dust emission scheme  

E-Print Network [OSTI]

[1] Improvements in modeling mineral aerosols over southwest Asia are made to the dust scheme in a regional climate model by representing subgrid variability of both wind speed and surface roughness length. The new module ...

Marcella, Marc Pace

152

Separating Cloud Forming Nuclei from Interstitial Aerosol  

SciTech Connect (OSTI)

It has become important to characterize the physicochemical properties of aerosol that have initiated the warm and ice clouds. The data is urgently needed to better represent the aerosol-cloud interaction mechanisms in the climate models. The laboratory and in-situ techniques to separate precisely the aerosol particles that act as cloud condensation nuclei (CCN) and ice nuclei (IN), termed as cloud nuclei (CN) henceforth, have become imperative in studying aerosol effects on clouds and the environment. This review summarizes these techniques, design considerations, associated artifacts and challenges, and briefly discusses the need for improved designs to expand the CN measurement database.

Kulkarni, Gourihar R.

2012-09-12T23:59:59.000Z

153

E-Print Network 3.0 - aerosol trapping effect Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of this infrared radiation is trapped... 'S TEMPERATURE IS RISING This is the greenhouse effect. Without it, the Earths climate would be ... Source: Brookhaven National...

154

CLOUD DROPLET NUCLEATION AND ITS CONNECTION TO AEROSOL PROPERTIES  

E-Print Network [OSTI]

CLOUD DROPLET NUCLEATION AND ITS CONNECTION TO AEROSOL PROPERTIES STEPHEN E. SCHWARTZ Environmental in cloud-free conditions and indirectly, by increasing concentratiol1S of cloud droplets thereby enhancing cloud shortwave reflectivity. These effecls are thought to be significant in the context of changes

155

Global distribution of solid and aqueous sulfate aerosols: Effect of the hysteresis of particle phase transitions  

E-Print Network [OSTI]

of dimethylsulfide from the ocean biosphere. The timescale of phase transitions, as driven by changes in relative radiation back to space less effectively [Ramaswamy et al., 2001; Martin et al., 2004; Wang and Martin, 2007

156

Urban-scale impacts on the global-scale composition and climate effects of anthropogenic aerosols  

E-Print Network [OSTI]

A reduced form meta model has been produced to simulate the effects of physical, chemical, and meteorological processing of highly reactive trace species in hypothetical urban areas, which is capable of efficiently simulating ...

Cohen, Jason Blake

2010-01-01T23:59:59.000Z

157

Impact of natural and anthropogenic aerosols on stratocumulus and precipitation in the Southeast Pacific: A regional modeling study using WRF-Chem  

SciTech Connect (OSTI)

Cloud-system resolving simulations with the chemistry version of the Weather Research and Forecasting (WRF-Chem) model are used to quantify the impacts of regional anthropogenic and oceanic emissions on changes in aerosol properties, cloud macro- and microphysics, and cloud radiative forcing over the Southeast Pacific (SEP) during the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) (15 OctĖNov 16, 2008). The effects of oceanic aerosols on cloud properties, precipitation, and the shortwave forcing counteract those of anthropogenic aerosols. Despite the relatively small changes in Na concentrations (2-12%) from regional oceanic emissions, their net effect (direct and indirect) on the surface shortwave forcing is opposite and comparable or even larger in magnitude compared to those of regional anthropogenic emissions over the SEP. Two distinct regions are identified in the VOCALS-REx domain. The near-coast polluted region is characterized with strong droplet activation suppression of small particles by sea-salt particles, the more important role of the first than the second indirect effect, low surface precipitation rate, and low aerosol-cloud interaction strength associated with anthropogenic emissions. The relatively clean remote region is characterized with large contributions of Cloud Condensation Nuclei (CCN, number concentration denoted by NCCN) and droplet number concentrations (Nd) from non-local sources (lateral boundaries), a significant amount of surface precipitation, and high aerosol-cloud interactions under a scenario of five-fold increase in anthropogenic emissions. In the clean region, cloud properties have high sensitivity (e.g., 13% increase in cloud-top height and a 9% surface albedo increase) to the moderate increase in CCN concentration (?Nccn = 13 cm-3; 25%) produced by a five-fold increase in regional anthropogenic emissions. The increased anthropogenic aerosols reduce the precipitation amount over the relatively clean remote ocean. The reduction of precipitation (as a cloud water sink) more than doubles the wet scavenging timescale, resulting in an increased aerosol lifetime in the marine boundary layer. Therefore, the aerosol impacts on precipitation are amplified by the positive feedback of precipitation on aerosol. The positive feedback ultimately alters the cloud micro- and macro-properties, leading to strong aerosol-cloud-precipitation interactions. The higher sensitivity of clouds to anthropogenic aerosols over this region is also related to a 16% entrainment rate increase due to anthropogenic aerosols. The simulated aerosol-cloud-precipitation interactions are stronger at night over the clean marine region, while during the day, solar heating results in more frequent decoupling, thinner clouds, reduced precipitation, and reduced sensitivity to anthropogenic emissions. The simulated high sensitivity to the increased anthropogenic emissions over the clean region suggests that the perturbation of the clean marine environment with anthropogenic aerosols may have a larger effect on climate than that of already polluted marine environments.

Yang, Qing; Gustafson, William I.; Fast, Jerome D.; Wang, Hailong; Easter, Richard C.; Wang, Minghuai; Ghan, Steven J.; Berg, Larry K.; Leung, Lai-Yung R.; Morrison, H.

2012-09-28T23:59:59.000Z

158

Indirect and Semi-Direct Aerosol Campaign: The Impact of Arctic Aerosols on  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinementEtching.348ASSEMBLY [ICO] Name LastNews ArchiveCampaignClouds

159

DISPERSION BIAS, DISPERSION EFFECT, AND AEROSOL-CLOUD Yangang Liu1*  

E-Print Network [OSTI]

that acts to offset the cooling from the Twomey effect. This work extends the previous studies by further radiative cooling by climate models compared to satellite observations, large uncertainty and discrepancy and southern hemispheres. Application of the new formulation to remote sensing spectral shape of the cloud

160

Satellite based retrieval of aerosol optical thickness: The effect of sun and satellite geometry  

E-Print Network [OSTI]

be retrieved using the ATSR-2 with an accuracy of 0.03. The advanced very high resolution radiometer (AVHRR in the earth's energy balance by scattering and absorbing solar and terrestrial radiation [Chylek and Coakley warming effects of green house gases [Hansen, 2002]. Due to a high spatial and temporal variability

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Effects of Black Carbon Aerosols on the Indian Monsoon GERALD A. MEEHL, JULIE M. ARBLASTER,* AND WILLIAM D. COLLINS  

E-Print Network [OSTI]

of the ABC on longwave radiation are contributed primarily by natural aerosols and are not appreciable combine with naturally occurring dust loading over the Tibetan Plateau to ac- centuate the elevated heat radiation reaching the surface during the dry season, as noted in previous studies. The increased meridional

Meehl, Gerald A.

162

Effective Radius of Cloud Droplets by Ground-Based Remote Sensing: Relationships to Aerosol?  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed NewcatalystNeutronEnvironmentZIRKLE FRUITYearEffect0/2002 Yun (Helen) He,

163

Health effects of acid aerosols on North American children: Respiratory symptoms  

SciTech Connect (OSTI)

We examined the respiratory health effects of exposure to acidic air pollution among 13,369 white children 8 to 12 years old from 24 communities in the United States and Canada between 1988 and 1991. Each child`s parent or guardian completed a questionnaire. Air quality and meteorology were measured in each community for a 1-year period. We used a two-stage logistic regression model to analyze the data, adjusting for the period confounding effects of sex, history of allergies, parental asthma, parental education, and current smoking in the home. Children living in the community with the highest levels of particle strong acidity were significantly more likely [odds ratio (OR) = 1.66; 95% confidence interval (CI) 1.11-2.48] to report at least one episode of bronchitis in the past year compared to children living in the least-polluted community. Fine particulate sulfate was also associated with higher reporting of bronchitis (OR = 1.65; 95% CI 1.12-2.42). No other respiratory symptoms were significantly higher in association with any of the air pollutants of interest. No sensitive subgroups were identified. Reported bronchitis, but neither asthma, wheeze, cough, nor phlegm, were associated with levels of particle strong acidity for these children living in a nonurban environment. 26 refs., 3 figs., 4 tabs.

Dockery, D.W. [Harvard School of Public Health, Boston, MA (United States)]|[Channing Lab., Boston, MA (United States); Cunningham, J.; Damokosh, A.I. [Harvard School of Public Health, Boston, MA (United States)] [and others

1996-05-01T23:59:59.000Z

164

Final Report for √?¬Ę√?¬?√?¬?Cloud-Aerosol Physics in Super-Parameterized Atmospheric Regional Climate Simulations (CAP-SPARCS)√?¬Ę√?¬?√?¬Ě (DE-SC0002003) for 8/15/2009 through 8/14/2012  

SciTech Connect (OSTI)

Improving the representation of local and non-local aerosol interactions in state-of-the-science regional climate models is a priority for the coming decade (Zhang, 2008). With this aim in mind, we have combined two new technologies that have a useful synergy: (1) an aerosol-enabled regional climate model (Advanced Weather Research and Forecasting Model with Chemistry WRF-Chem), whose primary weakness is a lack of high quality boundary conditions and (2) an aerosol-enabled multiscale modeling framework (PNNL Multiscale Aerosol Climate Model (MACM)), which is global but captures aerosol-convection-cloud feedbacks, and thus an ideal source of boundary conditions. Combining these two approaches has resulted in an aerosol-enabled modeling framework that not only resolves high resolution details in a particular region, but crucially does so within a global context that is similarly faithful to multi-scale aerosol-climate interactions. We have applied and improved the representation of aerosol interactions by evaluating model performance over multiple domains, with (1) an extensive evaluation of mid-continent precipitation representation by multiscale modeling, (2) two focused comparisons to transport of aerosol plumes to the eastern United States for comparison with observations made as part of the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT), with the first being idealized and the second being linked to an extensive wildfire plume, and (3) the extension of these ideas to the development of a new approach to evaluating aerosol indirect effects with limited-duration model runs by √?¬Ę√?¬?√?¬?nudging√?¬Ę√?¬?√?¬Ě to observations. This research supported the work of one postdoc (Zhan Zhao) for two years and contributed to the training and research of two graduate students. Four peer-reviewed publications have resulted from this work, and ground work for a follow-on project was completed.

Lynn M. Russell; Richard C.J. Somerville

2012-11-05T23:59:59.000Z

165

Near real time vapor detection and enhancement using aerosol adsorption  

SciTech Connect (OSTI)

A vapor sample detection method where the vapor sample contains vapor and ambient air and surrounding natural background particles. The vapor sample detection method includes the steps of generating a supply of aerosol that have a particular effective median particle size, mixing the aerosol with the vapor sample forming aerosol and adsorbed vapor suspended in an air stream, impacting the suspended aerosol and adsorbed vapor upon a reflecting element, alternatively directing infrared light to the impacted aerosol and adsorbed vapor, detecting and analyzing the alternatively directed infrared light in essentially real time using a spectrometer and a microcomputer and identifying the vapor sample.

Novick, Vincent J.; Johnson, Stanley A.

1997-12-01T23:59:59.000Z

166

Near real time vapor detection and enhancement using aerosol adsorption  

DOE Patents [OSTI]

A vapor sample detection method is described where the vapor sample contains vapor and ambient air and surrounding natural background particles. The vapor sample detection method includes the steps of generating a supply of aerosol that have a particular effective median particle size, mixing the aerosol with the vapor sample forming aerosol and adsorbed vapor suspended in an air stream, impacting the suspended aerosol and adsorbed vapor upon a reflecting element, alternatively directing infrared light to the impacted aerosol and adsorbed vapor, detecting and analyzing the alternatively directed infrared light in essentially real time using a spectrometer and a microcomputer and identifying the vapor sample. 13 figs.

Novick, V.J.; Johnson, S.A.

1999-08-03T23:59:59.000Z

167

Near real time vapor detection and enhancement using aerosol adsorption  

DOE Patents [OSTI]

A vapor sample detection method where the vapor sample contains vapor and ambient air and surrounding natural background particles. The vapor sample detection method includes the steps of generating a supply of aerosol that have a particular effective median particle size, mixing the aerosol with the vapor sample forming aerosol and adsorbed vapor suspended in an air stream, impacting the suspended aerosol and adsorbed vapor upon a reflecting element, alternatively directing infrared light to the impacted aerosol and adsorbed vapor, detecting and analyzing the alternatively directed infrared light in essentially real time using a spectrometer and a microcomputer and identifying the vapor sample.

Novick, Vincent J. (Downers Grove, IL); Johnson, Stanley A. (Countryside, IL)

1999-01-01T23:59:59.000Z

168

Improved solid aerosol generator  

DOE Patents [OSTI]

An improved solid aerosol generator used to produce a gas borne stream of dry, solid particles of predetermined size and concentration. The improved solid aerosol generator nebulizes a feed solution of known concentration with a flow of preheated gas and dries the resultant wet heated aerosol in a grounded, conical heating chamber, achieving high recovery and flow rates. 2 figs.

Prescott, D.S.; Schober, R.K.; Beller, J.

1988-07-19T23:59:59.000Z

169

Spatially indirect excitons in coupled quantum wells  

SciTech Connect (OSTI)

Microscopic quantum phenomena such as interference or phase coherence between different quantum states are rarely manifest in macroscopic systems due to a lack of significant correlation between different states. An exciton system is one candidate for observation of possible quantum collective effects. In the dilute limit, excitons in semiconductors behave as bosons and are expected to undergo Bose-Einstein condensation (BEC) at a temperature several orders of magnitude higher than for atomic BEC because of their light mass. Furthermore, well-developed modern semiconductor technologies offer flexible manipulations of an exciton system. Realization of BEC in solid-state systems can thus provide new opportunities for macroscopic quantum coherence research. In semiconductor coupled quantum wells (CQW) under across-well static electric field, excitons exist as separately confined electron-hole pairs. These spatially indirect excitons exhibit a radiative recombination time much longer than their thermal relaxation time a unique feature in direct band gap semiconductor based structures. Their mutual repulsive dipole interaction further stabilizes the exciton system at low temperature and screens in-plane disorder more effectively. All these features make indirect excitons in CQW a promising system to search for quantum collective effects. Properties of indirect excitons in CQW have been analyzed and investigated extensively. The experimental results based on time-integrated or time-resolved spatially-resolved photoluminescence (PL) spectroscopy and imaging are reported in two categories. (i) Generic indirect exciton systems: general properties of indirect excitons such as the dependence of exciton energy and lifetime on electric fields and densities were examined. (ii) Quasi-two-dimensional confined exciton systems: highly statistically degenerate exciton systems containing more than tens of thousands of excitons within areas as small as (10 micrometer){sup 2} were observed. The spatial and energy distributions of optically active excitons were used as thermodynamic quantities to construct a phase diagram of the exciton system, demonstrating the existence of distinct phases. Optical and electrical properties of the CQW sample were examined thoroughly to provide deeper understanding of the formation mechanisms of these cold exciton systems. These insights offer new strategies for producing cold exciton systems, which may lead to opportunities for the realization of BEC in solid-state systems.

Lai, Chih-Wei Eddy

2004-03-01T23:59:59.000Z

170

atmospheric aerosols basic: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of atmospheric aerosol. Aplin, KL 2012-01-01 13 1. Introduction The atmospheric greenhouse effect is the basic mechanism Environmental Sciences and Ecology Websites Summary: 1....

171

Performance improvement of direct- and indirect-fired heaters  

SciTech Connect (OSTI)

The operating performance of direct and indirect heaters is discussed, and principles and guidelines that can be applied to effect improvements in efficiency are presented. This paper also discusses the associated heater efficiencies and several useful operating techniques to approach the maximum, steady-state heater efficiency. The techniques presented apply to all types of direct-and indirect-fired heaters: salt bath heaters, propane vaporizers, heater/treaters, production heaters, and glycol and amine regenerators.

Sams, G.W.; Hunter, J.D.

1988-08-01T23:59:59.000Z

172

Capstone Depleted Uranium Aerosols: Generation and Characterization  

SciTech Connect (OSTI)

In a study designed to provide an improved scientific basis for assessing possible health effects from inhaling depleted uranium (DU) aerosols, a series of DU penetrators was fired at an Abrams tank and a Bradley fighting vehicle. A robust sampling system was designed to collect aerosols in this difficult environment and continuously monitor the sampler flow rates. Aerosols collected were analyzed for uranium concentration and particle size distribution as a function of time. They were also analyzed for uranium oxide phases, particle morphology, and dissolution in vitro. The resulting data provide input useful in human health risk assessments.

Parkhurst, MaryAnn; Szrom, Fran; Guilmette, Ray; Holmes, Tom; Cheng, Yung-Sung; Kenoyer, Judson L.; Collins, John W.; Sanderson, T. Ellory; Fliszar, Richard W.; Gold, Kenneth; Beckman, John C.; Long, Julie

2004-10-19T23:59:59.000Z

173

WRF-Chem Simulations of Aerosols and Anthropogenic Aerosol Radiative Forcing in East Asia  

SciTech Connect (OSTI)

This study aims to provide a first comprehensive evaluation of WRF-Chem for modeling aerosols and anthropogenic aerosol radiative forcing (RF) over East Asia. Several numerical experiments were conducted from November 2007 to December 2008. Comparison between model results and observations shows that the model can generally reproduce the observed spatial distributions of aerosol concentration, aerosol optical depth (AOD) and single scattering albedo (SSA) from measurements at different sites, including the relatively higher aerosol concentration and AOD over East China and the relatively lower AOD over Southeast Asia, Korean, and Japan. The model also depicts the seasonal variation and transport of pollutions over East Asia. Particulate matter of 10 um or less in the aerodynamic diameter (PM10), black carbon (BC), sulfate (SO42-), nitrate (NO3-) and ammonium (NH4+) concentrations are higher in spring than other seasons in Japan due to the pollutant transport from polluted area of East Asia. AOD is high over Southwest and Central China in winter, spring and autumn and over North China in summer while is low over South China in summer due to monsoon precipitation. SSA is lowest in winter and highest in summer. The model also captures the dust events at the Zhangye site in the semi-arid region of China. Anthropogenic aerosol RF is estimated to range from -5 to -20 W m-2 over land and -20 to -40 W m-2 over ocean at the top of atmosphere (TOA), 5 to 30 W m-2 in the atmosphere (ATM) and -15 to -40 W m-2 at the bottom (BOT). The warming effect of anthropogenic aerosol in ATM results from BC aerosol while the negative aerosol RF at TOA is caused by scattering aerosols such as SO4 2-, NO3 - and NH4+. Positive BC RF at TOA compensates 40~50% of the TOA cooling associated with anthropogenic aerosol.

Gao, Yi; Zhao, Chun; Liu, Xiaohong; Zhang, Meigen; Leung, Lai-Yung R.

2014-08-01T23:59:59.000Z

174

Climate Engineering with Stratospheric Aerosols and Associated Engineering Parameters  

SciTech Connect (OSTI)

Climate engineering with stratospheric aerosols, an idea inspired by large volcaniceruptions, could cool the Earthís surface and thus alleviate some of the predicted dangerous impacts of anthropogenic climate change. However, the effectiveness of climate engineering to achieve a particular climate goal, and any associated side effects, depend on certain aerosol parameters and how the aerosols are deployed in the stratosphere. Through the examples of sulfate and black carbon aerosols, this paper examines "engineering" parameters-aerosol composition, aerosol size, and spatial and temporal variations in deployment-for stratospheric climate engineering. The effects of climate engineering are sensitive to these parameters, suggesting that a particle could be found ordesigned to achieve specific desired climate outcomes. This prospect opens the possibility for discussion of societal goals for climate engineering.

Kravitz, Benjamin S.

2013-02-12T23:59:59.000Z

175

Effects of anthropogenic activities on the molecular composition of urban organic aerosols: an ultrahigh resolution mass spectrometry study  

E-Print Network [OSTI]

of Chemistry, Aarhus University, Aarhus, DK-8000, Denmark 11 4Department of Analytical Chemistry, Ghent University, Krijgslaan 281, S12, BE-9000 12 Ghent, Belgium 13 5Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, BE-14... ). 95 The objective of the current study is to apply nanoESI UHRMS to determine the molecular 96 composition of urban PM2.5 (particles with ?2.5Ķm). Aerosol samples were collected at the 97 industrial site in Cork Ireland during summer with the aim...

Kourtchev, I.; O'Connor, I. P.; Giorio, C.; Fuller, S.; Kristenen, K.; Maenhaut, W.; Wenger, J. C.; Sodeau, J. R.; Glasius, M.; Kalberer, M.

2014-02-23T23:59:59.000Z

176

Attachment of radon progeny to cigarette-smoke aerosols  

SciTech Connect (OSTI)

The daughter products of radon gas are now recognized as a significant contributor to radiation exposure to the general public. It is also suspected that a synergistic effect exists with the combination cigarette smoking and radon exposure. We have conducted an experimental investigation to determine the physical nature of radon progeny interactions with cigarette smoke aerosols. The size distributions of the aerosols are characterized and attachment rates of radon progeny to cigarette-smoke aerosols are determined. Both the mainstream and sidestream portions of the smoke aerosol are investigated. Unattached radon progeny are very mobile and, in the presence of aerosols, readily attach to the particle surfaces. In this study, an aerosol chamber is used to contain the radon gas, progeny and aerosol mixture while allowing the attachment process to occur. The rate of attachment is dependent on the size distribution, or diffusion coefficient, of the radon progeny as well as the aerosol size distribution. The size distribution of the radon daughter products is monitored using a graded-screen diffusion battery. The diffusion battery also enables separation of the unattached radon progeny from those attached to the aerosol particles. Analysis of the radon decay products is accomplished using alpha spectrometry. The aerosols of interest are size fractionated with the aid of a differential mobility analyzer and cascade impactor. The measured attachment rates of progeny to the cigarette smoke are compared to those found in similar experiments using an ambient aerosol. The lowest attachment coefficients observed, {approximately}10{sup {minus}6} cm{sup 3}/s, occurred for the ambient aerosol. The sidestream and mainstream smoke aerosols exhibited higher attachment rates in that order. The results compared favorably with theories describing the coagulation process of aerosols.

Biermann, A.H.; Sawyer, S.R.

1995-05-01T23:59:59.000Z

177

INDIRECT SELECTION IN POULTRY BREEDING WITH SPECIAL  

E-Print Network [OSTI]

INDIRECT SELECTION IN POULTRY BREEDING WITH SPECIAL REFERENCE TO SINGLE GENES P. M√?RAT Laboratoire Josas SUMMARY The interest of indirect selection in poultry breeding is discussed, with special

Paris-Sud XI, Université de

178

CLOUD PHYSICS From aerosol-limited to invigoration  

E-Print Network [OSTI]

CLOUD PHYSICS From aerosol-limited to invigoration of warm convective clouds Ilan Koren,1 * Guy Dagan,1 Orit Altaratz1 Among all cloud-aerosol interactions, the invigoration effect is the most elusive. Most of the studies that do suggest this effect link it to deep convective clouds with a warm base

Napp, Nils

179

Use of the ARM Measurements of Spectral Zenith Radiance for Better Understanding of 3D Cloud-Radiation Processes & Aerosol-Cloud Interaction  

SciTech Connect (OSTI)

We proposed a variety of tasks centered on the following question: what can we learn about 3D cloud-radiation processes and aerosol-cloud interaction from rapid-sampling ARM measurements of spectral zenith radiance? These ARM measurements offer spectacular new and largely unexploited capabilities in both the temporal and spectral domains. Unlike most other ARM instruments, which average over many seconds or take samples many seconds apart, the new spectral zenith radiance measurements are fast enough to resolve natural time scales of cloud change and cloud boundaries as well as the transition zone between cloudy and clear areas. In the case of the shortwave spectrometer, the measurements offer high time resolution and high spectral resolution, allowing new discovery-oriented science which we intend to pursue vigorously. Research objectives are, for convenience, grouped under three themes: ‚?Ę Understand radiative signature of the transition zone between cloud-free and cloudy areas using data from ARM shortwave radiometers, which has major climatic consequences in both aerosol direct and indirect effect studies. ‚?Ę Provide cloud property retrievals from the ARM sites and the ARM Mobile Facility for studies of aerosol-cloud interactions. ‚?Ę Assess impact of 3D cloud structures on aerosol properties using passive and active remote sensing techniques from both ARM and satellite measurements.

Alexander Marshak; Warren Wiscombe; Yuri Knyazikhin; Christine Chiu

2011-05-24T23:59:59.000Z

180

Climate impacts of carbonaceous and other non-sulfate aerosols: A proposed study  

SciTech Connect (OSTI)

In addition to sulfate aerosols, carbonaceous and other non-sulfate aerosols are potentially significant contributors to global climate change. We present evidence that strongly suggests that current assessments of the effects of aerosols on climate may be inadequate because major aerosol components, especially carbonaceous aerosols, are not included in these assessments. Although data on the properties and distributions of anthropogenic carbonaceous aerosols are insufficient to allow quantification of their climate impacts, the existing information suggests that climate forcing by this aerosol component may be significant and comparable to that by sulfate aerosols. We propose that a research program be undertaken to support a quantitative assessment of the role in climate forcing of non-sulfate, particularly carbonaceous, aerosols.

Andreae, M.O.; Crutzen, P.J. [Max Planck Institute for Chemistry, Mainz (Germany); Cofer, W.R. III; Hollande, J.M. [NASA Langley Research Center, Hampton, VA (United States). Atmospheric Sciences Division] [and others

1995-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Direct Aerosol Forcing Uncertainty  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

Understanding sources of uncertainty in aerosol direct radiative forcing (DRF), the difference in a given radiative flux component with and without aerosol, is essential to quantifying changes in Earth's radiation budget. We examine the uncertainty in DRF due to measurement uncertainty in the quantities on which it depends: aerosol optical depth, single scattering albedo, asymmetry parameter, solar geometry, and surface albedo. Direct radiative forcing at the top of the atmosphere and at the surface as well as sensitivities, the changes in DRF in response to unit changes in individual aerosol or surface properties, are calculated at three locations representing distinct aerosol types and radiative environments. The uncertainty in DRF associated with a given property is computed as the product of the sensitivity and typical measurement uncertainty in the respective aerosol or surface property. Sensitivity and uncertainty values permit estimation of total uncertainty in calculated DRF and identification of properties that most limit accuracy in estimating forcing. Total uncertainties in modeled local diurnally averaged forcing range from 0.2 to 1.3 W m-2 (42 to 20%) depending on location (from tropical to polar sites), solar zenith angle, surface reflectance, aerosol type, and aerosol optical depth. The largest contributor to total uncertainty in DRF is usually single scattering albedo; however decreasing measurement uncertainties for any property would increase accuracy in DRF. Comparison of two radiative transfer models suggests the contribution of modeling error is small compared to the total uncertainty although comparable to uncertainty arising from some individual properties.

Mccomiskey, Allison

182

Aerosol remote sensing in polar regions  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

Multi-year sets of ground-based sun-photometer measurements conducted at 12 Arctic sites and 9 Antarctic sites were examined to determine daily mean values of aerosol optical thickness ?(?) at visible and near-infrared wavelengths, from which best-fit values of ŇngstrŲm's exponent ? were calculated. Analysing these data, the monthly mean values of ?(0.50 ?m) and ? and the relative frequency histograms of the daily mean values of both parameters were determined for winterĖspring and summerĖautumn in the Arctic and for austral summer in Antarctica. The Arctic and Antarctic covariance plots of the seasonal median values of ? versus ?(0.50 ?m) showed: (i) a considerable increase in ?(0.50 ?m) for the Arctic aerosol from summer to winterĖspring, without marked changes in ?; and (ii) a marked increase in ?(0.50 ?m) passing from the Antarctic Plateau to coastal sites, whereas ? decreased considerably due to the larger fraction of sea-salt aerosol. Good agreement was found when comparing ground-based sun-photometer measurements of ?(?) and ? at Arctic and Antarctic coastal sites with Microtops measurements conducted during numerous AERONET/MAN cruises from 2006 to 2013 in three Arctic Ocean sectors and in coastal and off-shore regions of the Southern Atlantic, Pacific, and Indian Oceans, and the Antarctic Peninsula. Lidar measurements were also examined to characterise vertical profiles of the aerosol backscattering coefficient measured throughout the year at Ny-Ňlesund. Satellite-based MODIS, MISR, and AATSR retrievals of ?(?) over large parts of the oceanic polar regions during spring and summer were in close agreement with ship-borne and coastal ground-based sun-photometer measurements. An overview of the chemical composition of mode particles is also presented, based on in-situ measurements at Arctic and Antarctic sites. Fourteen log-normal aerosol number size-distributions were defined to represent the average features of nuclei, accumulation and coarse mode particles for Arctic haze, summer background aerosol, Asian dust and boreal forest fire smoke, and for various background austral summer aerosol types at coastal and high-altitude Antarctic sites. The main columnar aerosol optical characteristics were determined for all 14 particle modes, based on in-situ measurements of the scattering and absorption coefficients. Diurnally averaged direct aerosol-induced radiative forcing and efficiency were calculated for a set of multimodal aerosol extinction models, using various Bidirectional Reflectance Distribution Function models over vegetation-covered, oceanic and snow-covered surfaces. These gave a reliable measure of the pronounced effects of aerosols on the radiation balance of the surfaceĖatmosphere system over polar regions.

Tomasi, C.; Wagener, R.; Kokhanovsky, A. A.; Lupi, A.; Ritter, C.; Smirnov, A.; O Neill, N. T.; Stone, R. S.; Holben, B. N.; Nyeki, S.; Wehrli, C.; Stohl, A.; Mazzola, M.; Lanconelli, C.; Vitale, V.; Stebel, K.; Aaltonen, V.; de Leeuw, G.; Rodriguez, E.; Herber, A. B.; Radionov, V. F.; Zielinski, T.; Petelski, T.; Sakerin, S. M.; Kabanov, D. M.; Xue, Y.; Mei, L.; Istomina, L.; Wagener, R.; McArthur, B.; Sobolewski, P. S.; Kivi, R.; Courcoux, Y.; Larouche, P.; Broccardo, S.; Piketh, S. J.

2015-01-01T23:59:59.000Z

183

aerosol microphysical characteristics: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

in radiative flux calculations Engineering Websites Summary: the regional and global climate through its indirect effects by serving as cloud condensation nuclei 4 retrieving...

184

ARM: 1-minute Raman Lidar: aerosol extinction profiles and aerosol optical thickness, from first Ferrare algorithm  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

1-minute Raman Lidar: aerosol extinction profiles and aerosol optical thickness, from first Ferrare algorithm

Sivaraman, Chitra; Flynn, Connor

185

ARM: 10-minute Raman Lidar: aerosol extinction profiles and aerosol optical thickness, from first Ferrare algorithm  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

10-minute Raman Lidar: aerosol extinction profiles and aerosol optical thickness, from first Ferrare algorithm

Newsom, Rob; Goldsmith, John

186

Modal aerosol dynamics modeling  

SciTech Connect (OSTI)

The report presents the governing equations for representing aerosol dynamics, based on several different representations of the aerosol size distribution. Analytical and numerical solution techniques for these governing equations are also reviewed. Described in detail is a computationally efficient numerical technique for simulating aerosol behavior in systems undergoing simultaneous heat transfer, fluid flow, and mass transfer in and between the gas and condensed phases. The technique belongs to a general class of models known as modal aerosol dynamics (MAD) models. These models solve for the temporal and spatial evolution of the particle size distribution function. Computational efficiency is achieved by representing the complete aerosol population as a sum of additive overlapping populations (modes), and solving for the time rate of change of integral moments of each mode. Applications of MAD models for simulating aerosol dynamics in continuous stirred tank aerosol reactors and flow aerosol reactors are provided. For the application to flow aerosol reactors, the discussion is developed in terms of considerations for merging a MAD model with the SIMPLER routine described by Patankar (1980). Considerations for incorporating a MAD model into the U.S. Environmental Protection Agency's Regional Particulate Model are also described. Numerical and analytical techniques for evaluating the size-space integrals of the modal dynamics equations (MDEs) are described. For multimodal logonormal distributions, an analytical expression for the coagulation integrals of the MDEs, applicable for all size regimes, is derived, and is within 20% of accurate numerical evaluation of the same moment coagulation integrals. A computationally efficient integration technique, based on Gauss-Hermite numerical integration, is also derived.

Whitby, E.R.; McMurry, P.H.; Shankar, U.; Binkowski, F.S.

1991-02-01T23:59:59.000Z

187

Aerosol Cans? -Aerosol cans use a pressurized  

E-Print Network [OSTI]

? - The waste generated in the processing of images/photos contains silver. Silver is a toxic heavy metal the product. Propellants are often flammable and/or toxic. Therefore, never store aerosol cans near ignition of this pamphlet. -Carefully transfer the old paint thinner from the one gallon closable can to the 30 gallon metal

Jia, Songtao

188

aerosol ratio test: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

aerosol ratio test First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Effect of mineral dust aerosol...

189

Measurement Needs and Challenges for Absorbing Aerosol Black Carbon, Brown Carbon, Dust and Coatings  

E-Print Network [OSTI]

and Carmichael 2008) 1. BC mixing state. 2. BC vertical distributions. 3. Inventories. 4. Indirect effect mixing state. 2. BC vertical distributions. 3. Inventories. 4. Indirect effect. · Most information comes

190

Biomass Indirect Liquefaction Strategy Workshop: Summary Report...  

Broader source: Energy.gov (indexed) [DOE]

Strategy Workshop: Summary Report Biomass Indirect Liquefaction Strategy Workshop: Summary Report This report is based on the proceedings of the U.S. DOE's Bioenergy Technologies...

191

Hygroscopic growth of submicron and supermicron aerosols in the marine boundary layer  

E-Print Network [OSTI]

balance and climate directly through absorption and scattering of the incoming solar radiation and indirectly through modification of cloud properties [Intergovernmental Panel on Climate Change, 2007 behaviors of the dynamic and complex atmospheric aerosol consisting of particles with a wide range of sizes

192

Aerosol Sampler Operations Manual  

E-Print Network [OSTI]

-1123 Laboratory FAX (916) 752-4107 Standard Operating Procedures Technical Information Document TI 201A #12;TI 201.................................................................................................................................................. 3 1.0 Weekly Maintenance ProceduresIMPROVE Aerosol Sampler Operations Manual February 10, 1997 Air Quality Group Crocker Nuclear

Fischer, Emily V.

193

Modeling kinetic partitioning of secondary organic aerosol and size distribution dynamics: representing effects of volatility, phase state, and particle-phase reaction  

SciTech Connect (OSTI)

Evidence is mounting that the majority of the climatically active aerosols are produced through the growth of smaller particles via secondary organic aerosol (SOA) formation from gas-to-particle conversion of anthropogenic and biogenic volatile organic compounds (VOCs). The timescale of SOA partitioning and the associated size distribution dynamics are expected to depend on the gas-phase oxidation of the precursor VOCs and their products, volatility of these organic solutes, composition and phase state of the pre-existing particles, and diffusivity and reactivity of the solute within the particle phase. This paper describes a new framework for modeling kinetic gas-particle partitioning of SOA, with an analytical treatment for the diffusion-reaction process within the particle phase. The formulation is amenable for eventual use in regional and global climate models, although it currently awaits implementation of the actual particle-phase reactions that are important for SOA formation. In the present work, the model is applied to investigate the competitive growth dynamics of the Aitken and accumulation mode particles while the Kelvin effect and coagulation are neglected for simplicity. The timescale of SOA partitioning and evolution of number and composition size distributions are evaluated for a range of solute volatilities (C*), particle-phase bulk diffusivities (Db), and particle-phase reactivity, as exemplified by a pseudo-first-order rate constant (kc). Results show that irreversible condensation of non-volatile organic vapors (equivalent to ) produces significant narrowing of the size distribution. At the other extreme, non-reactive partitioning of semi-volatile organic vapors is volume-controlled in which the final (equilibrium) size distribution simply shifts to the right on the diameter axis while its shape remains unchanged. However, appreciable narrowing of the size distribution may occur when the pre-existing particles are highly viscous semi-solids such that small particles reach quasi-equilibrium much faster than the large ones. In the case of reactive partitioning (finite ), the size distribution experiences permanent narrowing, which is especially pronounced for Db < 10-13 cm2 s-1 and kc > 0.01 s-1. As a result, both number and composition size distributions are needed to effectively constrain and evaluate the next generation of SOA models that treat phase state thermodynamics, particle-phase diffusion and particle-phase chemical reactions.

Zaveri, Rahul A.; Easter, Richard C.; Shilling, John E.; Seinfeld, J. H.

2014-05-27T23:59:59.000Z

194

Indirect Estimation of Radioactivity in Containerized Cargo  

SciTech Connect (OSTI)

Detecting illicit nuclear and radiological material in containerized cargo challenges the state of the art in detection systems. Current systems are being evaluated and new systems envisioned to address the need for the high probability of detection and extremely low false alarm rates necessary to thwart potential threats and extremely low nuisance and false alarm rates while maintaining necessary to maintain the flow of commerce impacted by the enormous volume of commodities imported in shipping containers. Maintaining flow of commerce also means that primary inspection must be rapid, requiring relatively indirect measurements of cargo from outside the containers. With increasing information content in such indirect measurements, it is natural to ask how the information might be combined to improved detection. Toward this end, we present an approach to estimating isotopic activity of naturally occurring radioactive material in cargo grouped by commodity type, combining container manifest data with radiography and gamma spectroscopy aligned to location along the container. The heart of this approach is our statistical model of gamma counts within peak regions of interest, which captures the effects of background suppression, counting noise, convolution of neighboring cargo contributions, and down-scattered photons to provide physically constrained estimates of counts due to decay of specific radioisotopes in cargo alone. Coupled to that model, we use a mechanistic model of self-attenuated radiation flux to estimate the isotopic activity within cargo, segmented by location within each container, that produces those counts. We demonstrate our approach by applying it to a set of measurements taken at the Port of Seattle in 2006. This approach to synthesizing disparate available data streams and extraction of cargo characteristics holds the potential to improve primary inspection using current detection capabilities and to enable simulation-based evaluation of new candidate detection systems.

Jarman, Kenneth D.; Scherrer, Chad; Smith, Eric L.; Chilton, Lawrence; Anderson, K. K.; Ressler, Jennifer J.; Trease, Lynn L.

2011-01-01T23:59:59.000Z

195

Biofuels and indirect land use change  

E-Print Network [OSTI]

Biofuels and indirect land use change The case for mitigation October 2011 #12;About this study), Malaysian Palm Oil Board, National Farmers Union, Novozymes, Northeast Biofuels Collaborative, Patagonia Bio contributed views on a confidential basis. #12;1Biofuels and indirect land use change The case for mitigation

196

Inter-annual Tropospheric Aerosol Variability in Late Twentieth Century and its Impact on Tropical Atlantic and West African Climate by Direct and Semi-direct Effects  

SciTech Connect (OSTI)

A new high-resolution (0.9$^{\\circ}$x1.25$^{\\circ}$ in the horizontal) global tropospheric aerosol dataset with monthly resolution is generated using the finite-volume configuration of Community Atmosphere Model (CAM4) coupled to a bulk aerosol model and forced with recent estimates of surface emissions for the latter part of twentieth century. The surface emissions dataset is constructed from Coupled Model Inter-comparison Project (CMIP5) decadal-resolution surface emissions dataset to include REanalysis of TROpospheric chemical composition (RETRO) wildfire monthly emissions dataset. Experiments forced with the new tropospheric aerosol dataset and conducted using the spectral configuration of CAM4 with a T85 truncation (1.4$^{\\circ}$x1.4$^{\\circ}$) with prescribed twentieth century observed sea surface temperature, sea-ice and greenhouse gases reveal that variations in tropospheric aerosol levels can induce significant regional climate variability on the inter-annual timescales. Regression analyses over tropical Atlantic and Africa reveal that increasing dust aerosols can cool the North African landmass and shift convection southwards from West Africa into the Gulf of Guinea in the spring season in the simulations. Further, we find that increasing carbonaceous aerosols emanating from the southwestern African savannas can cool the region significantly and increase the marine stratocumulus cloud cover over the southeast tropical Atlantic ocean by aerosol-induced diabatic heating of the free troposphere above the low clouds. Experiments conducted with CAM4 coupled to a slab ocean model suggest that present day aerosols can shift the ITCZ southwards over the tropical Atlantic and can reduce the ocean mixed layer temperature beneath the increased marine stratocumulus clouds in the southeastern tropical Atlantic.

Evans, Katherine J [ORNL; Hack, James J [ORNL; Truesdale, John [National Center for Atmospheric Research (NCAR); Mahajan, Salil [ORNL; Lamarque, J-F [University Center for Atmospheric Research

2012-01-01T23:59:59.000Z

197

Development and Characterization of a Thermodenuder for Aerosol Volatility Measurements  

SciTech Connect (OSTI)

This SBIR Phase I project addressed the critical need for improved characterization of carbonaceous aerosol species in the atmosphere. The proposed work focused on the development of a thermodenuder (TD) system capable of systematically measuring volatility profiles of primary and secondary organic aerosol species and providing insight into the effects of absorbing and nonabsorbing organic coatings on particle absorption properties. This work provided the fundamental framework for the generation of essential information needed for improved predictions of ambient aerosol loadings and radiative properties by atmospheric chemistry models. As part of this work, Aerodyne Research, Inc. (ARI) continued to develop and test, with the final objective of commercialization, an improved thermodenuder system that can be used in series with any aerosol instrument or suite of instruments (e.g., aerosol mass spectrometers-AMS, scanning mobility particle sizers-SMPS, photoacoustic absorption spectrometers-PAS, etc.) to obtain aerosol chemical, physical, and optical properties as a function of particle volatility. In particular, we provided the proof of concept for the direct coupling of our improved TD design with a full microphysical model to obtain volatility profiles for different organic aerosol components and to allow for meaningful comparisons between different TD-derived aerosol measurements. In a TD, particles are passed through a heated zone and a denuding (activated charcoal) zone to remove semi-volatile material. Changes in particle size, number concentration, optical absorption, and chemical composition are subsequently detected with aerosol instrumentation. The aerosol volatility profiles provided by the TD will strengthen organic aerosol emission inventories, provide further insight into secondary aerosol formation mechanisms, and provide an important measure of particle absorption (including brown carbon contributions and identification, and absorption enhancements due to coatings on soot particles). The successfully completed Phase I project included construction of a prototype design for the TD with detailed physical modeling, testing with laboratory and ambient aerosol particles, and the initiation of a detailed microphysical model of the aerosol particles passing through the TD to extract vapor pressure distributions. The objective of the microphysical model is to derive vapor pressure distributions (i.e. vapor pressure ranges, including single chemical compounds, mixtures of known compounds, and complex Ďreal-worldí aerosols, such as SOA, and soot particles with absorbing and nonabsorbing coatings) from TD measurements of changes in particle size, mass, and chemical composition for known TD temperatures and flow rates (i.e. residence times). The proposed Phase II project was designed to optimize several TD systems for different instrument applications and to combine the hardware and modeling into a robust package for commercial sales.

Dr. Timothy Onasch

2009-09-09T23:59:59.000Z

198

Phase transformation and growth of hygroscopic aerosols  

SciTech Connect (OSTI)

Ambient aerosols play an important role in many atmospheric processes affecting air quality, visibility degradation, and climatic changes as well. Both natural and anthropogenic sources contribute to the formation of ambient aerosols, which are composed mostly of sulfates, nitrates, and chlorides in either pure or mixed forms. These inorganic salt aerosols are hygroscopic by nature and exhibit the properties of deliquescence and efflorescence in humid air. For pure inorganic salt particles with diameter larger than 0.1 micron, the phase transformation from a solid particle to a saline droplet occurs only when the relative humidity in the surrounding atmosphere reaches a certain critical level corresponding to the water activity of the saturated solution. The droplet size or mass in equilibrium with relative humidity can be calculated in a straightforward manner from thermodynamic considerations. For aqueous droplets 0.1 micron or smaller, the surface curvature effect on vapor pressure becomes important and the Kelvin equation must be used.

Tang, I.N.

1999-11-01T23:59:59.000Z

199

Uncertainties and Frontiers in Aerosol Research  

E-Print Network [OSTI]

;Transport Power Industry Biomass burning Residential Human activity Perspective Aerosol Sources (rather than, Mixing, Chemistry, Climate) Climate Effects Resource: AeroCom, an international model intercomparison of fossil fuel (coal, oil, diesel, gasoline), domestic wood burning, forest fires #12;Natural sources

200

Characterizing the formation of secondary organic aerosols  

SciTech Connect (OSTI)

Organic aerosol is an important fraction of the fine particulate matter present in the atmosphere. This organic aerosol comes from a variety of sources; primary organic aerosol emitted directly from combustion process, and secondary aerosol formed in the atmosphere from condensable vapors. This secondary organic aerosol (SOA) can result from both anthropogenic and biogenic sources. In rural areas of the United States, organic aerosols can be a significant part of the aerosol load in the atmosphere. However, the extent to which gas-phase biogenic emissions contribute to this organic load is poorly understood. Such an understanding is crucial to properly apportion the effect of anthropogenic emissions in these rural areas that are sometimes dominated by biogenic sources. To help gain insight on the effect of biogenic emissions on particle concentrations in rural areas, we have been conducting a field measurement program at the University of California Blodgett Forest Research Facility. The field location includes has been used to acquire an extensive suite of measurements resulting in a rich data set, containing a combination of aerosol, organic, and nitrogenous species concentration and meteorological data with a long time record. The field location was established in 1997 by Allen Goldstein, a professor in the Department of Environmental Science, Policy and Management at the University of California at Berkeley to study interactions between the biosphere and the atmosphere. The Goldstein group focuses on measurements of concentrations and whole ecosystem biosphere-atmosphere fluxes for volatile organic compounds (VOC's), oxygenated volatile organic compounds (OVOC's), ozone, carbon dioxide, water vapor, and energy. Another important collaborator at the Blodgett field location is Ronald Cohen, a professor in the Chemistry Department at the University of California at Berkeley. At the Blodgett field location, his group his group performs measurements of the concentrations of important gas phase nitrogen compounds. Experiments have been ongoing at the Blodgett field site since the fall of 2000, and have included portions of the summer and fall of 2001, 2002, and 2003. Analysis of both the gas and particle phase data from the year 2000 show that the particle loading at the site correlates with both biogenic precursors emitted in the forest and anthropogenic precursors advected to the site from Sacramento and the Central Valley of California. Thus the particles at the site are affected by biogenic processing of anthropogenic emissions. Size distribution measurements show that the aerosol at the site has a geometric median diameter of approximately 100 nm. On many days, in the early afternoon, growth of nuclei mode particles (<20 nm) is also observed. These growth events tend to occur on days with lower average temperatures, but are observed throughout the summer. Analysis of the size resolved data for these growth events, combined with typical measured terpene emissions, show that the particle mass measured in these nuclei mode particles could come from oxidation products of biogenic emissions, and can serve as a significant route for SOA partitioning into the particle phase. During periods of each year, the effect of emissions for forest fires can be detected at the Blodgett field location. During the summer of 2002 emissions from the Biscuit fire, a large fire located in Southwest Oregon, was detected in the aerosol data. The results show that increases in particle scattering can be directly related to increased black carbon concentration and an appearance of a larger mode in the aerosol size distribution. These results show that emissions from fires can have significant impact on visibility over large distances. The results also reinforce the view that forest fires can be a significant source of black carbon in the atmosphere, which has important climate and visibility. Continuing work with the 2002 data set, particularly the combination of the aerosol and gas phase data, will continue to provide important information o

Lunden, Melissa; Black, Douglas; Brown, Nancy

2004-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

5, 79658026, 2005 Simulating aerosol  

E-Print Network [OSTI]

composition, number concentration, and size distribution of the global submicrometer aerosol. The present, coagulation, condensation, nucleation of sulfuric acid vapor, aerosol chemistry, cloud processing, and sizeACPD 5, 7965­8026, 2005 Simulating aerosol microphysics with ECHAM/MADE A. Lauer et al. Title Page

Paris-Sud XI, Université de

202

Computational Fluid Dynamics Study of Aerosol Transport and Deposition Mechanisms  

E-Print Network [OSTI]

In this work, various aerosol particle transport and deposition mechanisms were studied through the computational fluid dynamics (CFD) modeling, including inertial impaction, gravitational effect, lift force, interception, and turbophoresis, within...

Tang, Yingjie

2012-07-16T23:59:59.000Z

203

Highly stable aerosol generator  

DOE Patents [OSTI]

An improved compressed air nebulizer has been developed such that a uniform aerosol particle size and concentration may be produced over long time periods. This result is achieved by applying a vacuum pressure to the makeup assembly and by use of a vent tube between the atmosphere and the makeup solution. By applying appropriate vacuum pressures to the makeup solution container and by proper positioning of the vent tube, a constant level of aspirating solution may be maintained within the aspirating assembly with aspirating solution continuously replaced from the makeup solution supply. This device may also be adapted to have a plurality of aerosol generators and only one central makeup assembly. 2 figs.

DeFord, H.S.; Clark, M.L.

1981-11-03T23:59:59.000Z

204

An Indirect Route for Ethanol Production  

SciTech Connect (OSTI)

The ZeaChem indirect method is a radically new approach to producing fuel ethanol from renewable resources. Sugar and syngas processing platforms are combined in a novel way that allows all fractions of biomass feedstocks (e.g. carbohydrates, lignins, etc.) to contribute their energy directly into the ethanol product via fermentation and hydrogen based chemical process technologies. The goals of this project were: (1) Collect engineering data necessary for scale-up of the indirect route for ethanol production, and (2) Produce process and economic models to guide the development effort. Both goals were successfully accomplished. The projected economics of the Base Case developed in this work are comparable to today's corn based ethanol technology. Sensitivity analysis shows that significant improvements in economics for the indirect route would result if a biomass feedstock rather that starch hydrolyzate were used as the carbohydrate source. The energy ratio, defined as the ratio of green energy produced divided by the amount of fossil energy consumed, is projected to be 3.11 to 12.32 for the indirect route depending upon the details of implementation. Conventional technology has an energy ratio of 1.34, thus the indirect route will have a significant environmental advantage over today's technology. Energy savings of 7.48 trillion Btu/yr will result when 100 MMgal/yr (neat) of ethanol capacity via the indirect route is placed on-line by the year 2010.

Eggeman, T.; Verser, D.; Weber, E.

2005-04-29T23:59:59.000Z

205

Electrostatics and radioactive aerosol behavior  

SciTech Connect (OSTI)

Radioactive aerosols differ from their nonradioactive counterparts by their ability to charge themselves by emitting charged particles during the radioactive decay process. Evidence that electrostatics, including this charging process, can affect the transport of the aerosols was summarized previously. Charge distributions and the mean charge for a monodisperse radioactive aerosol have been considered in detail. The principal results of theory to calculate charge distributions on a aerosol with a size distribution, changes to Brownian coagulation rates for an aerosol in a reactor containment, and possible changes to aerosol deposition resulting from the charging will be presented. The main purpose of the work has been to improve calculations of aerosol behavior in reactor containments, but behavior in less ionizing environments will be affected more strongly, and some problems remain to be solved in performing reliable calculations.

Clement, C.F.

1994-12-31T23:59:59.000Z

206

Thermochemical Ethanol via Indirect Gasification and Mixed Alcohol...  

Energy Savers [EERE]

Ethanol via Indirect Gasification and Mixed Alcohol Synthesis of Lignocellulosic Biomass Thermochemical Ethanol via Indirect Gasification and Mixed Alcohol Synthesis of...

207

aerosols and climate : uncertainties  

E-Print Network [OSTI]

contributes to creating a level playing field. (BC emissions tradeble like CO2 emissions?) OUTLINE #12;size. policy measures, is even more uncertain (emissions & their chemical fingerprint are uncertain (not just aerosol emissions, not just climate impacts) OUTLINE #12;- Standardization doesn't reduce

208

A high carrier injection terahertz quantum cascade laser based on indirectly pumped scheme  

E-Print Network [OSTI]

A Terahertz quantum cascade laser with a rather high injection coupling strength based on an indirectly pumped scheme is designed and experimentally implemented. To effectively suppress leakage current, the chosen quantum ...

Razavipour, S. G.

209

MELCOR 1. 8. 1 assessment: LACE aerosol experiment LA4  

SciTech Connect (OSTI)

The MELCOR code has been used to simulate LACE aerosol experiment LA4. In this test, the behavior of single- and double-component, hygroscopic and nonhygroscopic, aerosols in a condensing environment was monitored. Results are compared to experimental data, and to CONTAIN calculations. Sensitivity studies have been done on time step effects and machine dependencies; thermal/hydraulic parameters such as condensation on heat structures and on pool surface, and radiation heat transfer; and aerosol parameters such as number of MAEROS components and sections assumed, the degree to which plated aerosols are washed off heat structures by condensate film draining, and the effect of non-default values for shape factors and diameter limits. 9 refs., 50 figs., 13 tabs.

Kmetyk, L.N.

1991-09-01T23:59:59.000Z

210

Sensitivity of Remote Aerosol Distributions to Representation of Cloud-Aerosol Interactions in a Global Climate Model  

SciTech Connect (OSTI)

Many global aerosol and climate models, including the widely used Community Atmosphere Model version 5 (CAM5), have large biases in predicting aerosols in remote regions such as upper troposphere and high latitudes. In this study, we conduct CAM5 sensitivity simulations to understand the role of key processes associated with aerosol transformation and wet removal affecting the vertical and horizontal long-range transport of aerosols to the remote regions. Improvements are made to processes that are currently not well represented in CAM5, which are guided by surface and aircraft measurements together with results from a multi-scale aerosol-climate model (PNNL-MMF) that explicitly represents convection and aerosol-cloud interactions at cloud-resolving scales. We pay particular attention to black carbon (BC) due to its importance in the Earth system and the availability of measurements. We introduce into CAM5 a new unified scheme for convective transport and aerosol wet removal with explicit aerosol activation above convective cloud base. This new implementation reduces the excessive BC aloft to better simulate observed BC profiles that show decreasing mixing ratios in the mid- to upper-troposphere. After implementing this new unified convective scheme, we examine wet removal of submicron aerosols that occurs primarily through cloud processes. The wet removal depends strongly on the sub-grid scale liquid cloud fraction and the rate of conversion of liquid water to precipitation. These processes lead to very strong wet removal of BC and other aerosols over mid- to high latitudes during winter months. With our improvements, the Arctic BC burden has a10-fold (5-fold) increase in the winter (summer) months, resulting in a much better simulation of the BC seasonal cycle as well. Arctic sulphate and other aerosol species also increase but to a lesser extent. An explicit treatment of BC aging with slower aging assumptions produces an additional 30-fold (5-fold) increase in the Arctic winter (summer) BC burden. This BC aging treatment, however, has minimal effect on other under-predicted species. Interestingly, our modifications to CAM5 that aim at improving prediction of high-latitude and upper tropospheric aerosols also produce much better AOD and AAOD over various other regions globally when compared to multi-year AERONET retrievals. The improved aerosol distributions have impacts on other aspects of CAM5, improving the simulation of global mean liquid water path and cloud forcing.

Wang, Hailong; Easter, Richard C.; Rasch, Philip J.; Wang, Minghuai; Liu, Xiaohong; Ghan, Steven J.; Qian, Yun; Yoon, Jin-Ho; Ma, Po-Lun; Vinoj, V.

2013-06-05T23:59:59.000Z

211

ARM: 10-minute TEMPORARY Raman Lidar: aerosol extinction profiles and aerosol optical thickness, from first Ferrare algorithm  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

10-minute TEMPORARY Raman Lidar: aerosol extinction profiles and aerosol optical thickness, from first Ferrare algorithm

Sivaraman, Chitra; Flynn, Connor

212

Numerical solutions of the aerosol general dynamic equation for nuclear reactor safety studies  

SciTech Connect (OSTI)

Methods and approximations inherent in modeling of aerosol dynamics and evolution for nuclear reactor source term estimation have been investigated. Several aerosol evolution problems are considered to assess numerical methods of solving the aerosol dynamic equation. A new condensational growth model is constructed by generalizing Mason's formula to arbitrary particle sizes, and arbitrary accommodation of the condensing vapor and background gas at particle surface. Analytical solution is developed for the aerosol growth equation employing the new condensation model. The space-dependent aerosol dynamic equation is solved to assess implications of spatial homogenization of aerosol distributions. The results of our findings are as follows. The sectional method solving the aerosol dynamic equation is quite efficient in modeling of coagulation problems, but should be improved for simulation of strong condensation problems. The J-space transform method is accurate in modeling of condensation problems, but is very slow. For the situation considered, the new condensation model predicts slower aerosol growth than the corresponding isothermal model as well as Mason's model, the effect of partial accommodation is considerable on the particle evolution, and the effect of the energy accommodation coefficient is more pronounced than that of the mass accommodation coefficient. For the initial conditions considered, the space-dependent aerosol dynamics leads to results that are substantially different from those based on the spatially homogeneous aerosol dynamic equation.

Park, J.W.

1988-01-01T23:59:59.000Z

213

Aerodynamic size associations of natural radioactivity with ambient aerosols  

SciTech Connect (OSTI)

The aerodynamic size of /sup 214/Pb, /sup 212/Pb, /sup 210/Pb, /sup 7/Be, /sup 32/P, /sup 35/S (as SO/sub 4//sup 2 -/), and stable SO/sub 4//sup 2 -/ was measured using cascade impactors. The activity distribution of /sup 212/Pb and /sup 214/Pb, measured by alpha spectroscopy, was largely associated with aerosols smaller than 0.52 ..mu..m. Based on 46 measurements, the activity median aerodynamic diameter of /sup 212/Pb averaged 0.13 ..mu..m (sigma/sub g/ = 2.97), while /sup 214/Pb averaged 0.16 ..mu..m (sigma/sub g/ = 2.86). The larger median size of /sup 214/Pb was attributed to ..cap alpha..-recoil depletion of smaller aerosols following decay of aerosol-associated /sup 218/Po. Subsequent /sup 214/Pb condensation on all aerosols effectively enriches larger aerosols. /sup 212/Pb does not undergo this recoil-driven redistribution. Low-pressure impactor measurements indicated that the mass median aerodynamic diameter of SO/sub 4//sup 2 -/ was about three times larger than the activity median diameter /sup 212/Pb, reflecting differences in atmospheric residence times as well as the differences in surface area and volume distributions of the atmospheric aerosol. Cosmogenic radionuclides, especially /sup 7/Be, were associated with smaller aerosols than SO/sub 4//sup 2 -/ regardless of season, while /sup 210/Pb distributions in summer measurements were similar to sulfate but smaller in winter measurements. Even considering recoil following /sup 214/Po ..cap alpha..-decay, the avervage /sup 210/Pb labeled aerosol grows by about a factor of two during its atmospheric lifetime. The presence of 5 to 10% of the /sup 7/Be on aerosols greater than 1 ..mu..m was indicative of post-condensation growth, probably either in the upper atmosphere or after mixing into the boundary layer.

Bondietti, E.A.; Papastefanou, C.; Rangarajan, C.

1986-04-01T23:59:59.000Z

214

Experimental study of nuclear workplace aerosol samplers  

E-Print Network [OSTI]

LITERATURE REVIEW Aerosol Losses in an Inlet . Aerosol Losses in a Transport System Aerosol Losses in CAMs Critical Flow Venturi 8 13 15 16 EXPERIMENT PROCEDURE 18 CAM Evaluation Consideration FAS Evaluation Consideration Test Protocol Mixing... Chamber Setup High Speed Aerosol Wind Tunnel Setup Low Speed Aerosol Wind Tunnel Setup Critical Flow Venturi 18 19 21 22 24 25 27 RESULTS AND DISCUSSION Page 28 Aerosol Penetration through Transport Systems and CAM Areal Uniformity Deposits...

Parulian, Antony

2012-06-07T23:59:59.000Z

215

Molecular Characterization of Biomass Burning Aerosols Using...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Biomass Burning Aerosols Using High Resolution Mass Spectrometry. Molecular Characterization of Biomass Burning Aerosols Using High Resolution Mass Spectrometry. Abstract: Chemical...

216

Synthetic fuel production by indirect coal liquefaction  

E-Print Network [OSTI]

Synthetic fuel production by indirect coal liquefaction Eric D. Larson Princeton Environmental@princeton.edu Ren Tingjin Department of Thermal Engineering, Tsinghua University, 100084 Beijing, China This paper reports detailed process designs and cost assessments for production of clean liquid fuels (methanol

217

Global observations and spectral characteristics of desert dust and biomass burning aerosols  

E-Print Network [OSTI]

quantity, but a radiation difference in the UV. Its main advantages are its insensitivity to scattering in climate physics today is the effect of aerosols on the global energy budget. The amount and sign of the effect of aerosols on the incoming solar radiation are unknown and produce a large uncertainty

Graaf, Martin de

218

ARM - Measurement - Aerosol effective radius  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc Documentation RUC : XDCResearch Related InformationAcid RainThe Pacificabsorptioneffective

219

Will black carbon mitigation dampen aerosol indirect forcing?1 W.-T. Chen1  

E-Print Network [OSTI]

.J. Adams3 , A. Nenes4 , and J.H. Seinfeld5,* 2 1 Jet Propulsion Laboratory, Pasadena, CA, USA3 2 Department carbonaceous sources (fossil fuel, domestic biofuel, and20 biomass burning) (termed HC). Radiative forcing

Nenes, Athanasios

220

ARM - Field Campaign - Indirect and Semi-Direct Aerosol Campaign (ISDAC)  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLasDelivered¬ČPNGExperience4AJ01)3,CloudgovCampaignsIR Cloud Camera Feasibility

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

6, 75197562, 2006 Simulating aerosol  

E-Print Network [OSTI]

, particle number concentration and aerosol size-distribution. The model takes into account sulfate (SO4. This model system enables explicit simulations of the particle number concentration and size-distribution of aerosol dynamical processes (nucleation, condensation, coagulation) is evaluated by comparison

Paris-Sud XI, Université de

222

Aerosol Retrievals from ARM SGP MFRSR Data  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

The Multi-Filter Rotating Shadowband Radiometer (MFRSR) makes precise simultaneous measurements of the solar direct normal and diffuse horizontal irradiances at six wavelengths (nominally 415, 500, 615, 673, 870, and 940 nm) at short intervals (20 sec for ARM instruments) throughout the day. Time series of spectral optical depth are derived from these measurements. Besides water vapor at 940 nm, the other gaseous absorbers within the MFRSR channels are NO2 (at 415, 500, and 615 nm) and ozone (at 500, 615, and 670 nm). Aerosols and Rayleigh scattering contribute atmospheric extinction in all MFRSR channels. Our recently updated MFRSR data analysis algorithm allows us to partition the spectral aerosol optical depth into fine and coarse modes and to retrieve the fine mode effective radius. In this approach we rely on climatological amounts of NO2 from SCIAMACHY satellite retrievals and use daily ozone columns from TOMS.

Alexandrov, Mikhail

223

The modeling of aerosol dynamics during degraded core events  

SciTech Connect (OSTI)

There is substantial interest in developing simple, yet accurate, models for the prediction of aerosol dynamics during degraded core events. The exact aerosol transport equation is given by {partial derivative}n(v,t)/{partial derivative}t = 1/2 {integral}{sub 0}{sup {infinity}} K(u,v {minus} u)n(u,t)n(v {minus} u,t)du {minus} {integral}{sub 0}{sup {infinity}} K(u,v)n(v,t)n(u,t)du {minus} n(v,t)c(v)/h + n{sub p}(v), where n(v,t) is the particle size density distribution function. The kernel, K(v,u), is related to the frequency of coagulation between aerosol particles of volume u and v, and the quantity c(v) is the deposition velocity. The quantity h is the effective height for deposition of aerosol; it is the volume of the aerosol cloud divided by the projected horizontal area A. Finally, the term n{sub p} (v) is the source rate of aerosol. Evaluation of the above equation is discussed.

Clausse, A.; Lahey, R.T. Jr.

1989-01-01T23:59:59.000Z

224

The Nearby Supernova Factory Ozone + Aerosol + Rayleigh  

E-Print Network [OSTI]

Rayleigh + Aerosol Extinction monitor filter Auxiliary Camera CCD Spectrograph picko ff mirror Umbra

225

Association of asthma symptoms with peak particulate air pollution and effect modification by anti-inflammatory medication use.  

E-Print Network [OSTI]

respirable aerosol. Health Effects Institute Research Report38. Cambridge, MA:Health Effects Institute, 1990. Spektor

Delfino, Ralph J; Zeiger, Robert S; Seltzer, James M; Street, Donald H; McLaren, Christine E

2002-01-01T23:59:59.000Z

226

aerosol particles collected: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Saller 2002-05-07 6 Nanomaterials from Aerosols Aerosols are suspensions of liquid or solid particles in a gas. Aerosol particles Materials Science Websites Summary: being clouds...

227

Mexico City Aerosol Analysis during MILAGRO using High Resolution...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

2: Mexico City Aerosol Analysis during MILAGRO using High Resolution Aerosol Mass Spectrometry at the Urban Supersite (T0). Part 2: Abstract: Submicron aerosol was analyzed during...

228

Mexico City Aerosol Analysis during MILAGRO using High Resolution...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

1: Mexico City Aerosol Analysis during MILAGRO using High Resolution Aerosol Mass Spectrometry at the Urban Supersite (T0). Part 1: Abstract: Submicron aerosol was analyzed during...

229

Indirect Benefits (Increased Roof Life and HVAC Savings) from...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Indirect Benefits (Increased Roof Life and HVAC Savings) from a Solar PV System at the San Jos Convention Center Indirect Benefits (Increased Roof Life and HVAC Savings) from a...

230

GOME-2 ABSORBING AEROSOL INDEX: STATISTICAL ANALYSIS, COMPARISON TO GOME-1 AND IMPACT OF INSTRUMENT  

E-Print Network [OSTI]

DEGRADATION Lieuwe G. Tilstra, Olaf N.E. Tuinder, and Piet Stammes Royal Netherlands Meteorological Institute the presence of UV-absorbing aerosols. These aerosols are mainly injected into the atmosphere by desert dust that the GOME-2 AAI product is suffering more and more from the effects of instrument degradation. In particular

Tilstra, Gijsbert

231

1 Potential impacts of Asian carbon aerosols on future US warming 2 Haiyan Teng,1  

E-Print Network [OSTI]

-ocean fully coupled 6 climate model to investigate possible remote impacts of 7 Asian carbonaceous aerosols effect of aerosols is included) over Asia induces 15 tropospheric heating anomalies that force large.4 C warming over the eastern 18 US during winter and over most of the US during summer. 19 Such remote

232

AERONET: The Aerosol Robotic Network  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

AERONET collaboration provides globally distributed observations of spectral aerosol optical Depth (AOD), inversion products, and precipitable water in diverse aerosol regimes. Aerosol optical depth data are computed for three data quality levels: Level 1.0 (unscreened), Level 1.5 (cloud-screened), and Level 2.0 (cloud screened and quality-assured). Inversions, precipitable water, and other AOD-dependent products are derived from these levels and may implement additional quality checks.[Copied from http://aeronet.gsfc.nasa.gov/new_web/system_descriptions.html

233

REQUEST FOR INDIRECT COST WAIVER I. Project Director  

E-Print Network [OSTI]

REQUEST FOR INDIRECT COST WAIVER I. Project Director: Department: Project Title: Project Sponsor without fully recovering the institutional indirect costs which will be incurred in conducting the project COSTS 1. FULL: OF I. A. C. 2. PARTIAL: OF H. B. K. TOTAL PROJECT COSTS L. INDIRECT COSTS TO BE WAIVED, J

Krovi, Venkat

234

SAGE II long-term measurements of stratospheric and upper tropospheric aerosols  

SciTech Connect (OSTI)

The Stratospheric Aerosol and Gas Experiment (SAGE) II solar occultation instrument has been making measurements on stratospheric aerosols and gases continually since October 1984. Observations from the SAGE II instrument provide a valuable long-term data set for study of the aerosol in the stratosphere and aerosol and cloud in the upper troposphere. The period of observation covers the decay phase of material injected by the El Chichon volcanic eruption in 1982, the years 1988--1990 when stratospheric aerosol levels approached background levels, and the period after the eruption of Mount Pinatubo in 1991. The Mount Pinatubo eruption caused the largest perturbation in stratospheric aerosol loading in this century, with effects on stratospheric dynamics and chemistry. The SAGE II data sequence shows the global dispersion of aerosols following the Mount Pinatubo eruption, as well as the changes occurring in stratospheric aerosol mass and surface area. The downward transfer of stratospheric aerosols into the upper troposphere following the earlier eruption of El Chichon is clearly visible. Estimates have been made of the amount of volcanic material lying in the upper troposphere and the way in which this varies with latitude and season.

Wang, P.H.; Kent, G.S. [Science and Technology Corp., Hampton, VA (United States); McCormick, M.P.; Thomason, L.W. [NASA Langley Research Center, Hampton, VA (United States). Atmospheric Sciences Div.

1995-12-31T23:59:59.000Z

235

Biomass Indirect Liquefaction Workshop | Department of Energy  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-Up fromDepartmentTie Ltd: ScopeDepartment1, 2011 (BETO)and Fuel09 THISDepartmentIndirect

236

8, 68456901, 2008 Aerosol optical  

E-Print Network [OSTI]

of solar radiation by atmospheric aerosols is a key el- ement of the Earth's radiative energy balance, Germany 2 Helmholtz Center Munich, German Research Center for Environmental Health, Institute

Paris-Sud XI, Université de

237

Composition and Reactions of Atmospheric Aerosol Particles  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Source type and mechanism information for the four aerosol samples gathered from the Caribbean, the Sea of Japan, and New Jersey. One way to gauge an aerosol's ability to stay...

238

Electron mean free path from angle-dependent photoelectron spectroscopy of aerosol particles  

E-Print Network [OSTI]

We propose angle-resolved photoelectron spectroscopy of aerosol particles as an alternative way to determine the electron mean free path of low energy electrons in solid and liquid materials. The mean free path is obtained from fits of simulated photoemission images to experimental ones over a broad range of different aerosol particle sizes. The principal advantage of the aerosol approach is twofold. Firstly, aerosol photoemission studies can be performed for many different materials, including liquids. Secondly, the size-dependent anisotropy of the photoelectrons can be exploited in addition to size-dependent changes in their kinetic energy. These finite size effects depend in different ways on the mean free path and thus provide more information on the mean free path than corresponding liquid jet, thin film, or bulk data. The present contribution is a proof of principle employing a simple model for the photoemission of electrons and preliminary experimental data for potassium chloride aerosol particles.

Goldmann, Maximilian; West, Adam H C; Yoder, Bruce L; Signorell, Ruth

2015-01-01T23:59:59.000Z

239

REPRESENTING AEROSOL DYNAMICS AND PROPERTIES IN CHEMICAL TRANSPORT MODELS BY THE METHOD OF MOMENTS.  

SciTech Connect (OSTI)

Atmospheric aerosols, suspensions of solid or liquid particles, are an important multi-phase system. Aerosols scatter and absorb shortwave (solar) radiation, affecting climate (Charlson et al., 1992; Schwartz, 1996) and visibility; nucleate cloud droplet formation, modifying the reflectivity of clouds (Twomey et al., 1984; Schwartz and Slingo, 1996) as well as contributing to composition of cloudwater and to wet deposition (Seinfeld and Pandis, 1998); and affect human health through inhalation (NRC, 1998). Existing and prospective air quality regulations impose standards on concentrations of atmospheric aerosols to protect human health and welfare (EPA, 1998). Chemical transport and transformation models representing the loading and geographical distribution of aerosols and precursor gases are needed to permit development of effective and efficient strategies for meeting air quality standards, and for examining aerosol effects on climate retrospectively and prospectively for different emissions scenarios. Important aerosol properties and processes depend on their size distribution: light scattering, cloud nucleating properties, dry deposition, and penetration into airways of lungs. The evolution of the mass loading itself depends on particle size because of the size dependence of growth and removal processes. For these reasons it is increasingly recognized that chemical transport and transformation models must represent not just the mass loading of atmospheric particulate matter but also the aerosol microphysical properties and the evolution of these properties if aerosols are to be accurately represented in these models. If the size distribution of the aerosol is known, a given property can be evaluated as the integral of the appropriate kernel function over the size distribution. This has motivated the approach of determining aerosol size distribution, and of explicitly representing this distribution and its evolution in chemical transport models.

SCHWARTZ,S.E.; MCGRAW,R.; BENKOVITZ,C.M.; WRIGHT,D.L.

2001-04-01T23:59:59.000Z

240

A simplified model of aerosol removal by natural processes in reactor containments  

SciTech Connect (OSTI)

Simplified formulae are developed for estimating the aerosol decontamination that can be achieved by natural processes in the containments of pressurized water reactors and in the drywells of boiling water reactors under severe accident conditions. These simplified formulae were derived by correlation of results of Monte Carlo uncertainty analyses of detailed models of aerosol behavior under accident conditions. Monte Carlo uncertainty analyses of decontamination by natural aerosol processes are reported for 1,000, 2,000, 3,000, and 4,000 MW(th) pressurized water reactors and for 1,500, 2,500, and 3,500 MW(th) boiling water reactors. Uncertainty distributions for the decontamination factors and decontamination coefficients as functions of time were developed in the Monte Carlo analyses by considering uncertainties in aerosol processes, material properties, reactor geometry and severe accident progression. Phenomenological uncertainties examined in this work included uncertainties in aerosol coagulation by gravitational collision, Brownian diffusion, turbulent diffusion and turbulent inertia. Uncertainties in aerosol deposition by gravitational settling, thermophoresis, diffusiophoresis, and turbulent diffusion were examined. Electrostatic charging of aerosol particles in severe accidents is discussed. Such charging could affect both the coagulation and deposition of aerosol particles. Electrostatic effects are not considered in most available models of aerosol behavior during severe accidents and cause uncertainties in predicted natural decontamination processes that could not be taken in to account in this work. Median (50%), 90 and 10% values of the uncertainty distributions for effective decontamination coefficients were correlated with time and reactor thermal power. These correlations constitute a simplified model that can be used to estimate the decontamination by natural aerosol processes at 3 levels of conservatism. Applications of the model are described.

Powers, D.A.; Washington, K.E.; Sprung, J.L. [Sandia National Labs., Albuquerque, NM (United States); Burson, S.B. [Nuclear Regulatory Commission, Washington, DC (United States)

1996-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

6, 93519388, 2006 Aerosol-cloud  

E-Print Network [OSTI]

ACPD 6, 9351­9388, 2006 Aerosol-cloud interaction inferred from MODIS and models G. Myhre et al Chemistry and Physics Discussions Aerosol-cloud interaction inferred from MODIS satellite data and global 6, 9351­9388, 2006 Aerosol-cloud interaction inferred from MODIS and models G. Myhre et al. Title

Paris-Sud XI, Université de

242

Corrosion aspects in indirect systems with secondary refrigerants.  

E-Print Network [OSTI]

?? Aqueous solutions of organic or inorganic salts are used as secondary refrigerants in indirect refrigeration systems to transport and transfer heat. Water is knownÖ (more)

Ignatowicz, Monika

2008-01-01T23:59:59.000Z

243

Massively Parallel Indirect Dielectrophoresis Controlled Placement of Carbon Nanotubes.  

E-Print Network [OSTI]

??Placement of single walled carbon nanotubes is demonstrated through massively parallel indirect dielectrophoresis (MPID). MPID is shown to be able to control the placement ofÖ (more)

Conley, Hiram Jacob

2009-01-01T23:59:59.000Z

244

Aerosol collection characteristics of ambient aerosol samplers  

E-Print Network [OSTI]

the error for aniso- kinet1c sampl1ng with the smaller errors being associated w1th the larger orifices. For a higher accuracy in field sampling Watson suggested sampling with high volumetric rates and large sampling orifices to approximate isokinet1c..., was used to sample with a standard knife-edged orifice under isokinet1c conditions. May noted that the modified Casella cascade impactor was highly effective with sizes as small as about 1 um. Another excellent device for sampling down to 10 um...

Ortiz, Carlos A

2012-06-07T23:59:59.000Z

245

Direct and Indirect Impacts of Weed Management Practices on Soil Quality  

E-Print Network [OSTI]

: although effective weed management and enhancement of soil quality are necessary components of sustainable275 18 Direct and Indirect Impacts of Weed Management Practices on Soil Quality Richard G. Smith, crop yield, and agricultural sustainability (Kar- len et al., 2001), the impact that weed management

Maxwell, Bruce D.

246

Effect of Aerosol Humidification on the Column Aerosol Optical Thickness  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed NewcatalystNeutronEnvironmentZIRKLE FRUITYear 1

247

Effect of Hydrophobic Primary Organic Aerosols on Secondary Organic Aerosol  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed NewcatalystNeutronEnvironmentZIRKLE FRUITYear

248

Aerosol-to-Hydrosol Transfer Stages for use in bioaerosol sampling  

E-Print Network [OSTI]

(-10įF) outside air temperature. The AHTSs were tested using polystyrene solid and oleic acid liquid aerosol particles to determine the collection efficiencies. The effectiveness of the fractional collection efficiency for the Single-Jet and Multi...

Phan, Huy Ngoc

2002-01-01T23:59:59.000Z

249

Particle size distribution of indoor aerosol sources  

SciTech Connect (OSTI)

As concern about Indoor Air Quality (IAQ) has grown in recent years, it has become necessary to determine the nature of particles produced by different indoor aerosol sources and the typical concentration that these sources tend to produce. These data are important in predicting the dose of particles to people exposed to these sources and it will also enable us to take effective mitigation procedures. Further, it will also help in designing appropriate air cleaners. A new state of the art technique, DMPS (Differential Mobility Particle Sizer) System is used to determine the particle size distributions of a number of sources. This system employs the electrical mobility characteristics of these particles and is very effective in the 0.01--1.0 {mu}m size range. A modified system that can measure particle sizes in the lower size range down to 3 nm was also used. Experimental results for various aerosol sources is presented in the ensuing chapters. 37 refs., 20 figs., 2 tabs.

Shah, K.B.

1990-10-24T23:59:59.000Z

250

The ECA indirectly heated Stirling engine  

SciTech Connect (OSTI)

At the beginning of the 1980s the ECA Company designed and manufactured the first French Stirling engine, partially funded by the French government. The ECA engine has several design features of special interest: indirect heating by sodium heat pipes, cylinder block with four double-acting cylinders in line with a single crankshaft, four identical and demountable heat exchanger modules, piston rod seals with recuperation of leakage losses by means of four integrated rod pumps and with hermetic gas and oil seals using four roll socks, and power control by means of three gas valves and a 3.5-MPa helium bottle. The ECA engine ran for the first time and at the first attempt at the end of June 1982 and rapidly delivered a power of 5 kW at reduced pressure. Further testing of this 4-by 113-cm3 engine is under way to obtain a nominal power of 12 kW and an efficiency of 36% (heat to shaft power) with a very simplified design.

Carlqvist, S.G.; Darche, M.; Ducroux, P.

1983-08-01T23:59:59.000Z

251

Optical, physical, and chemical properties of springtime aerosol over Barrow Alaska in 2008  

SciTech Connect (OSTI)

Airborne observations from four flights during the 2008 Indirect and Semi-Direct Aerosol Campaign (ISDAC) are used to examine some cloud-free optical, physical, and chemical properties of aerosol particles in the springtime Arctic troposphere. The number concentrations of particles larger than 0.12 ?m (Na>120), important for light extinction and cloud droplet formation, ranged from 15 to 2260 cm?3, with the higher Na>120 cases dominated by measurements from two flights of long-range transported biomass burning (BB) aerosols. The two other flights examined here document a relatively clean aerosol and an Arctic Haze aerosol impacted by larger particles largely composed of dust. For observations from the cleaner case and the BB cases, the particle light scattering coefficients at low relative humidity (RH<20%) increased nonlinearly with increasing Na>120, driven mostly by an increase in mean sizes of particles with increasing Na>120 (BB cases). For those three cases, particle light absorption coefficients also increased nonlinearly with increasing Na>120 and linearly with increasing submicron particle volume concentration. In addition to black carbon, brown carbon was estimated to have increased light absorption coefficients by 27% (450 nm wavelength) and 14% (550 nm) in the BB cases. For the case with strong dust influence, the absorption relative to submicron particle volume was small compared with the other cases. There was a slight gradient of Passive Cavity Aerosol Spectrometer Probe (PCASP) mean volume diameter (MVD) towards smaller sizes with increasing height, which suggests more scavenging of the more elevated particles, consistent with a typically longer lifetime of particles higher in the atmosphere. However, in approximately 10% of the cases, the MVD increased (>0.4 ?m) with increasing altitude, suggesting transport of larger fine particle mass (possibly coarse particle mass) at high levels over the Arctic. This may be because of transport of larger particles at higher elevations and relatively slow deposition to the surface.

Shantz, Nicole C.; Gultepe, Ismail; Andrews, Elisabeth; Zelenyuk, Alla; Earle, Michael; MacDonald, A. M.; Liu, Peter S.; Leaitch, W. R.

2014-03-06T23:59:59.000Z

252

Review of models applicable to accident aerosols  

SciTech Connect (OSTI)

Estimations of potential airborne-particle releases are essential in safety assessments of nuclear-fuel facilities. This report is a review of aerosol behavior models that have potential applications for predicting aerosol characteristics in compartments containing accident-generated aerosol sources. Such characterization of the accident-generated aerosols is a necessary step toward estimating their eventual release in any accident scenario. Existing aerosol models can predict the size distribution, concentration, and composition of aerosols as they are acted on by ventilation, diffusion, gravity, coagulation, and other phenomena. Models developed in the fields of fluid mechanics, indoor air pollution, and nuclear-reactor accidents are reviewed with this nuclear fuel facility application in mind. The various capabilities of modeling aerosol behavior are tabulated and discussed, and recommendations are made for applying the models to problems of differing complexity.

Glissmeyer, J.A.

1983-07-01T23:59:59.000Z

253

INDIRECT COSTS OF RESEARCH University Policy No: FM5400  

E-Print Network [OSTI]

recoveries towards the indirect costs associated with externally funded Research conducted at the University Research Funding Agreements supported by external funds; to all University Members as defined Funding Agreements). Distribution 10.00 The Indirect Costs recovered by the university from Research

Victoria, University of

254

Indirect Search for Dark Matter with the ANTARES Neutrino Telescope  

E-Print Network [OSTI]

significant high energy neutrino fluxes. Indirect search for Dark Matter looking at such neutrino fluxes for the Cherenkov light induced by high energy muons during their travel in the sea water throughout the detectorIndirect Search for Dark Matter with the ANTARES Neutrino Telescope V. Bertin1 on behalf

Paris-Sud XI, Université de

255

Stratospheric Aerosol Geoengineering ALAN ROBOCK  

E-Print Network [OSTI]

Stratospheric Aerosol Geoengineering ALAN ROBOCK ABSTRACT In response to global warming, one suggested geoengineering response involves creating a cloud of particles in the stratosphere to reflect some, the volcano analog also warns against geoengineering because of responses such as ozone depletion, regional

Robock, Alan

256

Aerosol tests conducted at Aberdeen Proving Grounds MD.  

SciTech Connect (OSTI)

Test data are reported that demonstrate the deposition from a spray dispersion system (Illinois Tool Works inductively charging rotary atomization nozzle) for application of decontamination solution to various surfaces in the passenger cabin of a Boeing 737 aircraft. The decontamination solution (EnviroTru) was tagged with a known concentration of fluorescein permitting determination of both airborne decontaminant concentration and surface deposited decontaminant solution so that the effective deposition rates and surface coverage could be determined and correlated with the amount of material sprayed. Six aerosol dispersion tests were conducted. In each test, aluminum foil deposition coupons were set out throughout the passenger area and the aerosol was dispersed. The aerosol concentration was measured with filter samplers as well as with optical techniques Average aerosol deposition ranged from 3 to 15 grams of decontamination solution per square meter. Some disagreement was observed between various instruments utilizing different measurement principles. These results demonstrate a potentially effective method to disperse decontaminant to interior surfaces of a passenger aircraft.

Brockmann, John E.; Lucero, Daniel A.; Servantes, Brandon Lee; Hankins, Matthew Granholm

2012-06-01T23:59:59.000Z

257

Collection of Aerosol Particles by a Conducting Sphere in an External Electric Field-Continuum Regime Approximation  

E-Print Network [OSTI]

caseswhere some effects are absent. INTRODUCTION The collision and coagulation process of aerosol particles to a consid- erable extent the size distribution and thus the reaction rate of the reactants. In this paper weCollection of Aerosol Particles by a Conducting Sphere in an External Electric Field

Wang, Pao K.

258

CARES Helps Explain Secondary Organic Aerosols  

SciTech Connect (OSTI)

What happens when urban man-made pollution mixes with what we think of as pristine forest air? To know more about what this interaction means for the climate, the Carbonaceous Aerosol and Radiative Effects Study, or CARES, field campaign was designed in 2010. The sampling strategy during CARES was coordinated with CalNex 2010, another major field campaign that was planned in California in 2010 by the California Air Resources Board (CARB), the National Oceanic and Atmospheric Administration (NOAA), and the California Energy Commission (CEC). "We found two things. When urban pollution mixes with forest pollutions we get more secondary organic aerosols," said Rahul Zaveri, FCSD scientist and project lead on CARES. "SOAs are thought to be formed primarily from forest emissions but only when they interact with urban emissions. The data is saying that there will be climate cooling over the central California valley because of these interactions." Knowledge gained from detailed analyses of data gathered during the CARES campaign, together with laboratory experiments, is being used to improve existing climate models.

Zaveri, Rahul

2014-03-28T23:59:59.000Z

259

CARES Helps Explain Secondary Organic Aerosols  

ScienceCinema (OSTI)

What happens when urban man-made pollution mixes with what we think of as pristine forest air? To know more about what this interaction means for the climate, the Carbonaceous Aerosol and Radiative Effects Study, or CARES, field campaign was designed in 2010. The sampling strategy during CARES was coordinated with CalNex 2010, another major field campaign that was planned in California in 2010 by the California Air Resources Board (CARB), the National Oceanic and Atmospheric Administration (NOAA), and the California Energy Commission (CEC). "We found two things. When urban pollution mixes with forest pollutions we get more secondary organic aerosols," said Rahul Zaveri, FCSD scientist and project lead on CARES. "SOAs are thought to be formed primarily from forest emissions but only when they interact with urban emissions. The data is saying that there will be climate cooling over the central California valley because of these interactions." Knowledge gained from detailed analyses of data gathered during the CARES campaign, together with laboratory experiments, is being used to improve existing climate models.

Zaveri, Rahul

2014-06-02T23:59:59.000Z

260

Asthmatic responses to airborne acid aerosols  

SciTech Connect (OSTI)

Controlled exposure studies suggest that asthmatics may be more sensitive to the respiratory effects of acidic aerosols than individuals without asthma. This study investigates whether acidic aerosols and other air pollutants are associated with respiratory symptoms in free-living asthmatics. Daily concentrations of hydrogen ion (H+), nitric acid, fine particulates, sulfates and nitrates were obtained during an intensive air monitoring effort in Denver, Colorado, in the winter of 1987-88. A panel of 207 asthmatics recorded respiratory symptoms, frequency of medication use, and related information in daily diaries. We used a multiple regression time-series model to analyze which air pollutants, if any, were associated with health outcomes reported by study participants. Airborne H+ was found to be significantly associated with several indicators of asthma status, including moderate or severe cough and shortness of breath. Cough was also associated with fine particulates, and shortness of breath with sulfates. Incorporating the participants' time spent outside and exercise intensity into the daily measure of exposure strengthened the association between these pollutants and asthmatic symptoms. Nitric acid and nitrates were not significantly associated with any respiratory symptom analyzed. In this population of asthmatics, several outdoor air pollutants, particularly airborne acidity, were associated with daily respiratory symptoms.

Ostro, B.D.; Lipsett, M.J.; Wiener, M.B.; Selner, J.C. (California Department of Health Services, Berkeley (USA))

1991-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

DO AEROSOLS CHANGE CLOUD COVER AND AFFECT CLIMATE?  

E-Print Network [OSTI]

BALANCE Global and annual average energy fluxes in watts per square meter Schwartz, 1996, modified from;AEROSOL INFLUENCES ON CLIMATE AND CLIMATE CHANGE #12;DMS #12;AEROSOL IN MEXICO CITY BASIN #12;AEROSOL IN MEXICO CITY BASIN Light scattering by aerosols decreases absorption of solar radiation. #12;AEROSOLS

Schwartz, Stephen E.

262

Alveolar targeting of aerosol pentamidine. Toward a rational delivery system  

SciTech Connect (OSTI)

Nebulizer systems that deposit a high proportion of aerosolized pentamidine on large airways are likely to be associated with marked adverse side effects, which may lead to premature cessation of treatment. We have measured alveolar deposition and large airway-related side effects (e.g., cough, breathlessness, and effect on pulmonary function) after aerosolization of 150 mg pentamidine isethionate labeled with {sup 99m}Tc-Sn-colloid. Nine patients with AIDS were studied using three nebulizer systems producing different droplet size profiles: the Acorn System 22, Respirgard II, and Respirgard II with the inspiratory baffle removed. Alveolar deposition was greatest and side effects least with the nebulizer producing the smallest droplet size profile (Respirgard II), whereas large airway-related side effects were prominent and alveolar deposition lowest with the nebulizer producing the largest droplet size (Acorn System 22). Values for alveolar deposition and adverse airway effects were intermediate using the Respirgard with inspiratory baffle removed, thus indicating the importance of the baffle valve in determining droplet size. Addition of a similar baffle valve to the Acorn System 22 produced a marked improvement in droplet size profile. Selection of a nebulizer that produces an optimal droplet size range offers the advantage of enhancing alveolar targeting of aerosolized pentamidine while reducing large airway-related side effects.

Simonds, A.K.; Newman, S.P.; Johnson, M.A.; Talaee, N.; Lee, C.A.; Clarke, S.W. (Royal Free Hospital, London (England))

1990-04-01T23:59:59.000Z

263

X-ray Vision for Aerosol Scientists: LCLS Snapshots of Soot (Narrated)  

ScienceCinema (OSTI)

This short conceptual animation depicts how scientists can now simultaneously capture fractal morphology (structure), chemical composition and nanoscale imagery of individual aerosol particles in flight. These particles, known as "PM2.5" because they are smaller than 2.5 microns in diameter, affect climate by interacting with sunlight and impact human health by entering the lungs. The single LCLS laser pulses travel to the Atomic, Molecular and Optical Sciences (AMO) laboratory in the Near Experimental Hall. As we zoom in, we see deep inside a simplified aerosol inlet, where the complex fractal structure of the soot particles, each one completely unique, is shown. Individual soot particles are then delivered into the pulses of the LCLS beam, which destroys them. X-rays are scattered to the detector before the particle is destroyed, giving information about the morphology of the particle. Ion fragments released in the explosion are sent into a mass spectrometer, which measures their mass-to-charge ratio -- giving scientists information about the chemical composition of the particle. Many different particles are analyzed in this manner, allowing scientists to probe variations in the particles due to changes in their environment before being sent through the aerosol inlet. The final visual of aerosols emitted from a factory is representative of the goal that such LCLS aerosol dynamics experiments can provide critical feedback into modeling and understanding combustion, aerosol processes in manufacturing or aerosol effects on climate change.

None

2014-06-03T23:59:59.000Z

264

Remote sensing of terrestrial tropospheric aerosols from aircraft and satellites  

E-Print Network [OSTI]

Remote sensing of terrestrial tropospheric aerosols from aircraft and satellites M I Mishchenko1 instruments suitable for aerosol remote sensing and give examples of aerosol retrievals obtained forcing directly by absorbing and reflecting sunlight, thereby cooling or heating the atmosphere

265

Optimization of aerosol penetration through transport lines  

E-Print Network [OSTI]

will be minimum and -' he penetration of aerosols through the transport system will be maximal. It is the purpose of the study reported herein to experimentally investigate the optimization of aerosol penetration through transport systems and to obtain a... numbers less than 869, bounded the use of this model to Reynolds numbers less than or equal to 1100. 19 IV. SUNNARY OF WORK AND EXPERINENTAL NETHODOLOGY The purpose of the study reported herein was to further analyze the optimization of aerosol...

Wong Luque, Fermin Samuel

1992-01-01T23:59:59.000Z

266

Direct/Indirect Costs - DOE Directives, Delegations, and Requirements  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

(CCMD) and describes various estimating techniques for direct and indirect costs. g4301-1chp7.pdf -- PDF Document, 41 KB Writer: John Makepeace Subjects: ID: DOE G 430.1-1 Chp 7...

267

A model simulation of Pinatubo volcanic aerosols in the stratosphere  

SciTech Connect (OSTI)

A one-dimensional, time-dependent model is used to study the chemical, microphysical, and radiative properties of volcanic aerosols produced by the Mount Pinatubo eruption on June 15, 1991. The authors` model treats gas-phase sulfur photochemistry, gas-to-particle conversion of sulfur, and the microphysics of sulfate aerosols and ash particles under stratospheric conditions. The dilution and diffusion of the volcanic eruption clouds are also accounted for in these conditions. Heteromolecular homogeneous and heterogeneous binary H{sub 2}SO{sub 4}/H{sub 2}O nucleation, acid and water condensational growth, coagulation, and gravitational sedimentation are treated in detail in the model. Simulations suggested that after several weeks, the volcanic cloud was composed mainly of sulfuric acid/water droplets produced in situ from the SO{sub 2} emissions. The large amounts of SO{sub 2} (around 20 Mt) injected into the stratosphere by the Pinatubo eruption initiated homogeneous nucleation which generated a high concentration of small H{sub 2}SO{sub 4}/H{sub 2}O droplets. These newly formed particles grew rapidly by condensation and coagulation in the first few months and then reached their stabilized sizes with effective radii in a range between 0.3 and 0.5 {mu}m approximately one-half year after the eruption. The predicted volcanic cloud parameters reasonably agree with measurements in term of the vertical distribution and lifetime of the volcanic aerosols, their basic microphysical structures (e.g., size distribution, concentration, mass ratio, and surface area) and radiative properties. The persistent volcanic aerosols can produce significant anomalies in the radiation field, which have important climatic consequences. The large enhancement in aerosol surface area can result in measurable global stratospheric ozone depletion. 57 refs., 15 figs., 1 tab.

Zhao, J. [Univ. of Hawaii, Honolulu, HI (United States)] [Univ. of Hawaii, Honolulu, HI (United States); Turco, R.P. [Univ. of California, Los Angeles, CA (United States)] [Univ. of California, Los Angeles, CA (United States); Toon, O.B. [NASA Ames Research Center, Moffett Field, CA (United States)] [NASA Ames Research Center, Moffett Field, CA (United States)

1995-04-20T23:59:59.000Z

268

Comparative Analysis of Urban Atmospheric Aerosol by Particle...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Analysis of Urban Atmospheric Aerosol by Particle-Induced X-ray Emission (PIXE), Proton Elastic Scattering Analysis Comparative Analysis of Urban Atmospheric Aerosol by...

269

aerosol ratio program: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

contribute a major portion of atmospheric aerosol mass loading 5. The estimated global annual Liou, K. N. 2 Studying Clouds and Aerosols with Lidar Depolarization Ratio and...

270

Reduction in biomass burning aerosol light absorption upon humidificat...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

in biomass burning aerosol light absorption upon humidification: Roles of inorganically-induced hygroscopicity, Reduction in biomass burning aerosol light absorption upon...

271

aerosol optical thickness: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of solar radiation by atmospheric aerosols is a key el- ement of the Earth's radiative energy balance and climate. The optical properties of aerosol particles are, however,...

272

aerosol black carbon: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of solar radiation by atmospheric aerosols is a key el- ement of the Earth's radiative energy balance and climate. The optical properties of aerosol particles are, however,...

273

aerosols iii morphologic: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Sciences Websites Summary: of aerosols. Keywords: metal waste recycling; aerosols; fire hazard; explosion hazard. 1. OVERVIEW ProductsRisks generated by the treatment of...

274

ambient ultrafine aerosols: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

soluble in water: 2. Isolation of acid, neutral, and basic fractions by modified size Weber, Rodney 4 Ambient aerosol sampling using the Aerodyne Aerosol Mass Spectrometer...

275

Synergy between Secondary Organic Aerosols and Long Range Transport...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

between Secondary Organic Aerosols and Long Range Transport of Polycyclic Aromatic Hydrocarbons. Synergy between Secondary Organic Aerosols and Long Range Transport of Polycyclic...

276

acid aerosol exposure: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Nenes, Athanasios 8 Neutralization of soil aerosol and its impact on the distribution of acid rain over east Asia Geosciences Websites Summary: Neutralization of soil aerosol and...

277

Aerosol Composition and Source Apportionment in the Mexico City...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Aerosol Composition and Source Apportionment in the Mexico City Metropolitan Area with PIXEPESASTIM and Multivariate Analysis. Aerosol Composition and Source Apportionment in the...

278

Molecular Chemistry of Organic Aerosols Through the Application...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Chemistry of Organic Aerosols Through the Application of High Resolution Mass Spectrometry. Molecular Chemistry of Organic Aerosols Through the Application of High Resolution Mass...

279

aerosol samples collected: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

elements analysis of aerosol samples from some CiteSeer Summary: Aerosols deposits on filters from ten Romanian towns with different kinds and levels of industrial development...

280

Optical, physical, and chemical properties of springtime aerosol...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Optical, physical, and chemical properties of springtime aerosol over Barrow Alaska in 2008. Optical, physical, and chemical properties of springtime aerosol over Barrow Alaska in...

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

aerosol particles emitted: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

aerosols scatter and absorb solar, estimates of the impact of aerosols on visibility, the solar radiation balance, and crop production is presented. 1. INTRODUCTION The attenuation...

282

aerosol particle analysis: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Summary: data analysis algorithm is presented. Our earlier algorithm assumed a monomodal aerosol size distribution, while the new algorithm allows us to partition the aerosol...

283

aerosol research study: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

in atmospheric thermal structure, burning, bio-sources changes? 12;Aerosol microphysics: size distribution, mixing state, morphology, shape 9 Aerosol Science and Technology,...

284

Building America Webinar: Sealing of Home Enclosures with Aerosol...  

Energy Savers [EERE]

Sealing of Home Enclosures with Aerosol Particles Building America Webinar: Sealing of Home Enclosures with Aerosol Particles This webinar was presented by research team Building...

285

The dependence of ice microphysics on aerosol concentration in...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

The dependence of ice microphysics on aerosol concentration in arctic mixed-phase stratus clouds during ISDAC and M-PACE. The dependence of ice microphysics on aerosol...

286

Final Report, DOE grant DE-FG02-99ER45780, "Indirect Excitons in Coupled Quantum Wells"  

SciTech Connect (OSTI)

The is the final technical report for this project, which was funded by the DOE from 1999 to 2012. The project focused on experimental studies of spatially indirect excitons in coupled quantum wells, with the aim of understanding the quantum physics of these particles, including such effects as pattern formation due to electron-hole charge separation, the Mott plasma-insulator transition, luminescence up-conversion through field-assisted tunneling, luminescence line shifts due to many-body renormalization and magnetic field effects on tunneling, and proposed effects such as Bose-Einstein condensation of indirect excitons and phase separation of bright and dark indirect excitons. Significant results are summarized here and the relation to other work is discussed.

Snoke, david W. [University of Pittsburgh

2014-07-21T23:59:59.000Z

287

Heterogeneous Chemistry: Understanding Aerosol/Oxidant Interactions  

SciTech Connect (OSTI)

Global radiative forcing of nitrate and ammonium aerosols has mostly been estimated from aerosol concentrations calculated at thermodynamic equilibrium or using approximate treatments for their uptake by aerosols. In this study, a more accurate hybrid dynamical approach (DYN) was used to simulate the uptake of nitrate and ammonium by aerosols and the interaction with tropospheric reactive nitrogen chemistry in a three-dimensional global aerosol and chemistry model, IMPACT, which also treats sulfate, sea salt and mineral dust aerosol. 43% of the global annual average nitrate aerosol burden, 0.16 TgN, and 92% of the global annual average ammonium aerosol burden, 0.29 TgN, exist in the fine mode (D<1.25 {micro}m) that scatters most efficiently. Results from an equilibrium calculation differ significantly from those of DYN since the fraction of fine-mode nitrate to total nitrate (gas plus aerosol) is 9.8%, compared to 13% in DYN. Our results suggest that the estimates of aerosol forcing from equilibrium concentrations will be underestimated. We also show that two common approaches used to treat nitrate and ammonium in aerosol in global models, including the first-order gas-to-particle approximation based on uptake coefficients (UPTAKE) and a hybrid method that combines the former with an equilibrium model (HYB), significantly overpredict the nitrate uptake by aerosols especially that by coarse particles, resulting in total nitrate aerosol burdens higher than that in DYN by +106% and +47%, respectively. Thus, nitrate aerosol in the coarse mode calculated by HYB is 0.18 Tg N, a factor of 2 more than that in DYN (0.086 Tg N). Excessive formation of the coarse-mode nitrate in HYB leads to near surface nitrate concentrations in the fine mode lower than that in DYN by up to 50% over continents. In addition, near-surface HNO{sub 3} and NO{sub x} concentrations are underpredicted by HYB by up to 90% and 5%, respectively. UPTAKE overpredicts the NO{sub x} burden by 56% and near-surface NO{sub x} concentrations by a factor of 2-5. These results suggest the importance of using the more accurate hybrid dynamical method in the estimates of both aerosol forcing and tropospheric ozone chemistry.

Joyce E. Penner

2005-03-14T23:59:59.000Z

288

Characterization of aerosols produced by surgical procedures  

SciTech Connect (OSTI)

In many surgeries, especially orthopedic procedures, power tools such as saws and drills are used. These tools may produce aerosolized blood and other biological material from bone and soft tissues. Surgical lasers and electrocautery tools can also produce aerosols when tissues are vaporized and condensed. Studies have been reported in the literature concerning production of aerosols during surgery, and some of these aerosols may contain infectious material. Garden et al. (1988) reported the presence of papilloma virus DNA in the fumes produced from laser surgery, but the infectivity of the aerosol was not assessed. Moon and Nininger (1989) measured the size distribution and production rate of emissions from laser surgery and found that particles were generally less than 0.5 {mu}m diameter. More recently there has been concern expressed over the production of aerosolized blood during surgical procedures that require power tools. In an in vitro study, the production of an aerosol containing the human immunodeficiency virus (HIV) was reported when power tools were used to cut tissues with blood infected with HIV. Another study measured the size distribution of blood aerosols produced by surgical power tools and found blood-containing particles in a number of size ranges. Health care workers are anxious and concerned about whether surgically produced aerosols are inspirable and can contain viable pathogens such as HIV. Other pathogens such as hepatitis B virus (HBV) are also of concern. The Occupational Safety and Health funded a project at the National Institute for Inhalation Toxicology Research Institute to assess the extent of aerosolization of blood and other tissues during surgical procedures. This document reports details of the experimental and sampling approach, methods, analyses, and results on potential production of blood-associated aerosols from surgical procedures in the laboratory and in the hospital surgical suite.

Yeh, H.C.; Muggenburg, B.A.; Lundgren, D.L.; Guilmette, R.A.; Snipes, M.B.; Jones, R.K. [Inhalation Toxicology Research Institute, Albuquerque, NM (United States); Turner, R.S. [Lovelace Health Systems, Albuquerque, NM (United States)

1994-07-01T23:59:59.000Z

289

Aerosol particle transport modeling for preclosure safety studies of nuclear waste repositories  

SciTech Connect (OSTI)

An important concern for preclosure safety analysis of a nuclear waste repository is the potential release to the environment of respirable aerosol particles. Such particles, less than 10 {mu}m in aerodynamic diameter, may have significant adverse health effects if inhaled. To assess the potential health effects of these particles, it is not sufficient to determine the mass fraction of respirable aerosol. The chemical composition of the particles is also of importance since different radionuclides may pose vastly different health hazards. Thus, models are needed to determine under normal and accident conditions the particle size and the chemical composition distributions of aerosol particles as a function of time and of position in the repository. In this work a multicomponent sectional aerosol model is used to determine the aerosol particle size and composition distributions in the repository. A range of aerosol mass releases with varying mean particle sizes and chemical compositions is used to demonstrate the sensitivities and uncertainties of the model. Decontamination factors for some locations in the repository are presented. 8 refs., 1 tab.

Gelbard, F. [Sandia National Labs., Albuquerque, NM (USA)

1989-01-01T23:59:59.000Z

290

Measurements of aerosol thermophoretic deposition: Transition with temperature gradient  

SciTech Connect (OSTI)

Thermophoresis is the motion of aerosol particles due to a temperature gradient in the suspending gas. The thermophoretic velocity V{sub T} is expressed as: where a {alpha} = thermal diffusivity v = kinematic viscosity H= Pr K Pr = Prandtl number K = dimensionless coefficient that is a function of several parameters (particle radius, thermal conductivity, gas properties, gas surface interactions). This report describes measurements of the effects of temperature gradients on the deposition of polystyrene latex particles.

Varma, A.; Tompson, R.V.; Loyalka, S.K. [Univ. of Missouri, Columbia, MO (United States)

1995-12-31T23:59:59.000Z

291

Horizontal Inequity and Vertical Redistribution with Indirect Taxes: the Greek Case  

E-Print Network [OSTI]

license issue fee and an initial registration tax, varying according to the vehicleís engine power and technology. Cars are also subject to an annual transport due, also varying according to engine power. Stamp duties are levied on a large number... preferences, while improvements in vertical redistribution can be achieved, albeit at the cost of increased horizontal inequity. Keywords: distributional effect of taxes, horizontal inequality, vertical redistribution, indirect tax reform, Greece JEL...

Kaplanoglou, G; Newbery, David

292

THE EFFECTS OF FLAME TEMPERATURE, PARTICLE SIZE AND EUROPIUM DOPING CONCENTRATION ON THE PROPERTIES OF Y2O3:EU PARTICLES FORMED IN A FLAME AEROSOL PROCESS  

E-Print Network [OSTI]

Y2O3:Eu particles are phosphors that have found wide applications. Flamesynthesized Y2O3:Eu particles may have either the cubic or the monoclinic structure. The effects of particle size and Eu doping concentration on crystal structure...

Yim, Hoon

2010-07-14T23:59:59.000Z

293

Assessing regional scale predictions of aerosols, marine stratocumulus, and their interactions during VOCALS-REx using WRF-Chem  

SciTech Connect (OSTI)

This study assesses the ability of the recent chemistry version (v3.3) of the Weather Research and Forecasting (WRF-Chem) model to simulate boundary layer structure, aerosols, stratocumulus clouds, and energy fluxes over the Southeast Pacific Ocean. Measurements from the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) and satellite retrievals (i.e., products from the MODerate resolution Imaging Spectroradiometer (MODIS), Clouds and Earth's Radiant Energy System (CERES), and GOES-10) are used for this assessment. The Morrison double-moment microphysics scheme is newly coupled with interactive aerosols in the model. The 31-day (15 October-16 November 2008) WRF-Chem simulation with aerosol-cloud interactions (AERO hereafter) is also compared to a simulation (MET hereafter) with fixed cloud droplet number concentrations in the microphysics scheme and simplified cloud and aerosol treatments in the radiation scheme. The well-simulated aerosol quantities (aerosol number, mass composition and optical properties), and the inclusion of full aerosol-cloud couplings lead to significant improvements in many features of the simulated stratocumulus clouds: cloud optical properties and microphysical properties such as cloud top effective radius, cloud water path, and cloud optical thickness. In addition to accounting for the aerosol direct and semi-direct effects, these improvements feed back to the simulation of boundary-layer characteristics and energy budgets. Particularly, inclusion of interactive aerosols in AERO strengthens the temperature and humidity gradients within the capping inversion layer and lowers the marine boundary layer (MBL) depth by 130 m from that of the MET simulation. These differences are associated with weaker entrainment and stronger mean subsidence at the top of the MBL in AERO. Mean top-of-atmosphere outgoing shortwave fluxes, surface latent heat, and surface downwelling longwave fluxes are in better agreement with observations in AERO, compared to the MET simulation. Nevertheless, biases in some of the simulated meteorological quantities (e.g., MBL temperature and humidity) and aerosol quantities (e.g., underestimations of accumulation mode aerosol number) might affect simulated stratocumulus and energy fluxes over the Southeastern Pacific, and require further investigation. The well-simulated timing and outflow patterns of polluted and clean episodes demonstrate the model's ability to capture daily/synoptic scale variations of aerosol and cloud properties, and suggest that the model is suitable for studying atmospheric processes associated with pollution outflow over the ocean. The overall performance of the regional model in simulating mesoscale clouds and boundary layer properties is encouraging and suggests that reproducing gradients of aerosol and cloud droplet concentrations and coupling cloud-aerosol-radiation processes are important when simulating marine stratocumulus over the Southeast Pacific.

Yang Q.; Lee Y.; Gustafson†Jr., W. I.; Fast, J. D.; Wang, H.; Easter, R. C.; Morrison, H.; Chapman, E. G.; Spak, S. N.; Mena-Carrasco, M. A.

2011-12-02T23:59:59.000Z

294

2, 12871315, 2002 Aerosol sources and  

E-Print Network [OSTI]

in climate variability and climate change studies (IPCC, 2001). Radiative forcing of natural and their contribution to the chemical composition of aerosols in the Eastern Mediterranean Sea during summertime J aerosol sources in the Eastern Mediterranean5 Basin could be investigated at this location since the site

Paris-Sud XI, Université de

295

6, 1217912197, 2006 Aerosol formation in  

E-Print Network [OSTI]

troposphere and lower stratosphere. The model implements a first order scheme for resolving the aerosol size distribution within its geometric size10 sections, which efficiently suppresses numerical diffusion. We operate removes freshly nucleated particles by coagulation. The observation of high ultrafine aerosol

Paris-Sud XI, Université de

296

6, 32653319, 2006 Study aerosol with  

E-Print Network [OSTI]

ACPD 6, 3265­3319, 2006 Study aerosol with two emission inventories and time factors A. de Meij et in Europe to two different emission inventories and temporal distribution of emissions A. de Meij 1 , M Study aerosol with two emission inventories and time factors A. de Meij et al. Title Page Abstract

Paris-Sud XI, Université de

297

Biobriefcase electrostatic aerosol collector  

DOE Patents [OSTI]

A system for sampling air and collecting particles entrained in the air comprising a receiving surface, a liquid input that directs liquid to the receiving surface and produces a liquid surface, an air input that directs the air so that the air with particles entrained in the air impact the liquid surface, and an electrostatic contact connected to the liquid that imparts an electric charge to the liquid. The particles potentially including bioagents become captured in the liquid by the air with particles entrained in the air impacting the liquid surface. Collection efficiency is improved by the electrostatic contact electrically charging the liquid. The effects of impaction and adhesion due to electrically charging the liquid allows a unique combination in a particle capture medium that has a low fluid consumption rate while maintaining high efficiency.

Bell, Perry M. (Tracy, CA); Christian, Allen T. (Madison, WI); Bailey, Christopher G. (Pleasanton, CA); Willis, Ladona (Manteca, CA); Masquelier, Donald A. (Tracy, CA); Nasarabadi, Shanavaz L. (Livermore, CA)

2009-03-17T23:59:59.000Z

298

AEROSOL PARTICLE COLLECTOR DESIGN STUDY  

SciTech Connect (OSTI)

A computational evaluation of a particle collector design was performed to evaluate the behavior of aerosol particles in a fast flowing gas stream. The objective of the work was to improve the collection efficiency of the device while maintaining a minimum specified air throughput, nominal collector size, and minimal power requirements. The impact of a range of parameters was considered subject to constraints on gas flow rate, overall collector dimensions, and power limitations. Potential improvements were identified, some of which have already been implemented. Other more complex changes were identified and are described here for further consideration. In addition, fruitful areas for further study are proposed.

Lee, S; Richard Dimenna, R

2007-09-27T23:59:59.000Z

299

ARM - Field Campaign - Aerosol IOP  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLasDelivered¬ČPNGExperience4AJ01)3, 2010SeptemberInfrared SpectralgovCampaignsAerosol IOP

300

Aerosol size distribution evolution in large area fire plumes  

SciTech Connect (OSTI)

Large fires are significant seasonal contributors to western visibility reduction. We have found that the relative concentration of supermicron size particles (assumed to be a mixture of mechanically generated particles by high winds associated with large fires and low density chain aggregates from coagulation in the fire) and high turbulence in fire plumes can radically change the aerosol sizes in the fire plume. This is especially important for aerosols with high visibility reduction and long range transport potential. This calculation was done with a 10 level one dimensional model with parameterized vertical and horizontal diffusion, sedimentation and coagulation. The optical effects of the evolving concentration and size distributions were modeled using Mie scattering and absorption assumptions.

Porch, W.M.; Penner, J.E.

1986-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Global observations of desert dust and biomass burning aerosols  

E-Print Network [OSTI]

Global observations of desert dust and biomass burning aerosols Martin de Graaf KNMI #12; Outline · Absorbing Aerosol Index - Theory · Absorbing Aerosol Index - Reality · Biomass burning.6 Biomass burning over Angola, 09 Sep. 2004 Absorbing Aerosol Index PMD image #12;biomass burning ocean

Graaf, Martin de

302

Lidar Investigation of Tropical Nocturnal Boundary Layer Aerosols and Cloud Macrophysics  

SciTech Connect (OSTI)

Observational evidence of two-way association between nocturnal boundary layer aerosols and cloud macrophysical properties under different meteorological conditions is reported in this paper. The study has been conducted during 2008-09 employing a high space-time resolution polarimetric micro-pulse lidar over a tropical urban station in India. Firstly, the study highlights the crucial role of boundary layer aerosols and background meteorology on the formation and structure of low-level stratiform clouds in the backdrop of different atmospheric stability conditions. Turbulent mixing induced by the wind shear at the station, which is associated with a complex terrain, is found to play a pivotal role in the formation and structural evolution of nocturnal boundary layer clouds. Secondly, it is shown that the trapping of energy in the form of outgoing terrestrial radiation by the overlying low-level clouds can enhance the aerosol mixing height associated with the nocturnal boundary layer. To substantiate this, the long-wave heating associated with cloud capping has been quantitatively estimated in an indirect way by employing an Advanced Research Weather Research and Forecasting (WRF-ARW) model version 2.2 developed by National Center for Atmospheric Research (NCAR), Colorado, USA, and supplementary data sets; and differentiated against other heating mechanisms. The present investigation as well establishes the potential of lidar remote-sensing technique in exploring some of the intriguing aspects of the cloud-environment relationship.

Manoj, M. G.; Devara, PC S.; Taraphdar, Sourav

2013-10-01T23:59:59.000Z

303

Aerosol, Cloud, and Climate: From Observation to Model (457th Brookhaven Lecture)  

SciTech Connect (OSTI)

In the last 100 years, the Earth has warmed by about 1ļF, glaciers and sea ice have been melting more quickly than previously, especially during the past decade, and the level of the sea has risen about 6-8 inches worldwide. Scientists have long been investigating this phenomenon of ďglobal warming,Ē which is believed to be at least partly due to the increased carbon dioxide (CO2) concentration in the air from burning fossil fuels. Funded by DOE, teams of researchers from BNL and other national labs have been gathering data in the U.S. and internationally to build computer models of climate and weather to help in understanding general patterns, causes, and perhaps, solutions. Among many findings, researchers observed that atmospheric aerosols, minute particles in the atmosphere, can significantly affect global energy balance and climate. Directly, aerosols scatter and absorb sunlight. Indirectly, increased aerosol concentration can lead to smaller cloud droplets, changing clouds in ways that tend to cool global climate and potentially mask overall warming from man-made CO2.

Wang, Jian (Ph.D., Environmental Sciences Department) [Ph.D., Environmental Sciences Department

2010-05-12T23:59:59.000Z

304

Unintended consequences of atmospheric injection of sulphate aerosols.  

SciTech Connect (OSTI)

Most climate scientists believe that climate geoengineering is best considered as a potential complement to the mitigation of CO{sub 2} emissions, rather than as an alternative to it. Strong mitigation could achieve the equivalent of up to -4Wm{sup -2} radiative forcing on the century timescale, relative to a worst case scenario for rising CO{sub 2}. However, to tackle the remaining 3Wm{sup -2}, which are likely even in a best case scenario of strongly mitigated CO{sub 2} releases, a number of geoengineering options show promise. Injecting stratospheric aerosols is one of the least expensive and, potentially, most effective approaches and for that reason an examination of the possible unintended consequences of the implementation of atmospheric injections of sulphate aerosols was made. Chief among these are: reductions in rainfall, slowing of atmospheric ozone rebound, and differential changes in weather patterns. At the same time, there will be an increase in plant productivity. Lastly, because atmospheric sulphate injection would not mitigate ocean acidification, another side effect of fossil fuel burning, it would provide only a partial solution. Future research should aim at ameliorating the possible negative unintended consequences of atmospheric injections of sulphate injection. This might include modeling the optimum rate and particle type and size of aerosol injection, as well as the latitudinal, longitudinal and altitude of injection sites, to balance radiative forcing to decrease negative regional impacts. Similarly, future research might include modeling the optimum rate of decrease and location of injection sites to be closed to reduce or slow rapid warming upon aerosol injection cessation. A fruitful area for future research might be system modeling to enhance the possible positive increases in agricultural productivity. All such modeling must be supported by data collection and laboratory and field testing to enable iterative modeling to increase the accuracy and precision of the models, while reducing epistemic uncertainties.

Brady, Patrick Vane; Kobos, Peter Holmes; Goldstein, Barry

2010-10-01T23:59:59.000Z

305

EMSP Final Report: Electrically Driven Technologies for Radioactive Aerosol Abatement  

SciTech Connect (OSTI)

The purpose of this research project was to develop an improved understanding of how electrically driven processes, including electrocoalescence, acoustic agglomeration, and electric filtration, may be employed to efficiently treat problems caused by the formation of aerosols during DOE waste treatment operations. The production of aerosols during treatment and retrieval operations in radioactive waste tanks and during thermal treatment operations such as calcination presents a significant problem of cost, worker exposure, potential for release, and increased waste volume. There was anecdotal evidence in the literature that acoustic agglomeration and electrical coalescence could be used together to change the size distribution of aerosol particles in such a way as to promote easier filtration and less frequent maintenance of filtration systems. As such, those electrically driven technologies could potentially be used as remote technologies for improved treatment; however, existing theoretical models are not suitable for prediction and design. To investigate the physics of such systems, and also to prototype a system for such processes, a collaborative project was undertaken between Oak Ridge National Laboratory (ORNL) and the University of Texas at Austin (UT). ORNL was responsible for the larger-scale prototyping portion of the project, while UT was primarily responsible for the detailed physics in smaller scale unit reactors. It was found that both electrical coalescence and acoustic agglomeration do in fact increase the rate of aggregation of aerosols. Electrical coalescence requires significantly less input power than acoustic agglomeration, but it is much less effective in its ability to aggregate/coalesce aerosols. The larger-scale prototype showed qualitatively similar results as the unit reactor tests, but presented more difficulty in interpretation of the results because of the complex multi-physics coupling that necessarily occur in all larger-scale system tests. An additional finding from this work is that low-amplitude oscillation may provide an alternative, non-invasive, non-contact means of controlling settling and/or suspension of solids. Further investigation would be necessary to evaluate its utility for radioactive waste treatment applications. This project did not uncover a new technology for radioactive waste treatment. While it may be possible that an efficient electrically driven technology for aerosol treatment could be developed, it appears that other technologies, such as steel and ceramic HEPA filters, can suitably solve this problem. If further studies are to be undertaken, additional fundamental experimentation and modeling is necessary to fully capture the physics; in addition, larger-scale tests are needed to demonstrate the treatment of flowing gas streams through the coupling of acoustic agglomeration with electrocoalescence.

DePaoli, D.W.

2003-01-22T23:59:59.000Z

306

Studying trends in biomass burning aerosol using the Absorbing Aerosol Index derived from GOME, SCIAMACHY, and GOME-2  

E-Print Network [OSTI]

Studying trends in biomass burning aerosol using the Absorbing Aerosol Index derived from GOME the resulting time series, we use tropospheric NO2 data as a reference in the regions dominated by biomass sensitive to desert dust aerosols (DDA) and biomass burning aerosols (BBA). See Figure 1. The AAI

Tilstra, Gijsbert

307

Water augmented indirectly-fired gas turbine systems and method  

DOE Patents [OSTI]

An indirectly-fired gas turbine system utilizing water augmentation for increasing the net efficiency and power output of the system is described. Water injected into the compressor discharge stream evaporatively cools the air to provide a higher driving temperature difference across a high temperature air heater which is used to indirectly heat the water-containing air to a turbine inlet temperature of greater than about 1,000.degree. C. By providing a lower air heater hot side outlet temperature, heat rejection in the air heater is reduced to increase the heat recovery in the air heater and thereby increase the overall cycle efficiency.

Bechtel, Thomas F. (Lebanon, PA); Parsons, Jr., Edward J. (Morgantown, WV)

1992-01-01T23:59:59.000Z

308

The behavior of constant rate aerosol reactors  

SciTech Connect (OSTI)

An aerosol reactor is a gaseous system in which fine particles are formed by chemical reaction in either a batch or flow process. The particle sizes of interest range from less than 10 angstrom (molecular clusters) to 10 ..mu..m. Such reactors may be operated to study the aerosol formation process, as in a smog reactor, or to generate a product such as a pigment or a catalytic aerosol. Aerosol reactors can be characterized by three temporal or spatial zones or regions of operation for batch and flow reactors, respectively. In zone I, chemical reaction results in the formation of condensable molecular products which nucleate and form very high concentrations of small particles. The number density depends on the concentration of preexisting aerosol. Zone II is a transition region in which the aerosol number concentration levels off as a result of hetergeneous condensation by the stable aerosol. In zone III coagulation becomes sufficiently rapid to reduce the particle number concentration. There may be a zone IV in which agglomerates form.

Friedlander, S.K.

1982-01-01T23:59:59.000Z

309

Solar Physics (2004) 224: 34 C Springer 2005 The topical issue of "Space Climate: Direct and Indirect Observations of  

E-Print Network [OSTI]

Solar Physics (2004) 224: 3­4 C Springer 2005 PREFACE The topical issue of "Space Climate: Direct and Indirect Observations of Long-Term Solar Activity" is based on contributions presented at the First of solar activity, and their effects in the near-Earth environment and technoculture. As an analogy

Usoskin, Ilya G.

310

Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds  

SciTech Connect (OSTI)

Project goals: (1) Use the routine surface and airborne measurements at the ARM SGP site, and the routine surface measurements at the NSA site, to continue our evaluations of model aerosol simulations; (2) Determine the degree to which the Raman lidar measurements of water vapor and aerosol scattering and extinction can be used to remotely characterize the aerosol humidification factor; (3) Use the high temporal resolution CARL data to examine how aerosol properties vary near clouds; and (4) Use the high temporal resolution CARL and Atmospheric Emitted Radiance Interferometer (AERI) data to quantify entrainment in optically thin continental cumulus clouds.

Richard A. Ferrare; David D. Turner

2011-09-01T23:59:59.000Z

311

PARAGON - An Integrated Approach for Characterizing Aerosol Climate Impacts and Environmental Interactions  

SciTech Connect (OSTI)

Aerosols exert myriad influences on the Earth?s environment and climate and on human health. The complexity of aerosol-related processes requires that information gathered to improve our understanding of climate change must originate from multiple sources, and that effective strategies for data integration need to be established. Currently, the aerosol community lacks the necessary tools and infrastructure to reap maximum scientific benefit from a vast array of observed and modeled data. Spatial and temporal sampling differences among a diverse set of sensors, nonuniform data qualities, aerosol mesoscale variabilities, and difficulties in separating cloud effects are some of the challenges that need to be addressed. A sustained, long-term program also requires maintaining consistently well-understood accuracies as measurement approaches evolve and improve. Achieving a comprehensive understanding of how aerosol physical, chemical, and radiative processes impact the Earth system can only be achieved through a multidisciplinary, interagency, and international initiative capable of dealing with these issues. A systematic approach, capitalizing on modern measurement and modeling techniques, geospatial statistics methodologies, and high-performance information technologies can provide the necessary machinery to support this objective. We outline a framework for integrating and interpreting observations and models and establishing an accurate, consistent and cohesive long-term record, following a strategy whereby information and tools of progressively greater sophistication are incorporated as problems of increasing complexity are tackled. This concept is named the Progressive Aerosol Retrieval and Assimilation Global Observing Network (PARAGON). To encompass the breadth of effort required, we present a set of recommendations dealing with data interoperability, integration, synergy, summarization and mining, model evaluation, calibration and validation, augmentation of surface and in situ measurements, advances in passive and active remote sensing, and design of satellite missions. Without an initiative of this nature, the scientific and policy communities will continue to struggle with understanding the quantitative impact of complex aerosol processes on regional and global climate change and air quality.

Diner, David J.; Ackerman, Thomas P.; Anderson, Theodore L.; Bosenberg, Jens; Braverman, Amy J.; Charlson, Robert J.; Collins, William D.; Davies, Roger; Holben, B. N.; Hostetler, Chris A.; Kahn, Ralph A.; Martonchik, John V.; Menzies, Robert T.; Miller, Mark A.; Ogren, J. A.; Penner, Joyce E.; Rasch, P; Schwartz, Stephen E.; Seinfeld, John H.; Stephens, Graeme L.; Torres, Omar; Travis, Larry D.; Wielicki, Bruce A.; Yu, Bin

2004-10-01T23:59:59.000Z

312

Spectro-Microscopic Measurements of Carbonaceous Aerosol Aging in Central California  

SciTech Connect (OSTI)

Carbonaceous aerosols are responsible for large uncertainties in climate models, degraded visibility, and adverse health effects. The Carbonaceous Aerosols and Radiative Effects Study (CARES) was designed to study carbonaceous aerosols in the natural environment of Central Valley, California, and learn more about their atmospheric formation and aging. This paper presents results from spectro-microscopic measurements of carbonaceous particles collected during CARES at the time of pollution accumulation event (June 27-29, 2010), when in situ measurements indicated an increase in the organic carbon content of aerosols as the Sacramento urban plume aged. Computer controlled scanning electron microscopy coupled with an energy dispersive X-ray detector (CCSEM/EDX) and scanning transmission X-ray microscopy coupled with near edge X-ray absorption spectroscopy (STXM/NEXAFS) were used to probe the chemical composition and morphology of individual particles. It was found that the mass of organic carbon on individual particles increased through condensation of secondary organic aerosol. STXM/NEXAFS indicated that the number fraction of homogenous organic particles lacking inorganic inclusions (greater than ~50 nm diameter) increased with plume age as did the organic mass per particle. Comparison of the CARES spectro-microscopic data set with a similar dataset obtained in Mexico City during the MILAGRO campaign showed that individual particles in Mexico City contained twice as much carbon as those sampled during CARES. The number fraction of soot particles at the Mexico City urban site (30%) was larger than at the CARES urban site (10%) and the most aged samples from CARES contained less carbon-carbon double bonds. Differences between carbonaceous particles in Mexico City and California result from different sources, photochemical conditions, gas phase reactants, and secondary organic aerosol precursors. The detailed results provided by these spectro-microscopic measurements will allow for a comprehensive evaluation of aerosol process models used in climate research.

Moffet, Ryan C.; Rodel, Tobias; Kelly, Stephen T.; Yu, Xiao-Ying; Carroll, Gregory; Fast, Jerome D.; Zaveri, Rahul A.; Laskin, Alexander; Gilles, Mary K.

2013-10-29T23:59:59.000Z

313

Laboratory Studies of Processing of Carbonaceous Aerosols by Atmospheric Oxidants/Hygroscopicity and CCN Activity of Secondary & Processed Primary Organic Aerosols  

SciTech Connect (OSTI)

The atmosphere is composed of a complex mixture of gases and suspended microscopic aerosol particles. The ability of these particles to take up water (hygroscopicity) and to act as nuclei for cloud droplet formation significantly impacts aerosol light scattering and absorption, and cloud formation, thereby influencing air quality, visibility, and climate in important ways. A substantial, yet poorly characterized component of the atmospheric aerosol is organic matter. Its major sources are direct emissions from combustion processes, which are referred to as primary organic aerosol (POA), or in situ processes in which volatile organic compounds (VOCs) are oxidized in the atmosphere to low volatility reaction products that subsequent condense to form particles that are referred to as secondary organic aerosol (SOA). POA and VOCs are emitted to the atmosphere from both anthropogenic and natural (biogenic) sources. The overall goal of this experimental research project was to conduct laboratory studies under simulated atmospheric conditions to investigate the effects of the chemical composition of organic aerosol particles on their hygroscopicity and cloud condensation nucleation (CCN) activity, in order to develop quantitative relationships that could be used to more accurately incorporate aerosol-cloud interactions into regional and global atmospheric models. More specifically, the project aimed to determine the products, mechanisms, and rates of chemical reactions involved in the processing of organic aerosol particles by atmospheric oxidants and to investigate the relationships between the chemical composition of organic particles (as represented by molecule sizes and the specific functional groups that are present) and the hygroscopicity and CCN activity of oxidized POA and SOA formed from the oxidation of the major classes of anthropogenic and biogenic VOCs that are emitted to the atmosphere, as well as model hydrocarbons. The general approach for this project was to carry out reactions of representative anthropogenic and biogenic VOCs and organic particles with ozone (O3), and hydroxyl (OH), nitrate (NO3), and chlorine (Cl) radicals, which are the major atmospheric oxidants, under simulated atmospheric conditions in large-volume environmental chambers. A combination of on-line and off-line analytical techniques were used to monitor the chemical and physical properties of the particles including their hygroscopicity and CCN activity. The results of the studies were used to (1) improve scientific understanding of the relationships between the chemical composition of organic particles and their hygroscopicity and CCN activity, (2) develop an improved molecular level theoretical framework for describing these relationships, and (3) establish a large database that is being used to develop parameterizations relating organic aerosol chemical properties and SOA sources to particle hygroscopicity and CCN activity for use in regional and global atmospheric air quality and climate models.

Ziemann, P.J.; Arey, J.; Atkinson, R.; Kreidenweis, S.M.; Petters, M.D.

2012-06-13T23:59:59.000Z

314

LEGAL REALISM IN ACTION: INDIRECT COPYRIGHT LIABILITY'S CONTINUING TORT  

E-Print Network [OSTI]

1 LEGAL REALISM IN ACTION: INDIRECT COPYRIGHT LIABILITY'S CONTINUING TORT FRAMEWORK AND SONY'S DE standard, derived in Sony Corp. of America v. Universal City Studios, Inc. from patent law and reasserted for distributors of dual-use technologies. Yet, when one looks to cases decided since Sony, subsequent legislative

Kammen, Daniel M.

315

Southern hemisphere tropospheric aerosol microphysics  

SciTech Connect (OSTI)

Aerosol particle size distribution data have been obtained in the southern hemisphere from approximately 4{degree}S to 44{degree}S and between ground level and 6 km, in the vicinity of eastern Australia. The relative shape of the free-tropospheric size distribution for particles with radii larger than approximately 0.04 {mu}m was found to be remarkably stable with time, altitude, and location for the autumn-winter periods considered. This was despite some large concentration changes which were found to be typical of the southeastern Australian coastal region. The majority of free-troposphere large particles were found to have sulfuric acid or lightly ammoniated sulfate morphology. Large particles in the boundary layer almost exclusively had a sea-salt morphology.

Gras, J.L. (Commonwealth Scientific and Industrial Research Organization, Aspendale (Australia))

1991-03-20T23:59:59.000Z

316

Radiative and climate impacts of absorbing aerosols  

E-Print Network [OSTI]

incident radiation are distinguished, and albedos for oceanOceans using multiple satellite datasets in conjunction with MACR (Monte Carlo Aerosol-Cloud-Radiation)ocean temperature is coupled with the rest of the climate system, the dimming of surface radiation

Zhu, Aihua

2010-01-01T23:59:59.000Z

317

Carbonaceous Aerosols and Radiative Effects Study  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed New Substation Sites Proposed RouteNanotube TemplatedStorage Medium to

318

7, 1463914674, 2007 Aerosol effects on  

E-Print Network [OSTI]

in many ways. They act as cloud condensation and ice nuclei and may have an influence on the hydro.5 W m -2 when micro- physics are included both in stratiform and convective clouds. 1 Introduction15

Boyer, Edmond

319

Aerosol fabrication methods for monodisperse nanoparticles  

DOE Patents [OSTI]

Exemplary embodiments provide materials and methods for forming monodisperse particles. In one embodiment, the monodisperse particles can be formed by first spraying a nanoparticle-containing dispersion into aerosol droplets and then heating the aerosol droplets in the presence of a shell precursor to form core-shell particles. By removing either the shell layer or the nanoparticle core of the core-shell particles, monodisperse nanoparticles can be formed.

Jiang, Xingmao; Brinker, C Jeffrey

2014-10-21T23:59:59.000Z

320

Development of plutonium aerosol fractionation system  

E-Print Network [OSTI]

DEVELOPMENT OF A PLUTONIUM AEROSOL FRACTIONATION SYSTEM A Thesis by MALLA R. MEKALA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August... 1993 Major Subject: Mechanical Engineering DEVELOPMENT OP A PLUTONIUM AEROSOL FRACTIONATION SYSTEM A Thesis by MALLA R. MEKALA Approved as to style and content by: A. R. McFarland (Chair of Committee) N. K. Anand (Mer toer) (', & C. B...

Mekala, Malla R.

1993-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Electrically Driven Technologies for Radioactive Aerosol Abatement  

SciTech Connect (OSTI)

The purpose of this research project was to develop an improved understanding of how electriexecy driven processes, including electrocoalescence, acoustic agglomeration, and electric filtration, may be employed to efficiently treat problems caused by the formation of aerosols during DOE waste treatment operations. The production of aerosols during treatment and retrieval operations in radioactive waste tanks and during thermal treatment operations such as calcination presents a significant problem of cost, worker exposure, potential for release, and increased waste volume.

David W. DePaoli; Ofodike A. Ezekoye; Costas Tsouris; Valmor F. de Almeida

2003-01-28T23:59:59.000Z

322

An Aerosol Condensation Model for Sulfur Trioxide  

SciTech Connect (OSTI)

This document describes a model for condensation of sulfuric acid aerosol given an initial concentration and/or source of gaseous sulfur trioxide (e.g. fuming from oleum). The model includes the thermochemical effects on aerosol condensation and air parcel buoyancy. Condensation is assumed to occur heterogeneously onto a preexisting background aerosol distribution. The model development is both a revisiting of research initially presented at the Fall 2001 American Geophysical Union Meeting [1] and a further extension to provide new capabilities for current atmospheric dispersion modeling efforts [2]. Sulfuric acid is one of the most widely used of all industrial chemicals. In 1992, world consumption of sulfuric acid was 145 million metric tons, with 42.4 Mt (mega-tons) consumed in the United States [10]. In 2001, of 37.5 Mt consumed in the U.S., 74% went into producing phosphate fertilizers [11]. Another significant use is in mining industries. Lawuyi and Fingas [7] estimate that, in 1996, 68% of use was for fertilizers and 5.8% was for mining. They note that H{sub 2}SO{sub 4} use has been and should continue to be very stable. In the United States, the elimination of MTBE (methyl tertiary-butyl ether) and the use of ethanol for gasoline production are further increasing the demand for petroleum alkylate. Alkylate producers have a choice of either a hydrofluoric acid or sulfuric acid process. Both processes are widely used today. Concerns, however, over the safety or potential regulation of hydrofluoric acid are likely to result in most of the growth being for the sulfuric acid process, further increasing demand [11]. The implication of sulfuric acid being a pervasive industrial chemical is that transport is also pervasive. Often, this is in the form of oleum tankers, having around 30% free sulfur trioxide. Although sulfuric acid itself is not a volatile substance, fuming sulfuric acid (referred to as oleum) is [7], the volatile product being sulfur trioxide. Sulfate aerosols and mist may form in the atmosphere on tank rupture. From chemical spill data from 1990-1996, Lawuyi02 and Fingas [7] prioritize sulfuric acid as sixth most serious. During this period, they note 155 spills totaling 13 Mt, out of a supply volume of 3700 Mt. Lawuyi and Fingas [7] summarize information on three major sulfuric acid spills. On 12 February 1984, 93 tons of sulfuric acid were spilled when 14 railroad cars derailed near MacTier, Parry Sound, Ontario. On 13 December 1978, 51 railroad cars derailed near Springhill, Nova Scotia. One car, containing 93% sulfuric acid, ruptured, spilling nearly its entire contents. In July 1993, 20 to 50 tons of fuming sulfuric acid spilled at the General Chemical Corp. plant in Richmond, California, a major industrial center near San Francisco. The release occurred when oleum was being loaded into a nonfuming acid railroad tank car that contained only a rupture disk as a safety device. The tank car was overheated and this rupture disk blew. The resulting cloud of sulfuric acid drifted northeast with prevailing winds over a number of populated areas. More than 3,000 people subsequently sought medical attention for burning eyes, coughing, headaches, and nausea. Almost all were treated and released on the day of the spill. By the day after the release, another 5,000 people had sought medical attention. The spill forced the closure of five freeways in the region as well as some Bay Area Rapid Transit System stations. Apart from corrosive toxicity, there is the additional hazard that the reactions of sulfur trioxide and sulfuric acid vapors with water are extremely exothermic [10, 11]. While the vapors are intrinsically denser than air, there is thus the likelihood of strong, warming-induced buoyancy from reactions with ambient water vapor, water-containing aerosol droplets, and wet environmental surface. Nordin [12] relates just such an occurrence following the Richmond, CA spill, with the plume observed to rise to 300 m. For all practical purposes, sulfur trioxide was the constituent released from the heated tank

Grant, K E

2008-02-07T23:59:59.000Z

323

Impact of Aerosols on Tropical Cyclones: An Investigation Using Convection-permitting Model Simulation  

SciTech Connect (OSTI)

The role of aerosols effect on two tropical cyclones over Bay of Bengal are investigated using a convection permitting model with two-moment mixed-phase bulk cloud microphysics scheme. The simulation results show the role of aerosol on the microphysical and dynamical properties of cloud and bring out the change in efficiency of the clouds in producing precipitation. The tracks of the TCs are hardly affected by the changing aerosol types, but the intensity exhibits significant sensitivity due to the change in aerosol contribution. It is also clearly seen from the analyses that higher heating in the middle troposphere within the cyclone center is in response to latent heat release as a consequence of greater graupel formation. Greater heating in the middle level is particularly noticeable for the clean aerosol regime which causes enhanced divergence in the upper level which, in turn, forces the lower level convergence. As a result, the cleaner aerosol perturbation is more unstable within the cyclone core and produces a more intense cyclone as compared to other two perturbations of aerosol. All these studies show the robustness of the concept of TC weakening by storm ingestion of high concentrations of CCN. The consistency of these model results gives us confidence in stating there is a high probability that ingestion of high CCN concentrations in a TC will lead to weakening of the storm but has little impact on storm direction. Moreover, as pollution is increasing over the Indian sub-continent, this study suggests pollution may be weakening TCs over the Bay of Bengal.

Hazra, Anupam; Mukhopadhyay, P.; Taraphdar, Sourav; Chen, J. P.; Cotton, William R.

2013-07-16T23:59:59.000Z

324

Intercomparison and Evaluation of Global Aerosol Microphysical Properties among AeroCom Models of a Range of Complexity  

SciTech Connect (OSTI)

Many of the next generation of global climate models will include aerosol schemes which explicitly simulate the microphysical processes that determine the particle size distribution. These models enable aerosol optical properties and cloud condensation nuclei (CCN) concentrations to be determined by fundamental aerosol processes, which should lead to a more physically based simulation of aerosol direct and indirect radiative forcings. This study examines the global variation in particle size distribution simulated by twelve global aerosol microphysics models to quantify model diversity and to identify any common biases against observations. Evaluation against size distribution measurements from a new European network of aerosol supersites shows that the mean model agrees quite well with the observations at many sites on the annual mean, but there are some seasonal biases common to many sites. In particular, at many of these European sites, the accumulation mode number concentration is biased low during winter and Aitken mode concentrations tend to be overestimated in winter and underestimated in summer. At high northern latitudes, the models strongly underpredict Aitken and accumulation particle concentrations compared to the measurements, consistent with previous studies that have highlighted the poor performance of global aerosol models in the Arctic. In the marine boundary layer, the models capture the observed meridional variation in the size distribution, which is dominated by the Aitken mode at high latitudes, with an increasing concentration of accumulation particles with decreasing latitude. Considering vertical profiles, the models reproduce the observed peak in total particle concentrations in the upper troposphere due to new particle formation, although modelled peak concentrations tend to be biased high over Europe. Overall, the results suggest that most global aerosol microphysics models simulate the global variation of the particle size distribution with a good degree of skill, but some models are in poor agreement with the observations. Further work is required to better constrain size-resolved primary and secondary particle number sources, and an improved understanding of nucleation and growth (e.g. the role of nitrate and secondary organics) will improve the fidelity of simulated particle size distributions.

Mann, G. W.; Carslaw, K. S.; Reddington, C. L.; Pringle, K. J.; Schulz, M.; Asmi, A.; Spracklen, D. V.; Ridley, D. A.; Woodhouse, M. T.; Lee, L. A.; Zhang, Kai; Ghan, Steven J.; Easter, Richard C.; Liu, Xiaohong; Stier, P.; Lee, Y. H.; Adams, P. J.; Tost, H.; Lelieveld, J.; Bauer, S.; Tsigaridis, Kostas; van Noije, T.; Strunk, A.; Vignati, E.; Bellouin, N.; Dalvi, M.; Johnson, C. E.; Bergman, T.; Kokkola, H.; Von Salzen, Knut; Yu, Fangqun; Luo, Gan; Petzold, A.; Heintzenberg, J.; Clarke, A. D.; Ogren, J. A.; Gras, J.; Baltensperger, Urs; Kaminski, U.; Jennings, S. G.; O'Dowd, C. D.; Harrison, R. M.; Beddows, D. C.; Kulmala, M.; Viisanen, Y.; Ulevicius, V.; Mihalopoulos, Nikos; Zdimal, V.; Fiebig, M.; Hansson, H. C.; Swietlicki, E.; Henzing, J. S.

2014-05-13T23:59:59.000Z

325

AEROSOL CHEMICAL COMPOSITION CHARACTERIZATION AT THE ARM SOUTHERN GREAT PLAINS (SGP) SITE USING AN AEROSOL CHEMICAL  

E-Print Network [OSTI]

AEROSOL CHEMICAL COMPOSITION CHARACTERIZATION AT THE ARM SOUTHERN GREAT PLAINS (SGP) SITE USING AN AEROSOL CHEMICAL SPECIATION MONITOR Yin-Nan Lee1 , Fan Mei1 , Stephanie DeJong1 , Anne Jefferson2 1 Atmospheric Sciences Division, Brookhaven National Lab, Upton, NY 2 CIRES, University of Colorado, Boulder, CO

326

Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds  

SciTech Connect (OSTI)

The 'Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds' project focused extensively on the analysis and utilization of water vapor and aerosol profiles derived from the ARM Raman lidar at the Southern Great Plains ARM site. A wide range of different tasks were performed during this project, all of which improved quality of the data products derived from the lidar or advanced the understanding of atmospheric processes over the site. These activities included: upgrading the Raman lidar to improve its sensitivity; participating in field experiments to validate the lidar aerosol and water vapor retrievals; using the lidar aerosol profiles to evaluate the accuracy of the vertical distribution of aerosols in global aerosol model simulations; examining the correlation between relative humidity and aerosol extinction, and how these change, due to horizontal distance away from cumulus clouds; inferring boundary layer turbulence structure in convective boundary layers from the high-time-resolution lidar water vapor measurements; retrieving cumulus entrainment rates in boundary layer cumulus clouds; and participating in a field experiment that provided data to help validate both the entrainment rate retrievals and the turbulent profiles derived from lidar observations.

Turner, David, D.; Ferrare, Richard, A.

2011-07-06T23:59:59.000Z

327

Indirect Dark Matter search with large neutrino telescopes  

E-Print Network [OSTI]

Dark matter is one of the main goals of neutrino astronomy. At present, there are two big neutrino telescopes based on the Cherenkov technique in ice and water: IceCube at the South Pole and ANTARES in the northern hemisphere. Both telescopes are performing an indirect search for Dark Matter by looking for a statistical excess of neutrinos coming from astrophysical massive objects. This excess could be an evidence of the possible annihilation of dark matter particles in the centre of these objects. In one of the most popular scenarios the Dark Matter is composed of WIMP particles. The analysis and results of the ANTARES neutrino telescope for the indirect detection of Dark Matter fluxes from the Sun are here presented, as well as the latest IceCube published sensitivity results, for different Dark Matter models.

Fermani, Paolo

2013-01-01T23:59:59.000Z

328

Reactor Materials Program process water piping indirect failure frequency  

SciTech Connect (OSTI)

Following completion of the probabilistic analyses, the LOCA Definition Project has been subject to various external reviews, and as a result the need for several revisions has arisen. This report updates and summarizes the indirect failure frequency analysis for the process water piping. In this report, a conservatism of the earlier analysis is removed, supporting lower failure frequency estimates. The analysis results are also reinterpreted in light of subsequent review comments.

Daugherty, W.L.

1989-10-30T23:59:59.000Z

329

SLURRY PHASE IRON CATALYSTS FOR INDIRECT COAL LIQUEFACTION  

SciTech Connect (OSTI)

This report describes research conducted to support the DOE program in indirect coal liquefaction. Specifically, they have studied the attrition behavior of iron Fischer-Tropsch catalysts, their interaction with the silica binder and the evolution of iron phases in a synthesis gas conversion process. The results provide significant insight into factors that should be considered in the design of catalysts for converting coal based syngas into liquid fuels.

Abhaya K. Datye

1998-11-19T23:59:59.000Z

330

Slurry Phase Iron Catalysts for Indirect Coal Liquefaction  

SciTech Connect (OSTI)

This report describes research conducted to support the DOE program in indirect coal liquefaction. Specifically, we have studied the attrition behavior of Iron Fischer-Tropsch catalysts, their interaction with the silica binder and the evolution of iron phases in a synthesis gas conversion process. The results provide significant insight into factors that should be considered in the design of catalysts for the conversion of coal-derived synthesis gas into liquid fuels.

Abhaya K. Datye

1998-09-10T23:59:59.000Z

331

Tankless Coil and Indirect Water Heater Basics | Department of Energy  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: AlternativeEnvironment,Institutes and1 SpecialMaximizingResidential Buildings ¬ĽCoil and Indirect

332

Influence of sky radiance measurement errors on inversion-retrieved aerosol properties  

SciTech Connect (OSTI)

Remote sensing of the atmospheric aerosol is a well-established technique that is currently used for routine monitoring of this atmospheric component, both from ground-based and satellite. The AERONET program, initiated in the 90's, is the most extended network and the data provided are currently used by a wide community of users for aerosol characterization, satellite and model validation and synergetic use with other instrumentation (lidar, in-situ, etc.). Aerosol properties are derived within the network from measurements made by ground-based Sun-sky scanning radiometers. Sky radiances are acquired in two geometries: almucantar and principal plane. Discrepancies in the products obtained following both geometries have been observed and the main aim of this work is to determine if they could be justified by measurement errors. Three systematic errors have been analyzed in order to quantify the effects on the inversion-derived aerosol properties: calibration, pointing accuracy and finite field of view. Simulations have shown that typical uncertainty in the analyzed quantities (5% in calibration, 0.2 Degree-Sign in pointing and 1.2 Degree-Sign field of view) yields to errors in the retrieved parameters that vary depending on the aerosol type and geometry. While calibration and pointing errors have relevant impact on the products, the finite field of view does not produce notable differences.

Torres, B.; Toledano, C.; Cachorro, V. E.; Bennouna, Y. S.; Fuertes, D.; Gonzalez, R.; Frutos, A. M. de [Atmospheric Optics Group (GOA), University of Valladolid, Valladolid (Spain); Berjon, A. J. [Izana Atmospheric Research Center, Meteorological State Agency of Spain (AEMET), Sta. Cruz de Tenerife (Spain); Dubovik, O.; Goloub, P.; Podvin, T.; Blarel, L. [Laboratory of Atmospheric Optics, Universite Lille 1, Villeneuve d'Ascq (France)

2013-05-10T23:59:59.000Z

333

Indirect-fired gas turbine bottomed with fuel cell  

DOE Patents [OSTI]

An indirect-heated gas turbine cycle is bottomed with a fuel cell cycle with the heated air discharged from the gas turbine being directly utilized at the cathode of the fuel cell for the electricity-producing electrochemical reaction occurring within the fuel cell. The hot cathode recycle gases provide a substantial portion of the heat required for the indirect heating of the compressed air used in the gas turbine cycle. A separate combustor provides the balance of the heat needed for the indirect heating of the compressed air used in the gas turbine cycle. Hot gases from the fuel cell are used in the combustor to reduce both the fuel requirements of the combustor and the NOx emissions therefrom. Residual heat remaining in the air-heating gases after completing the heating thereof is used in a steam turbine cycle or in an absorption refrigeration cycle. Some of the hot gases from the cathode can be diverted from the air-heating function and used in the absorption refrigeration cycle or in the steam cycle for steam generating purposes. 1 fig.

Micheli, P.L.; Williams, M.C.; Parsons, E.L.

1995-09-12T23:59:59.000Z

334

Indirect-fired gas turbine bottomed with fuel cell  

DOE Patents [OSTI]

An indirect-heated gas turbine cycle is bottomed with a fuel cell cycle with the heated air discharged from the gas turbine being directly utilized at the cathode of the fuel cell for the electricity-producing electrochemical reaction occurring within the fuel cell. The hot cathode recycle gases provide a substantial portion of the heat required for the indirect heating of the compressed air used in the gas turbine cycle. A separate combustor provides the balance of the heat needed for the indirect heating of the compressed air used in the gas turbine cycle. Hot gases from the fuel cell are used in the combustor to reduce both the fuel requirements of the combustor and the NOx emissions therefrom. Residual heat remaining in the air-heating gases after completing the heating thereof is used in a steam turbine cycle or in an absorption refrigeration cycle. Some of the hot gases from the cathode can be diverted from the air-heating function and used in the absorption refrigeration cycle or in the steam cycle for steam generating purposes.

Micheli, Paul L. (Morgantown, WV); Williams, Mark C. (Morgantown, WV); Parsons, Edward L. (Morgantown, WV)

1995-01-01T23:59:59.000Z

335

Atmospheric Radiation Measurment (ARM) Data from the Ganges Valley, India for the Ganges Valley Aerosol Experiment (GVAX)  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

In 2011 and 2012, the Ganges Valley Aerosol Experiment (GVAX) began in the Ganges Valley region of India. The objective was to obtain measurements of clouds, precipitation, and complex aerosols to study their impact on cloud formation and monsoon activity in the region. During the Indian Ocean Experiment (INDOEX) field studies, aerosols from the Ganges Valley region were shown to affect cloud formation and monsoon activity over the Indian Ocean. The complex field study used the ARM Mobile Facility (AMF) to measure radiative, cloud, convection, and aerosol characteristics over the mainland. The resulting data set captured pre-monsoon to post-monsoon conditions to establish a comprehensive baseline for advancements in the study of the effects of atmospheric conditions of the Ganges Valley.

336

DOE research on atmospheric aerosols  

SciTech Connect (OSTI)

Atmospheric aerosols are the subject of a significant component of research within DOE`s environmental research activities, mainly under two programs within the Department`s Environmental Sciences Division, the Atmospheric Radiation Measurement (ARM) Program and the Atmospheric Chemistry Program (ACP). Research activities conducted under these programs include laboratory experiments, field measurements, and theoretical and modeling studies. The objectives and scope of these programs are briefly summarized. The ARM Program is the Department`s major research activity focusing on atmospheric processes pertinent to understanding global climate and developing the capability of predicting global climate change in response to energy related activities. The ARM approach consists mainly of testing and improving models using long-term measurements of atmospheric radiation and controlling variables at highly instrumented sites in north central Oklahoma, in the Tropical Western Pacific, and on the North Slope of Alaska. Atmospheric chemistry research within DOE addresses primarily the issue of atmospheric response to emissions from energy-generation sources. As such this program deals with the broad topic known commonly as the atmospheric source-receptor sequence. This sequence consists of all aspects of energy-related pollutants from the time they are emitted from their sources to the time they are redeposited at the Earth`s surface.

Schwartz, S.E.

1995-11-01T23:59:59.000Z

337

Application of computational fluid dynamics to aerosol sampling and concentration  

E-Print Network [OSTI]

An understanding of gas-liquid two-phase interactions, aerosol particle deposition, and heat transfer is needed. Computational Fluid Dynamics (CFD) is becoming a powerful tool to predict aerosol behavior for related design work. In this study...

Hu, Shishan

2009-05-15T23:59:59.000Z

338

Aerosol beam-focus laser-induced plasma spectrometer device  

DOE Patents [OSTI]

An apparatus for detecting elements in an aerosol includes an aerosol beam focuser for concentrating aerosol into an aerosol beam; a laser for directing a laser beam into the aerosol beam to form a plasma; a detection device that detects a wavelength of a light emission caused by the formation of the plasma. The detection device can be a spectrometer having at least one grating and a gated intensified charge-coupled device. The apparatus may also include a processor that correlates the wavelength of the light emission caused by the formation of the plasma with an identity of an element that corresponds to the wavelength. Furthermore, the apparatus can also include an aerosol generator for forming an aerosol beam from bulk materials. A method for detecting elements in an aerosol is also disclosed.

Cheng, Meng-Dawn (Oak Ridge, TN)

2002-01-01T23:59:59.000Z

339

aerosol particle penetration: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

the subsequent aerosol penetration performance through these tubes were conducted for a aerosol particle size range of 5 nm to 20 nm and a flow rate range of 28 Lmin to 169.9...

340

High Precision Control of Indirect Drive Systems Based on End-effector Sensor Information  

E-Print Network [OSTI]

Block diagram of a single-joint indirect drive train witha Figure 4.4: Block diagram of a single-joint indirect driveBlock diagram of the control system given in Section 3.6. Single-Joint

Han, Cheng-Huei

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Observer error in identifying species using indirect signs: analysis of a river otter track survey technique  

E-Print Network [OSTI]

procedure, participants misidentified the tracks of 12 species as otter. Inaccurate identification of indirect signs is a likely source of error in wildlife studies. I recommend that observer skill in identification of indirect signs be measured in order...

Evans, Jonah Wy

2007-09-17T23:59:59.000Z

342

Longwave radiative forcing of Saharan dust aerosols estimated from MODIS, MISR, and CERES observations on Terra  

E-Print Network [OSTI]

observations from the Advanced Very High Resolution Radiometer (AVHRR) [Ackerman and Chung, 1992] and the Total's Radiant Energy System (CERES) instruments onboard the Terra satellite; we present a new technique prevalent in the tropics [Prospero, 1999], dust aerosols are effective in reflecting solar energy back

Christopher, Sundar A.

343

Observations of Secondary Organic Aerosol Production and Soot Aging under Atmospheric Conditions Using a Novel Environmental Aerosol Chamber  

E-Print Network [OSTI]

of the processes leading to SOA production under ambient gaseous and particulate concentrations as well as the impact these aerosol types have on climate is poorly understood. Although the majority of atmospheric aerosols scatter radiation either directly...

Glen, Crystal

2012-02-14T23:59:59.000Z

344

Project of Aerosol Optical Depth Change in South America  

E-Print Network [OSTI]

AerosolDepth Brazil Bolivia French Guiana Suriname Guyana Venezuela Colombia Ecuador Peru Chile Argentina Suriname Guyana Venezuela Colombia Ecuador Peru Chile Argentina Paraguay Uruguay #12;Statistics of Aerosol M ean D ec 01 to 06 Mean Month AerosolDepth Brazil Bolivia French Guiana Suriname Guyana Venezuela

Frank, Thomas D.

345

Sulfuric acid deposition from stratospheric geoengineering with sulfate aerosols  

E-Print Network [OSTI]

aerosols can potentially result in an increase in acid deposition. [4] Acid rain has been studiedSulfuric acid deposition from stratospheric geoengineering with sulfate aerosols Ben Kravitz,1 Alan limit of hydration of all sulfate aerosols into sulfuric acid. For annual injection of 5 Tg of SO2

Robock, Alan

346

Organic and Inorganic Aerosol Below-Cloud Scavenging by  

E-Print Network [OSTI]

concentrations, with an average gravimetric PM1.0 of 8.2 ( 1.6 ¬Ķg m-3 and an average Fourier transform infrared-rinsing behavior was unaffected by source type. The aerosol OM was hydrophilic throughout the sampling period the description of aerosol lifetimes in global models. Introduction Wet and dry deposition of aerosol particles

Russell, Lynn

347

Indirect Combustion Noise: Experimental Investigation of the Vortex Sound Generation in a Choked  

E-Print Network [OSTI]

Indirect Combustion Noise: Experimental Investigation of the Vortex Sound Generation in a Choked-27 April 2012, Nantes, France 2315 #12;Combustion noise in gas turbines consists of direct noise related to the unsteady combustion process itself and indirect noise. As known, indirect noise is produced when entropy

Paris-Sud XI, Université de

348

CADS:Cantera Aerosol Dynamics Simulator.  

SciTech Connect (OSTI)

This manual describes a library for aerosol kinetics and transport, called CADS (Cantera Aerosol Dynamics Simulator), which employs a section-based approach for describing the particle size distributions. CADS is based upon Cantera, a set of C++ libraries and applications that handles gas phase species transport and reactions. The method uses a discontinuous Galerkin formulation to represent the particle distributions within each section and to solve for changes to the aerosol particle distributions due to condensation, coagulation, and nucleation processes. CADS conserves particles, elements, and total enthalpy up to numerical round-off error, in all of its formulations. Both 0-D time dependent and 1-D steady state applications (an opposing-flow flame application) have been developed with CADS, with the initial emphasis on developing fundamental mechanisms for soot formation within fires. This report also describes the 0-D application, TDcads, which models a time-dependent perfectly stirred reactor.

Moffat, Harry K.

2007-07-01T23:59:59.000Z

349

A high carrier injection terahertz quantum cascade laser based on indirectly pumped scheme  

SciTech Connect (OSTI)

A Terahertz quantum cascade laser with a rather high injection coupling strength based on an indirectly pumped scheme is designed and experimentally implemented. To effectively suppress leakage current, the chosen quantum cascade module of the device is based on a five-well GaAs/Al{sub 0.25}Ga{sub 0.75}As structure. The device lases up to 151?K with a lasing frequency of 2.67 THz. This study shows that the effect of higher energy states in carrier transport and the long-range tunnel coupling between states that belong to non-neighbouring modules have to be considered in quantum design of structures with a narrow injector barrier. Moreover, the effect of interface roughness scattering between the lasing states on threshold current is crucial.

Razavipour, S. G., E-mail: sgrazavi@uwaterloo.ca; Xu, C.; Wasilewski, Z. R.; Ban, D. [Department of Electrical and Computer Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Ave. W., Waterloo, Ontario N2L3G1 (Canada); Dupont, E.; Laframboise, S. R. [National Research Council, Blg. M-50, 1200 Montreal Rd., Ottawa, Ontario K1A0R6 (Canada); Chan, C. W. I.; Hu, Q. [Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2014-01-27T23:59:59.000Z

350

Aerodynamic Focusing Of High-Density Aerosols  

SciTech Connect (OSTI)

High-density micron-sized particle aerosols might form the basis for a number of applications in which a material target with a particular shape might be quickly ionized to form a cylindrical or sheet shaped plasma. A simple experimental device was built in order to study the properties of high-density aerosol focusing for 1#22; m silica spheres. Preliminary results recover previous findings on aerodynamic focusing at low densities. At higher densities, it is demonstrated that the focusing properties change in a way which is consistent with a density dependent Stokes number.

Ruiz, D. E.; Fisch, Nathaniel

2014-02-24T23:59:59.000Z

351

Complementarity between collider, direct detection, and indirect detection experiments  

E-Print Network [OSTI]

We examine the capabilities of planned direct detection, indirect detection, and collider experiments in exploring the 19-parameter p(henomenological)MSSM, focusing on the complementarity between the different search techniques. In particular, we consider dark matter searches at the 7, 8 (and eventually 14) TeV LHC, \\Fermi, CTA, IceCube/DeepCore, and LZ. We see that the search sensitivities depend strongly on the WIMP mass and annihilation mechanism, with the result that different search techniques explore orthogonal territory. We also show that advances in each technique are necessary to fully explore the space of Supersymmetric WIMPs.

Matthew Cahill-Rowley

2014-11-12T23:59:59.000Z

352

Indirect Gas Species Monitoring Using Tunable Diode Lasers  

DOE Patents [OSTI]

A method for indirect gas species monitoring based on measurements of selected gas species is disclosed. In situ absorption measurements of combustion species are used for process control and optimization. The gas species accessible by near or mid-IR techniques are limited to species that absorb in this spectral region. The absorption strength is selected to be strong enough for the required sensitivity and is selected to be isolated from neighboring absorption transitions. By coupling the gas measurement with a software sensor gas, species not accessible from the near or mid-IR absorption measurement can be predicted.

Von Drasek, William A. (Oak Forest, IL); Saucedo, Victor M. (Willowbrook, IL)

2005-02-22T23:59:59.000Z

353

Climatology of aerosol optical depth in north?central Oklahoma: 1992Ė2008  

SciTech Connect (OSTI)

Aerosol optical depth (AOD) has been measured at the Atmospheric Radiation Measurement Program central facility near Lamont, Oklahoma, since the fall of 1992. Most of the data presented are from the multifilter rotating shadowband radiometer, a narrow?band, interference?filter Sun radiometer with five aerosol bands in the visible and near infrared; however, AOD measurements have been made simultaneously and routinely at the site by as many as three different types of instruments, including two pointing Sun radiometers. Scatterplots indicate high correlations and small biases consistent with earlier comparisons. The early part of this 16 year record had a disturbed stratosphere with residual Mt. Pinatubo aerosols, followed by the cleanest stratosphere in decades. As such, the last 13 years of the record reflect changes that have occurred predominantly in the troposphere. The field calibration technique is briefly described and compared to Langley calibrations from Mauna Loa Observatory. A modified cloudscreening technique is introduced that increases the number of daily averaged AODs retrieved annually to about 250 days compared with 175 days when a more conservative method was employed in earlier studies. AODs are calculated when the air mass is less than six; that is, when the Sunís elevation is greater than 9.25į. The more inclusive cloud screen and the use of most of the daylight hours yield a data set that can be used to more faithfully represent the true aerosol climate for this site. The diurnal aerosol cycle is examined month?by?month to assess the effects of an aerosol climatology on the basis of infrequent sampling such as that from satellites.

Michalsky, Joseph J.; Denn, Frederick; Flynn, Connor J.; Hodges, G. B.; Kiedron, Piotr; Koontz, Annette S.; Schlemmer, James; Schwartz, Stephen E.

2010-04-13T23:59:59.000Z

354

Aerosol Science and Technology, 41:202216, 2007 Copyright c American Association for Aerosol Research  

E-Print Network [OSTI]

processes, such as con- densation, coagulation, gas-to-particle conversion (Reid et al. 1998), and particle Aerosol size distribution is, along with particle refractive in- dex and shape, one of important

355

Organic aerosol components observed in Northern Hemispheric datasets from Aerosol Mass Spectrometry  

E-Print Network [OSTI]

In this study we compile and present results from the factor analysis of 43 Aerosol Mass Spectrometer (AMS) datasets (27 of the datasets are reanalyzed in this work). The components from all sites, when taken together, ...

Kroll, Jesse

356

Two Hundred Fifty Years of Aerosols and Climate: The End of the Age of Aerosols  

SciTech Connect (OSTI)

Carbonaceous and sulfur aerosols have a substantial global and regional influence on climate in addition to their impact on health and ecosystems. The magnitude of this influence has changed substantially over the past and is expected to continue to change into the future. An integrated picture of the changing climatic influence of black carbon, organic carbon and sulfate over the period 1850 through 2100, focusing on uncertainty, is presented using updated historical inventories and a coordinated set of emission projections. While aerosols have had a substantial impact on climate over the past century, by the end of the 21st century aerosols will likely be only a minor contributor to radiative forcing due to increases in greenhouse gas forcing and a global decrease in pollutant emissions. This outcome is even more certain under a successful implementation of a policy to limit greenhouse gas emissions as low-carbon energy technologies that do not emit appreciable aerosol or SO2 are deployed.

Smith, Steven J.; Bond, Tami C.

2014-01-20T23:59:59.000Z

357

Small-Scale Spray Releases: Initial Aerosol Test Results  

SciTech Connect (OSTI)

One of the events postulated in the hazard analysis at the Waste Treatment and Immobilization Plant (WTP) and other U.S. Department of Energy (DOE) nuclear facilities is a breach in process piping that produces aerosols with droplet sizes in the respirable range. The current approach for predicting the size and concentration of aerosols produced in a spray leak involves extrapolating from correlations reported in the literature. These correlations are based on results obtained from small engineered spray nozzles using pure liquids with Newtonian fluid behavior. The narrow ranges of physical properties on which the correlations are based do not cover the wide range of slurries and viscous materials that will be processed in the WTP and across processing facilities in the DOE complex. Two key technical areas were identified where testing results were needed to improve the technical basis by reducing the uncertainty due to extrapolating existing literature results. The first technical need was to quantify the role of slurry particles in small breaches where the slurry particles may plug and result in substantially reduced, or even negligible, respirable fraction formed by high-pressure sprays. The second technical need was to determine the aerosol droplet size distribution and volume from prototypic breaches and fluids, specifically including sprays from larger breaches with slurries where data from the literature are scarce. To address these technical areas, small- and large-scale test stands were constructed and operated with simulants to determine aerosol release fractions and generation rates from a range of breach sizes and geometries. The properties of the simulants represented the range of properties expected in the WTP process streams and included water, sodium salt solutions, slurries containing boehmite or gibbsite, and a hazardous chemical simulant. The effect of anti-foam agents was assessed with most of the simulants. Orifices included round holes and rectangular slots. The round holes ranged in size from 0.2 to 4.46 mm. The slots ranged from (width ◊ length) 0.3 ◊ 5 to 2.74 ◊ 76.2 mm. Most slots were oriented longitudinally along the pipe, but some were oriented circumferentially. In addition, a limited number of multi-hole test pieces were tested in an attempt to assess the impact of a more complex breach. Much of the testing was conducted at pressures of 200 and 380 psi, but some tests were conducted at 100 psi. Testing the largest postulated breaches was deemed impractical because of the large size of some of the WTP equipment. This report presents the experimental results and analyses for the aerosol measurements obtained in the small-scale test stand. It includes a description of the simulants used and their properties, equipment and operations, data analysis methodologies, and test results. The results of tests investigating the role of slurry particles in plugging small breaches are reported in Mahoney et al. (2012). The results of the aerosol measurements in the large-scale test stand are reported in Schonewill et al. (2012) along with an analysis of the combined results from both test scales.

Mahoney, Lenna A.; Gauglitz, Phillip A.; Kimura, Marcia L.; Brown, Garrett N.; Kurath, Dean E.; Buchmiller, William C.; Smith, Dennese M.; Blanchard, Jeremy; Song, Chen; Daniel, Richard C.; Wells, Beric E.; Tran, Diana N.; Burns, Carolyn A.

2012-11-01T23:59:59.000Z

358

Small-Scale Spray Releases: Initial Aerosol Test Results  

SciTech Connect (OSTI)

One of the events postulated in the hazard analysis at the Waste Treatment and Immobilization Plant (WTP) and other U.S. Department of Energy (DOE) nuclear facilities is a breach in process piping that produces aerosols with droplet sizes in the respirable range. The current approach for predicting the size and concentration of aerosols produced in a spray leak involves extrapolating from correlations reported in the literature. These correlations are based on results obtained from small engineered spray nozzles using pure liquids with Newtonian fluid behavior. The narrow ranges of physical properties on which the correlations are based do not cover the wide range of slurries and viscous materials that will be processed in the WTP and across processing facilities in the DOE complex. Two key technical areas were identified where testing results were needed to improve the technical basis by reducing the uncertainty due to extrapolating existing literature results. The first technical need was to quantify the role of slurry particles in small breaches where the slurry particles may plug and result in substantially reduced, or even negligible, respirable fraction formed by high-pressure sprays. The second technical need was to determine the aerosol droplet size distribution and volume from prototypic breaches and fluids, specifically including sprays from larger breaches with slurries where data from the literature are scarce. To address these technical areas, small- and large-scale test stands were constructed and operated with simulants to determine aerosol release fractions and net generation rates from a range of breach sizes and geometries. The properties of the simulants represented the range of properties expected in the WTP process streams and included water, sodium salt solutions, slurries containing boehmite or gibbsite, and a hazardous chemical simulant. The effect of antifoam agents was assessed with most of the simulants. Orifices included round holes and rectangular slots. For the combination of both test stands, the round holes ranged in size from 0.2 to 4.46 mm. The slots ranged from (width ◊ length) 0.3 ◊ 5 to 2.74 ◊ 76.2 mm. Most slots were oriented longitudinally along the pipe, but some were oriented circumferentially. In addition, a limited number of multi-hole test pieces were tested in an attempt to assess the impact of a more complex breach. Much of the testing was conducted at pressures of 200 and 380 psi, but some tests were conducted at 100 psi. Testing the largest postulated breaches was deemed impractical because of the much larger flow rates and equipment that would be required. This report presents the experimental results and analyses for the aerosol measurements obtained in the small-scale test stand. It includes a description of the simulants used and their properties, equipment and operations, data analysis methodologies, and test results. The results of tests investigating the role of slurry particles in plugging small breaches are reported in Mahoney et al. (2012). The results of the aerosol measurements in the large-scale test stand are reported in Schonewill et al. (2012) along with an analysis of the combined results from both test scales.

Mahoney, Lenna A.; Gauglitz, Phillip A.; Kimura, Marcia L.; Brown, Garrett N.; Kurath, Dean E.; Buchmiller, William C.; Smith, Dennese M.; Blanchard, Jeremy; Song, Chen; Daniel, Richard C.; Wells, Beric E.; Tran, Diana N.; Burns, Carolyn A.

2013-05-29T23:59:59.000Z

359

Large-Scale Spray Releases: Initial Aerosol Test Results  

SciTech Connect (OSTI)

One of the events postulated in the hazard analysis at the Waste Treatment and Immobilization Plant (WTP) and other U.S. Department of Energy (DOE) nuclear facilities is a breach in process piping that produces aerosols with droplet sizes in the respirable range. The current approach for predicting the size and concentration of aerosols produced in a spray leak involves extrapolating from correlations reported in the literature. These correlations are based on results obtained from small engineered spray nozzles using pure liquids with Newtonian fluid behavior. The narrow ranges of physical properties on which the correlations are based do not cover the wide range of slurries and viscous materials that will be processed in the WTP and across processing facilities in the DOE complex. Two key technical areas were identified where testing results were needed to improve the technical basis by reducing the uncertainty due to extrapolating existing literature results. The first technical need was to quantify the role of slurry particles in small breaches where the slurry particles may plug and result in substantially reduced, or even negligible, respirable fraction formed by high-pressure sprays. The second technical need was to determine the aerosol droplet size distribution and volume from prototypic breaches and fluids, specifically including sprays from larger breaches with slurries where data from the literature are scarce. To address these technical areas, small- and large-scale test stands were constructed and operated with simulants to determine aerosol release fractions and generation rates from a range of breach sizes and geometries. The properties of the simulants represented the range of properties expected in the WTP process streams and included water, sodium salt solutions, slurries containing boehmite or gibbsite, and a hazardous chemical simulant. The effect of anti-foam agents was assessed with most of the simulants. Orifices included round holes and rectangular slots. The round holes ranged in size from 0.2 to 4.46 mm. The slots ranged from (width ◊ length) 0.3 ◊ 5 to 2.74 ◊ 76.2 mm. Most slots were oriented longitudinally along the pipe, but some were oriented circumferentially. In addition, a limited number of multi-hole test pieces were tested in an attempt to assess the impact of a more complex breach. Much of the testing was conducted at pressures of 200 and 380 psi, but some tests were conducted at 100 psi. Testing the largest postulated breaches was deemed impractical because of the large size of some of the WTP equipment. The purpose of this report is to present the experimental results and analyses for the aerosol measurements obtained in the large-scale test stand. The report includes a description of the simulants used and their properties, equipment and operations, data analysis methodology, and test results. The results of tests investigating the role of slurry particles in plugging of small breaches are reported in Mahoney et al. 2012a. The results of the aerosol measurements in the small-scale test stand are reported in Mahoney et al. (2012b).

Schonewill, Philip P.; Gauglitz, Phillip A.; Bontha, Jagannadha R.; Daniel, Richard C.; Kurath, Dean E.; Adkins, Harold E.; Billing, Justin M.; Burns, Carolyn A.; Davis, James M.; Enderlin, Carl W.; Fischer, Christopher M.; Jenks, Jeromy WJ; Lukins, Craig D.; MacFarlan, Paul J.; Shutthanandan, Janani I.; Smith, Dennese M.

2012-12-01T23:59:59.000Z

360

The Aerosol Modeling Testbed: A community tool to objectively evaluate aerosol process modules  

SciTech Connect (OSTI)

This study describes a new modeling paradigm that significantly advances how the third activity is conducted while also fully exploiting data and findings from the first two activities. The Aerosol Modeling Testbed (AMT) is a computational framework for the atmospheric sciences community that streamlines the process of testing and evaluating aerosol process modules over a wide range of spatial and temporal scales. The AMT consists of a fully-coupled meteorology-chemistry-aerosol model, and a suite of tools to evaluate the performance of aerosol process modules via comparison with a wide range of field measurements. The philosophy of the AMT is to systematically and objectively evaluate aerosol process modules over local to regional spatial scales that are compatible with most field campaigns measurement strategies. The performance of new treatments can then be quantified and compared to existing treatments before they are incorporated into regional and global climate models. Since the AMT is a community tool, it also provides a means of enhancing collaboration and coordination among aerosol modelers.

Fast, Jerome D.; Gustafson, William I.; Chapman, Elaine G.; Easter, Richard C.; Rishel, Jeremy P.; Zaveri, Rahul A.; Grell, Georg; Barth, Mary

2011-03-02T23:59:59.000Z

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Calibration of the On-Line Aerosol Monitor (OLAM) with ammonium chloride and sodium chloride aerosols  

SciTech Connect (OSTI)

The On-Line Aerosol Monitor (OLAM) is a light attenuation device designed and built at the Idaho National Engineering Laboratory (INEL) by EG&G Idaho. Its purpose is to provide an on-line indication of aerosol concentration in the PHEBUS-FP tests. It does this by measuring the attenuation of a light beam across a tube through which an aerosol is flowing. The OLAM does not inherently give an absolute response and must be calibrated. A calibration has been performed at Sandia National Laboratories` (SNL) Sandia Aerosol Research Laboratory (SARL) and the results are described here. Ammonium chloride and sodium chloride calibration aerosols are used for the calibration and the data for the sodium chloride aerosol is well described by a model presented in this report. Detectable instrument response is seen over a range of 0.1 cm{sup 3} of particulate material per m{sup 3} of gas to 10 cm{sup 3} of particulate material per m{sup 3} of gas.

Brockmann, J.E.; Lucero, D.A.; Romero, T. [Sandia National Labs., Albuquerque, NM (United States); Pentecost, G. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

1993-12-01T23:59:59.000Z

362

A new aerosol collector for quasi on-line analysis of particulate organic matter: the Aerosol Collection Module (ACM) and first applications with a GC/MS-FID  

E-Print Network [OSTI]

In many environments organic matter significantly contributes to the composition of atmospheric aerosol particles influencing its properties. Detailed chemical characterization of ambient aerosols is critical in order to ...

Hohaus, T.

363

Aerosol Spray Synthesis of Porous Molybdenum Sulfide  

E-Print Network [OSTI]

, and colloidal silica, SiO2, was ultrasonically nebulized using a household humidifier; the resulting aerosol in materials science because of their ability to be scaled-up for industrial applications.[2] USP solution, as indicated by Eq. 2. Typically, micron-sized particles are obtained; however, by adding

Suslick, Kenneth S.

364

3, 59195976, 2003 The nitrate aerosol  

E-Print Network [OSTI]

ACPD 3, 5919­5976, 2003 The nitrate aerosol field over Europe M. Schaap et al. Title Page Abstract of Utrecht, Institute of Marine and Atmospheric Science, PO Box 80005, 3508 TA, Utrecht, The Netherlands 2, The Netherlands 3 Netherlands Energy Research Foundation (ECN), PO Box 1, 1755 LE Petten, The Netherlands 4 Joint

Paris-Sud XI, Université de

365

Source Apportionment of Carbonaceous Aerosols using  

E-Print Network [OSTI]

are different than the collection of particles from water Filtration has high efficiency for all sizes Size Condensation Nuclei (CCN) Human health Carbonaceous aerosol implicated as important for toxicity and adverse of particulate matter Again, agreement between these two approaches would give a high level of confidence

Einat, Aharonov

366

Preparation of ferric-sulfide-based catalysts using an aerosol technique  

SciTech Connect (OSTI)

Iron sulfides are used as catalysts for direct coal liquefaction. They are reasonably active, cheap, and environmentally benign. This permits their use as once-through, non-regenerated catalysts. Our work in this area is based on the products of disproportionation of ferric sulfide, produced in sufficiently small particle sizes. The small particle sizes have been produced by in-situ impregnation or by using an aerosol reactor. This talk will concentrate on the aerosol process. The resulting particles have been characterized and used as catalysts for coal liquefaction. The effects of precursor solution concentration and the pressure and temperature in the aerosol reactor on the performance of the catalysts have been noted. We have recently investigated the effect of adding small amounts of a second metal to the catalyst. Multi-metal catalysts prepared to date with the aerosol technique include Fe-Cu-S and Fe-Zn-S, each with 10% additive, and Fe-Cu-Zn-S, with 10% Cu and 5% Zn.

Stiller, A.H.; Dadyburjor, D.B.; Stinespring, C.D. [West Virginia Univ., Morgantown, WV (United States)] [and others

1995-12-01T23:59:59.000Z

367

Estimates of the Global Indirect Energy-Use Emission Impacts of USA Biofuel Policy  

SciTech Connect (OSTI)

This paper evaluates the indirect energy-use emission implications of increases in the use of biofuels in the USA between 2001 and 2010 as mandates within a dynamic global computable general equilibrium model. The study incorporates explicit markets for biofuels, petroleum and other fossil fuels, and accounts for interactions among all sectors of an 18-region global economy. It considers bilateral trade, as well as the dynamics of capital allocation and investment. Simulation results show that the biofuel mandates in the USA generate an overall reduction in global energy use and emissions over the simulation period from 2001 to 2030. Consequently, the indirect energy-use emission change or emission leakage under the mandate is negative. That is, global emission reductions are larger than the direct emission savings from replacing petroleum with biofuels under the USA RFS2 over the last decade. Under our principal scenario this enhanced the direct emission reduction from biofuels by about 66%. The global change in lifecycle energy-use emissions for this scenario was estimated to be about 93 million tons of CO2e in 2010, 45 million tons of CO2e in 2020, and an increase of 5 million tons of CO2e in 2030, relative to the baseline scenario. Sensitivity results of six alternative scenarios provided additional insights into the pattern of the regional and global effects of biofuel mandates on energy-use emissions.

Oladosu, Gbadebo A [ORNL

2012-01-01T23:59:59.000Z

368

Deposition of biological aerosols on HVAC heat exchangers  

SciTech Connect (OSTI)

Many biologically active materials are transported as bioaerosols 1-10 {micro}m in diameter. These particles can deposit on cooling and heating coils and lead to serious indoor air quality problems. This paper investigates several of the mechanisms that lead to aerosol deposition on fin and tube heat exchangers. A model has been developed that incorporates the effects of several deposition mechanisms, including impaction, Brownian and turbulent diffusion, turbophoresis, thermophoresis, diffusiophoresis, and gravitational settling. The model is applied to a typical range of air velocities that are found in commercial and residential HVAC systems 1 - 6 m/s (200 - 1200 ft/min), particle diameters from 1 - 8 {micro}m, and fin spacings from 3.2 - 7.9 fins/cm (8 - 16 fins/inch or FPI). The results from the model are compared to results from an experimental apparatus that directly measures deposition on a 4.7 fins/cm (12 FPI) coil. The model agrees reasonably well with this measured data and suggests that cooling coils are an important sink for biological aerosols and consequently a potential source of indoor air quality problems.

Siegel, Jeffrey; Walker, Ian

2001-09-01T23:59:59.000Z

369

Options for controlling condensation aerosols to meet opacity standards  

SciTech Connect (OSTI)

The article gives results of an analysis of the condensing aerosol problem and an evaluation of possible control approaches to reduce the downwind detached plume opacity. The opacity of such plumes may be reduced by reducing the concentration of condensible vapors, the in-stack concentration of fine particles, or both. Results of the analysis indicate that, for low concentrations of condensible vapors, the detached-plume opacity may be adequately controlled by reducing the in-stack fine-particulate concentration alone. For high concentrations of condensible vapors, however, reduction of in-stack fine particulate concentration alone may not be effective: reduction of vapor concentration may be necessary along with particulate removal for adequate reduction of plume opacity. Different combinations of levels of reduction of vapor concentration and particulate-phase concentration are possible to achieve a desired result; and thus may be optimized to obtain a cost-effective combination.

Damle, A.S.; Ensor, D.S.; Sparks, L.E.

1987-01-01T23:59:59.000Z

370

Novel geminate recombination channel after indirect photoionization of water  

SciTech Connect (OSTI)

We studied the photolysis of neat protonated and heavy water using pump-probe and pump-repump-probe spectroscopy. A novel recombination channel is reported leading to ultrafast quenching (0.7 {+-} 0.1 ps) of almost one third of the initial number of photo-generated electrons. The efficiency and the recombination rate of this channel are lower in heavy water, 27 {+-} 5% and (0.9 {+-} 0.1 ps){sup -1}, respectively. Comparison with similar data measured after photodetachment of aqueous hydroxide provides evidence for the formation of short-lived OH:e{sup -} (OD:e{sup -}) pairs after indirect photoionization of water at 9.2 eV.

Fischer, Martin K.; Rossmadl, Hubert; Iglev, Hristo [Physik-Department E 11, Technische Universitaet Muenchen, D-85748 Garching (Germany)

2011-06-07T23:59:59.000Z

371

Linearity of Climate Response to Increases in Black Carbon Aerosols  

SciTech Connect (OSTI)

The impact of absorbing aerosols on global climate are not completely understood. Here, we present results of idealized experiments conducted with the Community Atmosphere Model (CAM4) coupled to a slab ocean model (CAM4-SOM) to simulate the climate response to increases in tropospheric black carbon aerosols (BC) by direct and semi-direct effects. CAM4-SOM was forced with 0, 1x, 2x, 5x and 10x an estimate of the present day concentration of BC while maintaining their estimated present day global spatial and vertical distribution. The top of the atmosphere (TOA) radiative forcing of BC in these experiments is positive (warming) and increases linearly as the BC burden increases. The total semi-direct effect for the 1x experiment is positive but becomes increasingly negative for higher BC concentrations. The global average surface temperature response is found to be a linear function of the TOA radiative forcing. The climate sensitivity to BC from these experiments is estimated to be 0.42 K $\\textnormal W^{-1} m^{2}$ when the semi-direct effects are accounted for and 0.22 K $\\textnormal W^{-1} m^{2}$ with only the direct effects considered. Global average precipitation decreases linearly as BC increases, with a precipitation sensitivity to atmospheric absorption of 0.4 $\\%$ $\\textnormal W^{-1} \\textnormal m^{2}$ . The hemispheric asymmetry of BC also causes an increase in southward cross-equatorial heat transport and a resulting northward shift of the inter-tropical convergence zone in the simulations at a rate of 4$^{\\circ}$N $\\textnormal PW^{-1}$. Global average mid- and high-level clouds decrease, whereas the low-level clouds increase linearly with BC. The increase in marine stratocumulus cloud fraction over the south tropical Atlantic is caused by increased BC-induced diabatic heating of the free troposphere.

Mahajan, Salil [ORNL; Evans, Katherine J [ORNL; Hack, James J [ORNL; Truesdale, John [National Center for Atmospheric Research (NCAR)

2013-01-01T23:59:59.000Z

372

Atmospheric aerosol microphysics: Formation, characterization, and interaction. Progress report, September 1, 1991--February 28, 1994  

SciTech Connect (OSTI)

This project conducts theoretical and computational studies of the physical transformation processes of aerosols which underlie their atmospheric formation, interaction, transport, and removal and derives results that contribute to improved capabilities for modelling aerosol physical and chemical evolution in support of the environmental component of the National Energy Strategy. The subject of study is submicrometer aerosol particles with primary focus upon the ultrafine fraction. This report summarizes technical progress during the first two and one-half years of the project. Results of calculations of equilibrium vapor pressures over adhering pairs of 50, 100, and 200 nm particles are reported showing substantial depression of equilibrium vapor pressure relative to isolated spheres. Calculations are given of collective, long-range intermolecular energies for irregular particles to be used for growth rate calculations for realistic particles. Molecular dynamic simulations of thermal collisions of small clusters with each other and with single atoms are presented as a function of cluster size in the range from 1 to 8 atoms. Calculations of aerosol condensation in which vapor depletion and heating effects are taken into account for atmospheric cloud nucleation modelling are reported.

Marlow, W.H.

1994-12-31T23:59:59.000Z

373

An indirect transmission measurement-based spectrum estimation method for computed tomography  

E-Print Network [OSTI]

The characteristics of an x-ray spectrum can greatly influence imaging and related tasks. In practice, due to the pile-up effect of the detector, it's difficult to directly measure the spectrum of a CT scanner using an energy resolved detector. An alternative solution is to estimate the spectrum using transmission measurements with a step phantom or other CT phantom. In this work, we present a new spectrum estimation method based on indirect transmission measurement and model spectra mixture approach. The estimated x-ray spectrum was expressed as weighted summation of a set of model spectra, which can significantly reduce the degrees of freedom (DOF) of the spectrum estimation problem. Next, an estimated projection can be calculated with the assumed spectrum. By iteratively updating the unknown weights, we minimized the difference between the estimated projection data and the raw projection data. The final spectrum was calculated with these calibrated weights and the model spectra. Both simulation and experim...

Zhao, Wei; Schafer, Sebastian; Royalty, Kevin

2015-01-01T23:59:59.000Z

374

Diagnosing residual motion via the x-ray self emission from indirectly driven inertial confinement implosions  

SciTech Connect (OSTI)

In an indirectly driven implosion, non-radial translational motion of the compressed fusion capsule is a signature of residual kinetic energy not coupled into the compressional heating of the target. A reduction in compression reduces the peak pressure and nuclear performance of the implosion. Measuring and reducing the residual motion of the implosion is therefore necessary to improve performance and isolate other effects that degrade performance. Using the gated x-ray diagnostic, the x-ray Bremsstrahlung emission from the compressed capsule is spatially and temporally resolved at x-ray energies of >8.7 keV, allowing for measurements of the residual velocity. Here details of the x-ray velocity measurement and fitting routine will be discussed and measurements will be compared to the velocities inferred from the neutron time of flight detectors.

Pak, A., E-mail: pak5@llnl.gov; Field, J. E.; Benedetti, L. R.; Caggiano, J.; Hatarik, R.; Izumi, N.; Khan, S. F.; Ma, T.; Spears, B. K.; Town, R. P. J.; Bradley, D. K. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Knauer, J. [Laboratory for Laser Energetics, Rochester, New York 14623 (United States)

2014-11-15T23:59:59.000Z

375

Retrieval of ozone and nitrogen dioxide concentrations from Stratospheric Aerosol and Gas Experiment III (SAGE III)  

E-Print Network [OSTI]

Retrieval of ozone and nitrogen dioxide concentrations from Stratospheric Aerosol and Gas extinction. We retrieve ozone and nitrogen dioxide number densities and aerosol extinction from transmission), Retrieval of ozone and nitrogen dioxide concentrations from Stratospheric Aerosol and Gas Experiment III

376

Correction to "Sulfuric acid deposition from stratospheric geoengineering with sulfate aerosols"  

E-Print Network [OSTI]

Correction to "Sulfuric acid deposition from stratospheric geoengineering with sulfate aerosols (2010), Correction to "Sulfuric acid deposition from stratospheric geoengineering with sulfate aerosols from stratospheric geoengineering with sulfate aerosols" (Journal of Geophysical Research, 114, D14109

Robock, Alan

377

Statistical analysis of aerosol species, trace gasses, and meteorology in Chicago  

E-Print Network [OSTI]

possible pollutant sources. Keywords Atmospheric aerosols . Canonical correlation analysis . Chicago air pollution studies involve collection and anal- ysis of atmospheric aerosols and concurrent meteorol- ogy) and principal component analysis (PCA) were applied to atmospheric aerosol and trace gas concentrations

O'Brien, Timothy E.

378

E-Print Network 3.0 - adjusted indirect comparison Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Technologies and Information Sciences 49 Summary of the August 2009 Forum Center for BioEnergy Sustainability (CBES) Summary: )? And how much would the indirect land-use...

379

Stackable differential mobility analyzer for aerosol measurement  

DOE Patents [OSTI]

A multi-stage differential mobility analyzer (MDMA) for aerosol measurements includes a first electrode or grid including at least one inlet or injection slit for receiving an aerosol including charged particles for analysis. A second electrode or grid is spaced apart from the first electrode. The second electrode has at least one sampling outlet disposed at a plurality different distances along its length. A volume between the first and the second electrode or grid between the inlet or injection slit and a distal one of the plurality of sampling outlets forms a classifying region, the first and second electrodes for charging to suitable potentials to create an electric field within the classifying region. At least one inlet or injection slit in the second electrode receives a sheath gas flow into an upstream end of the classifying region, wherein each sampling outlet functions as an independent DMA stage and classifies different size ranges of charged particles based on electric mobility simultaneously.

Cheng, Meng-Dawn (Oak Ridge, TN); Chen, Da-Ren (Creve Coeur, MO)

2007-05-08T23:59:59.000Z

380

ARM - PI Product - Niamey Aerosol Optical Depths  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc Documentation RUC : XDCResearchWarmingMethaneProductsCSSEFProductsMerged andAerosol Optical

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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381

Aerosol Working Group Contributions Accomplishments for 2006  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAbout the BuildingInnovation 2011 Simulation StudiesAerosol

382

3, 51395184, 2003 Urban aerosol  

E-Print Network [OSTI]

effects (Dockery and Pope, 1994). Heavily industrial-25 ized areas suffer from pollution fogs (smogs. The smaller concentrations in Kumpula were mainly due to building construction and also slight overall

Paris-Sud XI, Université de

383

TROPOSPHERIC AEROSOL PROGRAM, PROGRAM PLAN, MARCH 2001  

SciTech Connect (OSTI)

The goal of Tropospheric Aerosol Program (TAP) will be to develop the fundamental scientific understanding required to construct tools for simulating the life cycle of tropospheric aerosols--the processes controlling their mass loading, composition, and microphysical properties, all as a function of time, location, and altitude. The TAP approach to achieving this goal will be by conducting closely linked field, modeling, laboratory, and theoretical studies focused on the processes controlling formation, growth, transport, and deposition of tropospheric aerosols. This understanding will be represented in models suitable for describing these processes on a variety of geographical scales; evaluation of these models will be a key component of TAP field activities. In carrying out these tasks TAP will work closely with other programs in DOE and in other Federal and state agencies, and with the private sector. A forum to directly work with our counterparts in industry to ensure that the results of this research are translated into products that are useful to that community will be provided by NARSTO (formerly the North American Research Strategy on Tropospheric Ozone), a public/private partnership, whose membership spans government, the utilities, industry, and university researchers in Mexico, the US, and Canada.

SCHWARTZ,S.E.; LUNN,P.

2001-03-01T23:59:59.000Z

384

aerosol characteristic researching: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

as they have significant impacts both on localregional air pollution and global climate. Recent for Aerosol and Cloud Chemistry, Aerodyne Research, Incorporated, Billerica,...

385

aerosol challenge model: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

climate change is important because of its strong capability in causing extinction of solar radiation. A three-dimensional interactive aerosol-climate model has been used to...

386

Iron Speciation and Mixing in Single Aerosol Particles from the...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

iron from atmospheric aerosol is an essential nutrient that can control oceanic productivity, thereby impacting the global carbon budget and climate. Particles collected on...

387

aircraft exhaust aerosol: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Window Location on a King Air 200 Aircraft:aerosol.atmos.und.edu) Objective A Raytheon Beechcraft King Air 200 aircraft has been used to obtain Condensation Particle...

388

aerosol mass spectrometry: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

analysis of aerosol organic nitrates with electron ionization high-resolution mass spectrometry MIT - DSpace Summary: Four hydroxynitrates (R(OH)R'ONO2) representative of...

389

aerosol assisted chemical: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

soluble in water: 2. Isolation of acid, neutral, and basic fractions by modified size Weber, Rodney 5 Simulating Aerosols Using a Chemical Transport Model with Assimilation of...

390

ambient fine aerosols: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

soluble in water: 2. Isolation of acid, neutral, and basic fractions by modified size Weber, Rodney 4 Chemical characterization of the ambient organic aerosol soluble in water:...

391

aerosol chemical characteristion: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

soluble in water: 2. Isolation of acid, neutral, and basic fractions by modified size Weber, Rodney 5 Simulating Aerosols Using a Chemical Transport Model with Assimilation of...

392

aerosol characterization experiment: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

soluble in water: 2. Isolation of acid, neutral, and basic fractions by modified size Weber, Rodney 8 Desert dust aerosol age characterized by massage tracking of tracers...

393

aerosol generation characterization: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

soluble in water: 2. Isolation of acid, neutral, and basic fractions by modified size Weber, Rodney 5 Desert dust aerosol age characterized by massage tracking of tracers...

394

aerosol monitor development: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Paris May 2003John Matthews Monitoring the Aerosol Phase Function University of New Mexico 12;AstroParticles & Atmosphere, Paris May 2003John Matthews 12;AstroParticles &...

395

aerosol particle charger: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Introduction The Universal Serial Bus (USB) port Allen, Jont 9 New approaches for the chemical and physical characterization of aerosols using a single particle mass spectrometry...

396

aerosol mass spectrometer: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

2004. The concentration of a species Zhang, Qi 8 Development of a thermal desorption chemical ionization mobility mass spectrometer for the speciation of ultrafine aerosols. Open...

397

aerosol particles generated: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

the chemical and physical characterization of aerosols using a single particle mass spectrometry based technique University of California eScholarship Repository Summary: Real-...

398

aerosol monitors including: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

schemes which explicitly simulate the microphysical processes that determine the particle size distribution. These models enable aerosol optical ... Ridley, David Andrew 33...

399

aerosol retrieval validation: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

off the coast of Chile and Peru, where aerosol-cloud interactions are important to the energy balance (15), and limitations in current observing and modeling capabilities...

400

aerosol detection equipment: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Daniel, Rosenfeld 464 Mixtures of pollution, dust, sea salt, and volcanic aerosol during ACE-Asia: Radiative properties Energy Storage, Conversion and Utilization Websites...

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Aerosol generation and entrainment model for cough simulations.  

E-Print Network [OSTI]

??The airborne transmission of diseases is of great concern to the public health community. The possible spread of infectious disease by aerosols is of particularÖ (more)

Ersahin, Cem.

2007-01-01T23:59:59.000Z

402

Atmospheric pressure flow reactor / aerosol mass spectrometer studies of tropospheric aerosol nucleat and growth kinetics. Final report, June, 2001  

SciTech Connect (OSTI)

The objective of this program was to determine the mechanisms and rates of growth and transformation and growth processes that control secondary aerosol particles in both the clear and polluted troposphere. The experimental plan coupled an aerosol mass spectrometer (AMS) with a chemical ionization mass spectrometer to provide simultaneous measurement of condensed and particle phases. The first task investigated the kinetics of tropospheric particle growth and transformation by measuring vapor accretion to particles (uptake coefficients, including mass accommodation coefficients and heterogeneous reaction rate coefficients). Other work initiated investigation of aerosol nucleation processes by monitoring the appearance of submicron particles with the AMS as a function of precursor gas concentrations. Three projects were investigated during the program: (1) Ozonolysis of oleic acid aerosols as model of chemical reactivity of secondary organic aerosol; (2) Activation of soot particles by measurement deliquescence in the presence of sulfuric acid and water vapor; (3) Controlled nucleation and growth of sulfuric acid aerosols.

Worsnop, Douglas R.

2001-06-01T23:59:59.000Z

403

E-Print Network 3.0 - administrado como aerosol Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

del ozono estratosfrico, los aerosoles atmosfricos y... a los cambios en las emisiones que los GEI de larga duracin, como el CO2. Los aerosoles antropgenos... ms...

404

E-Print Network 3.0 - aerosol robotic network Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

), AERONET--A federated instrument network and data archive for aerosol characterization, Remote Sens... Period examining aerosol properties and radiative ... Source: Brookhaven...

405

E-Print Network 3.0 - aerosol condensation model Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Applied Science Collection: Environmental Sciences and Ecology 8 DETERMINING AEROSOL RADIATIVE FORCING AT ARM SITES Summary: OF AEROSOL DIRECT FORCING By linear model and by...

406

SciTech Connect: Results and code predictions for ABCOVE aerosol...  

Office of Scientific and Technical Information (OSTI)

Results and code predictions for ABCOVE aerosol code validation - Test AB5 Citation Details In-Document Search Title: Results and code predictions for ABCOVE aerosol code...

407

E-Print Network 3.0 - aerosolized polymerized type Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

spheric aerosol particles and isolated from fog... in atmospheric aerosol particles and rainwater in the 1980's (Si- moneit, 1980; Likens and ... Source: Ecole Polytechnique,...

408

E-Print Network 3.0 - aerosol radiative forcing Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

No. DE- Summary: : WHY MEASUREMENTS ALONE CANNOT QUANTIFY AEROSOL RADIATIVE FORCING OF CLIMATE CHANGE Stephen E. Schwartz... of radiative forcing of climate change by aerosols,...

409

E-Print Network 3.0 - aerosols nanometriques application Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

is studying how aerosol particles affect everything from Summary: of aerosol particles on climate change, public health, and renewable energy applications. In particular, he......

410

E-Print Network 3.0 - aerosol main physical Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AND INTEGRAL AEROSOL PROPERTIES RETRIEVAL FROM RAMAN LIDAR DATA USING PRINCIPLE COMPONENT ANALYSIS Summary: retrievals of physical aerosol parameters from ground-based and...

411

Aerosol-Cloud-Precipitation Interactions in the Trade Wind Boundary Layer.  

E-Print Network [OSTI]

??This dissertation includes an overview of aerosol, cloud, and precipitation properties associated with shallow marine cumulus clouds observed during the Barbados Aerosol Cloud Experiment (BACEX,Ö (more)

Jung, Eunsil

2012-01-01T23:59:59.000Z

412

E-Print Network 3.0 - aerosol light absorption Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AND Summary: population centers were used to calculate the aerosol forcing due to light scattering and absorption. Directly... , NY www.bnl.gov ABSTRACT Aerosols influence...

413

Large Aerosols Play Unexpected Role in Ganges Valley | U.S. DOE...  

Office of Science (SC) Website

The data have revealed that large aerosols in this region absorb a greater amount of light than expected. The Science Aerosol particles in the atmosphere may absorb solar...

414

E-Print Network 3.0 - aerosol atmospheric interactions Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

for Climate Summary: order estimates of aerosol-climate interaction But... only Earth System Models can include all... of the interactions (in theory at least) 12;Aerosols <>...

415

E-Print Network 3.0 - atmospheric aerosol size Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

for about ten percent of all aerosols in the atmosphere. We... , can actually absorb solar energy and warm the atmosphere. Atmospheric aerosols are very important... by...

416

E-Print Network 3.0 - aerosol particle size Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Summary: of aerosol over many orders-of-magnitude of particle size range, from subcritical clusters on the molecular... to modeling aerosol dynamics under conditions of new...

417

E-Print Network 3.0 - analysis od aerosol Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Tivanski, Rebecca Hopkins, Yury Desyaterik... of Aerosols 12;Aerosol Transport From Mexico City During MILAGRO T0 T1 T2 Mexico ... Source: Brookhaven National Laboratory,...

418

Direct and indirect detection of dissipative dark matter  

E-Print Network [OSTI]

We study the constraints from direct detection and solar capture on dark matter scenarios with a subdominant dissipative component. This dissipative dark matter component in general has both a symmetric and asymmetric relic abundance. Dissipative dynamics allow this subdominant dark matter component to cool, resulting in its partial or total collapse into a smaller volume inside the halo (e.g., a dark disk) as well as a reduced thermal velocity dispersion compared to that of normal cold dark matter. We first show that these features considerably relax the limits from direct detection experiments on the couplings between standard model (SM) particles and dissipative dark matter. On the other hand, indirect detection of the annihilation of the symmetric dissipative dark matter component inside the Sun sets stringent and robust constraints on the properties of the dissipative dark matter. In particular, IceCube observations force dissipative dark matter particles with mass above 50 GeV to either have a small coupling to the SM or a low local density in the solar system, or to have a nearly asymmetric relic abundance. Possible helioseismology signals associated with purely asymmetric dissipative dark matter are discussed, with no present constraints.

JiJi Fan; Andrey Katz; Jessie Shelton

2014-07-02T23:59:59.000Z

419

Laboratory Experiments and Instrument Development for the Study of Atmospheric Aerosols  

SciTech Connect (OSTI)

Soot particles are generated by incomplete combustion of fossil and biomass fuels. Through direct effects clear air aerosols containing black carbon (BC) such as soot aerosols, absorb incoming light heating the atmosphere, while most other aerosols scatter light and produce cooling. Even though BC represents only 1-2% of the total annual emissions of particulate mass to the atmosphere, it has been estimated that the direct radiative effect of BC is the second-most important contributor to global warming after absorption by CO2. Ongoing studies continue to underscore the climate forcing importance of black carbon. However, estimates of the radiative effects of black carbon on climate remain highly uncertain due to the complexity of particles containing black carbon. Quantitative measurement of BC is challenging because BC often occurs in highly non-spherical soot particles of complex morphology. Freshly emitted soot particles are typically fractal hydrophobic aggregates. The aggregates consist of black carbon spherules with diameters typically in the range of about 15-40 nm, and they are usually coated by adsorbed polyaromatic hydrocarbons (PAHs) produced during combustion. Diesel-generated soot particles are often emitted with an organic coating composed primarily of lubricating oil and unburned fuel, as well as well as PAH compounds. Sulfuric acid has also been detected in diesel and aircraft-emitted soot particles. In the course of aging, these particle coatings may be substantially altered by chemical reactions and/or the deposition of other materials. Such processes transform the optical and CCN properties of the soot aerosols in ways that are not yet well understood. Our work over the past seven years consisted of laboratory research, instrument development and characterization, and field studies with the central focus of improving our understanding of the black carbon aerosol climate impacts. During the sixth year as well as during this seventh year (no-cost extension period) of our grant, we extended our studies to perform experiments on the controlled production and characterization of secondary organic aerosol.

Davidovits, Paul

2011-12-10T23:59:59.000Z

420

INTEGRATED DIRECT/INDIRECT ADAPTIVE ROBUST CONTROL OF MULTI-DOF HYDRAULIC ROBOTIC ARMS  

E-Print Network [OSTI]

INTEGRATED DIRECT/INDIRECT ADAPTIVE ROBUST CONTROL OF MULTI-DOF HYDRAULIC ROBOTIC ARMS Amit/indirect adaptive robust control (DIARC) strategy for a hydraulically actuated 3-DOF robotic arm. To avoid the need FOUNDATION GRANT NO. CMS-0600516. draulic robot arm (a scaled down version of an industrial back- hoe

Yao, Bin

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Indirect Search of Dark Matter with the ANTARES Neutrino on behalf of the ANTARES Collaboration  

E-Print Network [OSTI]

significant high energy neutrino fluxes. Indirect search for Dark Matter looking at such neutrino fluxes for the Cherenkov light induced by high energy muons during their travel in the sea water throughout the detectorIndirect Search of Dark Matter with the ANTARES Neutrino Telescope V. Bertin1 on behalf

Paris-Sud XI, Université de

422

Optical absorption from an indirect transition in bismuth nanowires M. R. Black,1,  

E-Print Network [OSTI]

Optical absorption from an indirect transition in bismuth nanowires M. R. Black,1, * P. L; published 30 December 2003 Simulations of the optical absorption in bismuth nanowires resulting from an indirect interband L-T-point transition are presented. The absorption dependence at room temperature

Cronin, Steve

423

IX. IMPACT OF AEROSOLS FROM THE ERUPTION OF EL CHICHN ON BEAM RADIATION IN THE PACIFIC NORTHWEST  

E-Print Network [OSTI]

measured on clear days the effects of normal climatic differences are avoided. Solar radiation data taken of following this procedure for the clear day solar noon global radiation is shown in Fig. 21. The data shown27 IX. IMPACT OF AEROSOLS FROM THE ERUPTION OF EL CHICH√?N ON BEAM RADIATION IN THE PACIFIC

Oregon, University of

424

Airborne measurement of inorganic ionic components of fine aerosol particles using the particle-into-liquid sampler coupled to ion  

E-Print Network [OSTI]

. In addition to a sea-salt origin, Cl√? showed a source in urban emissions possibly related to biofuel and that NH3 and other alkaline materials were in sufficient supply to neutralize H2SO4. The [NH4 + ] to ([NO3 and health effects, knowledge of the various types of aerosol sources from different regions of the world

425

Aerosol radiative forcing and the accuracy of satellite aerosol optical depth retrieval  

E-Print Network [OSTI]

) of the AVHRR (Advanced Very High Resolution Radiometer) is typically between 0.06 and 0.15, while the RMSE between t = 0.1 and t = 0.8. The Department of Energy research satellite instrument, the Multispectral aerosol radiative forcing are known, the predictions of future global warming may remain unacceptably high

426

Sulfate Aerosol Geoengineering: The Question of Justice Toby Svoboda1,*  

E-Print Network [OSTI]

Sulfate Aerosol Geoengineering: The Question of Justice Toby Svoboda1,* , Klaus Keller2 , Marlos of geoengineering as a means to address global climate change. This paper focuses on the question of whether a particular form of geoengineering, namely deploying sulfate aerosols in the stratosphere to counteract some

427

An overview of geoengineering of climate using stratospheric sulphate aerosols  

E-Print Network [OSTI]

REVIEW An overview of geoengineering of climate using stratospheric sulphate aerosols BY PHILIP J, MD 21218, USA We provide an overview of geoengineering by stratospheric sulphate aerosols. The state after geoengineering, with some regions experiencing significant changes in temperature or precipitation

Robock, Alan

428

Organic Aerosol Formation Downwind from the Deepwater Horizon Oil Spill  

E-Print Network [OSTI]

Organic Aerosol Formation Downwind from the Deepwater Horizon Oil Spill Nicole ONeill - ATOC 3500 and aerosol composition of air over the Deepwater Horizon oil spill in the Gulf of Mexico. · The lightest chemicals in the oil evaporated within hours, as scientists expected them to do. What they didn't expect

Toohey, Darin W.

429

Spatial and Seasonal Trends in Biogenic Secondary Organic Aerosol  

E-Print Network [OSTI]

Spatial and Seasonal Trends in Biogenic Secondary Organic Aerosol Tracers and Water-Soluble Organic biogenic secondary organic aerosol (SOA) tracers via gas chromatography-mass spectrometry (GC natural and anthropogenic sources and is dominated by terrestrial plant foliage (7). The global

Zheng, Mei

430

Deposition of Biological Aerosols on HVAC Heat Exchangers  

E-Print Network [OSTI]

LBNL-47669 Deposition of Biological Aerosols on HVAC Heat Exchangers Jeffrey Siegel and Iain Walker of Biological Aerosols on HVAC Heat Exchangers Jeffrey A. Siegel Iain S. Walker, Ph.D. ASHRAE Student Member that are found in commercial and residential HVAC systems of 1 - 6 m/s (200 - 1200 ft/min), particle diameters

431

Climatology of aerosol optical depth in northcentral Oklahoma: 19922008  

E-Print Network [OSTI]

of aerosol models; for identification of aerosols from spe- cific events (e.g., the Central American fires Radiation Measurement Program central facility near Lamont, Oklahoma, since the fall of 1992. Most dimming; that is, the decrease in solar radiation reaching Earth's surface. Additionally, the wavelength

432

Absorption cross-section 139 Accumulation mode, of aerosol 146  

E-Print Network [OSTI]

133, 151 residence times 153 size distributions 144 Air composition 2 molecular weight 4, 6 Albedo 122 dioxide Coagulation (aerosol) 146 Column model 32 Conditional unstability 56 Continuity equation 75261 INDEX A Absorption cross-section 139 Accumulation mode, of aerosol 146 Acetaldehyde (CH3CHO

Jacob, Daniel J.

433

Laboratory Measurements of Sea Salt Aerosol Refractive Index  

E-Print Network [OSTI]

. . . . . . . . . . . . . . . . . . . . . . 6 1.2.3 Complex Refractive Index . . . . . . . . . . . . . . . . . . . . 6 1.2.4 Size Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1.3.5 Coagulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1.4 Sea Salt AerosolsLaboratory Measurements of Sea Salt Aerosol Refractive Index Thesis submitted for the degree

Oxford, University of

434

Cloud Condensation Nuclei (CCN) Analysis of Biogenic Secondary Organic Aerosol  

E-Print Network [OSTI]

Cloud Condensation Nuclei (CCN) Analysis of Biogenic Secondary Organic Aerosol Rachel L. Atlas1' gas-phase emissions and the aerosols they form (figure 6), including a cloud condensation nuclei Cloud condensation nuclei (CCN) are particles which water vapor condenses onto to form cloud droplets

Collins, Gary S.

435

A Computational Approach to Understanding Aerosol Formation and Oxidant Chemistry in the Troposphere  

SciTech Connect (OSTI)

An understanding of the mechanisms and kinetics of aerosol formation and ozone production in the troposphere is currently a high priority because these phenomena are recognized as two major effects of energy-related air pollution. Atmospheric aerosols are of concern because of their effect on visibility, climate, and human health. Equally important, aerosols can change the chemistry of the atmosphere, in dramatic fashion, by providing new chemical pathways (in the condensed phase) unavailable in the gas phase. The oxidation of volatile organic compounds (VOCs) and inorganic compounds (e.g., sulfuric acid, ammonia, nitric acid, ions, and mineral) can produce precursor molecules that act as nucleation seeds. The U.S. Department of Energy (DOE) Atmospheric Chemistry Program (ACP) has identified the need to evaluate the causes of variations in tropospheric aerosol chemical composition and concentrations, including determining the sources of aerosol particles and the fraction of such that are of primary and secondary origin. In particular, the ACP has called for a deeper understanding into aerosol formation because nucleation creates substantial concentrations of fresh particles that, via growth and coagulation, influence the Earth's radiation budget. Tropospheric ozone is also of concern primarily because of its impact on human health. Ozone levels are controlled by NOx and by VOCs in the lower troposphere. The VOCs can be either from natural emissions from such sources as vegetation and phytoplankton or from anthropogenic sources such as automobiles and oil-fueled power production plants. The major oxidant for VOCs in the atmosphere is the OH radical. With the increase in VOC emissions, there is rising concern regarding the available abundance of HOx species needed to initiate oxidation. Over the last five years, there have been four field studies aimed at initial measurements of HOx species (OH and HO? radicals). These measurements revealed HOx levels that are two to four times higher than expected from the commonly assumed primary sources. Such elevated abundances of HOx imply a more photochemically active troposphere than previously thought. This implies that rates of ozone formation in the lower region of the atmosphere and the oxidation of SO? can be enhanced, thus promoting the formation of new aerosol properties. Central to unraveling this chemistry is the ability to assess the photochemical product distributions resulting from the photodissociation of by-products of VOC oxidation. We propose to use state-of-the-art theoretical techniques to develop a detailed understanding of the mechanisms of aerosol formation in multicomponent (mixed chemical) systems and the photochemistry of atmospheric organic species. The aerosol studies involve an approach that determines homogeneous gas-particle nucleation rates from knowledge of the molecular interactions that are used to define properties of molecular clusters. Over the past several years we developed Dynamical Nucleation Theory (DNT), a novel advance in the theoretical description of homogeneous gas-liquid nucleation, and applied it to gas-liquid nucleation of a single component system (e.g., water). The goal of the present research is to build upon these advances by extending the theory to multicomponent systems important in the atmosphere (such as clusters containing sulfuric acid, water, ions, ammonia, and organics). In addition, high-level ab initio electronic structure calculations will be used to unravel the chemical reactivity of the OH radical and water clusters.

Francisco, Joseph S.; Kathmann, Shawn M.; Schenter, Gregory K.; Dang, Liem X.; Xantheas, Sotiris S.; Garrett, Bruce C.; Du, Shiyu; Dixon, David A.; Bianco, Roberto; Wang, Shuzhi; Hynes, James T.; Morita, Akihiro; Peterson, Kirk A.

2006-04-18T23:59:59.000Z

436

Aerosols generated by spills of viscous solutions and slurries  

SciTech Connect (OSTI)

Safety assessments and environmental impact statements for nuclear fuel cycle facilities require an estimate of potential airborne releases caused by accidents. Aerosols generated by accidents are being investigated by Pacific Northwest Laboratory to develop methods for estimating source terms from these accidents. Experiments were run by spilling viscous solutions and slurries to determine the mass and particle-size distribution of the material made airborne. In all cases, 1 L of solution was spilled from a height of 3 m. Aqueous solutions of sucrose (0 to 56%) gave a range of viscosities from 1.3 to 46 cp. The percent of spill mass made airborne from the spills of these solutions ranged from 0.001 to 0.0001. The mass of particles made airborne decreased as solution viscosity increased. Slurry loading ranged from 25 to 51% total solids. The maximum source airborne (0.0046 wt %) occurred with the slurry that had the lightest loading of soluble solids. The viscosity of the carrying solution also had an impact on the source term from spilling slurries. The effect of surface tension on the source term was examined in two experiments. Surface tension was halved in these spills by adding a surfactant. The maximum weight percent airborne from these spills was 0.0045, compared to 0.003 for spills with twice the surface tension. The aerodynamic mass medium diameters for the aerosols produced by spills of the viscous solutions, slurries, and low surface tension liquids ranged from 0.6 to 8.4 ..mu..m, and the geometric standard deviation ranged from 3.8 to 28.0.

Ballinger, M Y; Hodgson, W H

1986-12-01T23:59:59.000Z

437

Method of dispersing particulate aerosol tracer  

DOE Patents [OSTI]

A particulate aerosol tracer which comprises a particulate carrier of sheet silicate composition having a particle size up to one micron, and a cationic dopant chemically absorbed in solid solution in the carrier. The carrier is preferably selected from the group consisting of natural mineral clays such as bentonite, and the dopant is selected from the group consisting of rare earth elements and transition elements. The tracers are dispersed by forming an aqueous salt solution with the dopant present as cations, dispersing the carriers in the solution, and then atomizing the solution under heat sufficient to superheat the solution droplets at a level sufficient to prevent reagglomeration of the carrier particles.

O'Holleran, Thomas P. (Belleville, MI)

1988-01-01T23:59:59.000Z

438

Aerosol Remote Sealing System - Energy Innovation Portal  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAbout the BuildingInnovation 2011 Simulation StudiesAerosol Remote Sealing

439

Aerosol dispersion and coagulation from a coal-fired power plant: a three dimensional numerical model  

SciTech Connect (OSTI)

A computational model to simulate the dispersion and coagulation of aerosols emitted from coal-fired power plants was constructed. In modeling the dispersion of the aerosol, turbulent diffusion and wind-driven advection are treated by a finite-difference method. Molecular coagulation is incorporated in the model to follow shifts in the particle-size distribution. Particulate coagulation is mathematically described by Timiskii's equation. The relevent semi-empirical work of Smirnov is incorporated in the model to provide for the coagultion constant. Input for the model is a bimodal, particle-size distribution measured at an operating coal-fired power plant. Simulations indicate that dispersion competes against coagulation mechanisms to maintain the bimodal shaped distribution for 32 km. Turbulence and particle settling tend to enchance coagulation effects. The size-dependent spatial segregation of particles within the plume is predicted.

Buckholtz, H.T.; Biermann, A.H.

1980-01-01T23:59:59.000Z

440

Interpretation of Secondary Organic Aerosol Formation from Diesel Exhaust Photooxidation in an Environmental Chamber  

SciTech Connect (OSTI)

Secondary organic aerosol (SOA) formation from diesel exhaust in a smog chamber was investigated. Particle volume measurement based on mobility diameter is shown to underestimate SOA formation from diesel exhaust due to the external void space of agglomerate particles, in which case mass-based measurement technique is necessary. Rapid determination of particle effective density as a function of particle mass was performed by an Aerosol Particle Mass analyzer Ė Scanning Mobility Particle Sizer (APM-SMPS) to obtain particle mass concentration and fractal dimension. Continuous aging of aerosol was observed in terms of atomic ratio (O/C), from 0.05 to 0.25 in 12 hours, underscoring the importance of multi-generational oxidation of low-volatile organic vapors emitted from diesel engine as the significant source of oxygenated SOA. Experimental conditions possibly have strong impacts on physical evolution of diesel particulates in a smog chamber. Higher particle effective densities were observed when raw exhaust was injected into a full bag as opposed to filling a bag with diluted exhaust using an ejector diluter. When longer transfer line was used for injecting diesel exhaust into the smog chamber, rapid particle coagulation was observed, leading to increasing particle volume concentration in dark while its mass concentration is decreasing.

Nakao, Shunsuke; Shrivastava, ManishKumar B.; Nguyen, Anh; Jung, Hee-Jung; Cocker, David R.

2011-04-14T23:59:59.000Z

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

ARM: 10-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

10-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm

Newsom, Rob; Goldsmith, John

442

ARM: 2-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

2-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm

Sivaraman, Chitra; Flynn, Connor

443

ARM: 10-second Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

10-second Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm

Sivaraman, Chitra; Flynn, Connor

444

ARM: 1-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

1-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm

Sivaraman, Chitra; Flynn, Connor

445

spectra from size-resolved particle samples col-lected from the Southeastern Aerosol Visibility  

E-Print Network [OSTI]

and acrolein aerosols. We believe that these transformations are due to acid-catalyzed heterogeneous reac

Bishop, James K.B.

446

Assessment of the Upper Particle Size Limit for Quantitative Analysis of Aerosols Using  

E-Print Network [OSTI]

the vaporization dynamics of individual aerosol particles, such as thermophoretic forces and vapor expulsion. Since

Hahn, David W.

447

Hyperspectral Aerosol Optical Depths from TCAP Flights  

SciTech Connect (OSTI)

4STAR (Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research), the worldís first hyperspectral airborne tracking sunphotometer, acquired aerosol optical depths (AOD) at 1 Hz during all July 2012 flights of the Two Column Aerosol Project (TCAP). Root-mean square differences from AERONET ground-based observations were 0.01 at wavelengths between 500-1020 nm, 0.02 at 380 and 1640 nm and 0.03 at 440 nm in four clear-sky fly-over events, and similar in ground side-by-side comparisons. Changes in the above-aircraft AOD across 3-km-deep spirals were typically consistent with integrals of coincident in situ (on DOE Gulfstream 1 with 4STAR) and lidar (on NASA B200) extinction measurements within 0.01, 0.03, 0.01, 0.02, 0.02, 0.02 at 355, 450, 532, 550, 700, 1064 nm, respectively, despite atmospheric variations and combined measurement uncertainties. Finer vertical differentials of the 4STAR measurements matched the in situ ambient extinction profile within 14% for one homogeneous column. For the AOD observed between 350-1660 nm, excluding strong water vapor and oxygen absorption bands, estimated uncertainties were ~0.01 and dominated by (then) unpredictable throughput changes, up to +/-0.8%, of the fiber optic rotary joint. The favorable intercomparisons herald 4STARís spatially-resolved high-frequency hyperspectral products as a reliable tool for climate studies and satellite validation.

Shinozuka, Yohei; Johnson, Roy R.; Flynn, Connor J.; Russell, P. B.; Schmid, Beat; Redemann, Jens; Dunagan, Stephen; Kluzek, Celine D.; Hubbe, John M.; Segal-Rosenheimer, Michal; Livingston, J. M.; Eck, T.; Wagener, Richard; Gregory, L.; Chand, Duli; Berg, Larry K.; Rogers, Ray; Ferrare, R. A.; Hair, John; Hostetler, Chris A.; Burton, S. P.

2013-11-13T23:59:59.000Z

448

Vapor scavenging by atmospheric aerosol particles  

SciTech Connect (OSTI)

Particle growth due to vapor scavenging was studied using both experimental and computational techniques. Vapor scavenging by particles is an important physical process in the atmosphere because it can result in changes to particle properties (e.g., size, shape, composition, and activity) and, thus, influence atmospheric phenomena in which particles play a role, such as cloud formation and long range transport. The influence of organic vapor on the evolution of a particle mass size distribution was investigated using a modified version of MAEROS (a multicomponent aerosol dynamics code). The modeling study attempted to identify the sources of organic aerosol observed by Novakov and Penner (1993) in a field study in Puerto Rico. Experimentally, vapor scavenging and particle growth were investigated using two techniques. The influence of the presence of organic vapor on the particle`s hydroscopicity was investigated using an electrodynamic balance. The charge on a particle was investigated theoretically and experimentally. A prototype apparatus--the refractive index thermal diffusion chamber (RITDC)--was developed to study multiple particles in the same environment at the same time.

Andrews, E.

1996-05-01T23:59:59.000Z

449

The Radiative Role of Free Tropospheric Aerosols and Marine Clouds over the Central North Atlantic  

SciTech Connect (OSTI)

The scientific scope of the project was to exploit the unique location of the Pico Mountain Observatory (PMO) located in the summit caldera of the Pico Volcano in Pico Island in the Azores, for atmospheric studies. The observatory, located at 2225m a.s.l., typically samples free tropospheric aerosols laying above the marine low-level clouds and long-range transported from North America. The broad purpose of this research was to provide the scientific community with a better understanding of fundamental physical processes governing the effects of aerosols on radiative forcing and climate; with the ultimate goal of improving our abilities to understand past climate and to predict future changes through numerical models. The project was 'exploratory' in nature, with the plan to demonstrate the feasibility of deploying for the first time, an extensive aerosol research package at PMO. One of the primary activities was to test the deployment of these instruments at the site, to collect data during the 2012 summer season, and to further develop the infrastructure and the knowledge for performing novel research at PMO in follow-up longer-term aerosol-cloud studies. In the future, PMO could provide an elevated research outpost to support the renewed DOE effort in the Azores that was intensified in 2013 with the opening of the new sea-level ARM-DOE Eastern North Atlantic permanent facility at Graciosa Island. During the project period, extensive new data sets were collected for the planned 2012 season. Thanks to other synergistic activities and opportunities, data collection was then successfully extended to 2013 and 2014. Highlights of the scientific findings during this project include: a) biomass burning contribute significantly to the aerosol loading in the North Atlantic free troposphere; however, long-range transported black carbon concentrations decreased substantially in the last decade. b) Single black carbon particles Ė analyzed off-line at the electron microscope Ė were often very compacted, suggesting cloud processing and exhibiting different optical properties from fresh emissions. In addition, black carbon was found to be sometimes mixed with mineral dust, affecting its optical properties and potential forcing. c) Some aerosols collected at PMO acted as ice nuclei, potentially contributing to cirrus cloud formation during their transport in the upper free troposphere. Identified good ice nuclei were often mineral dust particles. d) The free tropospheric aerosols studied at PMO have relevance to low level marine clouds due, for example, to synoptic subsidence entraining free tropospheric aerosols into the marine boundary layer. This has potentially large consequences on cloud condensation nuclei concentrations and compositions in the marine boundary layer; therefore, having an effect on the marine stratus clouds, with potentially important repercussions on the radiative forcing. The scientific products of this project currently include contributions to two papers published in the Nature Publishing group (Nature Communications and Scientific Reports), one paper under revision for Atmospheric Chemistry and Physics, one in review in Geophysical Research Letters and one recently submitted to Atmospheric Chemistry and Physics Discussion. In addition, four manuscripts are in advanced state of preparation. Finally, twenty-eight presentations were given at international conferences, workshops and seminars.

Mazzoleni, Claudio [Michigan Technological University; Kumar, Sumit [Michigan Technological University; Wright, Kendra [Michigan Technological University; Kramer, Louisa [Michigan Technological University; Mazzoleni, Lynn [Michigan Technological University; Owen, Robert [Michigan Technological University; Helmig, Detlev [University of Colorado at Boulder

2014-12-09T23:59:59.000Z

450

Criteria pollutant and acid aerosol characterization study, Catano, Puerto Rico  

SciTech Connect (OSTI)

The primary objective of the Catano Criteria Pollutant and Acid Aerosol Characterization Study (CPAACS) was to measure criteria pollutant concentrations and acid aerosol concentrations in and around the Ward of Catano, Puerto Rico, during the summer of 1994. Continuous air sampling for criteria pollutants was performed at three fixed stations and one moobile station that was deployed to four locations. Air samples for acid aerosol analyses and particulate matter measurements were collected at three sites. Semicontinuous sulfate analysis was performed at the primary site. Continuous measurements of wind speed, wind direction, temperature, and relative humidity were also made at each site. The study was conducted from June 1 through September 30, 1994.

Edgerton, E.S.; Harlos, D.P.; Sune, J.M.; Akland, G.G.; Vallero, D.A.

1995-07-01T23:59:59.000Z

451

An indirectly pumped terahertz quantum cascade laser with low injection coupling strength operating above 150?K  

E-Print Network [OSTI]

We designed and demonstrated a terahertz quantum cascade laser based on indirect pump injection to the upper lasing state and phonon scattering extraction from the lower lasing state. By employing a rate equation formalism ...

Razavipour, S. G.

452

Development of an indirect competitive ELISA for the detection of protective antibodies in pasteurella pneumonia  

E-Print Network [OSTI]

An indirect competitive enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against Pasteurella haemolytica was developed. The capsular material of the bacteria was extracted in saline for use as antigen. The antigen...

Sewell, Julie Elizabeth

2012-06-07T23:59:59.000Z

453

A New Aerosol Flow System for Photochemical and Thermal Studies of Tropospheric Aerosols  

SciTech Connect (OSTI)

For studying the formation and photochemical/thermal reactions of aerosols relevant to the troposphere, a unique, high-volume, slow-flow, stainless steel aerosol flow system equipped with 5 UV lamps has been constructed and characterized experimentally. The total flow system length 6 is 8.5 m and includes a 1.2 m section used for mixing, a 6.1 m reaction section and a 1.2 m 7 transition cone at the end. The 45.7 cm diameter results in a smaller surface to volume ratio than is found in many other flow systems and thus reduces the potential contribution from wall reactions. The latter are also reduced by frequent cleaning of the flow tube walls which is made feasible by the ease of disassembly. The flow tube is equipped with ultraviolet lamps for photolysis. This flow system allows continuous sampling under stable conditions, thus increasing the amount of sample available for analysis and permitting a wide variety of analytical techniques to be applied simultaneously. The residence time is of the order of an hour, and sampling ports located along the length of the flow tube allow for time-resolved measurements of aerosol and gas-phase products. The system was characterized using both an inert gas (CO2) and particles (atomized NaNO3). Instruments interfaced directly to this flow system include a NOx analyzer, an ozone analyzer, relative humidity and temperature probes, a scanning mobility particle sizer spectrometer, an aerodynamic particle sizer spectrometer, a gas chromatograph-mass spectrometer, an integrating nephelometer, and a Fourier transform infrared spectrophotometer equipped with a long path (64 m) cell. Particles collected with impactors and filters at the various sampling ports can be analyzed subsequently by a variety of techniques. Formation of secondary organic aerosol from ?-pinene reactions (NOx photooxidation and ozonolysis) are used to demonstrate the capabilities of this new system.

Ezell, Michael J.; Johnson, Stanley N.; Yu, Yong; Perraud, Veronique; Bruns, Emily; Alexander, M. L.; Zelenyuk, Alla; Dabdub, Donald; Finlayson-Pitts, Barbara J.

2010-05-01T23:59:59.000Z

454

Case Study of Water-Soluble Metal Containing Organic Constituents of Biomass Burning Aerosol  

SciTech Connect (OSTI)

Natural and prescribed biomass fires are a major source of atmospheric aerosols that can persist in the atmosphere for long periods of time. Biomass burning aerosols (BBA) can be associated with long range transport of water soluble N?, S?, P?, and metal?containing species. In this study, BBA samples were collected using a particle?into?liquid sampler (PILS) from laboratory burns of vegetation collected on military bases in the southeastern and southwestern United States. The samples were then analyzed using high resolution electrospray ionization mass spectrometry (ESI/HR?MS) that enabled accurate mass measurements for hundreds of species with m/z values between 70 and 1000 and assignment of probable elemental formulae. Mg, Al, Ca, Cr, Mn, Fe, Ni, Cu, Zn, and Ba?containing organometallic species were identified. The results suggest that the biomass may have accumulated metal?containing species that were reemitted during biomass burning. Further research into the sources, persistence, and dispersion of metal?containing aerosols as well as their environmental effects is needed.

Chang-Graham, Alexandra L.; Profeta, Luisa Tm; Johnson, Timothy J.; Yokelson, Robert J.; Laskin, Alexander; Laskin, Julia

2011-01-10T23:59:59.000Z

455

Mexico City Aerosol Analysis During Milagro Using High Resolution Aerosol Mass Spectrometry at the Urban Supersite (T0) - Part 1: Fine Particle Composition and Organic Source Apportionment.  

E-Print Network [OSTI]

Submicron aerosol was analyzed during the MILAGRO field campaign in March 2006 at the T0 urban supersite in Mexico City with a High-Resolution Aerosol Mass Spectrometer (AMS) and complementary instrumentation. Positive ...

Aiken, A. C.

456

Sensitivity of aerosol properties to new particle formation mechanism and to primary emissions in a continental-scale chemical  

E-Print Network [OSTI]

of aerosol particles and in turn their number concentration and size distribution. Aerosol particles can grow contribution from coagulation. The aerosol mass concentration, which is primarily in the accumulation mode of aerosol number concentration and size distri- bution is important for considerations of the aerosol

457

Options for controlling condensation aerosols to meet opacity standards  

SciTech Connect (OSTI)

The opacity of detached plumes formed by condensation of vapors depends upon both the concentration of condensible vapors and the in-stack concentration of fine, submicron, particulate matter. This paper provides an analysis of the condensing aerosol problem and an evaluation of possible control approaches to reduce the downwind detached plume opacity. The opacity of such plumes may be reduced by reducing the concentration of condensible vapors or the in-stack concentration of fine particles or both. The results of the analysis indicate that for low concentrations of condensible vapors the detached plume opacity may be adequately controlled by reducing the in-stack fine particulate concentration alone. For high concentrations of condensible vapors, however, reduction of in-stack fine particulate concentration alone may not be effective, and reduction of vapor concentration may be necessary along with particular removal for adequate reduction of plume opacity. Different combinations of levels of reduction of vapor concentration and particulate phase concentration are possible to achieve a desired result; and thus may be optimized to obtain a cost-effective combination.

Damle, A.S.; Ensor, D.S.; Sparks, L.E.

1987-08-01T23:59:59.000Z

458

Direct Surface Analysis of Time-Resolved Aerosol Impactor Samples with Ultrahigh-Resolution Mass Spectrometry  

E-Print Network [OSTI]

.; Pan, Y.; Mitloehner, F. M. Atmos. Environ. 2012, Submitted. (21) Lundgren, D. A. Journal of the Air Pollution Control Association 1967, 17, 225-9. (22) Schultz, G. A.; Corso, T. N.; Prosser, S. J.; Zhang, S. Anal. Chem. 2000, 72, 4058-4063. 19... in negative health effects caused by air pollution and are linked to increases in respiratory and cardio-vascular diseases2,3. All these particle effects are influenced by the chemical composition of the aerosol particles. A major fraction, often more than 50...

Fuller, Stephen J.; Zhao, Yongjing; Cliff, Steven S.; Wexler, Anthony S.; Kalberer, Markus

2012-10-18T23:59:59.000Z

459

Present and potential future contributions of sulfate, black and organic carbon aerosols from China to global air quality, premature mortality and  

E-Print Network [OSTI]

analysis indicates that increased effort to reduce greenhouse gases is essential to address climate change mortality and climate change has not been well quantified. Through both direct radiative effects, they have not considered the effect of aerosols on radiative forcing (RF) and climate change. Although

Mauzerall, Denise

460

Frontiers in Global Change Seminar Series  

E-Print Network [OSTI]

particles ("aerosols") exert a net cooling effect by directly scattering and absorption of solar radiation (or ice crystal) formation; polluted clouds tend to have more droplets than their pristine that aerosol impacts on clouds (known as "aerosol indirect climatic effects") have a net cooling effect

Note: This page contains sample records for the topic "indirect aerosol effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Optimized beryllium target design for indirectly driven inertial confinement fusion experiments on the National Ignition Facility  

SciTech Connect (OSTI)

For indirect drive inertial confinement fusion, Beryllium (Be) ablators offer a number of important advantages as compared with other ablator materials, e.g., plastic and high density carbon. In particular, the low opacity and relatively high density of Be lead to higher rocket efficiencies giving a higher fuel implosion velocity for a given X-ray drive; and to higher ablation velocities providing more ablative stabilization and reducing the effect of hydrodynamic instabilities on the implosion performance. Be ablator advantages provide a larger target design optimization space and can significantly improve the National Ignition Facility (NIF) [J. D. Lindl et al., Phys. Plasmas 11, 339 (2004)] ignition margin. Herein, we summarize the Be advantages, briefly review NIF Be target history, and present a modern, optimized, low adiabat, Revision 6 NIF Be target design. This design takes advantage of knowledge gained from recent NIF experiments, including more realistic levels of laser-plasma energy backscatter, degraded hohlraum-capsule coupling, and the presence of cross-beam energy transfer.

Simakov, Andrei N., E-mail: simakov@lanl.gov; Wilson, Douglas C.; Yi, Sunghwan A.; Kline, John L.; Batha, Steven H. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545 (United States); Clark, Daniel S.; Milovich, Jose L.; Salmonson, Jay D. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)] [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)

2014-02-15T23:59:59.000Z

462

Indirect ultraviolet photodesorption from CO:N2 binary ices - an efficient grain-gas process  

E-Print Network [OSTI]

UV ice photodesorption is an important non-thermal desorption pathway in many interstellar environments that has been invoked to explain observations of cold molecules in disks, clouds and cloud cores. Systematic laboratory studies of the photodesorption rates, between 7 and 14 eV, from CO:N2 binary ices, have been performed at the DESIRS vacuum UV beamline of the synchrotron facility SOLEIL. The photodesorption spectral analysis demonstrates that the photodesorption process is indirect, i.e. the desorption is induced by a photon absorption in sub-surface molecular layers, while only surface molecules are actually desorbing. The photodesorption spectra of CO and N2 in binary ices therefore depend on the absorption spectra of the dominant species in the subsurface ice layer, which implies that the photodesorption efficiency and energy dependence are dramatically different for mixed and layered ices compared to pure ices. In particular, a thin (1-2 ML) N2 ice layer on top of CO will effectively quench CO photod...

Bertin, Mathieu; Romanzin, Claire; Poderoso, Hugo A M; Michaut, Xavier; Philippe, Laurent; Jeseck, Pascal; ÷berg, Karin I; Linnartz, Harold; Fillion, Jean-Hugues

2013-01-01T23:59:59.000Z

463

Aerosol mass spectrometry systems and methods  

DOE Patents [OSTI]

A system according to one embodiment includes a particle accelerator that directs a succession of polydisperse aerosol particles along a predetermined particle path; multiple tracking lasers for generating beams of light across the particle path; an optical detector positioned adjacent the particle path for detecting impingement of the beams of light on individual particles; a desorption laser for generating a beam of desorbing light across the particle path about coaxial with a beam of light produced by one of the tracking lasers; and a controller, responsive to detection of a signal produced by the optical detector, that controls the desorption laser to generate the beam of desorbing light. Additional systems and methods are also disclosed.

Fergenson, David P.; Gard, Eric E.

2013-08-20T23:59:59.000Z

464

Soot particle aerosol dynamics at high pressure  

SciTech Connect (OSTI)

The authors have used detailed calculations to analyze the coagulation dynamics of a soot aerosol at high pressures (20 and 50 atm). They find that the soot size distribution is altered compared to lower-pressure conditions because the mean free path at high pressures is reduced to the point that the particles are similar in size to the mean free path. At lower pressures the form of the size distribution becomes constant (self-preserving) in time, allowing optical measurements to be easily interpreted. However, the authors find that at pressures above about 5 atm the shape of the size distribution continually changes. As a result, proper and accurate interpretation of optical data at high pressures is more difficult than at lower pressures.

Harris, S.J. (General Motors Research Labs., Warren, MI (USA). Physics Dept.); Kennedy, I.M. (California Univ., Davis, CA (USA). Dept. of Mechanical Engineering)

1989-12-01T23:59:59.000Z

465

Diesel Aerosol Sampling in the Atmosphere  

SciTech Connect (OSTI)

The University of Minnesota Center for Diesel Research along with a research team including Caterpillar, Cummins, Carnegie Mellon University, West Virginia University (WVU), Paul Scherrer Institute in Switzerland, and Tampere University in Finland have performed measurements of Diesel exhaust particle size distributions under real-world dilution conditions. A mobile aerosol emission laboratory (MEL) equipped to measure particle size distributions, number concentrations, surface area concentrations, particle bound PAHs, as well as CO 2 and NO x concentrations in real time was built and will be described. The MEL was used to follow two different Cummins powered tractors, one with an older engine (L10) and one with a state-of-the-art engine (ISM), on rural highways and measure particles in their exhaust plumes. This paper will describe the goals and objectives of the study and will describe representative particle size distributions observed in roadway experiments with the truck powered by the ISM engine.

David Kittelson; Jason Johnson; Winthrop Watts; Qiang Wei; Marcus Drayton; Dwane Paulsen; Nicolas Bukowiecki

2000-06-19T23:59:59.000Z

466

aerosol content monitoring: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Rings, Jrg 2008-01-01 6 The impact of aerosols on simulated ocean temperature and heat content in the 20th century Environmental Sciences and Ecology Websites Summary: The...

467

Continuous air monitor for alpha-emitting aerosol particles  

SciTech Connect (OSTI)

A new alpha Continuous Air Monitor (CAM) sampler is being developed for use in detecting the presence of alpha-emitting aerosol particles. The effort involves design, fabrication and evaluation of systems for the collection of aerosol and for the processing of data to speciate and quantify the alpha emitters of interest. At the present time we have a prototype of the aerosol sampling system and we have performed wind tunnel tests to characterize the performance of the device for different particle sizes, wind speeds, flow rates and internal design parameters. The results presented herein deal with the aerosol sampling aspects of the new CAM sampler. Work on the data processing, display and alarm functions is being done in parallel with the particle sampling work and will be reported separately at a later date. 17 refs., 5 figs., 3 tabs.

McFarland, A.R.; Ortiz, C.A. (Texas A and M Univ., College Station, TX (USA). Dept. of Mechanical Engineering); Rodgers, J.C.; Nelson, D.C. (Los Alamos National Lab., NM (USA))

1990-01-01T23:59:59.000Z

468

Pressure-flow reducer for aerosol focusing devices  

DOE Patents [OSTI]

A pressure-flow reducer, and an aerosol focusing system incorporating such a pressure-flow reducer, for performing high-flow, atmosphere-pressure sampling while delivering a tightly focused particle beam in vacuum via an aerodynamic focusing lens stack. The pressure-flow reducer has an inlet nozzle for adjusting the sampling flow rate, a pressure-flow reduction region with a skimmer and pumping ports for reducing the pressure and flow to enable interfacing with low pressure, low flow aerosol focusing devices, and a relaxation chamber for slowing or stopping aerosol particles. In this manner, the pressure-flow reducer decouples pressure from flow, and enables aerosol sampling at atmospheric pressure and at rates greater than 1 liter per minute.

Gard, Eric (San Francisco, CA); Riot, Vincent (Oakland, CA); Coffee, Keith (Diablo Grande, CA); Woods, Bruce (Livermore, CA); Tobias, Herbert (Kensington, CA); Birch, Jim (Albany, CA); Weisgraber, Todd (Brentwood, CA)

2008-04-22T23:59:59.000Z

469