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1

ARM - PI Product - Direct Aerosol Forcing Uncertainty  

NLE Websites -- All DOE Office Websites (Extended Search)

ProductsDirect Aerosol Forcing Uncertainty ProductsDirect Aerosol Forcing Uncertainty Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send PI Product : Direct Aerosol Forcing Uncertainty Site(s) NSA SGP TWP General Description 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

2

Direct radiative forcing of anthropogenic organic aerosol  

E-Print Network (OSTI)

[1] This study simulates the direct radiative forcing of organic aerosol using the GFDL AM2 GCM. The aerosol climatology is provided by the MOZART chemical transport model (CTM). The approach to calculating aerosol optical properties explicitly considers relative humidity–dependent hygroscopic growth by employing a functional group– based thermodynamic model, and makes use of the size distribution derived from AERONET measurements. The preindustrial (PI) and present-day (PD) global burdens of organic carbon are 0.17 and 1.36 Tg OC, respectively. The annual global mean total-sky and clear-sky top-of-the atmosphere (TOA) forcings (PI to PD) are estimated as 0.34 and 0.71 W m 2, respectively. Geographically the radiative cooling largely lies over the source regions, namely part of South America, Central Africa, Europe and South and East Asia. The annual global mean total-sky and clear-sky surface forcings are 0.63 and 0.98 W m 2, respectively. A series of sensitivity analyses shows that the treatments of hygroscopic growth and optical properties of organic aerosol are intertwined in the determination of the global organic aerosol forcing. For example, complete deprivation of water uptake by hydrophilic organic particles reduces the standard (total-sky) and clearsky TOA forcing estimates by 18 % and 20%, respectively, while the uptake by a highly soluble organic compound (malonic acid) enhances them by 18 % and 32%, respectively. Treating particles as non-absorbing enhances aerosol reflection and increases the total-sky and clear-sky TOA forcing by 47 % and 18%, respectively, while neglecting the scattering brought about by the water associated with particles reduces them by 24% and 7%, respectively.

Yi Ming; V. Ramaswamy; Paul A. Ginoux; Larry H. Horowitz

2005-01-01T23:59:59.000Z

3

Direct Aerosol Forcing in the Infrared at the SGP Site?  

NLE Websites -- All DOE Office Websites (Extended Search)

Direct Aerosol Forcing in the Infrared at the SGP Site? Direct Aerosol Forcing in the Infrared at the SGP Site? D. D. Turner and C. N. Long Pacific Northwest National Laboratory Richland, Washington Introduction Low level haze is often observed during the night and early morning hours in many locations. This haze is typically formed during quiescent conditions by radiative cooling of the surface, which lowers the ambient temperature and consequently increases the near-surface relative humidity (RH). Many aerosols start to deliquesce around 75% relative humidity (RH) (depending on their chemical composition), and thus if the near surface RH increases above this level, haze will form. The Atmospheric Radiation Measurement (ARM) Program's ultimate goal, stated simply, is to improve the treatment of radiative transfer in global climate models. Global climate models typically do not

4

Toward a Minimal Representation of Aerosols in Climate Models: Comparative Decomposition of Aerosol Direct, Semidirect, and Indirect Radiative Forcing  

Science Conference Proceedings (OSTI)

The authors have decomposed the anthropogenic aerosol radiative forcing into direct contributions from each aerosol species to the planetary energy balance through absorption and scattering of solar radiation, indirect effects of anthropogenic ...

S. J. Ghan; X. Liu; R. C. Easter; R. Zaveri; P. J. Rasch; J.-H. Yoon; B. Eaton

2012-10-01T23:59:59.000Z

5

Direct Aerosol Radiative Forcing Uncertainty Based on a Radiative Perturbation Analysis  

Science Conference Proceedings (OSTI)

To provide a lower bound for the uncertainty in measurement-based clear- and all-sky direct aerosol radiative forcing (DARF), a radiative perturbation analysis is performed for the ideal case in which the perturbations in global mean aerosol ...

Norman G. Loeb; Wenying Su

2010-10-01T23:59:59.000Z

6

Radiative Forcing of a Tropical Direct Circulation by Soil Dust Aerosols  

Science Conference Proceedings (OSTI)

The effect of soil dust aerosols upon the tropical climate is estimated by forcing a simple model of a tropical direct circulation. The model consists of a region vertically mixed by deep convection and a nonconvecting region, for which budgets ...

R. L. Miller; I. Tegen

1999-07-01T23:59:59.000Z

7

Daytime Variation of Shortwave Direct Radiative Forcing of Biomass Burning Aerosols from GOES-8 Imager  

Science Conference Proceedings (OSTI)

Hourly Geostationary Operational Environmental Satellite-8 (GOES-8) imager data (1344–1944 UTC) from 20 July–31 August 1998 were used to study the daytime variation of shortwave direct radiative forcing (SWARF) of smoke aerosols over biomass ...

Sundar A. Christopher; Jianglong Zhang

2002-02-01T23:59:59.000Z

8

An “A-Train” Strategy for Quantifying Direct Climate Forcing by Anthropogenic Aerosols  

Science Conference Proceedings (OSTI)

This document outlines a practical strategy for achieving an observationally based quantification of direct climate forcing by anthropogenic aerosols. The strategy involves a four-step program for shifting the current assumption-laden estimates ...

Theodore L. Anderson; Robert J. Charlson; Nicolas Bellouin; Olivier Boucher; Mian Chin; Sundar A. Christopher; Jim Haywood; Yoram J. Kaufman; Stefan Kinne; John A. Ogren; Lorraine A. Remer; Toshihiko Takemura; Didier Tanré; Omar Torres; Charles R. Trepte; Bruce A. Wielicki; David M. Winker; Hongbin Yu

2005-12-01T23:59:59.000Z

9

General Circulation Model Calculations of the Direct Radiative Forcing by Anthropogenic Sulfate and Fossil-Fuel Soot Aerosol  

Science Conference Proceedings (OSTI)

A new radiation code within a general circulation model is used to assess the direct solar and thermal radiative forcing by sulfate aerosol of anthropogenic origin and soot aerosol from fossil-fuel burning. The radiative effects of different ...

J. M. Haywood; D. L. Roberts; A. Slingo; J. M. Edwards; K. P. Shine

1997-07-01T23:59:59.000Z

10

Toward a Minimal Representation of Aerosols in Climate Models: Comparative Decomposition of Aerosol Direct, Semidirect, and Indirect Radiative Forcing  

SciTech Connect

The authors have decomposed the anthropogenic aerosol radiative forcing into direct contributions from each aerosol species to the planetary energy balance through absorption and scattering of solar radiation, indirect effects of anthropogenic aerosol on solar and infrared radiation through droplet and crystal nucleation on aerosol, and semidirect effects through the influence of solar absorption on the distribution of clouds. A three-mode representation of the aerosol in version 5.1 of the Community Atmosphere Model (CAM5.1) yields global annual mean radiative forcing estimates for each of these forcing mechanisms that are within 0.1 W m–2 of estimates using a more complex seven-mode representation that distinguishes between fresh and aged black carbon and primary organic matter. Simulating fresh black carbon particles separately from internally mixed accumulation mode particles is found to be important only near fossil fuel sources. In addition to the usual large indirect effect on solar radiation, this study finds an unexpectedly large positive longwave indirect effect (because of enhanced cirrus produced by homogenous nucleation of ice crystals on anthropogenic sulfate), small shortwave and longwave semidirect effects, and a small direct effect (because of cancelation and interactions of direct effects of black carbon and sulfate). Differences between the threemode and seven-mode versions are significantly larger (up to 0.2 W m–2) when the hygroscopicity of primary organic matter is decreased from 0.1 to 0 and transfer of the primary carbonaceous aerosol to the accumulation mode in the seven-mode version requires more hygroscopic material coating the primary particles. Radiative forcing by cloudborne anthropogenic black carbon is only 20.07 W m–2.

Ghan, Steven J.; Liu, Xiaohong; Easter, Richard C.; Zaveri, Rahul A.; Rasch, Philip J.; Yoon, Jin-Ho; Eaton, Brian

2012-10-01T23:59:59.000Z

11

The sensitivity of tropical convective precipitation to the direct radiative forcings of black carbon aerosols emitted from major regions  

E-Print Network (OSTI)

Previous works have suggested that the direct radiative forcing (DRF) of black carbon (BC) aerosols are able to force a significant change in tropical convective precipitation ranging from the Pacific and Indian Ocean to ...

Wang, Chien

12

Estimation of Shortwave Direct Radiative Forcing of Biomass-Burning Aerosols Using New Angular Models  

Science Conference Proceedings (OSTI)

Using a new angular distribution model (ADM) for smoke aerosols, the instantaneous top-of-atmosphere (TOA) shortwave aerosol radiative forcing (SWARF) is calculated for selected days over biomass-burning regions in South America. The visible and ...

Xiang Li; Sundar A. Christopher; Joyce Chou; Ronald M. Welch

2000-12-01T23:59:59.000Z

13

Evolution of Ozone, Particulates, and Aerosol Direct Radiative Forcing in the Vicinity of Houston Using a Fully Coupled Meteorology-Chemistry-Aerosol Model  

SciTech Connect

A new fully-coupled meteorology-chemistry-aerosol model is used to simulate the urban to regional scale variations in trace gases, particulates, and aerosol direct radiative forcing in the vicinity of Houston over a five day summer period. Model performance is evaluated using a wide range of meteorological, chemistry, and particulate measurements obtained during 2000 Texas Air Quality Study. The predicted trace gas and particulate distributions were qualitatively similar to the surface and aircraft measurements with considerable spatial variations resulting from urban, power plant, and industrial sources of primary pollutants. Sulfate, organic carbon, and other inorganics were the largest constituents of the predicted particulates. The predicted shortwave radiation was 30 to 40 W m-2 closer to the observations when the aerosol optical properties were incorporated into the shortwave radiation scheme; however, the predicted hourly aerosol radiative forcing was still under-estimated by 10 to 50 W m-2. The predicted aerosol radiative forcing was larger over Houston and the industrial ship channel than over the rural areas, consistent with surface measurements. The differences between the observed and simulated aerosol radiative forcing resulted from transport errors, relative humidity errors in the upper convective boundary layer that affect aerosol water content, secondary organic aerosols that were not yet included in the model, and uncertainties in the primary particulate emission rates. The current model was run in a predictive mode and demonstrates the challenges of accurately simulating all of the meteorological, chemical, and aerosol parameters over urban to regional scales that can affect aerosol radiative forcing.

Fast, Jerome D.; Gustafson, William I.; Easter, Richard C.; Zaveri, Rahul A.; Barnard, James C.; Chapman, Elaine G.; Grell, Georg; Peckham, S. E.

2006-11-11T23:59:59.000Z

14

Intercomparison of Radiation Transfer Models Representing Direct Shortwave Forcing by Sulfate Aerosols  

E-Print Network (OSTI)

A study has been conducted, involving 15 models by 12 groups, to compare modeled forcing (change in shortwave radiation budget) due to sulfate aerosol for a wide range of values of particle radius, optical depth, surface albedo, and solar zenith angle (SZA). The models included high- and low-spectral resolution models, incorporating a variety of radiative transfer approximations, as well as a line-by-line model. The normalized forcings (forcing per sulfate column burden) obtained with the radiative transfer models were examined and the differences characterized. All models simulate forcings of comparable amplitude and exhibit a similar dependence on input parameters. As expected for a non-light-absorbing aerosol, forcings were negative (cooling influence), except at high surface albedo combined with low SZA. The relative standard deviation of the zenith-angle-average normalized broadband forcing for 15 models was 8% for particle radius near the maximum in magnitude of this forcing (ca....

Sulfate Aerosols; Stephen E Schwartz

1998-01-01T23:59:59.000Z

15

Seasonal Variation of Aerosol Direct Radiative Forcing and Optical Properties Estimated from Ground-Based Solar Radiation Measurements  

Science Conference Proceedings (OSTI)

The surface direct radiative forcing and optical properties of aerosols have been analyzed from a ground-based solar radiation measurement, which was made under clear-sky conditions in Tsukuba, Japan, over two years from April 1997 to March 1999. ...

Tomoaki Nishizawa; Shoji Asano; Akihiro Uchiyama; Akihiro Yamazaki

2004-01-01T23:59:59.000Z

16

The Impact of Direct Aerosol Radiative Forcing on Surface Insolation and Spring Snowmelt in the Southern Sierra Nevada  

Science Conference Proceedings (OSTI)

To understand the regional impact of the atmospheric aerosols on the surface energy and water cycle in the southern Sierra Nevada characterized by extreme variations in terrain elevation, the authors examine the aerosol radiative forcing on ...

Jinwon Kim; Yu Gu; K. N. Liou

2006-10-01T23:59:59.000Z

17

Aerosol Characterization and Direct Radiative Forcing Assessment over the Ocean. Part I: Methodology and Sensitivity Analysis  

Science Conference Proceedings (OSTI)

A method based on the synergistic use of low earth orbit (LEO) and geostationary earth orbit (GEO) satellite data for aerosol-type characterization, as well as aerosol optical thickness (AOT) retrieval and monitoring over the ocean, is presented. ...

Maria João Costa; Ana Maria Silva; Vincenzo Levizzani

2004-12-01T23:59:59.000Z

18

Downscaling Aerosols and the Impact of Neglected Subgrid Processes on Direct Aerosol Radiative Forcing for a Representative Global Climate Model Grid Spacing  

Science Conference Proceedings (OSTI)

Recent improvements to many global climate models include detailed, prognostic aerosol calculations intended to better reproduce the observed climate. However, the trace gas and aerosol fields are treated at the grid-cell scale with no attempt to account for sub-grid impacts on the aerosol fields. This paper begins to quantify the error introduced by the neglected sub-grid variability for the shortwave aerosol radiative forcing for a representative climate model grid spacing of 75 km. An analysis of the value added in downscaling aerosol fields is also presented to give context to the WRF-Chem simulations used for the sub-grid analysis. We found that 1) the impact of neglected sub-grid variability on the aerosol radiative forcing is strongest in regions of complex topography and complicated flow patterns, and 2) scale-induced differences in emissions contribute strongly to the impact of neglected sub-grid processes on the aerosol radiative forcing. The two of these effects together, when simulated at 75 km vs. 3 km in WRF-Chem, result in an average daytime mean bias of over 30% error in top-of-atmosphere shortwave aerosol radiative forcing for a large percentage of central Mexico during the MILAGRO field campaign.

Gustafson, William I.; Qian, Yun; Fast, Jerome D.

2011-07-13T23:59:59.000Z

19

Total aerosol effect: forcing or radiative flux perturbation?  

Science Conference Proceedings (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

20

Total aerosol effect: forcing or radiative flux perturbation?  

E-Print Network (OSTI)

of the ?rst indirect aerosol effect, Atmos. Chem. Phys. , 5,Cloud susceptibility and the ?rst aerosol indirect forcing:to black carbon and aerosol concentrations, J. Geophys.

Lohmann, Ulrike

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "direct aerosol forcing" 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

Model Assessment of the Ability of MODIS to Measure Top-of-Atmosphere Direct Radiative Forcing from Smoke Aerosols  

Science Conference Proceedings (OSTI)

The new generation of satellite sensors such as the moderate resolution imaging spectroradiometer (MODIS) will be able to detect and characterize global aerosols with an unprecedented accuracy. The question remains whether this accuracy will be ...

Lorraine A. Remer; Yoram J. Kaufman; Zev Levin; Steven Ghan

2002-02-01T23:59:59.000Z

22

Longwave radiative forcing by aqueous aerosols  

SciTech Connect

Recently, a great deal of interest has been focused on the role of aerosols in climatic change because of their potential cooling impacts due to light scattering. Recent advances in infrared spectroscopy using cylindrical internal reflectance have allowed the longwave absorption of dissolved aerosol species and the associated liquid water to be accurately determined and evaluated. Experimental measurements using these techniques have shown that dissolved sulfate, nitrate, and numerous other aerosol species will act to cause greenhouse effects. Preliminary calculations indicate that the longwave climate forcing (i.e., heating) for sulfate aerosol will be comparable in magnitude to the cooling effect produced by light scattering. However, more detailed modeling will clearly be needed to address the impact of the longwave forcing due to aerosols as a function of atmospheric height and composition. Their work has shown that aerosol composition will be important in determining longwave forcing, while shortwave forcing will be more related to the physical size of the aerosol droplets. On the basis of these studies, it is increasingly apparent that aerosols, fogs, and clouds play a key role in determining the radiative balance of the atmosphere and in controlling regional and global climates.

Gaffney, J.S.; Marley, N.A. [Argonne National Lab., IL (United States). Environmental Research Div.

1995-01-01T23:59:59.000Z

23

High Resolution Aerosol Modeling: Decadal Changes in Radiative Forcing  

Science Conference Proceedings (OSTI)

The Atmospheric Science Division of LLNL has performed high-resolution calculations of direct sulfate forcing using a DOE-provided computer resource at NERSC. We integrated our global chemistry-aerosol model (IMPACT) with the LLNL high-resolution global climate model (horizontal resolution as high as 100 km) to examine the temporal evolution of sulfate forcing since 1950. We note that all previous assessments of sulfate forcing reported in IPCC (2001) were based on global models with coarse spatial resolutions ({approx} 300 km or even coarser). However, the short lifetime of aerosols ({approx} days) results in large spatial and temporal variations of radiative forcing by sulfate. As a result, global climate models with coarse resolutions do not accurately simulate sulfate forcing on regional scales. It requires much finer spatial resolutions in order to address the effects of regional anthropogenic SO{sub 2} emissions on the global atmosphere as well as the effects of long-range transport of sulfate aerosols on the regional climate forcing. By taking advantage of the tera-scale computer resources at NERSC, we simulated the historic direct sulfate forcing at much finer spatial resolutions than ever attempted before. Furthermore, we performed high-resolution chemistry simulations and saved monthly averaged oxidant fields, which will be used in subsequent simulations of sulfate aerosol formation and their radiative impact.

Bergmann, D J; Chuang, C C; Govindasamy, B; Cameron-Smith, P J; Rotman, D A

2005-02-01T23:59:59.000Z

24

Anthropogenic Aerosol Radiative Forcing in Asia Derived From Regional Models With Atmospheric and Aerosol Data Assimilation  

DOE Green Energy (OSTI)

A high-resolution estimate of monthly 3D aerosol solar heating rates and surface solar fluxes in Asia from 2001 to 2004 is described here. This product stems from an Asian aerosol assimilation project, in which a) the PNNL regional model bounded by the NCEP reanalyses was used to provide meteorology, b) MODIS and AERONET data were integrated for aerosol observations, c) the Iowa aerosol/chemistry model STEM-2K1 used the PNNL meteorology and assimilated aerosol observations, and d) 3D (X-Y-Z) aerosol simulations from the STEM-2K1 were used in the Scripps Monte-Carlo Aerosol Cloud Radiation (MACR) model to produce total and anthropogenic aerosol direct solar forcing for average cloudy skies. The MACR model and STEM both used the PNNL model resolution of 0.45º×0.4º in the horizontal and of 23 layers in the troposphere. The 2001–2004 averaged anthropogenic all-sky aerosol forcing is ?1.3 Wm-2 (TOA), +7.3 Wm-2 (atmosphere) and ?8.6 Wm-2 (surface) averaged in Asia (60?138°E & Eq. ?45°N). In the absence of AERONET SSA assimilation, absorbing aerosol concentration (especially BC aerosol) is much smaller, giving ?2.3 Wm-2 (TOA), +4.5 Wm-2 (atmosphere) and ?6.8 Wm-2 (surface), averaged in Asia. In the vertical, monthly forcing is mainly concentrated below 600hPa with maxima around 800hPa. Seasonally, low-level forcing is far larger in dry season than in wet season in South Asia, whereas the wet season forcing exceeds the dry season forcing in East Asia. The anthropogenic forcing in the present study is similar to that in Chung et al.’s [2005] in overall magnitude but the former offers fine-scale features and simulated vertical profiles. The interannual variability of the computed anthropogenic forcing is significant and extremely large over major emission outflow areas. In view of this, the present study’s estimate is within the implicated range of the 1999 INDOEX result. However, NCAR/CCSM3’s anthropogenic aerosol forcing is much smaller than the present study’s estimate at the surface, and is outside of what the INDOEX findings can support.

Chung, Chul Eddy; Ramanathan, V.; Carmichael, Gregory; Kulkarni, S.; Tang, Youhua; Adhikary, Bhupesh; Leung, Lai-Yung R.; Qian, Yun

2010-07-05T23:59:59.000Z

25

Indirect and Semi-direct Aerosol Campaign  

Science Conference Proceedings (OSTI)

A comprehensive dataset of microphysical and radiative properties of aerosols and clouds in the boundary layer in the vicinity of Barrow, Alaska, was collected in April 2008 during the Indirect and Semi-Direct Aerosol Campaign (ISDAC). ISDAC's ...

Greg M. McFarquhar; Steven Ghan; Johannes Verlinde; Alexei Korolev; J. Walter Strapp; Beat Schmid; Jason M. Tomlinson; Mengistu Wolde; Sarah D. Brooks; Dan Cziczo; Manvendra K. Dubey; Jiwen Fan; Connor Flynn; Ismail Gultepe; John Hubbe; Mary K. Gilles; Alexander Laskin; Paul Lawson; W. Richard Leaitch; Peter Liu; Xiaohong Liu; Dan Lubin; Claudio Mazzoleni; Ann-Marie Macdonald; Ryan C. Moffet; Hugh Morrison; Mikhail Ovchinnikov; Matthew D. Shupe; David D. Turner; Shaocheng Xie; Alla Zelenyuk; Kenny Bae; Matt Freer; Andrew Glen

2011-02-01T23:59:59.000Z

26

RADIATIVE FORCING OF CLIMATE CHANGE BY AEROSOLS  

E-Print Network (OSTI)

nonbelievers. #12;Level of Scientific Understanding 2 1 0 1 2 3 Radiativeforcing(Wattspersquaremetre) Cooling scattering -- Cooling influence Light absorption -- Warming influence, depending on surface Indirect Effects is highly sensitive to modest aerosol loadings. Global-average AOT 0.1 corresponds to global-average forcing

Schwartz, Stephen E.

27

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

28

Climatic effects of 1950–2050 changes in US anthropogenic aerosols – Part 1: Aerosol trends and radiative forcing  

E-Print Network (OSTI)

We use the GEOS-Chem chemical transport model combined with the GISS general circulation model to calculate the aerosol direct and indirect (warm cloud) radiative forcings from US anthropogenic sources over the 1950–2050 ...

Leibensperger, Eric Michael

29

Aerosols in Central California: Unexpectedly Large Contribution of Coarse Mode to Aerosol Radiative Forcing  

Science Conference Proceedings (OSTI)

The majority of previous studies dealing with effect of coarse-mode aerosols on the radiation budget have focused primary on polluted regions with substantial aerosol loadings. We reexamine this effect for a relatively "pristine" area using a unique 1-month dataset collected during recent Carbonaceous Aerosol and Radiative Effects Study (CARES). We demonstrate that the coarse-mode (supermicron) particles can contribute substantially (more than 50%) and frequently (up to 85% of time) to the total volume. In contrast to the conventional expectations that the radiative impact of coarse-mode aerosols should be small for "pristine" regions, we find that the neglecting of the large particles may lead to significant overestimation (up to 45%) of direct aerosol radiative forcing at the top-of atmosphere despite of very small aerosol optical depth (about 0.05 at 0.5 ). Our findings highlight the potential for widespread impacts of the coarse-mode aerosols on the pristine radiative properties over land and the need for more explicit inclusion of the coarse-mode aerosols in climate-related observational and model studies.

Kassianov, Evgueni I.; Pekour, Mikhail S.; Barnard, James C.

2012-10-20T23:59:59.000Z

30

Sensitivity of aerosol radiative forcing calculations to spectral resolution  

DOE Green Energy (OSTI)

Potential impacts of aerosol radiative forcing on climate have generated considerable recent interest. An important consideration in estimating the forcing from various aerosol components is the spectral resolution used for the solar radiative transfer calculations. This paper examines the spectral resolution required from the viewpoint of overlapping spectrally varying aerosol properties with other cross sections. A diagnostic is developed for comparing different band choices, and the impact of these choices on the radiative forcing calculated for typical sulfate and biomass aerosols was investigated.

Grant, K.E.

1996-10-01T23:59:59.000Z

31

Evaluating the Direct and Indirect Aerosol Effect on Climate  

NLE Websites -- All DOE Office Websites (Extended Search)

one of the largest uncertainties in climate forcing studies is the effect of aerosols on the earth-atmosphere system. Aerosols affect the radiation budget under both clear...

32

Direct and semidirect aerosol effects of Southern African biomass burning aerosol  

Science Conference Proceedings (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

33

Radiative and climate impacts of absorbing aerosols  

E-Print Network (OSTI)

P.M. Forster (2004), The semi-direct aerosol effect: Impactof absorbing aerosols on marine stratocumulus. Q. J .2005), Global anthropogenic aerosol direct forcing derived

Zhu, Aihua

2010-01-01T23:59:59.000Z

34

The whitehouse effect: Shortwave radiative forcing of climate by anthropogenic aerosols, an overview  

E-Print Network (OSTI)

Abstraet--Loadings of tropospheric aerosols have increased substantially over the past 150 yr as a consequence of industrial activities. These aerosols enhance reflection of solar radiation by the Earth-atmosphere system both directly, by scattering light in clear air and, indirectly, by increasing the reflectivity of clouds. The magnitude of the resultant decrease in absorption of solar radiation is estimated to be comparable on global average to the enhancement in infrared forcing at the tropopause due to increases in concentrations of CO2 and other greenhouse gases over the same time period. Estimates of the aerosol shortwave forcing are quite uncertain, by more than a factor of two about the current best estimates. This article reviews the atmospheric chemistry and microphysical processes that govern the loading and light scattering properties of the aerosol particles responsible for the direct effect and delineates the basis for the present estimates of the magnitude and uncertainty in the resultant radiative forcing. The principal sources of uncertainty are in the loading of anthropogenic aerosols, which is highly variable spatially and temporally because of the relatively short residence time of these aerosols (ca. 1 week) and the episodic removal in precipitation, and in the dependence of light scattering on particle size, and in turn on relative humidity. Uncertainty in aerosol forcing is the greatest source of uncertainty in radiative forcing of climate

Stephen E. Schwartz

1996-01-01T23:59:59.000Z

35

Possible Influence of Anthropogenic Aerosols on Cirrus Clouds and Anthropogenic Forcing  

DOE Green Energy (OSTI)

Cirrus clouds have a net warming effect on the atmosphere and cover about 30% of the Earth’s area. Aerosol particles initiate ice formation in the upper troposphere through modes of action that include homogeneous freezing of solution droplets, heterogeneous nucleation on solid particles immersed in a solution, and deposition nucleation of vapor onto solid particles. Here, we examine the possible change in ice number concentration from anthropogenic soot originating from surface sources of fossil fuel and biomass burning, from anthropogenic sulfate aerosols, and from aircraft that deposit their aerosols directly in the upper troposphere. We find that fossil fuel and biomass burning soot aerosols exert a radiative forcing of -0.68 to 0.01 Wm-2 while anthropogenic sulfate aerosols exert a forcing of -0.01 to 0.18 Wm-2. Our calculations show that the sign of the forcing by aircraft soot depends on the model configuration and can be both positive or negative, ranging from -0.16 to 0.02 Wm-2. The magnitude of the forcing in cirrus clouds can be comparable to the forcing exerted by anthropogenic aerosols on warm clouds, but this forcing has not been included in past assessments of the total anthropogenic radiative forcing of climate.

Penner, Joyce E.; Chen, Yang; Wang, Minghuai; Liu, Xiaohong

2009-02-03T23:59:59.000Z

36

Saharan Dust Aerosol Radiative Forcing Measured from Space  

Science Conference Proceedings (OSTI)

This study uses data collected from the Clouds and the Earth's Radiant Energy System (CERES) and the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments to determine Saharan dust broadband shortwave aerosol radiative forcing over ...

F. Li; A. M. Vogelmann; V. Ramanathan

2004-07-01T23:59:59.000Z

37

Indirect and Semi-Direct Aerosol Campaign  

NLE Websites -- All DOE Office Websites (Extended Search)

Campaign Campaign For the month of April, researchers are descending on and above Barrow, Alaska, to obtain data from the atmosphere that will help them understand the impacts that aerosols have on Arctic clouds and climate. Scientists sponsored by the U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) Climate Research Facility are using a heavily instrumented aircraft to collect data from the sky, while instruments based at surface sites in Barrow and Atqasuk, Alaska, are obtaining measurements from the ground. Information obtained during the Indirect and Semi-Direct Aerosol Campaign, or ISDAC, will help scientists analyze the role of aerosols in climate, and represents a key contribution to Arctic climate research during International Polar Year.

38

Atmospheric Circulation Trends, 1950–2000: The Relative Roles of Sea Surface Temperature Forcing and Direct Atmospheric Radiative Forcing  

Science Conference Proceedings (OSTI)

The relative roles of direct atmospheric radiative forcing (due to observed changes in well-mixed greenhouse gases, tropospheric and stratospheric ozone, sulfate and volcanic aerosols, and solar output) and observed sea surface temperature (SST) ...

Clara Deser; Adam S. Phillips

2009-01-01T23:59:59.000Z

39

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

40

A Method to Estimate Aerosol Radiative Forcing from Spectral Optical Depths  

Science Conference Proceedings (OSTI)

Radiative forcing of aerosols is much more difficult to estimate than that of well-mixed gases due to the large spatial variability of aerosols and the lack of an adequate database on their radiative properties. Estimation of aerosol radiative ...

S. K. Satheesh; J. Srinivasan

2006-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "direct aerosol forcing" 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

Temporal Variability of Aerosol Properties during TCAP: Impact on Radiative Forcing  

SciTech Connect

Ground-based remote sensing and in situ observations of aerosol microphysical and optical properties have been collected during summertime (June-August, 2012) as part of the Two-Column Aerosol Project (TCAP; http://campaign.arm.gov/tcap/), which was supported by the U.S. Department of Energy’s (DOE’s) Atmospheric Radiation Measurement (ARM) Program (http://www.arm.gov/). The overall goal of the TCAP field campaign is to study the evolution of optical and microphysical properties of atmospheric aerosol transported from North America to the Atlantic and their impact on the radiation energy budget. During TCAP, the ground-based ARM Mobile Facility (AMF) was deployed on Cape Cod, an arm-shaped peninsula situated on the easternmost portion of Massachusetts (along the east coast of the United States) and that is generally downwind of large metropolitan areas. The AMF site was equipped with numerous instruments for sampling aerosol, cloud and radiative properties, including a Multi-Filter Rotating Shadowband Radiometer (MFRSR), a Scanning Mobility Particle Sizer (SMPS), an Aerodynamic Particle Sizer (APS), and a three-wavelength nephelometer. In this study we present an analysis of diurnal and day-to-day variability of the column and near-surface aerosol properties obtained from remote sensing (MFRSR data) and ground-based in situ measurements (SMPS, APS, and nephelometer data). In particular, we show that the observed diurnal variability of the MFRSR aerosol optical depth is strong and comparable with that obtained previously from the AERONET climatology in Mexico City, which has a larger aerosol loading. Moreover, we illustrate how the variability of aerosol properties impacts the direct aerosol radiative forcing at different time scales.

Kassianov, Evgueni I.; Barnard, James C.; Pekour, Mikhail S.; Berg, Larry K.; Fast, Jerome D.; Michalsky, Joseph J.; Lantz, K.; Hodges, G. B.

2013-11-01T23:59:59.000Z

42

Observations and Modeling of the Surface Aerosol Radiative Forcing during UAE2  

Science Conference Proceedings (OSTI)

Aerosol radiative forcing in the Persian Gulf region is derived from data collected during the United Arab Emirates (UAE) Unified Aerosol Experiment (UAE2). This campaign took place in August and September of 2004. The land–sea-breeze circulation ...

K. M. Markowicz; P. J. Flatau; J. Remiszewska; M. Witek; E. A. Reid; J. S. Reid; A. Bucholtz; B. Holben

2008-09-01T23:59:59.000Z

43

Measurements of the chemical, physical, and optical properties of single aerosol particles  

E-Print Network (OSTI)

composition of ambient aerosol particles, EnvironmentalParticle Measurement of Ambient Aerosol Particles Containingfor quantifying direct aerosol forcing of climate, Bull. Am.

Moffet, Ryan Christopher

2007-01-01T23:59:59.000Z

44

Aerosol Radiative Forcing and Forcing Efficiency in the UVB for Regions Affected by Saharan and Asian Mineral Dust  

Science Conference Proceedings (OSTI)

The influence of mineral dust on ultraviolet energy transfer is studied for two different mineralogical origins. The aerosol radiative forcing ?F and the forcing efficiency at the surface ?Feff in the range 290–325 nm were estimated in ground-...

O. E. García; A. M. Díaz; F. J. Expósito; J. P. Díaz; A. Redondas; T. Sasaki

2009-04-01T23:59:59.000Z

45

Direct and Indirect Shortwave Radiative Effects of Sea Salt Aerosols  

Science Conference Proceedings (OSTI)

Sea salt aerosols play a dual role in affecting the atmospheric radiative balance. Directly, sea salt particles scatter the incoming solar radiation and absorb the outgoing terrestrial radiation. By acting as cloud condensation nuclei, sea salt ...

Tarek Ayash; Sunling Gong; Charles Q. Jia

2008-07-01T23:59:59.000Z

46

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

E-Print Network (OSTI)

The direct and indirect effects of aerosols on the hurricane ‘Katrina’ have been investigated using the WRF model with a two-moment bulk microphysical scheme and modified Goddard shortwave radiation scheme. Simulations of the hurricane ‘Katrina’ 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 as polluted case but with a modified shortwave radiation scheme. The polluted and AR cases have much larger amounts of cloud water and water vapor in troposphere, and the increased cloud water can freeze to produce ice water paths. A tropical cyclone in dirty and dusty air has active rainbands outside the eyewall due to aerosol indirect effects. The aerosol direct effect can lead to the suppressing of convection and weakening of updraft intensity by warming the troposphere and cooling the surface temperature. However, these thermal changes in atmosphere are concerned with the enhanced amounts of cloud hydrometeors and modification of downdraft and corresponding the low level winds in rainband regions. Thus, the AR case can produce the enhanced precipitation even in the weakest hurricane. When comparing the model performance between aerosol indirect and direct effect by ensemble experiments, the adjustment time of the circulation due to modification of the aerosol radiative forcing by aerosol layers may take a longer time than the hurricane lifetime, and the results from the simulated hurricane show that it is more sensitive to aerosol indirect effects which are related to the cloud microphysics process changes. From this aerosol study, we can suggest that aerosols can influence the cloudiness, precipitation, and intensity of hurricanes significantly, and there may be different results in the meso-scale convective clouds cases. The hurricane system is a large and complex convective system with enormous heating energy and moistures. Moreover, relationships between various hydrometeors in hurricane systems are difficult to isolate and thus, it needs further study with more realistic cloud microphysical processes, aerosol distributions, and parameterizations.

Lee, Keun-Hee

2011-12-01T23:59:59.000Z

47

Indirect radiative forcing by ion-mediated nucleation of aerosol  

Science Conference Proceedings (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

48

Direct Atmospheric Forcing of Geostrophic Eddies  

Science Conference Proceedings (OSTI)

To assess the role of direct stochastic wind forcing in generating oceanic geostrophic eddies we calculate analytically the response of a simple ocean model to a realistic model wind-stress spectrum and compare the results with observations. The ...

Peter Müller; Claude Frankignoul

1981-03-01T23:59:59.000Z

49

Reply to Quaas et al.: Can satellites be used to estimate indirect climate forcing by aerosols?  

Science Conference Proceedings (OSTI)

We welcome the comments by Quaas et al. (1). In our paper (2), we used a model to show that the methods used to estimate indirect aerosol forcing using satellite data, especially those based on relating the slope of present-day (PD) drop number (Nc) to aerosol optical depth (AOD), underestimate the forcing calculated when both PD and preindustrial (PI) data are available.

Penner, J. E.; Zhou, Cheng; Xu, Li; Wang, Minghuai

2011-11-15T23:59:59.000Z

50

The whitehouse effect: shortwave radiative forcing of climate by anthropogenic aerosols  

SciTech Connect

Increases in atmospheric concentrations of carbon dioxide and other infrared active gases over the industrial period are thought to have increased the average flux of longwave (thermal infrared) radiation between the surface of the earth and the lower atmosphere, leading to an increase in global mean temperature. Over the same period it is though that concentrations of aerosol particles in the troposphere have similarly increased as a consequence of industrial emissions and that these increased concentrations of particles have increased the earth`s reflectivity of shortwave (solar) radiation incident on the planet both directly, by scattering radiation, and indirectly, by increasing the reflectivity of clouds. The term ``whitehouse effect`` is introduced to refer to this increased scattering of shortwave radiation by analogy to the term ``greenhouse effect,`` which refers to the enhanced trapping of longwave radiation resulting from increased concentrations of infrared active gases. Each of these phenomena is referred to as a ``forcing`` of the earth`s climate, that is a secular change imposed on the system; such a forcing is to be distinguished from a ``response`` of the system, such as a change in global mean temperature or other index of global climate. The forcing due to the direct and indirect effects induced by anthropogenic aerosols has been estimated to be comparable in global- average magnitude to that due to increased concentrations of greenhouse gases, but it is of opposite direction, that is exerting a cooling influence. The shortwave radiative influence of anthropogenic aerosols may thus be considered to be offsetting some, perhaps a great fraction, of the longwave radiative influence of anthropogenic greenhouse gases.

Schwartz, S.E.

1994-12-31T23:59:59.000Z

51

Sensitivity of shortwave radiative flux density, forcing, and heating rates to the aerosol vertical profile  

SciTech Connect

The effect of the aerosol vertical distribution on the solar radiation profiles, for idealized and measured profiles of optical properties (extinction and single-scattering albedo (SSA)) during the May 2003 Atmospheric Radiation Measurement (ARM) Aerosol Intensive Observation Period (AIOP), has been investigated using the Rapid Radiative Transfer Model Shortwave (RRTM_SW) code. Calculated profiles of down-welling and up-welling solar fluxes during the AIOP have been compared with the data measured by up- and down-looking solar broadband radiometers aboard a profiling research aircraft. The measured profiles of aerosol extinction, SSA, and water vapor obtained from the same aircraft that carried the radiometers served as the inputs for the model calculations. It is noteworthy that for this study, the uplooking radiometers were mounted on a stabilized platform that kept the radiometers parallel with respect to the earth’s horizontal plane. The results indicate that the shape of the aerosol extinction profiles has very little impact on direct radiative forcings at the top of atmosphere and surface in a cloud-free sky. However, as long as the aerosol is not purely scattering, the shape of the extinction profiles is important for forcing profiles. Identical extinction profiles with different absorption profiles drastically influence the forcing and heating rate profiles. Using aircraft data from 19 AIOP profiles over the Southern Great Plains (SGP), we are able to achieve broadband down-welling solar flux closure within 0.8% (bias difference) or 1.8% (rms difference), well within the expected measurement uncertainty of 1 to 3%. The poorer agreement in up-welling flux (bias -3.7%, rms 10%) is attributed to the use of inaccurate surface albedo data. The sensitivity tests reveal the important role accurate, vertically resolved aerosol extinction data plays in tightening flux closure. This study also suggests that in the presence of a strongly absorbing substance, aircraft flux measurements from a stabilized platform have the potential to determine heating rate profiles. These measurement-based heating rate profiles provide useful data for heating rate closure studies and indirect estimates of single scattering albedo assumed in radiative transfer calculations.

Guan, Hong; Schmid, Beat; Bucholtz, Anthony; Bergstrom, Robert

2010-03-31T23:59:59.000Z

52

Quantifying and Minimizing Uncertainty of Climate Forcing by Anthropogenic Aerosols  

Science Conference Proceedings (OSTI)

Anthropogenic aerosols are composed of a variety of aerosol types and components including water-soluble inorganic species (e.g., sulfate, nitrate, ammonium), condensed organic species, elemental or black carbon, and mineral dust. Previous ...

J. E. Penner; R. J. Charlson; S. E. Schwartz; J. M. Hales; N. S. Laulainen; L. Travis; R. Leifer; T. Novakov; J. Ogren; L. F. Radke

1994-03-01T23:59:59.000Z

53

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

SciTech Connect

A comprehensive dataset of microphysical and radiative properties of aerosols and clouds in the arctic boundary layer in the vicinity of Barrow, Alaska was collected in April 2008 during the Indirect and Semi-Direct Aerosol Campaign (ISDAC) sponsored by the Department of Energy Atmospheric Radiation Measurement (ARM) and Atmospheric Science Programs. The primary aim of ISDAC was to examine indirect effects of aerosols on clouds that contain both liquid and ice water. The experiment utilized the ARM permanent observational facilities at the North Slope of Alaska (NSA) in Barrow. These include a cloud radar, a polarized micropulse lidar, and an atmospheric emitted radiance interferometer as well as instruments specially deployed for ISDAC measuring aerosol, ice fog, precipitation and spectral shortwave radiation. The National Research Council of Canada Convair-580 flew 27 sorties during ISDAC, collecting data using an unprecedented 42 cloud and aerosol instruments for more than 100 hours on 12 different days. Data were obtained above, below and within single-layer stratus on 8 April and 26 April 2008. These data enable a process-oriented understanding of how aerosols affect the microphysical and radiative properties of arctic clouds influenced by different surface conditions. Observations acquired on a heavily polluted day, 19 April 2008, are enhancing this understanding. Data acquired in cirrus on transit flights between Fairbanks and Barrow are improving our understanding of the performance of cloud probes in ice. Ultimately the ISDAC data will be used to improve the representation of cloud and aerosol processes in models covering a variety of spatial and temporal scales, and to determine the extent to which long-term surface-based measurements can provide retrievals of aerosols, clouds, precipitation and radiative heating in the Arctic.

McFarquhar, Greg; Ghan, Steven J.; Verlinde, J.; Korolev, Alexei; Strapp, J. Walter; Schmid, Beat; Tomlinson, Jason M.; Wolde, Mengistu; Brooks, Sarah D.; Cziczo, Daniel J.; Dubey, Manvendra K.; Fan, Jiwen; Flynn, Connor J.; Gultepe, Ismail; Hubbe, John M.; Gilles, Mary K.; Laskin, Alexander; Lawson, Paul; Leaitch, W. R.; Liu, Peter S.; Liu, Xiaohong; Lubin, Dan; Mazzoleni, Claudio; Macdonald, A. M.; Moffet, Ryan C.; Morrison, H.; Ovchinnikov, Mikhail; Shupe, Matthew D.; Turner, David D.; Xie, Shaocheng; Zelenyuk, Alla; Bae, Kenny; Freer, Matthew; Glen, Andrew

2011-02-01T23:59:59.000Z

54

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

Science Conference Proceedings (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

55

Nonlinear Aspects of the Climate Response to Greenhouse Gas and Aerosol Forcing  

Science Conference Proceedings (OSTI)

In a series of equilibrium experiments the climate response to present-day radiative forcings of anthropogenic greenhouse gases and aerosol particles is calculated. The study was performed with a model system consisting of the ECHAM4 atmospheric ...

Johann Feichter; Erich Roeckner; Ulrike Lohmann; Beate Liepert

2004-06-01T23:59:59.000Z

56

Top-of-Atmosphere Direct Radiative Effect of Aerosols over Global Oceans from Merged CERES and MODIS Observations  

Science Conference Proceedings (OSTI)

The direct radiative effect of aerosols (DREA) is defined as the difference between radiative fluxes in the absence and presence of aerosols. In this study, the direct radiative effect of aerosols is estimated for 46 months (March 2000–December ...

Norman G. Loeb; Natividad Manalo-Smith

2005-09-01T23:59:59.000Z

57

Total aerosol effect: forcing or radiative flux perturbation?  

E-Print Network (OSTI)

heterogeneous ice nucleation in mixed-phase clouds, Environ.interactions with mixed-phase and ice clouds can be comparedice nuclei for the indirect aerosol effect on stratiform mixed-phase

Lohmann, Ulrike

2010-01-01T23:59:59.000Z

58

Potential Aerosol Indirect Effects on Atmospheric Circulation and Radiative Forcing through Deep Convection  

Science Conference Proceedings (OSTI)

Aerosol indirect effects, i.e., the interactions of aerosols with clouds by serving as cloud condensation nuclei (CCN) or ice nuclei (IN), constitute the largest uncertainty in climate forcing and projection. Previous IPCC reported aerosol indirect forcing is negative, which does not account for aerosol-convective cloud interactions because the complex processes involved are poorly understood and represented in climate models. Here we report that aerosol indirect effect on deep convective cloud systems can lead to enhanced regional convergence and a strong top-of atmosphere (TOA) warming. Aerosol invigoration effect on convection can result in a strong radiative warming in the atmosphere (+5.6 W m-2) due to strong night-time warming, a lofted latent heating, and a reduced diurnal temperature difference, all of which could remarkably impact regional circulation and modify weather systems. We further elucidated how aerosols change convective intensity, diabatic heating, and regional circulation under different environmental conditions and concluded that wind shear and cloud base temperature play key roles in determining the significance of aerosol invigoration effect for convective systems.

Fan, Jiwen; Rosenfeld, Daniel; Ding, Yanni; Leung, Lai-Yung R.; Li, Zhanqing

2012-05-10T23:59:59.000Z

59

Surface shortwave aerosol radiative forcing during the Atmospheric Radiation Measurement Mobile Facility deployment in Niamey, Niger  

SciTech Connect

This study presents ground-based remote sensing measurements of aerosol optical properties and corresponding shortwave surface radiative effect calculations for the deployment of the Atmospheric Radiation Measurement (ARM) Program’s Mobile Facility (AMF) to Niamey, Niger during 2006. Aerosol optical properties including aerosol optical depth (AOD), single scattering albedo (SSA), and asymmetry parameter (AP) were derived from multi-filter rotating shadowband radiometer (MFRSR) measurements during the two dry seasons (Jan-Apr and Oct-Dec) at Niamey. The vertical distribution of aerosol extinction was derived from the collocated micropulse lidar (MPL). The aerosol optical properties and vertical distribution of extinction varied significantly throughout the year, with higher AOD, lower SSA, and deeper aerosol layers during the Jan-Apr time period, when biomass burning aerosol layers were more frequent. Using the retrieved aerosol properties and vertical extinction profiles, broadband shortwave surface fluxes and atmospheric heating rate profiles were calculated. Corresponding calculations with no aerosol were used to estimate the aerosol direct radiative effect at the surface. Comparison of the calculated surface fluxes to observed fluxes for non-cloudy periods indicated that the remote sensing retrievals provided a reasonable estimation of the optical properties, with mean differences between calculated and observed fluxes of less than 5 W/m2 and RMS differences less than 25 W/m2. Sensitivity tests for a particular case study showed that the observed fluxes could be matched with variations of < 10% in the inputs to the radiative transfer model. We estimated the daily-averaged aerosol radiative effect at the surface by subtracting the clear calculations from the aerosol calculations. The average daily SW aerosol radiative effect over the study period was -27 W/m2, which is comparable to values estimated from satellite data and from climate models with sophisticated dust parameterizations.

McFarlane, Sally A.; Kassianov, Evgueni I.; Barnard, James C.; Flynn, Connor J.; Ackerman, Thomas P.

2009-03-18T23:59:59.000Z

60

Aerosol Radiative Forcing Under Cloudless Conditions.in Winter ZCAREX-2001  

NLE Websites -- All DOE Office Websites (Extended Search)

Forcing Under Cloudless Conditions Forcing Under Cloudless Conditions in Winter ZCAREX-2001 G. S. Golitsyn, I. A. Gorchakova, and I. I. Mokhov Institute of Atmospheric Physic Moscow, Russia Introduction Aerosol radiative forcing (ARF) is estimated for winter clear-sky conditions from measurements during ZCAREX-2001-Cloud-Aerosol-Radiation Experiment in February-March, 2001 at the Zvenigorod Scientific Station (ZSS) of the A.M. Obukhov Institute of Atmospheric Physics RAS. ARF in the shortwave range is determined by the difference between the net fluxes of the solar radiation, calculated with and without the aerosol component of the atmosphere. The estimates of ARF are made for conditions with high surface albedo. Data Used The following data of atmospheric characteristics observed during winter are used for the

Note: This page contains sample records for the topic "direct aerosol forcing" 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

Atmospheric Teleconnection over Eurasia Induced by Aerosol Radiative Forcing during Boreal Spring  

Science Conference Proceedings (OSTI)

The direct effects of aerosols on global and regional climate during boreal spring are investigated based on numerical simulations with the NASA Global Modeling and Assimilation Office finite-volume general circulation model (fvGCM) with ...

Maeng-Ki Kim; William K. M. Lau; Mian Chin; Kyu-Myong Kim; Y. C. Sud; Greg K. Walker

2006-09-01T23:59:59.000Z

62

Local and Remote Impacts of Aerosol Climate Forcing on Tropical Precipitation  

Science Conference Proceedings (OSTI)

Mechanisms that determine the direct and indirect effects of aerosols on the tropical climate involve moist dynamical processes and have local and remote impacts on regional tropical precipitation. These mechanisms are examined in a climate model ...

Chia Chou; J. David Neelin; Ulrike Lohmann; Johann Feichter

2005-11-01T23:59:59.000Z

63

GCM Simulations of Volcanic Aerosol Forcing. Part I: Climate Changes Induced by Steady-State Perturbations  

Science Conference Proceedings (OSTI)

The authors have used the Goddard Institute for Space Studies Climate Model II to simulate the response of the climate system to a spatially and temporally constant forcing by volcanic aerosols having an optical depth of 0.15. The climatic ...

James B. Pollack; David Rind; Andrew Lacis; James E. Hansen; Makiko Sato; Reto Ruedy

1993-09-01T23:59:59.000Z

64

The Impact of humidity above stratiform clouds on indirect aerosol climate forcing  

SciTech Connect

Some of the global warming effect of anthropogenic greenhouse gases is offset by increased solar reflection from clouds with smaller droplets that form on increased numbers of cloud condensation nuclei in polluted air. The global magnitude of the resulting indirect aerosol climate forcing is estimated to be comparable (and opposed) to the anthropogenic carbon dioxide forcing, but estimates are highly uncertain because of complexities in characterizing the physical process that determine global aerosol and cloud populations and their interactions. Beyond reflecting sunlight more effectively, smaller droplets are less efficient at producing precipitation, and decreased precipitation is expected to result in increased cloud water and cloud cover, further increasing the indirect forcing. Yet polluted marine boundary-layer clouds are not generally observed to hold more water. Here we use model simulations of stratocumulus clouds to show that suppression of precipitation from increased droplet concentrations leads to increased cloud water only when sufficient precipitation reaches the surface, a condition favored when the overlying air is moist. Otherwise, aerosol induced suppression of precipitation enhances entrainment of overlying dry air, thereby reducing cloud water and diminishing the indirect climate forcing.

Ackerman, A S; Kirkpatrick, M P; Stevens, D E; Toon, O B

2004-12-20T23:59:59.000Z

65

Direct Aerosol Forcing: Sensitivity to Uncertainty in Measurements...  

NLE Websites -- All DOE Office Websites (Extended Search)

i.e., single scattering albedo and asymmetry parameter, and situational variables, i.e., solar geometry and surface albedo, and the wavelength dependencies of these quantities....

66

Predicting Aerosol Direct Radiative Forcing over Mexico using...  

NLE Websites -- All DOE Office Websites (Extended Search)

* Computationally expensive biomass burning mobile area point Two Primary Components Use Weather Research and Forecasting (WRF) model as the foundation of computational framework...

67

Sulfate Aerosol Indirect Effect and CO2 Greenhouse Forcing: EquilibriumResponse of the LMD GCM and Associated Cloud Feedbacks  

Science Conference Proceedings (OSTI)

The climate sensitivity to various forcings, and in particular to changes in CO2 and sulfate aerosol concentrations, imposed separately or in a combined manner, is studied with an atmospheric general circulation model coupled to a simple slab ...

Hervé Le Treut; Michèle Forichon; Olivier Boucher; Zhao-Xin Li

1998-07-01T23:59:59.000Z

68

Aerosol organic carbon to black carbon ratios: Analysis of published data and implications for climate forcing  

E-Print Network (OSTI)

Ryu (2004), Carbonaceous aerosol characteristics ofPM 2.5Allen (1990), Transported acid aerosols measured in southernconference international aerosol carbon round robin test

Novakov, T.; Menon, S.; Kirchstetter, T.W.; Koch, D.; Hansen, J.E.

2005-01-01T23:59:59.000Z

69

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

SciTech Connect

The ARM Climate Research Facility’s (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

70

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

Science Conference Proceedings (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

71

An Aerosol Climatology at Kyoto: Observed Local Radiative Forcing and Columnar Optical Properties  

Science Conference Proceedings (OSTI)

In order to evaluate the radiative effect of the atmospheric aerosol at Kyoto, Japan, surface solar irradiance and columnar aerosol optical properties were observed in the period between September 1998 and December 2001. The aerosol optical ...

Takahiro Yabe; Robert Höller; Susumu Tohno; Mikio Kasahara

2003-06-01T23:59:59.000Z

72

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

Science Conference Proceedings (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 reported climate impacts ...

Shao-Yi Lee; Ho-Jeong Shin; Chien Wang

2013-08-01T23:59:59.000Z

73

Effect of Direct Radiative Forcing of Asian Dust on the Meteorological Fields in East Asia during an Asian Dust Event Period  

Science Conference Proceedings (OSTI)

Coupled and noncoupled models in a grid of 60 × 60 km2 in the eastern Asian domain have been employed to examine the effect of the direct radiative forcing of the Asian dust aerosol on meteorological fields for an intense Asian dust event ...

Hyun-Ju Ahn; Soon-Ung Park; Lim-Seok Chang

2007-10-01T23:59:59.000Z

74

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

NLE Websites -- All DOE Office Websites (Extended Search)

govCampaignsIndirect and Semi-Direct Aerosol Campaign (ISDAC) govCampaignsIndirect and Semi-Direct Aerosol Campaign (ISDAC) Campaign Links ISDAC Website Related Campaigns Parameterization of Extinction Coefficient in Ice and Mixed-Phase Arctic Clouds During ISDAC 2010.10.01, Korolev, AAF ISDAC - Second Year Supplemental Surface Spectral Irradiance Measurements 2009.04.07, Lubin, NSA ISDAC - NASA ARCTAS Coordination with ARM 2008.04.01, Ferrare, NSA ISDAC / RISCAM - Humidified Tandem Differential Mobility Analyzer (HTDMA) 2008.04.01, Collins, NSA ISDAC - Hemispheric Flux Spectroradiometer 2008.03.31, Lubin, NSA Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Indirect and Semi-Direct Aerosol Campaign (ISDAC) 2008.04.01 - 2008.04.30 Website : http://acrf-campaign.arm.gov/isdac/

75

Engineering details of a stable force-directed placer  

E-Print Network (OSTI)

Analytic placement methods that simultaneously minimize wire length and spread cells are receiving renewed attention from both academia and industry. In this paper, we describe the implementation details of a force-directed placer, FDP. Specifically, we provide (1) a description of efficient force computation for spreading cells, (2) an illustration of numerical instability in these methods and a means by which these instabilities are avoided, (3) spread metrics for measuring cell distribution throughout the placement region and (4) a complementary technique which aids in directly minimizing HPWL. We present results comparing our analytic placer to other academic tools for both standard cell and mixed-size designs. Compared to Kraftwerk and Capo 8.7, our tool produces results with an average improvement of 9 % and 3%, respectively.

Kristofer Vorwerk

2004-01-01T23:59:59.000Z

76

The Effects of Hand Motion on Haptic Perception of Force Direction  

E-Print Network (OSTI)

Most studies on the haptic perception of force direction have been conducted without hand movements, whereas hand movements are normally required in real-world applications. This paper reports a study on the perception of haptic force direction during hand movement. Discrimination thresholds for force direction were determined for two hand movement speeds, slow and fast, and for five reference force directions. The results show that the perception of force direction is not affected by hand movement speed. We also found that the perception of force direction was not impaired by the hand motion, nor by the direction of the reference force.

Xing-dong Yang; Walter F. Bischof; Pierre Boulanger

2008-01-01T23:59:59.000Z

77

Interannual Tropospheric Aerosol Variability in the Late Twentieth Century and Its Impact on Tropical Atlantic and West African Climate by Direct and Semidirect Effects  

Science Conference Proceedings (OSTI)

A new high-resolution global tropospheric aerosol dataset with monthly resolution is generated using version 4 of the Community Atmosphere Model (CAM4) coupled to a bulk aerosol model and forced with recent estimates of surface emissions for the ...

Salil Mahajan; Katherine J. Evans; John E. Truesdale; James J. Hack; Jean-François Lamarque

2012-12-01T23:59:59.000Z

78

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

Science Conference Proceedings (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

79

Microphysical Processes Evident in Aerosol Forcing of Tropical Deep Convective Clouds  

Science Conference Proceedings (OSTI)

This study investigates the effects of aerosols on tropical deep convective clouds (DCCs). A series of large-scale, two-dimensional cloud-resolving model simulations was completed, differing only in the concentration of aerosols available to act ...

Rachel L. Storer; Susan C. van den Heever

2013-02-01T23:59:59.000Z

80

Radiative Forcing of Climate Change  

SciTech Connect

Chapter 6 of the IPCC Third Assessment Report Climate Change 2001: The Scientific Basis. Sections include: Executive Summary 6.1 Radiative Forcing 6.2 Forcing-Response Relationship 6.3 Well-Mixed Greenhouse Gases 6.4 Stratospheric Ozone 6.5 Radiative Forcing By Tropospheric Ozone 6.6 Indirect Forcings due to Chemistry 6.7 The Direct Radiative Forcing of Tropospheric Aerosols 6.8 The Indirect Radiative Forcing of Tropospheric Aerosols 6.9 Stratospheric Aerosols 6.10 Land-use Change (Surface Albedo Effect) 6.11 Solar Forcing of Climate 6.12 Global Warming Potentials hydrocarbons 6.13 Global Mean Radiative Forcings 6.14 The Geographical Distribution of the Radiative Forcings 6.15 Time Evolution of Radiative Forcings Appendix 6.1 Elements of Radiative Forcing Concept References.

Ramaswamy, V.; Boucher, Olivier; Haigh, J.; Hauglustaine, D.; Haywood, J.; Myhre, G.; Nakajima, Takahito; Shi, Guangyu; Solomon, S.; Betts, Robert E.; Charlson, R.; Chuang, C. C.; Daniel, J. S.; Del Genio, Anthony D.; Feichter, J.; Fuglestvedt, J.; Forster, P. M.; Ghan, Steven J.; Jones, A.; Kiehl, J. T.; Koch, D.; Land, C.; Lean, J.; Lohmann, Ulrike; Minschwaner, K.; Penner, Joyce E.; Roberts, D. L.; Rodhe, H.; Roelofs, G.-J.; Rotstayn, Leon D.; Schneider, T. L.; Schumann, U.; Schwartz, Stephen E.; Schwartzkopf, M. D.; Shine, K. P.; Smith, Steven J.; Stevenson, D. S.; Stordal, F.; Tegen, I.; van Dorland, R.; Zhang, Y.; Srinivasan, J.; Joos, Fortunat

2001-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "direct aerosol forcing" 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

Direct Atmospheric Forcing of Geostrophic Eddies. Part II: Coherence Maps  

Science Conference Proceedings (OSTI)

The theory of stochastic atmospheric forcing of quasigeostrophic eddies is applied to calculate coherence maps, that is, the coherence between the oceanic response at one location and the atmospheric forcing at another location as a function of ...

Angelika Lippert; Peter Müller

1995-01-01T23:59:59.000Z

82

Retrieval of Key Aerosol Optical Parameters from Spectral Direct and Diffuse Irradiances Observed by a Radiometer with Nonideal Cosine Response Characteristic  

Science Conference Proceedings (OSTI)

The spectral direct and diffuse irradiances observed by a radiometer with a horizontal surface detector have been frequently used to study aerosol optical parameters, such as aerosol optical thickness (?aer) and single scattering albedo (?). Such ...

Pradeep Khatri; Tamio Takamura; Akihiro Yamazaki; Yutaka Kondo

2012-05-01T23:59:59.000Z

83

Mechanisms of Formation of Secondary Organic Aerosols and Implications for Global Radiative Forcing  

Science Conference Proceedings (OSTI)

Organic material constitutes about 50% of global atmospheric aerosol mass, and the dominant source of organic aerosol is the oxidation of volatile hydrocarbons, to produce secondary organic aerosol (SOA). Understanding the formation of SOA is crucial to predicting present and future climate effects of atmospheric aerosols. The goal of this program is to significantly increase our understanding of secondary organic aerosol (SOA) formation in the atmosphere. Ambient measurements indicate that the amount of SOA in the atmosphere exceeds that predicted in current models based on existing laboratory chamber data. This would suggest that either the SOA yields measured in laboratory chambers are understated or that all major organic precursors have not been identified. In this research program we are systematically exploring these possibilities.

John H. Seinfeld

2011-12-08T23:59:59.000Z

84

ARM - Evaluation Product - Organic Aerosol Component VAP  

NLE Websites -- All DOE Office Websites (Extended Search)

ProductsOrganic Aerosol Component VAP ProductsOrganic Aerosol Component VAP Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Evaluation Product : Organic Aerosol Component VAP 2011.01.08 - 2012.03.24 Site(s) SGP General Description Organic aerosol (OA, i.e., the organic fraction of particles) accounts for 10-90% of the fine aerosol mass globally and is a key determinant of aerosol radiative forcing. But atmospheric OA is poorly characterized and its life cycle insufficiently represented in models. As a result, current models are unable to simulate OA concentrations and properties. This deficiency represents a large source of uncertainty in the quantification of aerosol direct and indirect effects and the prediction of future climate change. The Organic Aerosol Component (OACOMP) value-added product (VAP) uses

85

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  

Science Conference Proceedings (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

86

Do We Observe Aerosol Impacts on DSDs in Strongly Forced Tropical Thunderstorms?  

Science Conference Proceedings (OSTI)

Rain drop size distributions retrieved from polarimetric radar measurements over regularly occurring thunderstorms over the islands north of Darwin, Australia, are used to test if aerosol contributions to the probability distributions of the drop ...

P. T. May; V. N. Bringi; M. Thurai

2011-09-01T23:59:59.000Z

87

Global distribution and climate forcing of marine organic aerosol: 1. Model improvements and evaluation  

Science Conference Proceedings (OSTI)

Marine organic aerosol emissions have been implemented and evaluated within the National Center of Atmospheric Research (NCAR)'s Community Atmosphere Model (CAM5) with the Pacific Northwest National Laboratory's 7-mode Modal Aerosol Module (MAM-7). Emissions of marine primary organic aerosols (POA), phytoplanktonproduced isoprene- and monoterpenes-derived secondary organic aerosols (SOA) and methane sulfonate (MS{sup -}) are shown to affect surface concentrations of organic aerosols in remote marine regions. Global emissions of submicron marine POA is estimated to be 7.9 and 9.4 Tg yr{sup -1}, for the Gantt et al. (2011) and Vignati et al. (2010) emission parameterizations, respectively. Marine sources of SOA and particulate MS{sup -} (containing both sulfur and carbon atoms) contribute an additional 0.2 and 5.1 Tg yr{sup -1}, respectively. Widespread areas over productive waters of the Northern Atlantic, Northern Pacific, and the Southern Ocean show marine-source submicron organic aerosol surface concentrations of 100 ngm{sup -3}, with values up to 400 ngm{sup -3} over biologically productive areas. Comparison of long-term surface observations of water insoluble organic matter (WIOM) with POA concentrations from the two emission parameterizations shows that despite revealed discrepancies (often more than a factor of 2), both Gantt et al. (2011) and Vignati et al. (2010) formulations are able to capture the magnitude of marine organic aerosol concentrations, with the Gantt et al. (2011) parameterization attaining better seasonality. Model simulations show that the mixing state of the marine POA can impact the surface number concentration of cloud condensation nuclei (CCN). The largest increases (up to 20 %) in CCN (at a supersaturation (S) of 0.2 %) number concentration are obtained over biologically productive ocean waters when marine organic aerosol is assumed to be externally mixed with sea-salt. Assuming marine organics are internally-mixed with sea-salt provides diverse results with increases and decreases in the concentration of CCN over different parts of the ocean. The sign of the CCN change due to the addition of marine organics to seasalt aerosol is determined by the relative significance of the increase in mean modal diameter due to addition of mass, and the decrease in particle hygroscopicity due to compositional changes in marine aerosol. Based on emerging evidence for increased CCN concentration over biologically active surface ocean areas/periods, our study suggests that treatment of sea spray in global climate models (GCMs) as an internal mixture of marine organic aerosols and sea-salt will likely lead to an underestimation in CCN number concentration.

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

2011-11-23T23:59:59.000Z

88

DRAFT, Revised June 2012 Aerosol cloud-mediated radiative forcing: highly uncertain and  

E-Print Network (OSTI)

clouds is even lower than for the shallow clouds, as mixed phase and ice processes play an important role state of cloud and aerosol parameterizations, but intense research efforts aimed at improving. Respectively, the parameterization of these processes for GCMs is further away than for the low clouds

Daniel, Rosenfeld

89

DRAFT, last update 5 January 2012 Aerosol cloud-mediated radiative forcing: highly uncertain and  

E-Print Network (OSTI)

phase and ice processes. Respectively, the parameterization of these processes for GCMs is further away and aerosol parameterizations, but intense research efforts aimed at improving the realism of cloud lower than for the shallow clouds, as the deep clouds are much more complicated, because mixed phase

Wood, Robert

90

Single-Scattering Albedo and Radiative Forcing of Various Aerosol Species with a Global Three-Dimensional Model  

Science Conference Proceedings (OSTI)

Global distributions of the aerosol optical thickness, Ångström exponent, and single-scattering albedo are simulated using an aerosol transport model coupled with an atmospheric general circulation model. All the main tropospheric aerosols are ...

Toshihiko Takemura; Teruyuki Nakajima; Oleg Dubovik; Brent N. Holben; Stefan Kinne

2002-02-01T23:59:59.000Z

91

The Use of Direct Observations over the Aerosol Particle Size Distribution for Inverting Lidar Data  

Science Conference Proceedings (OSTI)

The work is concerned with the inversion of horizontal lidar data into the aerosol particle size distribution (APSD). The aerosol is assumed to consist of spherical particles of continental and oceanic origin. The particular refraction index is ...

Kusiel S. Shifrin; Ilia G. Zolotov

2003-10-01T23:59:59.000Z

92

TROPOSPHERIC AEROSOLS: THE WILD CARD IN RADIATIVE FORCING OF CLIMATE CHANGE  

E-Print Network (OSTI)

forcings of climate change over the industrial period. Cooling forcings of tens of watts per square meter Understanding 2 1 0 1 2 3 Radiativeforcing(Wattspersquaremetre) CoolingWarming The global mean radiative forcing scattering -- Cooling influence Light absorption -- Warming influence, depending on surface Indirect Effects

Schwartz, Stephen E.

93

The spatial distribution of mineral dust and its shortwave radiative forcing over North Africa: Modeling sensitivities to dust emissions and aerosol size treatments  

Science Conference Proceedings (OSTI)

A fully coupled meteorology-chemistry-aerosol model (WRF-Chem) with the implementation of two dust emission schemes (GOCART and DUSTRAN) into two aerosol models (MADE/SORGAM and MOSAIC) is applied over North Africa to investigate the modeling sensitivities to dust emissions and aerosol size treatments in simulating mineral dust and its shortwave (SW) radiative forcing. Model results of the spatial distribution of mineral dust and its radiative forcing are evaluated using measurements from the AMMA SOP0 campaign in January and February of 2006 over North Africa. Our study suggests that the size distribution of emitted dust can result in significant differences (up to 100%) in simulating mineral dust and its SW radiative forcing. With the same dust emission and dry deposition processes, two aerosol models, MADE/SORGAM and MOSAIC, can yield large difference in size distributions of dust particles due to their different aerosol size treatments using modal and sectional approaches respectively. However, the difference between the two aerosol models in simulating the mass concentrations and the SW radiative forcing of mineral dust is small (< 10%). The model simulations show that mineral dust increases AOD by a factor of 2, heats the lower atmosphere (1-3 km) with a maximum rate of 0.7?0.5 K day-1 below 1 km, and reduces the downwelling SW radiation by up to 25 W m-2 on 24-hour average at surface, highlighting the importance of including dust radiative impact in understanding the regional climate of North Africa. When compared to the available measurements, WRF-Chem simulations can generally capture the measured features of mineral dust and its radiative properties over North Africa, suggesting that the model can be used to perform more extensive simulations of regional climate over North Africa.

Zhao, Chun; Liu, Xiaohong; Leung, Lai-Yung R.; Johnson, Ben; McFarlane, Sally A.; Gustafson, William I.; Fast, Jerome D.; Easter, Richard C.

2010-09-20T23:59:59.000Z

94

Response of the NCAR Community Climate Model to the Radiative Forcing by the Naturally Occurring Tropospheric Aerosol  

Science Conference Proceedings (OSTI)

We insert the effect of naturally occurring tropospheric aerosols on solar radiation into the NCAR Community Climate Model (CCM). The effect of the aerosol depends on concentration and type (continental, maritime), surface albedo, solar zenith ...

James A. Coakley Jr.; Robert D. Cess

1985-08-01T23:59:59.000Z

95

Analyzing signatures of aerosol-cloud interactions from satellite retrievals and the GISS GCM to constrain the aerosol indirect effect  

E-Print Network (OSTI)

dust, and pollution aerosol on shallow cloud developmentclouds on indirect aerosol climate forcing, Nature, 432,1014– Albrecht, B. A. , Aerosols, cloud microphysics, and

2008-01-01T23:59:59.000Z

96

Broadband Extinction Method to Determine Aerosol Optical Depth from Accumulated Direct Solar Radiation  

Science Conference Proceedings (OSTI)

There are two important problems in the aerosol optical depth (AOD) retrievals from hourly/daily/monthly accumulated pyrheliometer data, that is, how to select a suitable cosine of the solar zenith angle (?0) and how to eliminate or minimize ...

Jinhuan Qiu

2003-11-01T23:59:59.000Z

97

Direct Insertion of MODIS Radiances in a Global Aerosol Transport Model  

Science Conference Proceedings (OSTI)

In this paper results are presented from a simple offline assimilation system that uses radiances from the Moderate Resolution Imaging Spectroradiometer (MODIS) channels that sense atmospheric aerosols over land and ocean. The MODIS information ...

Clark Weaver; Arlindo da Silva; Mian Chin; Paul Ginoux; Oleg Dubovik; Dave Flittner; Aahmad Zia; Lorraine Remer; Brent Holben; Watson Gregg

2007-03-01T23:59:59.000Z

98

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

Science Conference Proceedings (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 particles’ 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

On Aerosol Direct Shortwave Forcing and the Henyey–Greenstein Phase Function  

Science Conference Proceedings (OSTI)

This technical note extends previous Mie calculations to show that there are complex relationships between the asymmetry parameter g and the upscatter fractions for monodirectional incident radiation ?(?0). Except for intermediate zenith angles ...

Olivier Boucher

1998-01-01T23:59:59.000Z

100

Direct patterning of surface quantum wells with an atomic force J. Cortes Rosa, M. Wendel, H. Lorenz,a)  

E-Print Network (OSTI)

Direct patterning of surface quantum wells with an atomic force microscope J. Cortes Rosa, MAs­AlSb surface quantum wells. Sharp and sturdy electron beam deposited tips are developed to withstand the comparatively high N forces in the direct patterning process. By direct patterning the InAs surface quantum well

Ludwig-Maximilians-Universität, München

Note: This page contains sample records for the topic "direct aerosol forcing" 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

Time Series of Aerosol Column Optical Depth at the Barrow, Alaska, ARM Climate Research Facility for 2008 Fourth Quarter 2009 ARM and Climate Change Prediction Program Metric Report  

Science Conference Proceedings (OSTI)

The uncertainties in current estimates of anthropogenic radiative forcing are dominated by the effects of aerosols, both in relation to the direct absorption and scattering of radiation by aerosols and also with respect to aerosol-related changes in cloud formation, longevity, and microphysics (See Figure 1; Intergovernmental Panel on Climate Change, Assessment Report 4, 2008). Moreover, the Arctic region in particular is especially sensitive to changes in climate with the magnitude of temperature changes (both observed and predicted) being several times larger than global averages (Kaufman et al. 2009). Recent studies confirm that aerosol-cloud interactions in the arctic generate climatologically significant radiative effects equivalent in magnitude to that of green house gases (Lubin and Vogelmann 2006, 2007). The aerosol optical depth is the most immediate representation of the aerosol direct effect and is also important for consideration of aerosol-cloud interactions, and thus this quantity is essential for studies of aerosol radiative forcing.

C Flynn; AS Koontz; JH Mather

2009-09-01T23:59:59.000Z

102

Trend in Atmospheric Angular Momentum in a Transient Climate Change Simulation with Greenhouse Gas and Aerosol Forcing  

Science Conference Proceedings (OSTI)

The authors investigate the change of atmospheric angular momentum (AAM) in long, transient, coupled atmosphere–ocean model simulations with increasing atmospheric greenhouse gas concentration and sulfate aerosol loading. A significant increase ...

Huei-Ping Huang; Klaus M. Weickmann; C. Juno Hsu

2001-04-01T23:59:59.000Z

103

Measurements of Some Aerosol Properties Relevant to Radiative Forcing on the East Coast of the United States  

Science Conference Proceedings (OSTI)

Airborne measurements of aerosol light-scattering efficiencies are presented for a portion of the northeast Atlantic seaboard of the United State during July 1993. The measurements suggest a value for the sulfate light-scattering efficiency in ...

Dean A. Hegg; Peter V. Hobbs; Ronald J. Ferek; Alan P. Waggoner

1995-10-01T23:59:59.000Z

104

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

DOE Data Explorer (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.

105

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

E-Print Network (OSTI)

J. : A parameterization of aerosol activation - 3. Sectionalclouds on indirect aerosol climate forcing, Nature, 432,2004. Albrecht, B. A. : Aerosols, cloud microphysics, and

Quaas, Johannes

2010-01-01T23:59:59.000Z

106

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

E-Print Network (OSTI)

Cloud susceptibility and the first aerosol indirect forcing:Sensitivity to BC and aerosol concentrations. J. Geophys.of cloud droplet and aerosols number concentrations:

Menon, Surabi

2008-01-01T23:59:59.000Z

107

On the Importance of Organic Oxygen for Understanding Organic Aerosol Particles  

E-Print Network (OSTI)

carbon fractions in atmospheric aerosols, J. Geophys. Res. -particulate diesel exhaust, Aerosol Sci. Technol. 25: 221-climate forcing of carbonaceous aerosols, J. Geophys. Res. -

Pang, Y.; Turpin, B.J.; Gundel, L.A.

2005-01-01T23:59:59.000Z

108

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

E-Print Network (OSTI)

Oscillation influence aerosol variability? , J. Geophys.clouds on indirect aerosol climate forcing, Nature, 432,2004. Albrecht, B. A. : Aerosols, cloud microphysics, and

Quaas, Johannes

2010-01-01T23:59:59.000Z

109

Solar and Greenhouse Gas Forcing and Climate Response in the Twentieth Century  

Science Conference Proceedings (OSTI)

Ensemble experiments with a global coupled climate model are performed for the twentieth century with time-evolving solar, greenhouse gas, sulfate aerosol (direct effect), and ozone (tropospheric and stratospheric) forcing. Observed global ...

Gerald A. Meehl; Warren M. Washington; T. M. L. Wigley; Julie M. Arblaster; Aiguo Dai

2003-02-01T23:59:59.000Z

110

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

Science Conference Proceedings (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

111

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 to investigate the aerosol effects on clouds and precipitation. First, aerosol indirect effects on clouds are separately investigated under different aerosol compositions, concentrations and size distributions. Then, an updated GCE model coupled with the radiative transfer and land surface processes is employed to investigate the aerosol radiative effects on deep convective clouds. The cloud microphysical and macrophysical properties change considerably with the aerosol properties. With varying the aerosol composition from only (NH4)2SO4, (NH4)2SO4 with soluble organics, to (NH4)2SO4 with slightly soluble organics, the number of activated aerosols decreases gradually, leading to a decrease in the cloud droplet number concentration (CDNC) and an increase in the droplet size. Ice processes are more sensitive to the changes of aerosol chemical properties than the warm rain processes. The most noticeable effect of increasing aerosol number concentrations is an increase of CDNC and cloud water content but a decrease in droplet size. It is indicated that the aerosol indirect effect on deep convection is more pronounced in relatively clean air than in heavily polluted air. The aerosol effects on clouds are strongly dependent on RH: the effect is very significant in humid air. Aerosol radiative effects (ARE) on clouds are very pronounced for mid-visible single-scattering albedo (SSA) of 0.85. Relative to the case without the ARE, cloud fraction and optical depth decrease by about 18% and 20%, respectively. The daytime-mean direct forcing is about 2.2 W m-2 at the TOA and -17.4 W m-2 at the surface. The semi-direct forcing is positive, about 10 and 11.2 W m-2 at the TOA and surface, respectively. Aerosol direct and semi-direct effects are very sensitive to SSA. The cloud fraction, optical depth, convective strength, and precipitation decrease with the increase of absorption, resulting from a more stable atmosphere due to enhanced surface cooling and atmospheric heating.

Fan, Jiwen

2007-08-01T23:59:59.000Z

112

Electrostatic Potentials in Rhodopseudomonas Wiridis Reaction Centers: Implications for the Driving Force and Directionality of Electron Transfer  

E-Print Network (OSTI)

Force and Directionality of Electron Transfer M. R. Gunner* Department of Physics, City College of New membrane protein to have a structure solved to atomic resolu- tion.4,5 Since then a higher resolution

Gunner, Marilyn

113

Nuclear Aerosols: Direct Simulation and Elucidation of the Role of Multiple Components, Radioactivity, Charge, Shape and Spatial Inhomogeneity  

Science Conference Proceedings (OSTI)

Nuclear aerosols can originate from severe core damae in light water reactors, core disruptive accidents in fast reactors, nuclear accidents during nuclear material transport, at waste disposal sites, or explosions. These aerosols evolve under natural transport processes as well as under the influence of engineered safety features. Such aerosols can be hazardous for the equipment inside the reactor, and when leaked into the environment, pose potential risks to the public. Hence, the origin, movement and distribution of these aerosols need to be studied and controlled.

Sudarshan K. Loyalka

2008-10-12T23:59:59.000Z

114

Aerosol organic carbon to black carbon ratios: Analysis of published...  

NLE Websites -- All DOE Office Websites (Extended Search)

Aerosol organic carbon to black carbon ratios: Analysis of published data and implications for climate forcing Title Aerosol organic carbon to black carbon ratios: Analysis of...

115

Atmospheric Aerosols  

NLE Websites -- All DOE Office Websites (Extended Search)

Tom Kirchstetter with aerosol measurement instrument Atmospheric Aerosols Atmospheric aerosol research at LBNL seeks to understand the air quality and climate impacts of particles...

116

Mesoscale Variations of Tropospheric Aerosols  

Science Conference Proceedings (OSTI)

Tropospheric aerosols are calculated to cause global-scale changes in the earth's heat balance, but these forcings are space/time integrals over highly variable quantities. Accurate quantification of these forcings will require an unprecedented ...

Theodore L. Anderson; Robert J. Charlson; David M. Winker; John A. Ogren; Kim Holmén

2003-01-01T23:59:59.000Z

117

GCM Aerosol Radiative Effects Using Geographically Varying Aerosol Sizes Deduced from AERONET Measurements  

Science Conference Proceedings (OSTI)

Aerosol optical properties, and hence the direct radiative effects, are largely determined by the assumed aerosol size distribution. In order to relax the fixed aerosol size constraint commonly used in general circulation models (GCMs), ...

Glen Lesins; Ulrike Lohmann

2003-11-01T23:59:59.000Z

118

Aerosols in a Changing Atmosphere: From Detailed Aerosol Microphysics to  

NLE Websites -- All DOE Office Websites (Extended Search)

Aerosols in a Changing Atmosphere: From Detailed Aerosol Microphysics to Aerosols in a Changing Atmosphere: From Detailed Aerosol Microphysics to Policy Applications Speaker(s): Susanne Bauer Date: December 6, 2011 - 4:00pm Location: 90-4133 Seminar Host/Point of Contact: Surabi Menon The anthropogenic increase in aerosol concentrations since preindustrial times and its net cooling effect on the atmosphere is thought to mask some of the greenhouse gas induced warming. Although the overall effect of aerosols on solar radiation and clouds is most certainly negative, some individual forcing agents and feedbacks have positive forcing effects. Recent studies have tried to identify some of those positive forcing agents and their individual emission sectors, However, understanding the net effect of multi-source emitting sectors and the involved cloud feedbacks is

119

Climate Response to Soil Dust Aerosols  

Science Conference Proceedings (OSTI)

The effect of radiative forcing by soil dust aerosols upon climate is calculated. Two atmospheric GCM (AGCM) simulations are compared, one containing a prescribed seasonally varying concentration of dust aerosols, and the other omitting dust. ...

R. L. Miller; I. Tegen

1998-12-01T23:59:59.000Z

120

Future Direction of Supersonic Combustion Research: Air Force/NASA Workshop on Supersonic Combustion  

Science Conference Proceedings (OSTI)

The Air Force Office of Scientific Research, the Air Force Wright Laboratory Aero Propulsion and Power Directorate, and the NASA Langley Research Center held a joint supersonic combustion workshop on 14-16 May 1996. The intent of this meeting was to: ...

Tishkoff Julian M.; Drummond J. Philip; Edwards T.; Nejad A. S.

1997-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "direct aerosol forcing" 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

Overview of the Cumulus Humilis Aerosol Processing Study.  

Science Conference Proceedings (OSTI)

Aerosols influence climate directly by scattering and absorbing radiation and indirectly through their influence on cloud microphysical and dynamical properties. The Intergovernmental Panel on Climate Change (IPCC) concluded that the global radiative forcing due to aerosols is large and in general cools the planet. But the uncertainties in these estimates are also large due to our poor understanding of many of the important processes related to aerosols and clouds. To address this uncertainty an integrated strategy for addressing issues related to aerosols and aerosol processes was proposed. Using this conceptual framework, the Cumulus Humilis Aerosol Processing Study (CHAPS) is a stage 1 activity, that is, a detailed process study. The specific focus of CHAPS was to provide concurrent observations of the chemical composition of the activated [particles that are currently serving as cloud condensation nuclei (CCN)] and nonactivated aerosols, the scattering and extinction profiles, and detailed aerosol and droplet size spectra in the vicinity of Oklahoma City, Oklahoma, during June 2007. Numerous campaigns have examined aerosol properties downwind from large pollution sources, including the Megacity Initiative: Local and Global Research Observations (MILAGRO) campaign and the two of the three Aerosol Characterization Experiments, ACE-2 and ACE-Asia. Other studies conducted near cities have examined changes in both aerosols and clouds downwind of urban areas. For example wintertime stratiform clouds associated with the urban plumes of Denver, Colorado, and Kansas City, Missouri, have a larger number concentration and smaller median volume diameter of droplets than clouds that had not been affected by the urban plume. Likewise, a decrease in precipitation in polluted regions along the Front Range of the Rocky Mountains was discovered. In a modeling study, it was found that precipitation downwind of urban areas may be influenced by changes in aerosols as well as the convergence pattern caused by the city. Recently, the New England Air Quality Study (NEAQS), and the 2004 International Consortium for Atmospheric Research on Transport and Transformation, which were conducted during the summer of 2004, examined the transport of pollutants and aerosols eastward from New England over the Atlantic Ocean. The Texas Air Quality Study/Gulf of Mexico Atmospheric Composition and Climate Study (TexAQS/GoMACCS) also looked at relationships between clouds and aerosols in polluted conditions around Houston, Texas. In contrast to these recent studies near large or very dirty cities, CHAPS was conducted near a moderately sized city that is representative of a large number of cities around the United States. CHAPS was also one of the first times that a Aerodyne aerosol mass spectrometer was used in conjunction with a counterflow virtual impactor (CVI) inlet on an aircraft. The AMS provides information on the nonrefractory (i.e., materials that are chemically and physically unstable at high temperatures) composition of aerosols, while the CVI uses a counterflow relative to the main incoming airstream to exclude small droplets and nonactivated particles from the inlet, allowing only larger cloud droplets to enter the inlet. The combination of the CVI and AMS allow the examination of the chemical composition of the dried aerosol kernel from the cloud droplets. A key objective of the U.S. Department of Energy's (DOE)'s Atmospheric Sciences Program (ASP) is to improve the understanding of aerosol radiative effects on climate. This objective encompasses not only clear sky observations but also studies relating the effects of both aerosols on clouds and clouds on aerosols - in particular, how clouds affect the chemical and optical properties of aerosols. The latter was the science driver in the design of CHAPS. The measurement strategy for CHAPS was intended to provide measurements relevant to four questions associated with the aerosol radiative forcing issues of interest to the ASP: (1) How do the below-cloud and above-cloud aerosol optical and clou

Berg, L. K.; Berkowitz, C. M.; Ogren, J. A.; Hostetler, C. A.; Ferrare, R. A.; Dubey, M.; Andrews, E.; Coulter, R. L.; Hair, J. W.; Hubbe, J. M.Lee, Y. N.; Mazzoleni, C; Olfert, J; Springston, SR; Environmental Science Division; PNNL; NOAA Earth System Research Lab.; NASA Langley Research Center; LANL; BNL; Univ.of Alberta; Univ. of Colorado

2009-11-01T23:59:59.000Z

122

Impact of Desert Dust Radiative Forcing on Sahel Precipitation: Relative Importance of Dust Compared to Sea Surface Temperature Variations, Vegetation Changes, and Greenhouse Gas Warming  

Science Conference Proceedings (OSTI)

The role of direct radiative forcing of desert dust aerosol in the change from wet to dry climate observed in the African Sahel region in the last half of the twentieth century is investigated using simulations with an atmospheric general ...

Masaru Yoshioka; Natalie M. Mahowald; Andrew J. Conley; William D. Collins; David W. Fillmore; Charles S. Zender; Dani B. Coleman

2007-04-01T23:59:59.000Z

123

BNL | Aerosol, Cloud, Precipitation Interactions  

NLE Websites -- All DOE Office Websites (Extended Search)

Cloud-Aerosol-Precipitation Interactions Cloud-Aerosol-Precipitation Interactions Atmospheric aerosols exert important "indirect effects" on clouds and climate by serving as cloud condensation nuclei (CCN) and ice nuclei that affect cloud radiative and microphysical properties. For example, an increase in CCN increases the number concentration of droplets enhances cloud albedo, and suppresses precipitation that alters cloud coverage and lifetime. However, in the case of moist and strong convective clouds, increasing aerosols may increase precipitation and enhance storm development. Although aerosol-induced indirect effects on climate are believed to have a significant impact on global climate change, estimating their impact continues to be one of the most uncertain climate forcings.

124

Direct observation and localization of colloidal nanoparticles on patterned surface by capillary forces  

Science Conference Proceedings (OSTI)

Precise localization of nanoparticles is often required to fully exploit the intrinsic physical properties as well as to develop methodologies for large-scale integration of nanodevice building-blocks with the macroscopic world. In this work, a simple ... Keywords: Indexing nanoparticles, Interfacial capillary forces, Nanoparticles wall, Tracking nanoparticles

D. Peyrade; M. Gordon; G. Hyvert; K. Berton; J. Tallal

2006-04-01T23:59:59.000Z

125

Atmospheric Aerosols  

NLE Websites -- All DOE Office Websites (Extended Search)

measuring equipment Atmospheric Aerosols Atmospheric aerosol research at Berkeley Lab seeks to understand the air quality and climate impacts of particles in the atmosphere. On...

126

The Effects of Black Carbon and Sulfate Aerosols in ChinaRegions on East Asia Monsoons  

Science Conference Proceedings (OSTI)

In this paper we examine the direct effects of sulfate and black carbon aerosols in China on East Asia monsoons and its precipitation processes by using the CAM3.0 model. It is demonstrated that sulfate and black carbon aerosols in China both have the effects to weaken East Asia monsoons in both summer and winter seasons. However, they certainly differ from each other in affecting vertical structures of temperature and atmospheric circulations. Their differences are expected because of their distinct optical properties, i.e., scattering vs. absorbing. Even for a single type of aerosol, its effects on temperature structures and atmospheric circulations are largely season-dependent. Applications of T-test on our results indicate that forcing from black carbon aerosols over China is relatively weak and limited. It is also evident from our results that the effects of synthetic aerosols (sulfate and black carbon together) on monsoons are not simply a linear summation between these two types of aerosols. Instead, they are determined by their integrated optical properties. Synthetic aerosols to a large degree resemble effects of sulfate aerosols. This implies a likely scattering property for the integration of black carbon and sulfate aerosols in China.

Yang, Bai [ORNL; Liu, Yu [Chinese Academy of Meteorological Sciences, Beijing, China; Sun, Jiaren [South China Institute of Environmental Sciences, Guangzhou, China

2009-01-01T23:59:59.000Z

127

Higher Fourier Harmonics of the Directional Distribution of an Equilibrium Wave Field under Steady Wind Forcing  

Science Conference Proceedings (OSTI)

Recently, directional wave spectra have been obtained by applying the two-dimensional fast Fourier transform (2D FFT) to the three-dimensional spatial topography of ocean surface waves collected by an airborne scanning laser ranging system during ...

David W. Wang; Paul A. Hwang

2003-01-01T23:59:59.000Z

128

Radiative Forcing of the Stratosphere by SO2 Gas, Silicate Ash, and H2SO4 Aerosols Shortly after the 1982 Eruptions of El Chichón  

Science Conference Proceedings (OSTI)

The 1982 eruptions of the El Chichón volcano injected large quantities of sulfur dioxide gas and silicate ash into the stratosphere. Several studies have shown that the long-lived sulfuric acid aerosols derived from these volcanic effluents ...

M. F. Gerstell; Joy Crisp; David Crisp

1995-05-01T23:59:59.000Z

129

EMSL: Science: Atmospheric Aerosol Systems  

NLE Websites -- All DOE Office Websites (Extended Search)

Atmospheric Aerosol Systems Atmospheric Aerosol Systems atmospheric logo Nighttime enhancement of nitrogen-containing organic compounds, or NOC Observed nighttime enhancement of nitrogen-containing organic compounds, or NOC, showed evidence of being formed by reactions that transform carbonyls into imines. The Atmospheric Aerosol Systems Science Theme focuses on understanding the chemistry, physics and molecular-scale dynamics of aerosols for model parameterization to improve the accuracy of climate model simulations and develop a predictive understanding of climate. By elucidating the role of natural and anthropogenic regional and global climate forcing mechanisms, EMSL can provide DOE and others with the ability to develop cost-effective strategies to monitor, control and mitigate them.

130

Massively parallel direct numerical simulations of forced compressible turbulence: a hybrid MPI/OpenMP approach  

Science Conference Proceedings (OSTI)

A highly scalable simulation code for turbulent flows which solves the fully compressible Navier-Stokes equations is presented. The code, which supports one, two and three dimensional domain decompositions is shown to scale well on up to 262,144 cores. ... Keywords: direct numerical simulations, multilevel parallelism, parallel performance, turbulent flows

Shriram Jagannathan; Diego A. Donzis

2012-07-01T23:59:59.000Z

131

Aerosol Observing System (AOS) Handbook  

Science Conference Proceedings (OSTI)

The Aerosol Observing System (AOS) is a suite of in situ surface measurements of aerosol optical and cloud-forming properties. The instruments measure aerosol properties that influence the earth’s radiative balance. The primary optical measurements are those of the aerosol scattering and absorption coefficients as a function of particle size and radiation wavelength and cloud condensation nuclei (CCN) measurements as a function of percent supersaturation. Additional measurements include those of the particle number concentration and scattering hygroscopic growth. Aerosol optical measurements are useful for calculating parameters used in radiative forcing calculations such as the aerosol single-scattering albedo, asymmetry parameter, mass scattering efficiency, and hygroscopic growth. CCN measurements are important in cloud microphysical models to predict droplet formation.

Jefferson, A

2011-01-17T23:59:59.000Z

132

Hydrothermal research and development assessment. Task Force report: projections for direct-heat applications  

DOE Green Energy (OSTI)

Low and moderate temperature hydrothermal resources suitable for direct-heat applications have been identified in 37 states. The extent to which three resources might be used over the next 20 years were evaluated and the probable impact of Federal programs on hydrothermal resource utilization was assessed. The use types that comprise the bulk of the market were determined. Representative firms and municipalities were interviewed to determine their willingness to use hydrothermal energy, and to determine the investment decision criteria that would influence their actions. (MHR)

Not Available

1982-04-01T23:59:59.000Z

133

Fast and Slow Responses of the South Asian Monsoon System to Anthropogenic Aerosols  

Science Conference Proceedings (OSTI)

Using a global climate model with fully predictive aerosol life cycle, we investigate the fast and slow responses of the South Asian monsoon system to anthropogenic aerosol forcing. Our results show that the feedbacks associated with sea surface temperature (SST) change caused by aerosols play a more important role than the aerosol's direct impact on radiation, clouds and land surface (rapid adjustments) in shaping the total equilibrium climate response of the monsoon system to aerosol forcing. Inhomogeneous SST cooling caused by anthropogenic aerosols eventually reduces the meridional tropospheric temperature gradient and the easterly shear of zonal winds over the region, slowing down the local Hadley cell circulation, decreasing the northward moisture transport, and causing a reduction in precipitation over South Asia. Although total responses in precipitation are closer to the slow responses in general, the fast component dominates over land areas north of 25°N. Our results also show an east-west asymmetry in the fast responses to anthropogenic aerosols causing increases in precipitation west of 80°E but decreases east of it.

Ganguly, Dilip; Rasch, Philip J.; Wang, Hailong; Yoon, Jin-Ho

2012-09-25T23:59:59.000Z

134

Aerosol Data Sources and Their Roles within PARAGON  

Science Conference Proceedings (OSTI)

We briefly but systematically review major sources of aerosol data, emphasizing suites of measurements that seem most likely to contribute to assessments of global aerosol climate forcing. The strengths and limitations of existing satellite, ...

Ralph A. Kahn; John A. Ogren; Thomas P. Ackerman; Jens Bösenberg; Robert J. Charlson; David J. Diner; Brent N. Holben; Robert T. Menzies; Mark A. Miller; John H. Seinfeld

2004-10-01T23:59:59.000Z

135

Aerosol Impacts on the Diurnal Cycle of Marine Stratocumulus  

Science Conference Proceedings (OSTI)

Recent large-eddy simulation (LES) studies of the impact of aerosol on the dynamics of nocturnal marine stratocumulus revealed that, depending on the large-scale forcings, an aerosol-induced increase of the droplet concentration can lead to ...

Irina Sandu; Jean-Louis Brenguier; Olivier Geoffroy; Odile Thouron; Valery Masson

2008-08-01T23:59:59.000Z

136

Climate response of the South Asian monsoon system to anthropogenic aerosols  

Science Conference Proceedings (OSTI)

The equilibrium climate response to the total effects (direct, indirect and semi-direct effects) of aerosols arising from anthropogenic and biomass burning emissions on the South Asian summer monsoon system is studied using a coupled atmosphere-slab ocean model. Our results suggest that anthropogenic and biomass burning aerosols generally induce a reduction in mean summer monsoon precipitation over most parts of the Indian subcontinent, strongest along the western coastline of the Indian peninsula and eastern Nepal region, but modest increases also occur over the north western part of the subcontinent. While most of the noted reduction in precipitation is triggered by increased emissions of aerosols from anthropogenic activities, modest increases in the north west are mostly associated with decreases in local emissions of aerosols from forest fire and grass fire sources. Anthropogenic aerosols from outside Asia also contribute to the overall reduction in precipitation but the dominant contribution comes from aerosol sources within Asia. Local emissions play a more important role in the total rainfall response to anthropogenic aerosol sources during the early monsoon period, whereas both local as well as remote emissions of aerosols play almost equally important roles during the later part of the monsoon period. While precipitation responses are primarily driven by local aerosol forcing, regional surface temperature changes over the region are strongly influenced by anthropogenic aerosols from sources further away (non-local changes). Changes in local anthropogenic organic and black carbon emissions by as much as a factor of two (preserving their ratio) produce the same basic signatures in the model's summer monsoon temperature and precipitation responses.

Ganguly, Dilip; Rasch, Philip J.; Wang, Hailong; Yoon, Jin-Ho

2012-07-13T23:59:59.000Z

137

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

Science Conference Proceedings (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 in the present study using three satellite datasets. The satellite datasets are taken as reference bearing in mind that cloud and aerosol retrievals include uncertainties. We compute statistical relationships between aerosol optical depth (?a) and various cloud and radiation quantities consistently in models and 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 oceans. The relationship between ?a and liquid water path is simulated much too strongly by the models. It is shown that this is partly related to rep¬resentation of the second aerosol indirect effect in terms of autoconversion. A positive re¬lationship between total cloud fraction (fcld) and ?a as found in the satellite data is simulated by the majority of the models, albeit less strongly in most of them. In a discussion of the hypo¬theses proposed in the literature to explain the satellite-derived strong fcld – ?a relation¬ship, we find that none is unequivocally confirmed by our results. Relationships similar to the ones found in satellite data between ?a and cloud top tem¬perature and outgoing long-wave radiation (OLR) are simulated by only a few GCMs. The GCMs that simulate a negative OLR - ?a relationship show a strong positive cor¬relation between ?a and cloud fraction. The short-wave total aerosol radiative forcing as simulated by the GCMs is strongly influenced by the simulated anthropogenic fraction of ?a, and parameterisation assumptions such as a lower bound on Nd. Nevertheless, the strengths of the statistical relationships are good predictors for the short-wave total 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 estim¬ate obtained by scaling the simulated clear- and cloudy-sky forcings with estimates of anthropogenic ?a and satellite-retrieved Nd – ?a regression slopes, respectively, yields a global annual mean clear-sky (aerosol direct effect) es¬timate 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, T.; Wang, Minghuai; Penner, Joyce E.; Gettelman, A.; Lohmann, U.; Bellouin, N.; Boucher, Olivier; Sayer, Andrew M.; Thomas, Gareth E.; McComiskey, A.; Feingold, G.; Hoose, Corinna; Kristjansson, J. E.; Liu, Xiaohong; Balkanski, Y.; Donner, Leo J.; Ginoux, P.; Stier, P.; Grandey, B.; Feichter, J.; Sednev, Igor; Bauer, Susanne E.; Koch, D.; Grainger, Roy G.; Kirkevag, A.; Iversen, T.; Seland, O.; Easter, Richard C.; Ghan, Steven J.; Rasch, Philip J.; Morrison, H.; Lamarque, J. F.; Iacono, Michael J.; Kinne, Stefan; Schulz, M.

2009-11-16T23:59:59.000Z

138

Speciation of Organic Aerosols in the Tropical Mid-Pacific and Their Relationship to Light Scattering  

Science Conference Proceedings (OSTI)

Although the importance of the aerosol contribution to the global radiative budget has been recognized, the forcings of aerosols in general, and specifically the role of the organic component in these forcings, still contain large uncertainties. ...

Kathleen K. Crahan; Dean A. Hegg; David S. Covert; Haflidi Jonsson; Jeffrey S. Reid; Djamal Khelif; Barbara J. Brooks

2004-11-01T23:59:59.000Z

139

Aerosol Properties from Multi-spectral and Multi-angular Aircraft 4STAR Observations: Expected Advantages and Challenges  

SciTech Connect

The airborne Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) is developed to retrieve aerosol microphysical and optical properties from multi-angular and multi-spectral measurements of sky radiance and direct-beam sun transmittance. The necessarily compact design of the 4STAR may cause noticeable apparent enhancement of sky radiance at small scattering angles. We assess the sensitivity of expected 4STAR-based aerosol retrieval to such enhancement by applying the operational AERONET retrieval code and constructed synthetic 4STARlike data. Also, we assess the sensitivity of the broadband fluxes and the direct aerosol radiative forcing to uncertainties in aerosol retrievals associated with the sky radiance enhancement. Our sensitivity study results suggest that the 4STARbased aerosol retrieval has limitations in obtaining detailed information on particle size distribution and scattering phase function. However, these limitations have small impact on the retrieved bulk optical parameters, such as the asymmetry factor (up to 4%, or ±0.02) and single-scattering albedo (up to 2%, or ±0.02), and the calculated direct aerosol radiative forcing (up to 6%, or 2 Wm-2).

Kassianov, Evgueni I.; Flynn, Connor J.; Redemann, Jens; Schmid, Beat; Russell, P. B.; Sinyuk, Alexander

2012-11-01T23:59:59.000Z

140

New approaches for the chemical and physical characterization of aerosols using a single particle mass spectrometry based technique  

E-Print Network (OSTI)

mass fractions in particles. Aerosol Science and Technology,mediated lung injury, J. Aerosol Sci. , 29 (5-6), 553-560,from natural to anthropogenic aerosol radiative forcing:

Spencer, Matthew Todd

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "direct aerosol forcing" 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

Distinguishing Aerosol Impacts on Climate Over the Past Century  

SciTech Connect

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

142

Climate Impacts of Atmospheric Sulfate and Black Carbon Aerosols  

SciTech Connect

Although the global average surface temperature has increased by about 0.6°C during the last century (IPCC, 2001), some regions such as East Asia, Eastern North America, and Western Europe have cooled rather than warmed during the past decades (Jones, 1988; Qian and Giorgi, 2000). Coherent changes at the regional scale may reflect responses to different climate forcings that need to be understood in order to predict the future net climate response at the global and regional scales under different emission scenarios. Atmospheric aerosols play an important role in global climate change (IPCC 2001). They perturb the earth’s radiative budget directly by scattering and absorbing solar and long wave radiation, and indirectly by changing cloud reflectivity, lifetime, and precipitation efficiency via their role as cloud condensation nuclei. Because aerosols have much shorter lifetime (days to weeks) compared to most greenhouse gases, they tend to concentrate near their emission sources and distribute very unevenly both in time and space. This non-uniform distribution of aerosols, in conjunction with the greenhouse effect, may lead to differential net heating in some areas and net cooling in others (Penner et al. 1994). Sulfate aerosols come mainly from the oxidation of sulfur dioxide (SO2) emitted from fossil fuel burning. Black carbon aerosols are directly emitted during incomplete combustion of biomass, coal, and diesel derived sources. Due to the different optical properties, sulfate and black carbon affect climate in different ways. Because of the massive emissions of sulfur and black carbon that accompany the rapid economic expansions in East Asia, understanding the effects of aerosols on climate is particularly important scientifically and politically in order to develop adaptation and mitigation strategies.

Qian, Yun; Song, Qingyuan; Menon, Surabi; Yu, Shaocai; Liu, Shaw C.; Shi, Guangyu; Leung, Lai R.; Luo, Yunfeng

2008-09-19T23:59:59.000Z

143

Determination of the most probable slip surface in 3D slopes considering the effect of earthquake force direction  

Science Conference Proceedings (OSTI)

Considering the effect of earthquake forces on stability of slopes has always been of crucial importance in seismic analysis of geotechnical structures like dams, roads and embankments and there has been much concern about stability of cuts, fills and ... Keywords: 3D slopes, Earthquake force inclination, Stability analysis

A. Ahangar-Asr; M. M. Toufigh; A. Salajegheh

2012-08-01T23:59:59.000Z

144

Original article: Lumped-parameter-based thermal analysis of a doubly radial forced-air-cooled direct-driven permanent magnet wind generator  

Science Conference Proceedings (OSTI)

A lumped-parameter-based thermal analysis of a direct-driven permanent magnet wind generator with double radial forced-air cooling is presented. In the proposed thermal model, the thermal conduction and convection as well as the heating of the cooling ... Keywords: Air cooling, Permanent magnet synchronous generator, Thermal analysis, Thermal resistance networks

Janne Nerg, Vesa Ruuskanen

2013-04-01T23:59:59.000Z

145

ARM - Measurement - Aerosol scattering  

NLE Websites -- All DOE Office Websites (Extended Search)

Spectrometer RL : Raman Lidar Field Campaign Instruments AOS : Aerosol Observing System DRI-GND : Desert Research Institute Ground-Based Aerosol Instruments AEROSOL-TOWER-EML :...

146

ARM - Measurement - Aerosol extinction  

NLE Websites -- All DOE Office Websites (Extended Search)

CSPHOT : Cimel Sunphotometer CLDAEROSMICRO : Cloud and Aerosol Microphysical Properties DRI-GND : Desert Research Institute Ground-Based Aerosol Instruments IAP : In-situ Aerosol...

147

Eastern Pacific Emitted Aerosol Cloud Experiment  

Science Conference Proceedings (OSTI)

Aerosol–cloud–radiation interactions are widely held to be the largest single source of uncertainty in climate model projections of future radiative forcing due to increasing anthropogenic emissions. The underlying causes of this uncertainty among modeled ...

Lynn M. Russell; Armin Sorooshian; John H. Seinfeld; Bruce A. Albrecht; Athanasios Nenes; Lars Ahlm; Yi-Chun Chen; Matthew Coggon; Jill S. Craven; Richard C. Flagan; Amanda A. Frossard; Haflidi Jonsson; Eunsil Jung; Jack J. Lin; Andrew R. Metcalf; Robin Modini; Johannes Mülmenstädt; Greg Roberts; Taylor Shingler; Siwon Song; Zhen Wang; Anna Wonaschütz

2013-05-01T23:59:59.000Z

148

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

SciTech Connect

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 parameterises aerosol effects on convective clouds. We compute statistical relationships between aerosol optical depth ({tau}{sub a}) 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 (N{sub d}) compares relatively well to the satellite data at least over the ocean. The relationship between {tau}{sub a} and liquid water path is simulated much too strongly by the models. This suggests that the implementation of the second aerosol indirect effect mainly in terms of an autoconversion parameterisation has to be revisited in the GCMs. A positive relationship between total cloud fraction (f{sub cld}) and {tau}{sub a} 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 f{sub cld} - {tau}{sub a} relationship, our results indicate that none can be identified as a unique explanation. Relationships similar to the ones found in satellite data between {tau}{sub a} and cloud top temperature or outgoing long-wave radiation (OLR) are simulated by only a few GCMs. The GCMs that simulate a negative OLR - {tau}{sub a} relationship show a strong positive correlation between {tau}{sub a} and f{sub cld} The short-wave total aerosol radiative forcing as simulated by the GCMs is strongly influenced by the simulated anthropogenic fraction of {tau}{sub a}, and parameterization assumptions such as a lower bound on N{sub d}. 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{sup -2}. In an alternative approach, the radiative flux perturbation due to anthropogenic aerosols can be broken down into a component over the cloud-free portion of the globe (approximately the aerosol direct effect) and a component over the cloudy portion of the globe (approximately the aerosol indirect effect). An estimate obtained by scaling these simulated clear- and cloudy-sky forcings with estimates of anthropogenic {tau}{sub a} and satellite-retrieved Nd - {tau}{sub a} regression slopes, respectively, yields a global, annual-mean aerosol direct effect estimate of -0.4 {+-} 0.2 Wm{sup -2} and a cloudy-sky (aerosol indirect effect) estimate of -0.7 {+-} 0.5 Wm{sup -2}, with a total estimate of -1.2 {+-} 0.4 Wm{sup -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; Kristansson, Jon Egill; Liu, Xiaohong; Balkanski, Yves; Donner, Leo J.; Ginoux, Paul A.; Stier, Philip; Grandey, Benjamin; 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

2010-03-12T23:59:59.000Z

149

Assessment of Aerosol Radiative Impact over Oceanic Regions Adjacent to Indian Subcontinent using Multi-Satellite Analysis  

SciTech Connect

Using data from Ozone Monitoring Instrument (OMI) and Moderate Resolution Imaging Spectroradiometer (MODIS) instruments, we have retrieved regional distribution of aerosol column single scattering albedo (parameter indicative of the relative dominance of aerosol absorption and scattering effects), a most important, but least understood aerosol property in assessing its climate impact. Consequently we provide improved assessment of short wave aerosol radiative forcing (ARF) (on both regional and seasonal scales) estimates over this region. Large gradients in north-south ARF were observed as a consequence of gradients in single scattering albedo as well as aerosol optical depth. The highest ARF (-37 W m-2 at the surface) was observed over the northern Arabian Sea during June to August period (JJA). In general, ARF was higher over northern Bay of Bengal (NBoB) during winter and pre-monsoon period, whereas the ARF was higher over northern Arabian Sea (NAS) during the monsoon and post- monsoon period. The largest forcing observed over NAS during JJA is the consequence of large amounts of desert dust transported from the west Asian dust sources. High as well as seasonally invariant aerosol single scattering albedos (~0.98) were observed over the southern Indian Ocean region far from continents. The ARF estimates based on direct measurements made at a remote island location, Minicoy (8.3°N, 73°E) in the southern Arabian Sea are in good agreement with the estimates made following multisatellite analysis.

Satheesh, S. K.; Vinoj, V.; Krishnamoorthy, K.

2010-10-01T23:59:59.000Z

150

Distinguishing Aerosol Impacts on Climate over the Past Century  

Science Conference Proceedings (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 ...

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

2009-05-01T23:59:59.000Z

151

Aerosol climate effects and air quality impacts from 1980 to 2030  

SciTech Connect

We investigate aerosol effects on climate for 1980, 1995 (meant to reflect present-day) and 2030 using the NASA Goddard Institute for Space Studies climate model coupled to an on-line aerosol source and transport model with interactive oxidant and aerosol chemistry. Aerosols simulated include sulfates, organic matter (OM), black carbon (BC), sea-salt and dust and additionally, the amount of tropospheric ozone is calculated, allowing us to estimate both changes to air quality and climate for different time periods and emission amounts. We include both the direct aerosol effect and indirect aerosol effects for liquid-phase clouds. Future changes for the 2030 A1B scenario are examined, focusing on the Arctic and Asia, since changes are pronounced in these regions. Our results for the different time periods include both emission changes and physical climate changes. We find that the aerosol indirect effect (AIE) has a large impact on photochemical processing, decreasing ozone amount and ozone forcing, especially for the future (2030-1995). Ozone forcings increase from 0 to 0.12 Wm{sup -2} and the total aerosol forcing increases from -0.10 Wm{sup -2} to -0.94 Wm{sup -2} (AIE increases from -0.13 to -0.68 Wm{sup -2}) for 1995-1980 versus 2030-1995. Over the Arctic we find that compared to ozone and the direct aerosol effect, the AIE contributes the most to net radiative flux changes. The AIE, calculated for 1995-1980, is positive (1.0 Wm{sup -2}), but the magnitude decreases (-0.3Wm{sup -2}) considerably for the future scenario. Over Asia, we evaluate the role of biofuel and transportation-based emissions (for BC and OM) via a scenario (2030A) that includes a projected increase (factor of two) in biofuel and transport-based emissions for 2030 A1B over Asia. Projected changes from present-day due to the 2030A emissions versus 2030 A1B are a factor of 4 decrease in summertime precipitation in Asia. Our results are sensitive to emissions used. Uncertainty in present-day emissions suggest that future climate projections warrant particular scrutiny.

Menon, Surabi; Menon, Surabi; Unger, Nadine; Koch, Dorothy; Francis, Jennifer; Garrett, Tim; Sednev, Igor; Shindell, Drew; Streets, David

2007-11-26T23:59:59.000Z

152

A Comparison of Model- and Satellite-Derived Aerosol Optical Depth and Reflectivity  

Science Conference Proceedings (OSTI)

The determination of an accurate quantitative understanding of the role of tropospheric aerosols in the earth's radiation budget is extremely important because forcing by anthropogenic aerosols presently represents one of the most uncertain ...

Joyce E. Penner; Sophia Y. Zhang; Mian Chin; Catherine C. Chuang; Johann Feichter; Yan Feng; Igor V. Geogdzhayev; Paul Ginoux; Michael Herzog; Akiko Higurashi; Dorothy Koch; Christine Land; Ulrike Lohmann; Michael Mishchenko; Teruyuki Nakajima; Giovanni Pitari; Brian Soden; Ina Tegen; Lawrence Stowe

2002-02-01T23:59:59.000Z

153

Variability of Absorption and Optical Properties of Key Aerosol Types Observed in Worldwide Locations  

Science Conference Proceedings (OSTI)

Aerosol radiative forcing is a critical, though variable and uncertain, component of the global climate. Yet climate models rely on sparse information of the aerosol optical properties. In situ measurements, though important in many respects, ...

Oleg Dubovik; Brent Holben; Thomas F. Eck; Alexander Smirnov; Yoram J. Kaufman; Michael D. King; Didier Tanré; Ilya Slutsker

2002-02-01T23:59:59.000Z

154

Evaluating the Potential for Retrieving Aerosol Optical Depth over Land from AVHRR Pathfinder Atmosphere Data  

Science Conference Proceedings (OSTI)

In spite of numerous studies on the remote sensing of aerosols from satellites, the magnitude of aerosol climate forcing remains uncertain. However, data from the Advanced Very High Resolution Radiometer (AVHRR) Pathfinder-Atmosphere (PATMOS) ...

Kenneth R. Knapp; Larry L. Stowe

2002-02-01T23:59:59.000Z

155

Coupling Aerosol-Cloud-Radiative Processes in the WRF-Chem Model: Investigating the Radiative Impact of Elevated Point Sources  

Science Conference Proceedings (OSTI)

The local and regional influence of elevated point sources on summertime aerosol forcing and cloud-aerosol interactions in northeastern North America was investigated using the WRF-Chem community model. The direct effects of aerosols on incoming solar radiation were simulated using existing modules to relate aerosol sizes and chemical composition to aerosol optical properties. Indirect effects were simulated by adding a prognostic treatment of cloud droplet number and adding modules that activate aerosol particles to form cloud droplets, simulate aqueous phase chemistry, and tie a two-moment treatment of cloud water (cloud water mass and cloud droplet number) to an existing radiation scheme. Fully interactive feedbacks thus were created within the modified model, with aerosols affecting cloud droplet number and cloud radiative properties, and clouds altering aerosol size and composition via aqueous processes, wet scavenging, and gas-phase-related photolytic processes. Comparisons of a baseline simulation with observations show that the model captured the general temporal cycle of aerosol optical depths (AODs) and produced clouds of comparable thickness to observations at approximately the proper times and places. The model slightly overpredicted SO2 mixing ratios and PM2.5 mass, but reproduced the range of observed SO2 to sulfate aerosol ratios, suggesting that atmospheric oxidation processes leading to aerosol sulfate formation are captured in the model. The baseline simulation was compared to a sensitivity simulation in which all emissions at model levels above the surface layer were set to zero, thus removing stack emissions. Instantaneous, site-specific differences for aerosol and cloud related properties between the two simulations could be quite large, as removing above-surface emission sources influenced when and where clouds formed within the modeling domain. When summed spatially over the finest resolution model domain (the extent of which corresponds to the typical size of a single GCM grid cell) and temporally over a three day analysis period, total rainfall in the sensitivity simulation increased by 31% over that in the baseline simulation. Fewer optically thin clouds, arbitrarily defined as a cloud exhibiting an optical depth less than 1, formed in the sensitivity simulation. Domain-averaged AODs dropped from 0.46 in the baseline simulation to 0.38 in the sensitivity simulation. The overall net effect of additional aerosols attributable to primary particulates and aerosol precursors from point source emissions above the surface was a domain-averaged reduction of 5 W m-2 in mean daytime downwelling shortwave radiation.

Chapman, Elaine G.; Gustafson, William I.; Easter, Richard C.; Barnard, James C.; Ghan, Steven J.; Pekour, Mikhail S.; Fast, Jerome D.

2009-02-01T23:59:59.000Z

156

Direct measurements of the effects of salt and surfactant on interaction forces between colloidal particles at water-oil interfaces  

E-Print Network (OSTI)

The forces between colloidal particles at a decane-water interface, in the presence of low concentrations of a monovalent salt (NaCl) and of the surfactant sodium dodecylsulfate (SDS) in the aqueous subphase, have been studied using laser tweezers. In the absence of electrolyte and surfactant, particle interactions exhibit a long-range repulsion, yet the variation of the interaction for different particle pairs is found to be considerable. Averaging over several particle pairs was hence found to be necessary to obtain reliable assessment of the effects of salt and surfactant. It has previously been suggested that the repulsion is consistent with electrostatic interactions between a small number of dissociated charges in the oil phase, leading to a decay with distance to the power -4 and an absence of any effect of electrolyte concentration. However, the present work demonstrates that increasing the electrolyte concentration does yield, on average, a reduction of the magnitude of the interaction force with electrolyte concentration. This implies that charges on the water side also contribute significantly to the electrostatic interactions. An increase in the concentration of SDS leads to a similar decrease of the interaction force. Moreover the repulsion at fixed SDS concentrations decreases over longer times. Finally, measurements of three-body interactions provide insight into the anisotropic nature of the interactions. The unique time-dependent and anisotropic interactions between particles at the oil-water interface allow tailoring of the aggregation kinetics and structure of the suspension structure.

B. J. Park; J. P. Pantina; E. Furst; M. Oettel; S. Reynaert; J. Vermant

2007-09-07T23:59:59.000Z

157

Inertia–Gravity Wave and Neutral Eady Wave Trains Forced by Directionally Sheared Flow over Isolated Hills  

Science Conference Proceedings (OSTI)

Analytical solutions are obtained to the linearized equations describing a particular class of directionally sheared flow over isolated hills or ridges. The flows are characterized by constant buoyancy frequency and vertical wind shear, though ...

Glenn Shutts

2003-02-01T23:59:59.000Z

158

Linearity of Climate Response to Increases in Black Carbon Aerosols  

Science Conference Proceedings (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.

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

2013-01-01T23:59:59.000Z

159

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

SciTech Connect

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

160

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.; Johnson, Stanley A.

1997-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "direct aerosol forcing" 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

FY 2011 Second Quarter: Demonstration of New Aerosol Measurement Verification Testbed for Present-Day Global Aerosol Simulations  

SciTech Connect

The regional-scale Weather Research and Forecasting (WRF) model is being used by a DOE Earth System Modeling (ESM) project titled “Improving the Characterization of Clouds, Aerosols and the Cryosphere in Climate Models” to evaluate the performance of atmospheric process modules that treat aerosols and aerosol radiative forcing in the Arctic. We are using a regional-scale modeling framework for three reasons: (1) It is easier to produce a useful comparison to observations with a high resolution model; (2) We can compare the behavior of the CAM parameterization suite with some of the more complex and computationally expensive parameterizations used in WRF; (3) we can explore the behavior of this parameterization suite at high resolution. Climate models like the Community Atmosphere Model version 5 (CAM5) being used within the Community Earth System Model (CESM) will not likely be run at mesoscale spatial resolutions (10–20 km) until 5–10 years from now. The performance of the current suite of physics modules in CAM5 at such resolutions is not known, and current computing resources do not permit high-resolution global simulations to be performed routinely. We are taking advantage of two tools recently developed under PNNL Laboratory Directed Research and Development (LDRD) projects for this activity. The first is the Aerosol Modeling Testbed (Fast et al., 2011b), a new computational framework designed to streamline the process of testing and evaluating aerosol process modules over a range of spatial and temporal scales. The second is the CAM5 suite of physics parameterizations that have been ported into WRF so that their performance and scale dependency can be quantified at mesoscale spatial resolutions (Gustafson et al., 2010; with more publications in preparation).

Koch, D

2011-03-20T23:59:59.000Z

162

Recommended mission directed goals for electric vehicle battery research and development. The task force on electric vehicle battery goals  

SciTech Connect

Research and development goal packages were developed for the state-of-the-art, flow-through, and bipolar lead-acid batteries, nickel/iron, nickel/zinc, nickel/cadmium, zinc/bromine, iron/air, lithium/iron sulfide, and sodium/sulfur technologies. Since each battery must satisfy mission power/energy requirements throughout every cycle of its operating life, the principal ''design point'' is the end-of-life condition. Since all batteries exhibit deteriorating performance with age, excess kWh capacity of 20 to 30 percent is required early in life. The Battery Panel first identified present state-of-the-art performance characteristics and design interrelationships for each battery technology, and projected the degree of advance expected by 1995. Near-term and 1995 design tradeoffs were modeled using the EVA computerized system developed by ANL. The next step was to target each battery system for a single range (80, 120 or 160 km), depending on its projected 1995 capabilities. For each battery, baseline calculations were carried out assuming the maximum battery weight (695 kg) to be on board. In addition to performance, life, and cost goals, development targets were also established for efficiency, maintenance, and allowable self-discharge rate. The Task Force attempted to establish battery cost requirements, assuming economic parity (in 1995) with other modes of transportation.

Not Available

1986-03-01T23:59:59.000Z

163

BNL | Aerosol Lifecycle Research  

NLE Websites -- All DOE Office Websites (Extended Search)

identified strategic process-science foci: aerosol nucleation and growth and aerosol aging and mixing state. BNL is the lead laboratory responsible for the design and...

164

Aerosol Can Failure  

Science Conference Proceedings (OSTI)

Presentation Title, Aerosol Can Failure ... Abstract Scope, A three-piece, welded seam aerosol can of liquid undercoating material failed catastrophically, ...

165

Aerosol Modeling at LLNL - Our capability, results, and perspective  

NLE Websites -- All DOE Office Websites (Extended Search)

Aerosol Indirect Effects to Cloud Aerosol Indirect Effects to Cloud Parameterizations in Short-Range Weather Forecasts with CAM3 Over the Southern Great Plains during May 2003 IOP Lawrence Livermore National Laboratory This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 Catherine Chuang, James Boyle Shaocheng Xie and James Kelly LLNL-POST-401948 March 11, 2008 Why are aerosol/cloud interactions important? The greatest uncertainty in the assessment of radiative forcing arises from the interactions of aerosols with clouds. Radiative forcing of climate between 1750 and 2005 (IPCC, 2007) Sources of uncertainty Emissions Gas to particle conversion Aerosol size distribution Linkage between aerosols

166

Modeling the spectral optical properties of ammonium sulfate and biomass burning aerosols  

SciTech Connect

The importance of including the global and regional radiative effects of aerosols in climate models has increasingly been realized. Accurate modeling of solar radiative forcing due to aerosols from anthropogenic sulfate and biomass burning emissions requires adequate spectral resolution and treatment of spatial and temporal variability. The variation of aerosol spectral optical properties with local relative humidity and dry aerosol composition must be considered. Because the cost of directly including Mie calculations within a climate model is prohibitive, parameterizations from offline calculations must be used. Starting from a log-normal size distribution of dry ammonium sulfate, we developed optical properties for tropospheric sulfate aerosol at 15 relative humidities up to 99 percent. The resulting aerosol size distributions were then used to calculate bulk optical properties at wavelengths between 0.175 {micro}m and 4 {micro}m. Finally, functional fits of optical properties were made for each of 12 wavelength bands as a function of relative humidity. Significant variations in optical properties occurred across the total solar spectrum. Relative increases in specific extinction and asymmetry factor with increasing relative humidity became larger at longer wavelengths. Significant variation in single-scattering albedo was found only in the longest near-IR band. This is also the band with the lowest albedo. A similar treatment was done for aerosols from biomass burning. In this case, size distributions were taken as having two carbonaceous size modes and a larger dust mode. The two carbonaceous modes were considered to be humidity dependent. Equilibrium size distributions and compositions were calculated for 15 relative humidities and five black carbon fractions. Mie calculations and Chandrasekhar averages of optical properties were done for each of the resulting 75 cases. Finally, fits were made for each of 12 spectral bands as functions of relative humidity and black carbon fraction.

Grant, K.E.; Chuang, C.C.; Grossman, A.S.; Penner, J.E. [Michigan Univ., Ann Arbor, MI (United States)

1997-09-01T23:59:59.000Z

167

Aerosol beam-focus laser-induced plasma spectrometer device  

SciTech Connect

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

168

Aerosol Radiative Impact on Spectral Solar Flux at the Surface, Derived from Principal-Plane Sky Measurements  

Science Conference Proceedings (OSTI)

Accurate measurements of the spectral solar flux reaching the surface in cloud-free conditions are required to determine the aerosol radiative impact and to test aerosol models that are used to calculate radiative forcing of climate. Spectral ...

Y. J. Kaufman; D. Tanré; B. N. Holben; S. Mattoo; L. A. Remer; T. F. Eck; J. Vaughan; Bernadette Chatenet

2002-02-01T23:59:59.000Z

169

3-D nonlinear force-free field reconstruction of solar active region 11158 by direct boundary integral equation  

E-Print Network (OSTI)

A 3-D coronal magnetic field is reconstructed for NOAA 11158 on Feb 14, 2011. A GPU-accelerated direct boundary integral equation (DBIE) method is implemented. This is about 1000 times faster than the original DBIE used on solar NLFFF modeling. Using the SDO/HMI vector magnetogram as the bottom boundary condition, the reconstructed magnetic field lines are compared with the projected EUV loop structures from different views three-dimensionally by SDO/AIA and STEREO A/B spacecraft simultaneously for the first time. They show very good agreement so that the topological configurations of the magnetic fields can be analyzed, thus its role in the flare process of the active region can be better understood. A quantitative comparison with some stereoscopically reconstructed coronal loops shows that the present averaged misalignment angles are at the same order as the state-of-the-art results obtained with reconstructed coronal loops as prescribed conditions and better than other NLFFF methods. It is found that the o...

Wang, Rui; Tan, Baolin

2013-01-01T23:59:59.000Z

170

Seasonal variations of aerosol optical properties, vertical distribution and associated radiative effects in the Yangtze Delta Region of China  

Science Conference Proceedings (OSTI)

Four years of columnar aerosol particle optical properties (2006 to 2009) and one year database worth of aerosol particle vertical profile of 527 nm extinction coefficient (June 2008 to May 2009) are analyzed at Taihu in the central Yangtze Delta region in eastern China. Seasonal variations of aerosol optical properties, vertical distribution, and influence on shortwave radiation and heating rates were investigated. Multiyear variations of aerosol optical depths (AOD), Angstrom exponents, single scattering albedo (SSA) and asymmetry factor (ASY) are analyzed, together with the vertical profile of aerosol extinction. AOD is largest in summer and smallest in winter. SSAs exhibit weak seasonal variation with the smallest values occurring during winter and the largest during summer. The vast majority of aerosol particles are below 2 km, and about 62%, 67%, 67% and 83% are confined to below 1 km in spring, summer, autumn and winter, respectively. Five-day back trajectory analyses show that the some aerosols aloft are traced back to northern/northwestern China, as far as Mongolia and Siberia, in spring, autumn and winter. The presence of dust aerosols were identified based on the linear depolarization measurements together with other information (i.e., back trajectory, precipitation, aerosol index). Dust strongly impacts the vertical particle distribution in spring and autumn, with much smaller effects in winter. The annual mean aerosol direct shortwave radiative forcing (efficiency) at the bottom, top and within the atmosphere are -34.8 {+-} 9.1 (-54.4 {+-} 5.3), -8.2 {+-} 4.8 (-13.1 {+-} 1.5) and 26.7 {+-} 9.4 (41.3 {+-} 4.6) W/m{sup 2} (Wm{sup -2} T{sup -1}), respectively. The mean reduction in direct and diffuse radiation reaching surface amount to 109.2 {+-} 49.4 and 66.8 {+-} 33.3 W/m{sup 2}, respectively. Aerosols significantly alter the vertical profile of solar heating, with great implications for atmospheric stability and dynamics within the lower troposphere.

Liu, Jianjun; Zheng, Youfei; Li, Zhanqing; Flynn, Connor J.; Cribb, Maureen

2012-02-09T23:59:59.000Z

171

Observed Aerosol Radiative Forcings: Comparison for Natural...  

NLE Websites -- All DOE Office Websites (Extended Search)

are from 1997, when the El Nio suppressed the rainfall in that region and biomass burning was widespread in the area. These observations are compared to those observed during...

172

ARM - Measurement - Aerosol backscattered radiation  

NLE Websites -- All DOE Office Websites (Extended Search)

backscattered radiation backscattered radiation ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Aerosol backscattered radiation The scattering of radiant energy into the hemisphere of space bounded by a plane normal to the direction of the incident radiation and lying on the same side as the incident ray. Categories Aerosols Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments AOS : Aerosol Observing System MPL : Micropulse Lidar NEPHELOMETER : Nephelometer

173

A Multisensor Perspective on the Radiative Impacts of Clouds and Aerosols  

Science Conference Proceedings (OSTI)

The launch of CloudSat and Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) in 2006 provided the first opportunity to incorporate information about the vertical distribution of cloud and aerosols directly into global ...

David S. Henderson; Tristan L’Ecuyer; Graeme Stephens; Phil Partain; Miho Sekiguchi

2013-04-01T23:59:59.000Z

174

Initial Assessment of the Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR)-Based Aerosol Retrieval: Sensitivity Study  

SciTech Connect

The Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) being developed for airborne measurements will offer retrievals of aerosol microphysical and optical properties from multi-angular and multi-spectral measurements of sky radiance and direct-beam sun transmittance. In this study, we assess the expected accuracy of the 4STAR-based aerosol retrieval and its sensitivity to major sources of anticipated perturbations in the 4STAR measurements by adapting a theoretical approach previously developed for the AERONET measurements. The major anticipated perturbations are (1) an apparent enhancement of sky radiance at small scattering angles associated with the necessarily compact design of the 4STAR and (2) and an offset (i.e. uncertainty) of sky radiance calibration independent of scattering angle. The assessment is performed through application of the operational AERONET aerosol retrieval and constructed synthetic 4STAR-like data. Particular attention is given to the impact of these perturbations on the upwelling and downwelling broadband fluxes and the direct aerosol radiative forcing at the bottom and top of the atmosphere. The results from this study suggest that limitations in the accuracy of 4STAR-retrieved particle size distributions and scattering phase functions have diminished impact on the accuracy of retrieved bulk microphysical parameters, permitting quite accurate retrievals of properties including the effective radius (up to 10%, or 0.03), and the radiatively important optical properties, such as the asymmetry factor (up to 4%, or ±0.02) and single-scattering albedo (up to 6%, or ±0.04). Also, the obtained results indicate that the uncertainties in the retrieved aerosol optical properties are quite small in the context of the calculated fluxes and direct aerosol radiative forcing (up to 15%, or 3 Wm-2).

Kassianov, Evgueni I.; Flynn, Connor J.; Redemann, Jens; Schmid, Beat; Russell, P. B.; Sinyuk, Alexander

2012-10-24T23:59:59.000Z

175

The mixing state of carbonaceous aerosol particles in northern and southern California measured during CARES and CalNex 2010  

Science Conference Proceedings (OSTI)

Carbonaceous aerosols impact climate directly by scattering and absorbing radiation, and hence play a major, although highly uncertain, role in global radiative forcing. Commonly, ambient carbonaceous aerosols are internally mixed with secondary species such as nitrate, sulfate, and ammonium, which influence their climate impacts through optical properties, hygroscopicity, and atmospheric lifetime. Aircraft-aerosol time-of-flight mass spectrometry (A-ATOFMS), which measures single-particle mixing state, was used to determine the fraction of organic and soot aerosols that were internally mixed and the variability of their mixing state in California during the Carbonaceous Aerosol and Radiative Effects Study (CARES) and the Research at the Nexus of Air Quality and Climate Change (CalNex) field campaigns in the late spring and early summer of 2010. Nearly 88% of all A-ATOFMS measured particles (100-1000 nm in diameter) were internally mixed with secondary species, with 96% and 75% of particles internally mixed with nitrate and/or sulfate in southern and northern California, respectively. Even though atmospheric particle composition in both regions was primarily influenced by urban sources, the mixing state was found to vary greatly, with nitrate and soot being the dominant species in southern California, and sulfate and organic carbon in northern California. Furthermore, mixing state varied temporally in northern California, with soot becoming the prevalent particle type towards the end of the study as regional pollution levels increased. The results from these studies demonstrate that the majority of ambient carbonaceous particles are internally mixed and are heavily influenced by secondary species that are most predominant in each region. Based on these findings, considerations of regionally dominant sources and secondary species, as well as temporal variations of aerosol physical and optical properties, will be required to obtain more accurate predictions of the climate impacts of aerosol in California.

Cahill, John F.; Suski, Kaitlyn; Seinfeld, John H.; Zaveri, Rahul A.; Prather, Kimberly A.

2012-11-21T23:59:59.000Z

176

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

SciTech Connect

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

177

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.

Prescott, Donald S. (Shelley, ID); Schober, Robert K. (Midwest City, OK); Beller, John (Idaho Falls, ID)

1992-01-01T23:59:59.000Z

178

Wavelength Dependence of the Absorption of Black Carbon Particles: Predictions and Results from the TARFOX Experiment and Implications for the Aerosol Single Scattering Albedo  

Science Conference Proceedings (OSTI)

Measurements are presented of the wavelength dependence of the aerosol absorption coefficient taken during the Tropical Aerosol Radiative Forcing Observational Experiment (TARFOX) over the northern Atlantic. The data show an approximate ??1 ...

Robert W. Bergstrom; Philip B. Russell; Phillip Hignett

2002-02-01T23:59:59.000Z

179

Evolution of Organic Aerosols in the Atmosphere.  

SciTech Connect

Organic aerosol (OA) particles affect climate forcing and human health, but their sources and evolution remain poorly characterized. We present a unifying model framework that describes the atmospheric evolution of OA and is constrained and motivated by new, high time resolution, experimental characterizations of their composition, volatility, and oxidation state. OA and OA-precursor gases evolve by becoming increasingly oxidized, less volatile, and more hygroscopic, leading to the formation of large amounts of oxygenated organic aerosol (OOA) mass that has comparable concentrations to sulfate aerosol over the Northern Hemisphere. Our new model framework captures the dynamic aging behavior observed in the atmosphere and the laboratory and can serve as a basis for improving parameterizations in regional and global models.

Jimenez, J. L.; Canagaratna, M. R.; Donahue, N. M.; Prevot, A. S. H.; Zhang, Qi; Kroll, Jesse H.; DeCarlo, Peter F.; Allan, James D.; Coe, H.; Ng, N. L.; Aiken, Allison; Docherty, Kenneth S.; Ulbrich, Ingrid M.; Grieshop, A. P.; Robinson, A. L.; Duplissy, J.; Smith, J. D.; Wilson, K. R.; Lanz, V. A.; Hueglin, C.; Sun, Y. L.; Tian, J.; Laaksonen, A.; Raatikainen, T.; Rautiainen, J.; Vaattovaara, P.; Ehn, M.; Kulmala, M.; Tomlinson, Jason M.; Collins, Donald R.; Cubison, Michael J.; Dunlea, E. J.; Huffman, John A.; Onasch, Timothy B.; Alfarra, M. R.; Williams, Paul I.; Bower, K.; Kondo, Yutaka; Schneider, J.; Drewnick, F.; Borrmann, S.; Weimer, S.; Demerjian, K.; Salcedo, D.; Cottrell, L.; Griffin, Robert; Takami, A.; Miyoshi, T.; Hatakeyama, S.; Shimono, A.; Sun, J. Y.; Zhang, Y. M.; Dzepina, K.; Kimmel, Joel; Sueper, D.; Jayne, J. T.; Herndon, Scott C.; Trimborn, Achim; Williams, L. R.; Wood, Ezra C.; Middlebrook, A. M.; Kolb, C. E.; Baltensperger, Urs; Worsnop, Douglas R.

2009-12-11T23:59:59.000Z

180

Polarimetric Remote Sensing of Aerosols over Land  

Science Conference Proceedings (OSTI)

The sensitivity of accurate polarized reflectance measurements over a broad spectral (410 -2250 nm) and angular (±60° from nadir) range to the presence of aerosols over land is analyzed and the consequent ability to retrieve the aerosol burden and microphysical model is assessed. Here we present a new approach to the correction of polarization observations for the effects of the surface that uses longer wavelength observations to provide a direct estimate of the surface polarized reflectance. This approach to surface modeling is incorporated into an optimal estimation framework for retrieving the particle number density and a detailed aerosol microphysical model: effective radius, effective variance and complex refractive index of aerosols. A sensitivity analysis shows that the uncertainties in aerosol optical thickness (AOT) increase with AOT while the uncertainties in the microphysical model decrease. Of particular note is that the uncertainty in the single scattering albedo is less than 0.05 by the time the AOT is greater than 0.2. We also find that calibration is the major source of uncertainty and that perfect angular and spectral correlation of calibration errors reduces the uncertainties in retrieved quantities compared with the case of uncorrelated errors. Finally, in terms of required spectral range, we observe that shorter wavelength (aerosols from polarized reflectance observations. The optimal estimation scheme is then tested on observations made by the Research Scanning Polarimeter during the Aerosol Lidar Validation experiment and over Southern California wild fires. These two sets of observations test the retrieval scheme under pristine and polluted conditions respectively. In both cases we find that the retrievals are within the combined uncertainties of the retrieval and the Aerosol Robotic Network Cimel products and Total Ozone Mapping Spectrometer Aerosol Index that we are comparing to. This confirms the validity of the sensitivity analysis of the polarized reflectance observations to the aerosol number density and microphysical model and demonstrates the unique capability to accurately retrieve aerosol optical depths under pristine conditions and also the single scattering albedo of aerosols at higher optical depths.

Waquet, F.; Cairns, Brian; Knobelspiesse, Kirk D.; Chowdhary, J.; Travis, Larry D.; Schmid, Beat; Mishchenko, M.

2009-01-26T23:59:59.000Z

Note: This page contains sample records for the topic "direct aerosol forcing" 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

ARM - Measurement - Aerosol absorption  

NLE Websites -- All DOE Office Websites (Extended Search)

absorption absorption ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Aerosol absorption The process in which radiation energy is retained by aerosols. Categories Aerosols Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments AOS : Aerosol Observing System CSPHOT : Cimel Sunphotometer IAP : In-situ Aerosol Profiles (Cessna Aerosol Flights) PSAP : Particle Soot Absorption Photometer PASS : Photoacoustic Soot Spectrometer External Instruments OMI : Ozone Monitoring Instrument

182

ARM - Measurement - Aerosol concentration  

NLE Websites -- All DOE Office Websites (Extended Search)

concentration concentration ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Aerosol concentration A measure of the amount of aerosol particles (e.g. number, mass, volume) per unit volume of air. Categories Aerosols Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments AOS : Aerosol Observing System CSPHOT : Cimel Sunphotometer CPC : Condensation Particle Counter IAP : In-situ Aerosol Profiles (Cessna Aerosol Flights) TDMA : Tandem Differential Mobility Analyzer

183

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

Science Conference Proceedings (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 Oct–Nov 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

184

Aerosols and solar energy  

DOE Green Energy (OSTI)

A brief description is presented of the involvement of the Solar Energy Research Institute (SERI) in atmospheric research, including aerosol characterization and modeling. The use of both rigorous and simple models for radiation transport is described. Modeled broadband solar irradiance data are shown to illustrate the important influence that aerosols have on the energy available to solar systems and the economics of solar systems design. Standard aerosol measurement methods for solar applications are discussed along with the need for improved instrumentation and methods.

Bird, R. E.; Hulstrom, R. L.

1979-01-01T23:59:59.000Z

185

Carbonaceous Aerosols and Radiative...  

NLE Websites -- All DOE Office Websites (Extended Search)

Aerosols and Radiative Effects Study Science Objective This field campaign is designed to increase scientific knowledge about the evolution of black carbon, primary organic...

186

Computational simulation of aerosol behaviour.  

E-Print Network (OSTI)

??In this thesis, computational methods have been developed for the simulation of aerosol dynamics and transport. Two different coupled aerosol-computational fluid dynamics (CFD) models are… (more)

Pyykönen, Jouni

2002-01-01T23:59:59.000Z

187

Tropical Tropospheric-Only Responses to Absorbing Aerosols  

Science Conference Proceedings (OSTI)

Absorbing aerosols affect the earth’s climate through direct radiative heating of the troposphere. This study analyzes the tropical tropospheric-only response to a globally uniform increase in black carbon, simulated with an atmospheric general ...

Geeta G. Persad; Yi Ming; V. Ramaswamy

2012-04-01T23:59:59.000Z

188

Aerosol Route Synthesis of Copper Oxide Nanoparticles Using ...  

Science Conference Proceedings (OSTI)

Presentation Title, Aerosol Route Synthesis of Copper Oxide Nanoparticles Using Copper Nitrate Solution ... Phase Transformation Hardening by Using High -Power Direct Diode Laser ... Defect Energetics and Fission Product Transport in ZrC.

189

Mt. St. Helens' Aerosols: Some Tropospheric and Stratospheric Effects  

Science Conference Proceedings (OSTI)

Aerosol optical depth measurements based on the attenuation of direct solar radiation before and after the six major explosive eruptions of Mt. St. Helens during 1980 are presented. These automated measurements are from a site 200 km mostly cut ...

J. J. Michalsky; G. M. Stokes

1983-04-01T23:59:59.000Z

190

Nonlinear Climate and Hydrological Responses to Aerosol Effects  

Science Conference Proceedings (OSTI)

The equilibrium temperature and hydrological responses to the total aerosol effects (i.e., direct, semidirect, and indirect effects) are studied using a modified version of the Geophysical Fluid Dynamics Laboratory atmosphere general circulation ...

Yi Ming; V. Ramaswamy

2009-03-01T23:59:59.000Z

191

Ganges valley aerosol experiment.  

Science Conference Proceedings (OSTI)

In June 2011, the Ganges Valley Aerosol Experiment (GVAX) began in the Ganges Valley region of India. The objective of this field campaign is to obtain measurements of clouds, precipitation, and complex aerosols to study their impact on cloud formation and monsoon activity in the region.

Kotamarthi, V.R.; Satheesh, S.K. (Environmental Science Division); (Indian Institute of Science, Bangalore, India)

2011-08-01T23:59:59.000Z

192

Indirect and Semi-Direct Aerosol Campaign  

NLE Websites -- All DOE Office Websites (Extended Search)

probes Temperature Mengistu Wolde NCAR reverse flow probe Temperature Walter Strapp EGG chilled mirror hygrometer Humidity Walter Strapp LICOR Water vapor and CO 2 mixing ratio...

193

BNL | Aerosol Lifecycle IOP  

NLE Websites -- All DOE Office Websites (Extended Search)

Program Program Aerosol Life Cycle IOP The primary objectives that make up the Aerosol Life Cycle IOP can be broken down into three categories: Scientific; Logistical; and GVAX preparation. Scientific Objectives The science goals are to conduct intensive aerosol observations in a region exposed to anthropogenic, biogenic, and marine emissions with atmospheric processing times depending on air mass trajectories and time of day. Take advantage of new instruments in the MAOS (e.g., SP2, HR-PTRMS, ACSM, Trace Gas Suite, PASS-3, Aethelometer, UHSAS). Within this broad umbrella are embedded three main foci: Aerosol light absorption: How does the aerosol mass absorption coefficient (absorption per unit mass of BC) vary with atmospheric processing? Do observations agree with a shell-core model?

194

Thermophoretic separation of aerosol particles from a sampled gas stream  

DOE Patents (OSTI)

A method for separating gaseous samples from a contained atmosphere that includes aerosol particles uses the step of repelling particles from a gas permeable surface or membrane by heating the surface to a temperature greater than that of the surrounding atmosphere. The resulting thermophoretic forces maintain the gas permeable surface clear of aerosol particles. The disclosed apparatus utilizes a downwardly facing heated plate of gas permeable material to combine thermophoretic repulsion and gravity forces to prevent particles of any size from contacting the separating plate surfaces.

Postma, Arlin K. (Halfway, OR)

1986-01-01T23:59:59.000Z

195

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

DOE Data Explorer (OSTI)

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

Rob Newsom; John Goldsmith

196

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

DOE Data Explorer (OSTI)

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

Chitra Sivaraman; Connor Flynn

197

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

SciTech Connect

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

Chitra Sivaraman; Connor Flynn

2010-12-15T23:59:59.000Z

198

Carbonaceous Aerosol Study Using Advanced Particle Instrumentation  

E-Print Network (OSTI)

and atmospheric organic aerosol formation. Envir. Sci.of secondary organic aerosol mass fraction, Atmos. Chem.composition of ambient aerosol particles. Environ. Sci.

Qi, Li

2010-01-01T23:59:59.000Z

199

Accurate Monitoring of Terrestrial Aerosols and Total Solar Irradiance: Introducing the Glory Mission  

Science Conference Proceedings (OSTI)

The NASA Glory mission is intended to facilitate and improve upon long-term monitoring of two key forcings influencing global climate. One of the mission's principal objectives is to determine the global distribution of detailed aerosol and cloud ...

Michael I. Mishchenko; Brian Cairns; James E. Hansen; Larry D. Travis; Greg Kopp; Carl F. Schueler; Bryan A. Fafaul; Ronald J. Hooker; Hal B. Maring; Tom Itchkawich

2007-05-01T23:59:59.000Z

200

Effects of Aerosol and Horizontal Inhomogeneity on the Broadband Albedo of Marine Stratus: Numerical Simulations  

Science Conference Proceedings (OSTI)

Recent estimates of the effect of increasing amounts 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 CO2. Much of this ...

D. P. Duda; G. L. Stephens; B. Stevens; W. R. Cotton

1996-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "direct aerosol forcing" 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

Nuclear forces  

Science Conference Proceedings (OSTI)

These lectures present an introduction into the theory of nuclear forces. We focus mainly on the modern approach

2013-01-01T23:59:59.000Z

202

Long-term Statistics of Continental Cumuli: Does Aerosol Trigger Cumulus Variability?  

Science Conference Proceedings (OSTI)

Atmospheric aerosols may control the formation, maintenance, and dissipation of cumuli by changing their microphysics. Recent observational and modeling results exist both in support and against strong potential impacts of aerosol [1-3]. Typically, the aerosol impact on water clouds has been investigated for regions with high aerosol loading and/or large atmospheric moisture [4]. Can we provide observational evidence of the aerosol-cloud relationship for a relatively dry continental region with low/moderate aerosol burden? To address this question, we revisit the aerosol-cloud relationship at the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) Southern Great Plains (SGP) site. In comparison with highly polluted regions, the SGP site is characterized by relatively small-to-moderate aerosol loading. Also, moisture content is small-to-moderate (compared to marine and coastal regions) for the SGP site. Because cumulus clouds have important impacts on climate forcing estimations [5] and are susceptible to aerosol effects [6], we focus on fair-weather cumuli (FWC) and their association with aerosol concentration and other potentially important factors. This association is investigated using a new 8-year aerosol and cloud climatology (2000-2007) developed with collocated and coincident surface and satellite observations.

Kassianov, Evgueni I.; Berg, Larry K.; McFarlane, Sally A.; Flynn, Connor J.; Turner, David D.

2009-02-01T23:59:59.000Z

203

426 JOURNAL OF CLIMATE VOLUME 16 Solar and Greenhouse Gas Forcing and Climate Response in the Twentieth Century  

E-Print Network (OSTI)

Ensemble experiments with a global coupled climate model are performed for the twentieth century with time-evolving solar, greenhouse gas, sulfate aerosol (direct effect), and ozone (tropospheric and stratospheric) forcing. Observed global warming in the twentieth century occurred in two periods, one in the early twentieth century from about the early 1900s to the 1940s, and one later in the century from, roughly, the late 1960s to the end of the century. The model’s response requires the combination of solar and anthropogenic forcing to approximate the early twentieth-century warming, while the radiative forcing from increasing greenhouse gases is dominant for the response in the late twentieth century, confirming previous studies. Of particular interest here is the model’s amplification of solar forcing when this acts in combination with anthropogenic forcing. This difference is traced to the fact that solar forcing is more spatially heterogeneous (i.e., acting most strongly in areas where sunlight reaches the surface) while greenhouse gas forcing is more spatially uniform. Consequently, solar forcing is subject to coupled regional feedbacks involving the combination of temperature gradients, circulation regimes, and clouds. The magnitude of these feedbacks depends on the climate’s base state. Over relatively cloud-free oceanic regions in the subtropics, the enhanced solar forcing produces greater evaporation. More moisture then converges into the precipitation convergence zones, intensifying the regional monsoon and

unknown authors

2001-01-01T23:59:59.000Z

204

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

NLE Websites -- All DOE Office Websites (Extended Search)

Quantifying the Aerosol Indirect Effect Quantifying the Aerosol Indirect Effect Using Ground-Based Remote Sensors and Models G. Feingold National Oceanic and Atmospheric Administration Environmental Technology Laboratory Boulder, Colorado D. E. Lane Rutgers University Camden, New Jersey Q.-L. Min Atmospheric Sciences Research Center State University of New York Albany, New York Introduction The effect of aerosols on cloud microphysical and radiative properties (the "indirect effect") has the greatest uncertainty of all known climate-forcing mechanisms. Increases in aerosol concentrations result in higher concentrations of cloud condensation nuclei (CCN), increased cloud droplet concentrations, and smaller droplet sizes (Twomey 1974). A possible secondary effect is the suppression of rainfall.

205

Simulation of Aerosol-Cloud Interactions in the WRF Model at the Southern Great Plains Site  

E-Print Network (OSTI)

The aerosol direct and indirect effects were investigated for three specific cases during the March 2000 Cloud IOP at the SGP site by using a modified WRF model. The WRF model was previously altered to include a two-moment bulk microphysical scheme for the aerosol indirect effect and a modified Goddard shortwave radiation scheme for the aerosol direct effect. The three cases studied include a developing low pressure system, a low precipitation event of mainly cirrus clouds, and a cold frontal passage. Three different aerosol profiles were used with surface concentrations ranging from 210 cm-3 to 12,000 cm-3. In addition, each case and each aerosol profile was run both with and without the aerosol direct effect. Regardless of the case, increasing the aerosol concentration generally increased cloud water and droplet values while decreasing rain water and droplet values. Increased aerosols also decreased the surface shortwave radiative flux for every case; which was greatest when the aerosol direct effect was included. For convective periods during polluted model runs, the aerosol direct effect lowered the surface temperature and reduced convection leading to a lower cloud fraction. During most convective periods, the changes to cloud, rain, and ice water mixing ratios and number concentrations produced a nonlinear precipitation trend. A balance between these values was achieved for moderate aerosol profiles, which produced the highest convective precipitation rates. In non-convective cases, due to the presence of ice particles, aerosol concentration and precipitation amounts were positively correlated. The aerosol threshold between precipitation enhancement and suppression should be further studied for specific cloud types as well as for specific synoptic weather patterns to determine its precise values.

Vogel, Jonathan 1988-

2012-12-01T23:59:59.000Z

206

Inherent fluctuation-mediated equivalent force drives directional motions of nanoscale asymmetric particles -- Surf-riding of asymmetric molecules in thermal fluctuations  

E-Print Network (OSTI)

Using a simple theoretical model of a nanoscale asymmetric particle/molecule with asymmetric structure or/and asymmetric charge distribution, here using a charge dipole as an example, we show that there is unidirectional transportation mediated by non-white fluctuations if the asymmetric orientation of the particle/molecule is constrained. This indicates the existence of an inherent equivalent force, which drives the particle/molecule itself along the orientation of the asymmetric particle in the environment of fluctuations. In practical systems, equivalent force also exist in the asymmetric molecules, such as water and ethanol, at the ambient condition since thermal fluctuations are not white anymore at nanoscale [Wan, R., J. Hu, and H. Fang, Sci. China Phys. Mech. Astron. 2012, 55, 751]. Molecular dynamic simulations show that there is unidirectional transportation of an ultrathin water layer on solid surface at room temperature when the orientations of water molecules have a preference. The finding will play an essential role in the understanding of the world from a molecular view and the developing of novel technology for various nanoscale and bulk applications, such as chemical separation, water treatment, sensing and drug delivery.

Yusong Tu; Nan Sheng; Rongzheng Wan; Haiping Fang

2013-07-23T23:59:59.000Z

207

Development and Characterization of a Thermodenuder for Aerosol Volatility Measurements  

SciTech Connect

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 ‘real-world’ 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

208

ARM - Measurement - Aerosol particle size  

NLE Websites -- All DOE Office Websites (Extended Search)

particle size particle size ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Aerosol particle size Linear size (e.g. radius or diameter) of an aerosol particle. Categories Aerosols Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. Field Campaign Instruments AEROSMASSSPEC : Aerosol Mass Spectrometer CPI : Cloud Particle Imager DRI-GND : Desert Research Institute Ground-Based Aerosol Instruments DRUM-AEROSOL : Drum Aerosol Sampler AEROSOL-TOWER-EML : EML Tower based Aerosol Measurements

209

Monodisperse aerosol generator  

DOE Patents (OSTI)

An aerosol generator is described which is capable of producing a monodisperse aerosol within narrow limits utilizing an aqueous solution capable of providing a high population of seed nuclei and an organic solution having a low vapor pressure. The two solutions are cold nebulized, mixed, vaporized, and cooled. During cooling, particles of the organic vapor condense onto the excess seed nuclei, and grow to a uniform particle size.

Ortiz, L.W.; Soderholm, S.C.

1988-09-19T23:59:59.000Z

210

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

Science Conference Proceedings (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

211

RACORO aerosol data processing  

Science Conference Proceedings (OSTI)

The RACORO aerosol data (cloud condensation nuclei (CCN), condensation nuclei (CN) and aerosol size distributions) need further processing to be useful for model evaluation (e.g., GCM droplet nucleation parameterizations) and other investigations. These tasks include: (1) Identification and flagging of 'splash' contaminated Twin Otter aerosol data. (2) Calculation of actual supersaturation (SS) values in the two CCN columns flown on the Twin Otter. (3) Interpolation of CCN spectra from SGP and Twin Otter to 0.2% SS. (4) Process data for spatial variability studies. (5) Provide calculated light scattering from measured aerosol size distributions. Below we first briefly describe the measurements and then describe the results of several data processing tasks that which have been completed, paving the way for the scientific analyses for which the campaign was designed. The end result of this research will be several aerosol data sets which can be used to achieve some of the goals of the RACORO mission including the enhanced understanding of cloud-aerosol interactions and improved cloud simulations in climate models.

Elisabeth Andrews

2011-10-31T23:59:59.000Z

212

The Two-Column Aerosol Project (TCAP) Science Plan  

Science Conference Proceedings (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

213

Mechanisms Linking Volcanic Aerosols to the Atlantic Meridional Overturning Circulation  

Science Conference Proceedings (OSTI)

This study examines the sensitivity of the climate system to volcanic aerosol forcing in the third climate configuration of the Met Office Unified Model (HadCM3). The main test case was based on the 1880s when there were several volcanic eruptions,...

Alan M. Iwi; Leon Hermanson; Keith Haines; Rowan T. Sutton

2012-04-01T23:59:59.000Z

214

Priorities for In-situ Aerosol Measurements  

NLE Websites -- All DOE Office Websites (Extended Search)

Priorities for In-situ Priorities for In-situ Aerosol Measurements Parameters * Aerosol light absorption coefficient - spectral, including UV, vis, and IR - as f(RH), and at ambient RH * Phase function - or relevant integral properties (how many?) * Ice nuclei * Scattering vs. RH, for RH>90% * CCN, as f(S, D p ) * Size distribution * Chemical composition - for determining climate forcing, vs. radiative effect Calibration * Number concentration * Size and shape * Light absorption reference method Characterization * Accuracy and precision - need well-understood error bars * Algorithm comparisons * Closure studies * Facilities for method testing - aircraft time Methods * Inlets - shattering/splashing - location on airplane - passing efficiency - inletless analyzers/samplers * Packaging - modular/portable "pods" for multiple a/c

215

Wavelength Dependence of Aerosol Extinction Coefficient for Stratospheric Aerosols  

Science Conference Proceedings (OSTI)

A simple empirical formula for the wavelength dependence of the aerosol extinction coefficient is proposed. The relationship between the constants in the formula and the variable parameter in the aerosol size distribution is explicitly expressed. ...

Glenn K. Yue

1986-11-01T23:59:59.000Z

216

Aerosols in a Changing Atmosphere: From Detailed Aerosol Microphysics...  

NLE Websites -- All DOE Office Websites (Extended Search)

Aerosols in a Changing Atmosphere: From Detailed Aerosol Microphysics to Policy Applications Speaker(s): Susanne Bauer Date: December 6, 2011 - 4:00pm Location: 90-4133 Seminar...

217

Aerosol–CCN Closure at a Semi-rural Site  

Science Conference Proceedings (OSTI)

aerosol size distributions and size-resolved aerosol compositions measured by ... Keywords Cloud condensation nuclei, closure study, organic aerosols, Köhler.

218

Formation mechanisms and quantification of organic nitrates in atmospheric aerosol  

E-Print Network (OSTI)

Atmospheric submicron aerosol . . . . . . . 2.3 Partitioningon SOA organic aerosol formation alkyl nitrate and secondaryPeroxy radical fate . . . . . . Aerosol . . . . . . . .

Rollins, Andrew Waite

2010-01-01T23:59:59.000Z

219

Laboratory investigation of chemical and physical properties of soot-containing aerosols  

E-Print Network (OSTI)

Soot particles released from fossil fuel combustion and biomass burning have a large impact on the regional/global climate by altering the atmospheric radiative properties and by serving as cloud condensation nuclei (CCN). However, the exact forcing is affected by the mixing of soot with other aerosol constituents, such as sulfuric acid. In this work, experimental studies have been carried out focusing on three integral parts: (1) heterogeneous uptake of sulfuric acid on soot; (2) hygroscopic growth of H2SO4-coated soot aerosols; (3) effect of H2SO4 coating on scattering and extinction properties of soot particles. A low-pressure laminar-flow reactor, coupled to ion driftchemical ionization mass spectrometry (ID-CIMS) detection, is used to study uptake coefficients of H2SO4 on combustion soot. The results suggest that uptake of H2SO4 takes place efficiently on soot particles, representing an important route to convert hydrophobic soot to hydrophilic aerosols. A tandem differential mobility analyzing (TDMA) system is employed to determine the hygroscopicity of freshly generated soot in the presence of H2SO4 coating. It is found that fresh soot particles are highly hydrophobic, while coating of H2SO4 significantly facilitates water uptake on soot even at sub-saturation relative humidities. The results indicate that aged soot particles in the atmosphere can potentially be an efficient source of CCN. Scattering and extinction coefficient measurements of the soot-H2SO4 mixed particles are conducted using a threewavelength Nephelometer and a multi-path extinction cell. Coating of H2SO4 is found to increase the single scattering albedo (SSA) of soot particles which has impact on the aerosol direct radiative effect. Other laboratory techniques such as transmission electron microscopy (TEM) and Fourier transform infrared spectrometry (FTIR) are utilized to examine the morphology and chemical composition of the soot-H2SO4 particles. This work provides critical information concerning the heterogeneous interaction of soot and sulfuric acid, and how their mixing affects the hygroscopic and optical properties of soot. The results will improve our ability to model and assess the soot direct and indirect forcing and hence enhance our understanding of the impact of anthropogenic activities on the climate.

Zhang, Dan

2003-05-01T23:59:59.000Z

220

Climate implications of carbonaceous aerosols: An aerosol microphysical study using the GISS/MATRIX climate model  

E-Print Network (OSTI)

and R. Ruedy, Matrix (multiconfiguration aerosol tracker ofmixing state): An aerosol microphysical module for globalAn investigative review, Aerosol Sci. Technol. , Vol. 40,

Bauer, Susanne E.

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "direct aerosol forcing" 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

ARM's Aerosol Observing System (AOS) Data  

DOE Data Explorer (OSTI)

The aerosol observing system (AOS) is the primary Atmospheric Radiation Measurement (ARM) platform for in situ aerosol measurements at the surface. The principal measurements are those of the aerosol absorption and scattering coefficients as a function of the particle size and radiation wavelength. Additional measurements include those of the particle number concentration, size distribution, hygroscopic growth, and inorganic chemical composition. The AOS measures aerosol optical properties to better understand how particles interact with solar radiation and influence the earth's radiation balance. The measurements are useful for calculating parameters used in radiative forcing calculations such as the aerosol single scattering albedo, asymmetry parameter, mass scattering efficiency, and hygroscopic growth. [Copied from http://www.arm.gov/instruments/aos]

The ARM Archive at Oak Ridge National Laboratory holds aerosol data from the AOS for two of the permanent ARM sites, North Slope Alaska (NSA) and Southern Great Plains (SGP), as well as from mobile facilities used during specific field campaigns. The AOS has collected data since 1995.

222

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.

DeFord, Henry S. (Kennewick, WA); Clark, Mark L. (Kennewick, WA)

1981-01-01T23:59:59.000Z

223

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

224

Airborne Sunphotometry and Integrated Analyses of Dust, Other Aerosols, and Water Vapor in the Puerto Rico Dust Experiment (PRIDE)  

E-Print Network (OSTI)

in the Puerto Rico Dust Experiment (PRIDE) PI: Philip B. Russell MS 245-5, NASA Ames Research Center Moffett new analyses of aerosol radiative forcing sensitivity, single scattering albedo, and the solar spectral radiative energy budget. (h) Derive aerosol size distributions from optical depth and extinction

225

Geometrical Optics of Dense Aerosols  

SciTech Connect

Assembling a free-standing, sharp-edged slab of homogeneous material that is much denser than gas, but much more rare ed than a solid, is an outstanding technological challenge. The solution may lie in focusing a dense aerosol to assume this geometry. However, whereas the geometrical optics of dilute aerosols is a well-developed fi eld, the dense aerosol limit is mostly unexplored. Yet controlling the geometrical optics of dense aerosols is necessary in preparing such a material slab. Focusing dense aerosols is shown here to be possible, but the nite particle density reduces the eff ective Stokes number of the flow, a critical result for controlled focusing. __________________________________________________

Hay, Michael J.; Valeo, Ernest J.; Fisch, Nathaniel J.

2013-04-24T23:59:59.000Z

226

Jankovic Aerosol Characterization.ppt  

NLE Websites -- All DOE Office Websites (Extended Search)

Characterization, Characterization, Aerosol Characterization, Interpretation, and Interpretation, and Application of Data Application of Data NSRC Symposium NSRC Symposium July 8, 2008 John Jankovic, CIH CIH Center for Nanophase Materials Sciences Center for Nanophase Materials Sciences Aerosol Characterization, Interpretation, and Aerosol Characterization, Interpretation, and Application of Data Application of Data Department of Energy (DOE) Nanoscale Science Research Centers (NSRC) developing Approach to Nanomaterial ES&H - The CNMS Approach * Establish Exposure Control Guideline (ECG) - Characterize Aerosol * Collect and interpret data * Assign Process to a Control Band Aerosol Particle Characterization * Size distribution (geometric mean and geometric standard deviation related to either mass, surface, or number)

227

OOTW Force Design Tools  

Science Conference Proceedings (OSTI)

This report documents refined requirements for tools to aid the process of force design in Operations Other Than War (OOTWs). It recommends actions for the creation of one tool and work on other tools relating to mission planning. It also identifies the governmental agencies and commands with interests in each tool, from whom should come the user advisory groups overseeing the respective tool development activities. The understanding of OOTWs and their analytical support requirements has matured to the point where action can be taken in three areas: force design, collaborative analysis, and impact analysis. While the nature of the action and the length of time before complete results can be expected depends on the area, in each case the action should begin immediately. Force design for OOTWs is not a technically difficult process. Like force design for combat operations, it is a process of matching the capabilities of forces against the specified and implied tasks of the operation, considering the constraints of logistics, transport and force availabilities. However, there is a critical difference that restricts the usefulness of combat force design tools for OOTWs: the combat tools are built to infer non-combat capability requirements from combat capability requirements and cannot reverse the direction of the inference, as is required for OOTWs. Recently, OOTWs have played a larger role in force assessment, system effectiveness and tradeoff analysis, and concept and doctrine development and analysis. In the first Quadrennial Defense Review (QDR), each of the Services created its own OOTW force design tool. Unfortunately, the tools address different parts of the problem and do not coordinate the use of competing capabilities. These tools satisfied the immediate requirements of the QDR, but do not provide a long-term cost-effective solution.

Bell, R.E.; Hartley, D.S.III; Packard, S.L.

1999-05-01T23:59:59.000Z

228

Radiative Forcing of Saharan Dust: GOCART Model Simulations Compared with ERBE Data  

Science Conference Proceedings (OSTI)

This study uses information on Saharan aerosol from a dust transport model to calculate radiative forcing values. The transport model is driven by assimilated meteorological fields from the Goddard Earth Observing System Data Assimilation System. ...

Clark J. Weaver; Paul Ginoux; N. Christina Hsu; Ming-Dah Chou; Joanna Joiner

2002-02-01T23:59:59.000Z

229

Volcanic and Solar Forcing of Climate Change during the Preindustrial Era  

Science Conference Proceedings (OSTI)

The climate response to variability in volcanic aerosols and solar irradiance, the primary forcings during the preindustrial era, is examined in a stratosphere-resolving general circulation model. The best agreement with historical and proxy data ...

Drew T. Shindell; Gavin A. Schmidt; Ron L. Miller; Michael E. Mann

2003-12-01T23:59:59.000Z

230

Adjustment to Radiative Forcing in a Simple Coupled Ocean–Atmosphere Model  

Science Conference Proceedings (OSTI)

This study calculates the adjustment to radiative forcing in a simple model of a mixed layer ocean coupled to the overlying atmosphere. One application of the model is to calculate how dust aerosols perturb the temperature of the atmosphere and ...

R. L. Miller

2012-11-01T23:59:59.000Z

231

Chemical Bonding and Structural Information of Black Carbon Reference Materials and Individual Carbonaceous Atmospheric Aerosols  

E-Print Network (OSTI)

HULIS) in biomass-burning aerosols, Atmospheric Chemistrymicroscopical and aerosol dynamical characterizationof soot aerosols, Journal of Aerosol Science , 34 , 1347-

Hopkins, Rebecca J.; Tivanski, Alexei V.; Marten, Bryan D.; Gilles, Mary K.

2007-01-01T23:59:59.000Z

232

Impact of biomass burning aerosol on the monsoon circulation transition over Amazonia  

DOE Green Energy (OSTI)

Ensemble simulations of a regional climate model (RegCM3) forced by aerosol radiative forcing suggest that biomass burning aerosols can work against the seasonal monsoon circulation transition, thus re-enforce the dry season rainfall pattern for Southern Amazonia. Strongly absorbing smoke aerosols warm and stabilize the lower troposphere within the smoke center in southern Amazonia (where aerosol optical depth > 0.3). These changes increase the surface pressure in the smoke center, weaken the southward surface pressure gradient between northern and southern Amazonia, and consequently induce an anomalous moisture divergence in the smoke center and an anomalous convergence occurs in northwestern Amazonia (5°S-5°N, 60°W-40 70°W). The increased atmospheric thermodynamic stability, surface pressure, and divergent flow in Southern Amazonia may inhibit synoptic cyclonic activities propagated from extratropical South America, and re-enforce winter-like synoptic cyclonic activities and rainfall in southeastern Brazil, Paraguay and northeastern Argentina.

Zhang, Y.; Fu, Rong; Yu, Hongbin; Qian, Yun; Dickinson, Robert; Silva Dias, Maria Assuncao F.; da Silva Dias, Pedro L.; Fernandes, Katia

2009-05-30T23:59:59.000Z

233

ARM - Mobile Aerosol Observing System  

NLE Websites -- All DOE Office Websites (Extended Search)

FacilitiesMobile Aerosol Observing System FacilitiesMobile Aerosol Observing System AMF Information Science Architecture Baseline Instruments AMF1 AMF2 AMF3 Data Operations AMF Fact Sheet Images Contacts AMF Deployments Hyytiälä, Finland, 2014 Manacapuru, Brazil, 2014 Oliktok Point, Alaska, 2013 Los Angeles, California, to Honolulu, Hawaii, 2012 Cape Cod, Massachusetts, 2012 Gan Island, Maldives, 2011 Ganges Valley, India, 2011 Steamboat Springs, Colorado, 2010 Graciosa Island, Azores, 2009-2010 Shouxian, China, 2008 Black Forest, Germany, 2007 Niamey, Niger, 2006 Point Reyes, California, 2005 Mobile Aerosol Observing System Intensive aerosol observations conducted on the campus of Brookhaven National Laboratory on Long Island, New York, using the ARM Mobile Aerosol Observing System. Intensive aerosol observations conducted on the campus of Brookhaven

234

THE ROLE OF SOOT IN AEROSOL CHEMISTRY  

E-Print Network (OSTI)

characterization of aerosols." in Nature. Aim. and MethodsLAWRENCE THE ROLE OF SOOT IN AEROSOL CHEMISTRY T. NovakovTHE ROLE OF SOOT IN AEROSOL CHEMISTRY* T. Novakov Lawrence

Novakov, T.

2010-01-01T23:59:59.000Z

235

Characterizing the formation of secondary organic aerosols  

E-Print Network (OSTI)

and Flagan, R.C. (1990) Aerosol Sci. and Technol. 13 , 230.and Seinfeld, J.H. (2002) Aerosol Science and Technology ,light absorption by atmospheric aerosol, in preparation for

Lunden, Melissa; Black, Douglas; Brown, Nancy

2004-01-01T23:59:59.000Z

236

Optical Properties of Secondary Organic Aerosols  

E-Print Network (OSTI)

Paulson, S. E. ; Chung, A. Aerosol Sci. Technol. 2007 , 41,Y. G. ; Daum, P. H. J. Aerosol Sci 2008 , 39, 974-986. (32)Accurate Monitoring of Terrestrial Aerosols and Total Solar

Kim, Hwajin

2012-01-01T23:59:59.000Z

237

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

DOE Data Explorer (OSTI)

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

Chitra Sivaraman; Connor Flynn

238

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

SciTech Connect

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

Chitra Sivaraman; Connor Flynn

2010-12-15T23:59:59.000Z

239

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

Science Conference Proceedings (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

240

Aerosols and clouds in chemical transport models and climate models.  

Science Conference Proceedings (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

Note: This page contains sample records for the topic "direct aerosol forcing" 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

Aerosol Metrology for Climate Workshop  

Science Conference Proceedings (OSTI)

... the interaction of aerosols with solar radiation ... that will accelerate the development of new ... together experts from government, industry and academia ...

2012-04-26T23:59:59.000Z

242

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

SciTech Connect

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 aerosol’s 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

243

Researchers Model Impact of Aerosols Over California  

NLE Websites -- All DOE Office Websites (Extended Search)

Researchers Model Impact of Aerosols Over California Researchers Model Impact of Aerosols Over California Research may clarify the effectiveness of regional pollution controls May...

244

Direct insolation models  

DOE Green Energy (OSTI)

Several recently published models of the direct component of the broadband insolation are compared for clear sky conditions. The comparison includes seven simple models and one rigorous model that is used as a basis for determining accuracy. Where possible, the comparison is made between the results of each model for each atmospheric constituent (H/sub 2/O, CO/sub 2/, O/sub 3/, O/sub 2/, aerosol and molecular scattering) separately as well as for the combined effect of all of the constituents. Two optimum simple models of varying degrees of complexity are developed as a result of this comparison. The study indicates: aerosols dominate the attenuation of the direct beam for reasonable atmospheric conditions; molecular scattering is next in importance; water vapor is an important absorber; and carbon dioxide and oxygen are relatively unimportant as attenuators of the broadband solar energy.

Bird, R.; Hulstrom, R.L.

1980-01-01T23:59:59.000Z

245

MODELING RADIATIVE FORCING BY AEROSOLS HOW GOOD IS GOOD ENOUGH?  

E-Print Network (OSTI)

1 2 3 Radiativeforcing(Wattspersquaremetre) CoolingWarming High Medium Medium Low Very Low Very Low Understanding -2 -1 0 1 2 3 Radiativeforcing(Wattspersquaremetre) CoolingWarming High Medium Medium Low Very Low(Wattspersquaremetre) CoolingWarming High Medium Medium Low Very Low Very Low Very Low Very Low Very Low Very Low CO2 Very Low

Schwartz, Stephen E.

246

Uncertainties in the Radiative Forcing Due to Sulfate Aerosols  

Science Conference Proceedings (OSTI)

Radiative transfer calculations based on a new sulfate distribution from a chemistry-transport model simulation have been performed. A wide range of sensitivity experiments have been performed to illustrate the large uncertainty in the radiative ...

Gunnar Myhre; Frode Stordal; Tore F. Berglen; Jostein K. Sundet; Ivar S. A. Isaksen

2004-03-01T23:59:59.000Z

247

Simultaneously Constraining Climate Sensitivity and Aerosol Radiative Forcing  

Science Conference Proceedings (OSTI)

An energy balance climate model with latitudinal, surface–air, and land–sea resolution is coupled to a two-dimensional (latitude–depth) ocean model and used to simulate changes in surface and surface air temperature since 1765. The climate model ...

L. D. Danny Harvey; Robert K. Kaufmann

2002-10-01T23:59:59.000Z

248

Turbulent thermal diffusion of aerosols in geophysics and laboratory experiments  

E-Print Network (OSTI)

We discuss a new phenomenon of turbulent thermal diffusion associated with turbulent transport of aerosols in the atmosphere and in laboratory experiments. The essence of this phenomenon is the appearance of a nondiffusive mean flux of particles in the direction of the mean heat flux, which results in the formation of large-scale inhomogeneities in the spatial distribution of aerosols that accumulate in regions of minimum mean temperature of the surrounding fluid. This effect of turbulent thermal diffusion was detected experimentally. In experiments turbulence was generated by two oscillating grids in two directions of the imposed vertical mean temperature gradient. We used Particle Image Velocimetry to determine the turbulent velocity field, and an Image Processing Technique based on an analysis of the intensity of Mie scattering to determine the spatial distribution of aerosols. Analysis of the intensity of laser light Mie scattering by aerosols showed that aerosols accumulate in the vicinity of the minimum mean temperature due to the effect of turbulent thermal diffusion. Geophysical applications of the obtained results are discussed.

A. Eidelman; T. Elperin; N. Kleeorin; A. Krein; I. Rogachevskii; J. Buchholz; G. Gruenefeld

2004-11-11T23:59:59.000Z

249

TROPOSPHERIC AEROSOL PROGRAM, PROGRAM PLAN, MARCH 2001  

Science Conference Proceedings (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

250

Temporal Variation of Aerosol Optical Properties at M?gurele, Romania  

Science Conference Proceedings (OSTI)

Even though much research has been conducted regarding the study of atmospheric aerosols, significant uncertainties still exist in this direction. The uncertainties are related to different physical and microphysical properties of these fine ...

Laura Mihai; Sabina Stefan

2011-10-01T23:59:59.000Z

251

Generation of concentration density maxima of small dispersive coal dust particles in horizontal iodine air filter at air-dust aerosol blow  

E-Print Network (OSTI)

The spatial distributions of the small dispersive coal dust particles with the nano and micro sizes in the granular filtering medium with the cylindrical coal granules in the absorber in the horizontal iodine air filter during its long term operation at the nuclear power plant are researched. It is shown that the concentration density maxima of the small dispersive coal dust particles appear in the granular filtering medium with the cylindrical coal absorbent granules in the horizontal iodine air filter at an action by the air dust aerosol blow. The comparison of the measured aerodynamic resistances of the horizontal and vertical iodine air filters is conducted. The main conclusion is that the magnitude of the aerodynamic resistance of the horizontal iodine air filters is much smaller in comparison with the magnitude of the aerodynamic resistance of the vertical iodine air filters at the same loads of the air dust aerosol volumes. It is explained that the direction of the air dust aerosol blow and the direction of the gravitation force in the horizontal iodine air filter are orthogonal, hence the effective accumulation of the small dispersive coal dust particles takes place at the bottom of absorber in the horizontal iodine air filter. It is found that the air dust aerosol stream flow in the horizontal iodine air filter is not limited by the appearing structures, made of the precipitated small dispersive coal dust particles, in distinction from the vertical iodine air filter, in the process of long term operation of the iodine air filters at the nuclear power plant.

I. M. Neklyudov; O. P. Ledenyov; L. I. Fedorova; P. Ya. Poltinin

2013-06-11T23:59:59.000Z

252

Organic Aerosol Partition Module Documentation  

Science Conference Proceedings (OSTI)

With the promulgation of new National Ambient Air Quality Standards (NAAQS) for fine particulate matter (PM-2.5), data and analytical tools are needed to support their implementation. This report documents an EPRI modeling component for efficiently simulating aspects of organic aerosol formation. Without this component, simulations would tend to overestimate the contribution of power plant emissions to atmospheric aerosol mass.

1999-07-14T23:59:59.000Z

253

Nanomaterials from Aerosols Aerosols are suspensions of liquid or solid particles in a gas. Aerosol particles  

E-Print Network (OSTI)

arid regions in China and Africa. Such aerosol streams have been shown to travel around the globe with silica aerosols from China impacting air quality in the continental US and #12;2 alumina and titania delivery mechanisms for a variety of drugs as an alternative to injections. As delivery devices

Beaucage, Gregory

254

Aerosol optical depth increase in partly cloudy conditions  

Science Conference Proceedings (OSTI)

Remote sensing observations of aerosol from surface and satellite instruments are extensively used for atmospheric and climate research. From passive sensors, the apparent cloud-free atmosphere in the vicinity of clouds often appears to be brighter then further away from the clouds, leading to an enhancement in the retrieved aerosol optical depth. Mechanisms contributing to this enhancement, including contamination by undetected clouds, hygroscopic growth of aerosol particles, and meteorological conditions, have been debated in recent literature, but an extent to which each of these factors influence the observed enhancement is poorly known. Here we used 11 years of daily global observations at 10x10 km2 resolution from the MODIS on the NASA Terra satellite to quantify as a function of cloud fraction (CF). Our analysis reveals that, averaged over the globe, the clear sky is enhanced by ? = 0.05 which corresponds to relative enhancements of 25% in cloudy conditions (CF=0.8-0.9) compared with relatively clear conditions (CF=0.1-0.2). Unlike the absolute enhancement ?, the relative increase in ? is rather consistent in all seasons and is 25-35% in the subtropics and 15-25% at mid and higher latitudes. Using a simple Gaussian probability density function model to connect cloud cover and the distribution of relative humidity, we argue that much of the enhancement is consistent with aerosol hygroscopic growth in the humid environment surrounding clouds. Consideration of these cloud-dependent effects will facilitate understanding aerosol-cloud interactions and reduce the uncertainty in estimates of aerosol radiative forcing by global climate models.

Chand, Duli; Wood, R.; Ghan, Steven J.; Wang, Minghuai; Ovchinnikov, Mikhail; Rasch, Philip J.; Miller, Steven D.; Schichtel, Bret; Moore, Tom

2012-09-14T23:59:59.000Z

255

Thermophoretic separation of aerosol particles from a sampled gas stream  

DOE Patents (OSTI)

This disclosure relates to separation of aerosol particles from gas samples withdrawn from within a contained atmosphere, such as containment vessels for nuclear reactors or other process equipment where remote gaseous sampling is required. It is specifically directed to separation of dense aerosols including particles of any size and at high mass loadings and high corrosivity. The United States Government has rights in this invention pursuant to Contract DE-AC06-76FF02170 between the US Department of Energy and Westinghouse Electric Corporation.

Postma, A.K.

1984-09-07T23:59:59.000Z

256

Aerosol Laboratory - Nuclear Engineering Division (Argonne)  

NLE Websites -- All DOE Office Websites (Extended Search)

Capabilities > Engineering Capabilities > Engineering Experimentation > Aerosol Laboratory Capabilities Engineering Experimentation Reactor Safety Experimentation Aerosol Experiments System Components Laser Applications Robots Applications Other Facilities Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Aerosol Laboratory The Aerosol Laboratory (AL) houses equipment to measure and record the physical parameters necessary to characterize the formation and transport of aerosols. Bookmark and Share The Aerosol Laboratory (AL) has extensive analytic and experimental capabilities to characterize the formation and transport of aerosols formed from the condensation of vapors. Computer codes have been developed to

257

ARM Aerosol Working Group Meeting  

NLE Websites -- All DOE Office Websites (Extended Search)

and MFRSR Measurements ARM STM 2008 Norfolk, VA Connor Flynn 1 , Annette Koontz 1 , Anne Jefferson 2 , Jim Barnard 1 , Sally McFarlane 1 1 Pacific Northwest National Laboratory 2 CIRES, University of Colorado, Boulder Progress towards ARM DOE 2008 Performance Metric 3 & 4 * Produce and make available new continuous time series of aerosol total column depth, based on results from the AMF deployment in Niger, Africa. * Produce and make available new continuous time series of retrieved dust properties, based on results from the AMF deployment in Niger, Africa. 0 100 200 300 400 0 20 40 60 80 100 ITF movement and surface RH % RH day of year (2006) 0 100 200 300 400 0 50 100 150 200 250 300 350 day of year wind direction (N = 0, E = 90) 2 4 6 8 10 12 14 Wind speed m/s 0 100 200 300 1.4 1.6 1.8 2 MFRSR Vo for filter2, Niamey

258

Parameter exploration of optically trapped liquid aerosols  

E-Print Network (OSTI)

When studying the motion of optically trapped particles on the $\\mu s$ time scale, in low viscous media such as air, inertia cannot be neglected. Resolution of unusual and interesting behaviour not seen in colloidal trapping experiments is possible. In attempt to explain the phenomena we use power spectral methods to perform a parameter study of the Brownian motion of optically trapped liquid aerosol droplets concentrated around the critically damped regime. We present evidence that the system is suitably described by a simple harmonic oscillator model which must include a description of Fax\\'{e}n's correction, but not necessarily frequency dependent hydrodynamic corrections to Stokes' law. We also provide results describing how the system behaves under several variables and discuss the difficulty in decoupling the parameters responsible for the observed behaviour. We show that due to the relatively low dynamic viscosity and high trap stiffness it is easy to transfer between over- and under-damped motion by experimentally altering either trap stiffness or damping. Our results suggest stable aerosol trapping may be achieved in under-damped conditions, but the onset of deleterious optical forces at high trapping powers prevents the probing of the upper stability limits due to Brownian motion.

D. R. Burnham; P. J. Reece; D. McGloin

2009-07-27T23:59:59.000Z

259

Relating Secondary Organic Aerosol Characteristics with Cloud Condensation Nuclei Activity  

E-Print Network (OSTI)

and microphysical characterization of ambient aerosols withthe aerodyne aerosol mass spectrometer, Mass Spectrom Rev,of secondary organic aerosol under near atmospheric

Tang, Xiaochen

2013-01-01T23:59:59.000Z

260

Soft ionization of thermally evaporated hypergolic ionic liquid aerosols  

E-Print Network (OSTI)

+ ][Dca ? ]. Figure 2. Aerosol particle size distribution ofhypergolic ionic liquid aerosols Christine J. Koh † , Chen-ionization of evaporated IL aerosols Isolated ion pairs of a

Koh, Christine J.

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "direct aerosol forcing" 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

ATMOSPHERIC AEROSOL RESEARCH ANNUAL REPORT 1975-76  

E-Print Network (OSTI)

this room ATMOSPHERIC AEROSOL RESEARCH -RECEIVED •I.AWSSKCEDIVISION ATMOSPHERIC AEROSOL RESEARCH ANNUAL REPORTMass and Composition of Aerosol as a Function of Time,

Novakov, T.

2010-01-01T23:59:59.000Z

262

Response of California temperature to regional anthropogenic aerosol changes  

E-Print Network (OSTI)

to regional anthropogenic aerosol changes T. Novakov, T.W.indicator of anthropogenic aerosols – with observed surfacetemperature increase. Seasonal aerosol concentration trends

Novakov, T.

2008-01-01T23:59:59.000Z

263

Aerosol measurements with laser-induced breakdown spectroscopy  

E-Print Network (OSTI)

anthropogenic sulfate aerosols. Tellus, Ser. A, vol. 43, p.Twomey, Atmospheric Aerosols. New York : Elsevier ScientificCo. , 45. B.A. Albrecht, Aerosols, cloud microphysics, and

Lithgow, Gregg Arthur

2007-01-01T23:59:59.000Z

264

ATMOSPHERIC AEROSOL RESEARCH, ANNUAL REPORT 1976-77  

E-Print Network (OSTI)

DIVISION ATMOSPHERIC AEROSOL RESEARCH ANNUAL REPORTLow-Z Elements in Atmospheric Aerosol Particles by Nuclearof sulfur dioxide by aerosols of manganese sulfate," Ind.

Novakov, T.

2010-01-01T23:59:59.000Z

265

Black carbon aerosols and the third polar ice cap  

E-Print Network (OSTI)

estimations in global aerosol models, Atmos. Chem. Phys. ,Cloud mi- crophysics and aerosol indirect efefcts in theuncertainties in assessing aerosol effects on climate, Ann.

Menon, Surabi

2010-01-01T23:59:59.000Z

266

Full-Time, Eye-Safe Cloud and Aerosol Lidar Observation at Atmospheric Radiation Measurement Program Sites: Instruments and Data Processing  

Science Conference Proceedings (OSTI)

Atmospheric radiative forcing, surface radiation budget, and top-of-the-atmosphere radiance interpretation involve knowledge of the vertical height structure of overlying cloud and aerosol layers. During the last decade, the U.S. Department of ...

James R. Campbell; Dennis L. Hlavka; Ellsworth J. Welton; Connor J. Flynn; David D. Turner; James D. Spinhirne; V. Stanley Scott III; I. H. Hwang

2002-04-01T23:59:59.000Z

267

Equilibrium Response of an Atmosphere–Mixed Layer Ocean Model to Different Radiative Forcing Agents: Global and Zonal Mean Response  

Science Conference Proceedings (OSTI)

The equilibrium response to various forcing agents, including CO2, solar irradiance, tropospheric ozone, black carbon, organic carbon, sulfate, and volcanic aerosols, is investigated using an atmospheric general circulation model coupled to a ...

Masakazu Yoshimori; Anthony J. Broccoli

2008-09-01T23:59:59.000Z

268

Vertical distribution and radiative effects of mineral dust and biomass burning aerosol over West Africa during DABEX  

SciTech Connect

This paper presents measurements of the vertical distribution of aerosol extinction coefficient over West Africa, during the Dust and Biomass burning aerosol Experiment (DABEX) / African Monsoon Multidisciplinary Analysis dry season Special Observing period zero (AMMA-SOP0). In situ aircraft measurements from the UK FAAM aircraft are compared with two ground based lidars (POLIS and ARM MPL) and an airborne lidar on an ultra-light aircraft. In general mineral dust was observed at low altitudes (up to 2km) and a mixture of biomass burning aerosol and dust was observed at altitudes of 2-5km. The study exposes difficulties associated with spatial and temporal variability when inter-comparing aircraft and ground measurements. Averaging over many profiles provided a better means of assessing consistent errors and biases associated with in situ sampling instruments and retrievals of lidar ratios. Shortwave radiative transfer calculations and a 3-year simulation with the HadGEM2-A climate model show that the radiative effect of biomass burning aerosol is somewhat sensitive to the vertical distribution of aerosol. Results show a 15% increase in absorption of solar radiation by elevated biomass burning aerosol when the observed low-level dust layer is included as part of the background atmospheric state in the model. This illustrates that the radiative forcing of anthropogenic absorbing aerosol is sensitive to the treatment of other aerosol species and that care is needed in simulating natural aerosols assumed to exist in the pre-industrial, or natural state of the atmosphere.

Johnson, Ben; Heese, B.; McFarlane, Sally A.; Chazette, P.; Jones, A.; Bellouin, N.

2008-09-12T23:59:59.000Z

269

ARM - Evaluation Product - Aerosol Optical Depths from SASHE  

NLE Websites -- All DOE Office Websites (Extended Search)

ProductsAerosol Optical Depths from SASHE ProductsAerosol Optical Depths from SASHE Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Evaluation Product : Aerosol Optical Depths from SASHE Site(s) PVC SGP General Description The Shortwave Array Spectroradiometer Hemispheric (SASHE) is a ground-based instrument that measures both direct and diffuse shortwave irradiance. In this regard, the instrument is similar to the multifilter rotating shadowband radiometer (MFRSR)-an instrument that has been in the ARM Facility stable for more than 15 years. However, the two instruments differ significantly in wavelength resolution and range. In particular, the SASHE provides hyperspectral measurements from about 350 nm to 1700 nm at a wavelength resolution from 1 to several nanometers, while the MFRSR only

270

ARM - PI Product - Aerosol Retrievals from ARM SGP MFRSR Data  

NLE Websites -- All DOE Office Websites (Extended Search)

ProductsAerosol Retrievals from ARM SGP MFRSR Data ProductsAerosol Retrievals from ARM SGP MFRSR Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send PI Product : Aerosol Retrievals from ARM SGP MFRSR Data 2000.01.01 - 2000.12.31 Site(s) SGP General Description 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

271

The Radiative Effects of Aerosols on Photochemical Smog: Measurements and Modeling  

E-Print Network (OSTI)

. High concentrations of both ozone and aerosols are observed in the eastern United States during stagnant weather conditions associated with transport from the W or NW; they show similar spatial and temporal patterns. We discuss a causal mechanism that may contribute to this correlation - the radiative effects of aerosols on photolysis rates. We measured j(NO 2 ), the rate coefficient for nitrogen dioxide photolysis, and column aerosol optical depths at NASA/Goddard Space Flight Center in Greenbelt, MD (39.01 ffi N and 76.87 ffi W) during the smog seasons of 1995 and 1997. Direct measurements and radiative transfer model calculations show that particles can reduce surface j(NO 2 ) by 5 - 60%, depending on solar zenith angle and aerosol loading. Although particle scattering by dense aerosol loading on smoggy days decreases near-surface photolysis rates, it increases the integrated boundary layer photolysis rates by up to 20% and leads to accelerated photochemical smog formation in ...

Kondragunta Dickerson Stenchikov; S. Kondragunta; R. R. Dickerson; G. Stenchikov; W. F. Ryan; B. Holben; R. W. Stewart

2000-01-01T23:59:59.000Z

272

AERONET: The Aerosol Robotic Network  

DOE Data Explorer (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

273

The impact of biogenic carbon emissions on aerosol absorption inMexico City  

Science Conference Proceedings (OSTI)

In order to determine the wavelength dependence of atmospheric aerosol absorption in the Mexico City area, the absorption angstrom exponents (AAEs) were calculated from aerosol absorption measurements at seven wavelengths obtained with a seven-channel aethalometer during two field campaigns, the Mexico City Metropolitan Area study in April 2003 (MCMA 2003) and the Megacity Initiative: Local and Global Research Observations in March 2006 (MILAGRO). The AAEs varied from 0.76 to 1.56 in 2003 and from 0.54 to 1.52 in 2006. The AAE values determined in the afternoon were consistently higher than the corresponding morning values, suggesting the photochemical formation of absorbing secondary organic aerosols (SOA) in the afternoon. The AAE values were compared to stable and radiocarbon isotopic measurements of aerosol samples collected at the same time to determine the sources of the aerosol carbon. The fraction of modern carbon (fM) in the aerosol samples, as determined from {sup 14}C analysis, showed that 70% of the carbonaceous aerosols in Mexico City were from modern sources, indicating a significant impact from biomass burning during both field campaigns. The {sup 13}C/{sup 12}C ratios of the aerosol samples illustrate the significant impact of Yucatan forest fires (C-3 plants) in 2003 and local grass fires (C-4 plants) at site T1 in 2006. A direct comparison of the fM values, stable carbon isotope ratios, and calculated aerosol AAEs suggested that the wavelength dependence of the aerosol absorption was controlled by the biogenically derived aerosol components.

Marley, N; Gaffney, J; Tackett, M J; Sturchio, N; Hearty, L; Martinez, N; Hardy, K D; Machany-Rivera, A; Guilderson, T P; MacMillan, A; Steelman, K

2009-02-24T23:59:59.000Z

274

What is Force  

Science Conference Proceedings (OSTI)

... force may be balanced by an opposing force so that no energy is expended ... The unit of force is the Newton (N). By definition, the newton is the force ...

2011-10-03T23:59:59.000Z

275

Black carbon aerosols and the third polar ice cap  

SciTech Connect

Recent thinning of glaciers over the Himalayas (sometimes referred to as the third polar region) have raised concern on future water supplies since these glaciers supply water to large river systems that support millions of people inhabiting the surrounding areas. Black carbon (BC) aerosols, released from incomplete combustion, have been increasingly implicated as causing large changes in the hydrology and radiative forcing over Asia and its deposition on snow is thought to increase snow melt. In India BC emissions from biofuel combustion is highly prevalent and compared to other regions, BC aerosol amounts are high. Here, we quantify the impact of BC aerosols on snow cover and precipitation from 1990 to 2010 over the Indian subcontinental region using two different BC emission inventories. New estimates indicate that Indian BC emissions from coal and biofuel are large and transport is expected to expand rapidly in coming years. We show that over the Himalayas, from 1990 to 2000, simulated snow/ice cover decreases by {approx}0.9% due to aerosols. The contribution of the enhanced Indian BC to this decline is {approx}36%, similar to that simulated for 2000 to 2010. Spatial patterns of modeled changes in snow cover and precipitation are similar to observations (from 1990 to 2000), and are mainly obtained with the newer BC estimates.

Menon, Surabi; Koch, Dorothy; Beig, Gufran; Sahu, Saroj; Fasullo, John; Orlikowski, Daniel

2010-04-15T23:59:59.000Z

276

Spray bottle apparatus with force multiply pistons  

DOE Patents (OSTI)

The present invention comprises a spray bottle in which the pressure resulting from the gripping force applied by the user is amplified and this increased pressure used in generating a spray such as an aerosol or fluid stream. In its preferred embodiment, the invention includes a high pressure chamber and a corresponding piston which is operative for driving fluid out of this chamber at high pressure through a spray nozzle and a low pressure chamber and corresponding piston which is acted upon by the hydraulic pressure within the bottle resulting from the gripping force. The low pressure chamber and piston are of larger size than the high pressure chamber and piston. The pistons are rigidly connected so that the force created by the pressure acting on the piston in the low pressure chamber is transmitted to the piston in the high pressure chamber where it is applied over a more limited area thereby generating greater hydraulic pressure for use in forming the spray.

Eschbach, Eugene A. (Richland, WA)

1992-01-01T23:59:59.000Z

277

ARM - Surface Aerosol Observing System  

NLE Websites -- All DOE Office Websites (Extended Search)

FacilitiesSurface Aerosol Observing System FacilitiesSurface Aerosol Observing System AMF Information Science Architecture Baseline Instruments AMF1 AMF2 AMF3 Data Operations AMF Fact Sheet Images Contacts AMF Deployments Hyytiälä, Finland, 2014 Manacapuru, Brazil, 2014 Oliktok Point, Alaska, 2013 Los Angeles, California, to Honolulu, Hawaii, 2012 Cape Cod, Massachusetts, 2012 Gan Island, Maldives, 2011 Ganges Valley, India, 2011 Steamboat Springs, Colorado, 2010 Graciosa Island, Azores, 2009-2010 Shouxian, China, 2008 Black Forest, Germany, 2007 Niamey, Niger, 2006 Point Reyes, California, 2005 Surface Aerosol Observing System The ARM Mobile Facility (AMF) is equipped to quantify the interaction between clouds and aerosol particles. A counter-flow virtual impactor (CVI) is used to selectively sample cloud drops. The CVI takes advantage of the

278

Two-Column Aerosol Project  

NLE Websites -- All DOE Office Websites (Extended Search)

Climate Research Facility is conducting the Two-Column Aerosol Project (TCAP) at Cape Cod National Seashore. From July 2012 to June 2013, the ARM Mobile Facility-a portable...

279

Method for producing monodisperse aerosols  

DOE Patents (OSTI)

An aerosol generator is described which is capable of producing a monodisperse aerosol within narrow limits utilizing an aqueous solution capable of providing a high population of seed nuclei and an organic solution having a low vapor pressure. The two solutions are cold nebulized, mixed, vaporized, and cooled. During cooling, particles of the organic vapor condense onto the excess seed nuclei, and grow to a uniform particle size.

Ortiz, Lawrence W. (Los Alamos, NM); Soderholm, Sidney C. (Pittsford, NY)

1990-01-01T23:59:59.000Z

280

Background Stratospheric Aerosol Variations Deduced from Satellite Observations  

Science Conference Proceedings (OSTI)

The Stratospheric Aerosol and Gas Experiment II (SAGE II) aerosol products from 1998 to 2004 have been analyzed for the tendency of changes in background stratospheric aerosol properties. The aerosol extinction coefficient E has apparently ...

Yu Liu; Xuepeng Zhao; Weiliang Li; Xiuji Zhou

2012-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "direct aerosol forcing" 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

Evaluating WRF-Chem multi-scale model in simulating aerosol radiative properties over the tropics – A case study over India  

Science Conference Proceedings (OSTI)

We utilized WRF-Chem multi-scale model to simulate the regional distribution of aerosols, optical properties and its effect on radiation over India for a winter month. The model is evaluated using measurements obtained from upper-air soundings, AERONET sun photometers, various satellite instruments, and pyranometers operated by the Indian Meteorological Department. The simulated downward shortwave flux was overestimated when the effect of aerosols on radiation and clouds was neglected. Downward shortwave radiation from a simulation that included aerosol-radiation interaction processes was 5 to 25 Wm{sup -2} closer to the observations, while a simulation that included aerosol-cloud interaction processes were another 1 to 20 Wm{sup -2} closer to the observations. For the few observations available, the model usually underestimated particulate concentration. This is likely due to turbulent mixing, transport errors and the lack of secondary organic aerosol treatment in the model. The model efficiently captured the broad regional hotspots such as high aerosol optical depth over Indo-Gangetic basin as well as the northwestern and southern part of India. The regional distribution of aerosol optical depth compares well with AVHRR aerosol optical depth and the TOMS aerosol index. The magnitude and wavelength-dependence of simulated aerosol optical depth was also similar to the AERONET observations across India. Differences in surface shortwave radiation between simulations that included and neglected aerosol-radiation interactions were as high as -25 Wm{sup -2}, while differences in surface shortwave radiation between simulations that included and neglect aerosol-radiation-cloud interactions were as high as -30 Wm{sup -2}. The spatial variations of these differences were also compared with AVHRR observation. This study suggests that the model is able to qualitatively simulate the impact of aerosols on radiation over India; however, additional measurements of particulate mass and composition are needed to fully evaluate whether the aerosol precursor emissions are adequate when simulating radiative forcing in the region.

Seethala, C.; Pandithurai, G.; Fast, Jerome D.; Polade, Suraj D.; Reddy, M. S.; Peckham, Steven E.

2012-01-24T23:59:59.000Z

282

Thermodynamic Characterization of Mexico City Aerosol during MILAGRO 2006  

E-Print Network (OSTI)

Thermodynamic Characterization of Mexico City Aerosol duringA computationally efficient thermodynamic equilibrium modelurban aerosols determined by thermodynamic equilibrium? An

Fountoukis, C.

2009-01-01T23:59:59.000Z

283

Registration, Force Protection Equipment Demonstration - May 2009 |  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Registration, Force Protection Equipment Demonstration - May 2009 Registration, Force Protection Equipment Demonstration - May 2009 Registration, Force Protection Equipment Demonstration - May 2009 May 2009 Demonstrating commercially availale physical security/force protection soultions around the world The bombing of Khobar Towers in Saudi Arabia on 25 June 1996 revealed the need for continal vigilance and protection againist terrorist forces intent on harming US personnel and interests. The Chairman if the Joint Chiefs of Staff directed the Services to investigate COTS equipments solutions for physical security/force protection needs. The Office of the Under Secretary of Defense for Acquistion, Technology, and Logistics (OUSD {at&l}) tasked the Office of the US Army Product Manager, force Protection Systems (PM-FPS), to coordiante and facilitate a Force Protection Equipment

284

Subarctic atmospheric aerosol composition: 1. Ambient aerosol characterization  

SciTech Connect

Sub-Arctic aerosol was sampled during July 2007 at the Abisko Research Station Stordalen field site operated by the Royal Swedish Academy of Sciences. Located in northern Sweden at 68º latitude and 385 meters above sea level (msl), this site is classified as a semi-continuous permafrost mire. Number density, size distribution, cloud condensation nucleus properties, and chemical composition of the ambient aerosol were determined. Backtrajectories showed that three distinct airmasses were present over Stordalen during the sampling period. Aerosol properties changed and correlated with airmass origin to the south, northeast, or west. We observe that Arctic aerosol is not compositionally unlike that found in the free troposphere at mid-latitudes. Internal mixtures of sulfates and organics, many on insoluble biomass burning and/or elemental carbon cores, dominate the number density of particles from ~200 to 2000 nm aerodynamic diameter. Mineral dust which had taken up gas phase species was observed in all airmasses. Sea salt, and the extent to which it had lost volatile components, was the aerosol type that most varied with airmass.

Friedman, Beth; Herich, Hanna; Kammermann, Lukas; Gross, Deborah S.; Ameth, Almut; Holst, Thomas; Lohmann, U.; Cziczo, Daniel J.

2009-07-10T23:59:59.000Z

285

ARM - Field Campaign - Fall 1997 Aerosol IOP  

NLE Websites -- All DOE Office Websites (Extended Search)

Aerosol IOP Aerosol IOP Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Fall 1997 Aerosol IOP 1997.09.15 - 1997.10.05 Lead Scientist : Stephen Schwartz For data sets, see below. Summary The Aerosol IOP was highlighted by the Gulfstream-1 aircraft flying clear-sky aerosol missions over the Central Facility to study the effect of aerosol loading on clear sky radiation fields, with weather particularly favorable for these flights during the first and third weeks of the IOP. A secondary but important goal of this IOP was to fly cloudy-sky missions over the Central Facility to study the effect of aerosol loading on cloud microphysics, and the effect of the microphysics on cloud optical properties. The Gulfstream obtained aerosol data in support of some of the

286

Volcanoes and Climate Effects of Aerosols  

E-Print Network (OSTI)

CONTENTS 8.1 Importance of volcanoes, natural aerosols, and anthropogenic aerosols 341 8.2 Major scientific questions and hypotheses 342 8.2.1 Stratospheric volcanic aerosols and climate 342 8.2.1.1 Source gases for stratospheric aerosols 342 8.2.1.2 Explosiveness and plume history during individual eruptions 343 8.2.1.3 Frequency of eruptions, tectonic setting, rock/ash vs. SO 2 343 8.2.1.4 Gas-to-particle conversion and removal mechanisms 343 8.2.1.5 Radiative properties and climatic effects of stratospheric aerosols 345 8.2.1.6 Needed satellite and in situ measurements 347 8.2.1.6.1 Global observations of stratospheric aerosol optical properties 347 8.2.1.6.2 Lidar measurements of aerosols 347 8.2.2 Volcanic aerosols and stratospheric ozone depletion 349 8.2.3 Climatic effects of t

Hartmann And Mouginis-Mark; Volcanoes; D. L. Hartmann; P. Mouginis-mark; G. J. Bluth; J. A. Coakley; J. Crisp; R. E. Dickinson; P. W. Francis; J. E. Hansen; P. V. Hobbs; B. L. Isacks; Y. J. Kaufman; M. D. King; W. I. Rose; S. Self; L. D. Travis

1999-01-01T23:59:59.000Z

287

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

E-Print Network (OSTI)

detection efficiencies of aerosol time of flight masscomposition of ambient aerosol particles. Environmentalsize dependent response of aerosol counters, Atmospheric

Shields, Laura Grace

2008-01-01T23:59:59.000Z

288

The Accuracy of Marine Shadow-Band Sun Photometer Measurements of Aerosol Optical Thickness and Ångström Exponent  

Science Conference Proceedings (OSTI)

An analytical uncertainty propagation model is used in conjunction with laboratory and field data to quantify the uncertainty in measurements of the direct-normal irradiance, aerosol optical thickness, and Ångström exponent made with a ship-...

Mark A. Miller; Mary Jane Bartholomew; R. Michael Reynolds

2004-03-01T23:59:59.000Z

289

ATI TDA 5A aerosol generator evaluation  

SciTech Connect

Oil based aerosol ``Smoke`` commonly used for testing the efficiency and penetration of High Efficiency Particulate Air filters (HEPA) and HEPA systems can produce flammability hazards that may not have been previously considered. A combustion incident involving an aerosol generator has caused an investigation into the hazards of the aerosol used to test HEPA systems at Hanford.

Gilles, D.A.

1998-07-27T23:59:59.000Z

290

Secondary organic aerosol from ozone-initiated reactions with terpene-rich household products  

E-Print Network (OSTI)

analysis of competition between aerosol particle removal andof secondary organic aerosol. Part I: ?-pinene/ozone system.data when measuring ambient aerosol. Aerosol Science and

Coleman, Beverly K.

2008-01-01T23:59:59.000Z

291

Scanning Transmission X-ray Microscopy: Applications in Atmospheric Aerosol Research  

E-Print Network (OSTI)

in secondary organic aerosol. Environ. Sci. Technol. 41 ,particles from an urban aerosol. Environ. Sci. Technol. 26 ,carbonaceous atmospheric aerosols. Journal of Aerosol

Moffet, Ryan C.

2011-01-01T23:59:59.000Z

292

ARM - Measurement - Aerosol optical properties  

NLE Websites -- All DOE Office Websites (Extended Search)

properties properties ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Aerosol optical properties The optical properties of aerosols, including asymmetry factor, phase-function, single-scattering albedo, refractive index, and backscatter fraction. Categories Aerosols Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments CSPHOT : Cimel Sunphotometer NEPHELOMETER : Nephelometer Field Campaign Instruments AOS-PMFOV : Acoustical Optical Spectrometer-Photometer with Multiple

293

ARM - Measurement - Aerosol optical depth  

NLE Websites -- All DOE Office Websites (Extended Search)

depth depth ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Aerosol optical depth A measure of how much light aerosols prevent from passing through a column of atmosphere. Categories Aerosols Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments HSRL : High Spectral Resolution Lidar MPL : Micropulse Lidar MFRSR : Multifilter Rotating Shadowband Radiometer NIMFR : Normal Incidence Multifilter Radiometer Field Campaign Instruments AOS-PMFOV : Acoustical Optical Spectrometer-Photometer with Multiple

294

Isolation of ambient aerosols of known critical supersaturation: the differential critical supersaturation separator (DSCS)  

E-Print Network (OSTI)

A field-deployable instrument has been developed that isolates from an ambient aerosol population only those particles that have critical supersaturations, Sc, within a narrow, user-specified, range. This Differential Critical Supersaturation Separator (DScS) is designed to supply one or more particle size and/or composition analyzers to permit the direct examination of the factors that influence the activation properties of ambient aerosols. The DScS consists of two coupled parallel plate continuous flow thermal gradient diffusion cloud chambers housed within a single enclosure. Descriptions of instrument operation, construction and calibration data collected, when pure ammonium sulfate aerosols were injected into the DScS for operation at 0.15%aerosol size distributions and size-resolved hygroscopicity of DScS separated aerosol. The dry diameter (Dp*) of particles sampled in the TDMA system as well as the known Sc prescribed in the DScS were combined in a modified version of K�¶hler Theory to make predictions of particle hygroscopicity. These predictions frequently overestimated the measurements. Further analysis of DScS separated aerosols compares the known particle Sc to a predicted particle Sc, providing insight into particle activation efficiency. Overall, the sampled aerosol exhibited properties that indicate they were more efficient at activation than K�¶hler Theory would predict.

Osborn, Robert John

2003-05-01T23:59:59.000Z

295

Real time infrared aerosol analyzer  

DOE Patents (OSTI)

Apparatus for analyzing aerosols in essentially real time includes a virtual impactor which separates coarse particles from fine and ultrafine particles in an aerosol sample. The coarse and ultrafine particles are captured in PTFE filters, and the fine particles impact onto an internal light reflection element. The composition and quantity of the particles on the PTFE filter and on the internal reflection element are measured by alternately passing infrared light through the filter and the internal light reflection element, and analyzing the light through infrared spectrophotometry to identify the particles in the sample.

Johnson, Stanley A. (Countryside, IL); Reedy, Gerald T. (Bourbonnais, IL); Kumar, Romesh (Naperville, IL)

1990-01-01T23:59:59.000Z

296

Efficiency of Mixing Forced by Unsteady Shear Flow  

Science Conference Proceedings (OSTI)

The dependence of mixing efficiency on time-varying forcing is studied by direct numerical simulation (DNS) of Kelvin–Helmholtz (KH) instability. Time-dependent forcing fields are designed to reproduce a wavelike oscillation by solving the ...

Ryuichiro Inoue; William D. Smyth

2009-05-01T23:59:59.000Z

297

Computational fluid dynamics (CFD) simulations of aerosol in a u-shaped steam generator tube  

E-Print Network (OSTI)

To quantify primary side aerosol retention, an Eulerian/Lagrangian approach was used to investigate aerosol transport in a compressible, turbulent, adiabatic, internal, wall-bounded flow. The ARTIST experimental project (Phase I) served as the physical model replicated for numerical simulation. Realizable k-? and standard k-? turbulence models were selected from the computational fluid dynamics (CFD) code, FLUENT, to provide the Eulerian description of the gaseous phase. Flow field simulation results exhibited: a) onset of weak secondary flow accelerated at bend entrance towards the inner wall; b) flow separation zone development on the convex wall that persisted from the point of onset; c) centrifugal force concentrated high velocity flow in the direction of the concave wall; d) formation of vortices throughout the flow domain resulted from rotational (Dean-type) flow; e) weakened secondary flow assisted the formation of twin vortices in the outflow cross section; and f) perturbations induced by the bend influenced flow recovery several pipe diameters upstream of the bend. These observations were consistent with those of previous investigators. The Lagrangian discrete random walk model, with and without turbulent dispersion, simulated the dispersed phase behavior, incorrectly. Accurate deposition predictions in wall-bounded flow require modification of the Eddy Impaction Model (EIM). Thus, to circumvent shortcomings of the EIM, the Lagrangian time scale was changed to a wall function and the root-mean-square (RMS) fluctuating velocities were modified to account for the strong anisotropic nature of flow in the immediate vicinity of the wall (boundary layer). Subsequent computed trajectories suggest a precision that ranges from 0.1% to 0.7%, statistical sampling error. The aerodynamic mass median diameter (AMMD) at the inlet (5.5 ?m) was consistent with the ARTIST experimental findings. The geometric standard deviation (GSD) varied depending on the scenario evaluated but ranged from 1.61 to 3.2. At the outlet, the computed AMMD (1.9 ?m) had GSD between 1.12 and 2.76. Decontamination factors (DF), computed based on deposition from trajectory calculations, were just over 3.5 for the bend and 4.4 at the outlet. Computed DFs were consistent with expert elicitation cited in NUREG-1150 for aerosol retention in steam generators.

Longmire, Pamela

2007-05-01T23:59:59.000Z

298

Impact of Aerosols on Atmospheric Attenuation Loss in Central Receiver Systems: Preprint  

Science Conference Proceedings (OSTI)

Atmospheric attenuation loss between the heliostat field and receiver has been recognized as a significant source of loss in Central Receiver Systems. In clear sky situations, extinction of Direct Normal Irradiance (DNI) is primarily by aerosols in the atmosphere. When aerosol loading is high close to the surface the attenuation loss between heliostat and receivers is significantly influenced by the amount of aerosols present on a particular day. This study relates measured DNI to aerosol optical depths close to the surface of the earth. The model developed in the paper uses only measured DNI to estimate the attenuation between heliostat and receiver in a central receiver system. The requirement that only a DNI measurement is available potentially makes the model a candidate for widespread use.

Sengupta, M.; Wagner, M. J.

2011-08-01T23:59:59.000Z

299

Evaluation of Empirical Aerosol Correlations  

Science Conference Proceedings (OSTI)

This study examined the adequacy of novel scaling and correlation methods used to analyze aerosol behavior in versions 2.0 and 3.0 of the MAAP computer code. The results show that the MAAP 2.0 method suffers from inaccurate scaling. The method used in MAAP 3.0 is theoretically superior and more consistent with experimental data.

1986-12-17T23:59:59.000Z

300

Simulating Aerosols Using a Chemical Transport Model with Assimilation of Satellite Aerosol Retrievals: Methodology for INDOEX  

E-Print Network (OSTI)

A system for simulating aerosols has been developed using a chemical transport model together with an assimilation of satellite aerosol retrievals. The methodology and model components are described in this paper, and the modeled distribution of aerosols for the Indian Ocean Experiment (INDOEX) is presented by Rasch et al. [this issue]. The system generated aerosol forecasts to guide deployment of ships and aircraft during INDOEX. The system consists of the Model of Atmospheric Transport and Chemistry (MATCH) combined with an assimilation package developed for applications in atmospheric chemistry. MATCH predicts the evolution of sulfate, carbonaceous, and mineral dust aerosols, and it diagnoses the distribution of sea salt aerosols. The model includes a detailed treatment of the sources, chemical transformation, transport, and deposition of the aerosol species. The aerosol forecasts involve a two-stage process. During the assimilation phase the total column aerosol optical depth (AOD) is estimated from the model aerosol fields. The model state is then adjusted to improve the agreement between the simulated AOD and satellite retrievals of AOD. During the subsequent integration phase the aerosol fields are evolved using meteorological fields from an external model. Comparison of the modeled AOD against estimates of the AOD from INDOEX Sun photometer data show that the differences in daily means are #0.03 # 0.06. Although the initial application is limited to the Indian Ocean, the methodology could be extended to derive global aerosol analyses combining in situ and remotely sensed aerosol observations.

William D. Collins; Phillip J. Rasch; Brian E. Eaton; Boris V. Khattatov; Jean-francois Lamarque; C. Zender

2001-01-01T23:59:59.000Z

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301

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

NLE Websites -- All DOE Office Websites (Extended Search)

Effective Radius of Cloud Droplets by Ground-Based Effective Radius of Cloud Droplets by Ground-Based Remote Sensing: Relationships to Aerosol? B.-G. Kim, S. E. Schwartz, and M. A. Miller Environmental Sciences Department Brookhaven National Laboratory Upton, New York Q.-L. Min Atmospheric Science Research Center State University of New York Albany, New York Introduction Aerosol Indirect Effect Increases in anthropogenic sources of cloud condensation nuclei can increase cloud albedo by increasing the concentration and reducing the size of cloud droplets, usually referred to as the indirect effect of aerosol on climate (Twomey 1977). However, the magnitudes of the various kinds of indirect forcing are particularly uncertain, because they involve subtle changes in cloud radiative properties and lifetimes

302

Addition of Tropospheric Chemistry and Aerosols to the NCAR Community Climate System Model  

SciTech Connect

Atmospheric chemistry and aerosols have several important roles in climate change. They affect the Earth's radiative balance directly: cooling the earth by scattering sunlight (aerosols) and warming the Earth by trapping the Earth's thermal radiation (methane, ozone, nitrous oxide, and CFCs are greenhouse gases). Atmospheric chemistry and aerosols also impact many other parts of the climate system: modifying cloud properties (aerosols can be cloud condensation nuclei), fertilizing the biosphere (nitrogen species and soil dust), and damaging the biosphere (acid rain and ozone damage). In order to understand and quantify the effects of atmospheric chemistry and aerosols on the climate and the biosphere in the future, it is necessary to incorporate atmospheric chemistry and aerosols into state-of-the-art climate system models. We have taken several important strides down that path. Working with the latest NCAR Community Climate System Model (CCSM), we have incorporated a state-of-the-art atmospheric chemistry model to simulate tropospheric ozone. Ozone is not just a greenhouse gas, it damages biological systems including lungs, tires, and crops. Ozone chemistry is also central to the oxidizing power of the atmosphere, which destroys a lot of pollutants in the atmosphere (which is a good thing). We have also implemented a fast chemical mechanism that has high fidelity with the full mechanism, for significantly reduced computational cost (to facilitate millennium scale simulations). Sulfate aerosols have a strong effect on climate by reflecting sunlight and modifying cloud properties. So in order to simulate the sulfur cycle more fully in CCSM simulations, we have linked the formation of sulfate aerosols to the oxidizing power of the atmosphere calculated by the ozone mechanisms, and to dimethyl sulfide emissions from the ocean ecosystem in the model. Since the impact of sulfate aerosols depends on the relative abundance of other aerosols in the atmosphere, we also implemented interactive simulation of nitrate, sea-salt, black carbon, and both primary and secondary organic aerosols into CCSM (using assumed size distributions). These new capabilities are opening the door to studies of the role atmospheric chemistry and aerosols in climate change, and their impact on the biosphere, that were previously impossible.

Cameron-Smith, P; Lamarque, J; Connell, P; Chuang, C; Rotman, D; Taylor, J

2005-11-14T23:59:59.000Z

303

FEDERAL SMART GRID TASK FORCE - February 26, 2009 Task Force...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

FEDERAL SMART GRID TASK FORCE - February 26, 2009 Task Force Meeting Agenda FEDERAL SMART GRID TASK FORCE - February 26, 2009 Task Force Meeting Agenda February 26, 2009 Task Force...

304

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

Science Conference Proceedings (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

305

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

E-Print Network (OSTI)

Secondary organic aerosols (SOA) comprise a substantial fraction of the total global aerosol budget. While laboratory studies involving smog chambers have advanced our understanding of the formation mechanisms responsible for SOA, our knowledge 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 or indirectly by serving as cloud condensation nuclei, soot is thought to have a significant warming effect through absorption. Like inorganic salts, soot may undergo atmospheric transformation through the vapor condensation of non-volatile gaseous species which will alter both its chemical and physical properties. Typical smog chamber studies investigating the formation and growth of SOA as well as the soot aging process are temporally limited by the initial gaseous concentrations injected into the chamber environment. Furthermore, data interpretation from such experiments is generally restricted to the singular gaseous species under investigation. This dissertation discusses the use of a new aerosol chamber designed to study the formation and growth of SOA and soot aging under atmospherically relevant conditions. The Ambient Aerosol Chamber for Evolution Studies (AACES) was deployed at three field sites where size and hygroscopic growth factor (HGF) of ammonium sulfate seed particles was monitored over time to examine the formation and growth of SOA. Similar studies investigating the soot aging process were also conducted in Houston, TX. It is shown that during the ambient growth of ammonium sulfate seed particles, as particle size increases, hygroscopic growth factors decrease considerably resulting in a significant organic mass fraction in the particle phase concluding an experiment. Observations of soot aging show an increase in measured size, HGF, mass and single scattering albedo. Ambient growth rate comparisons with chamber growth yielded similar trends verifying the use of AACES to study aerosol aging. Based on the results from this study, it is recommended that AACES be employed in future studies involving the production and growth of SOA and soot aging under ambient conditions in order to bridge the gaps in our current scientific knowledge.

Glen, Crystal

2010-12-01T23:59:59.000Z

306

Discrete-element modeling of particulate aerosol flows  

Science Conference Proceedings (OSTI)

A multiple-time step computational approach is presented for efficient discrete-element modeling of aerosol flows containing adhesive solid particles. Adhesive aerosol particulates are found in numerous dust and smoke contamination problems, including smoke particle transport in the lungs, particle clogging of heat exchangers in construction vehicles, industrial nanoparticle transport and filtration systems, and dust fouling of electronic systems and MEMS components. Dust fouling of equipment is of particular concern for potential human occupation on dusty planets, such as Mars. The discrete-element method presented in this paper can be used for prediction of aggregate structure and breakup, for prediction of the effect of aggregate formation on the bulk fluid flow, and for prediction of the effects of small-scale flow features (e.g., due to surface roughness or MEMS patterning) on the aggregate formation. After presentation of the overall computational structure, the forces and torques acting on the particles resulting from fluid motion, particle-particle collision, and adhesion under van der Waals forces are reviewed. The effect of various parameters of normal collision and adhesion of two particles are examined in detail. The method is then used to examine aggregate formation and particle clogging in pipe and channel flow.

Marshall, J.S. [School of Engineering, University of Vermont, 33 Colchecter Avenue, Burlington, Vermont 05405 (United States)], E-mail: jeffm@cems.uvm.edu

2009-03-20T23:59:59.000Z

307

Design and Sampling Characteristics of a New Airborne Aerosol Inlet for Aerosol Measurements in Clouds  

Science Conference Proceedings (OSTI)

Design of a new submicron aerosol inlet (SMAI) for airborne sampling of aerosol particles is introduced and its performance characteristics under a range of sampling conditions are presented. Analysis of inlet performance in clear-air and cloud ...

Lucas Craig; Allen Schanot; Arash Moharreri; David C. Rogers; Suresh Dhaniyala

2013-06-01T23:59:59.000Z

308

The Aerosol Modeling Testbed: A Community Tool to Objectively Evaluate Aerosol Process Modules  

Science Conference Proceedings (OSTI)

The current paradigm of developing and testing new aerosol process modules is haphazard and slow. Aerosol modules are often tested for short simulation periods using limited data so that their overall performance over a wide range of ...

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

2011-03-01T23:59:59.000Z

309

Another Look at the Influence of Absorbing Aerosols in Drops on Cloud Absorption: Large Aerosols  

Science Conference Proceedings (OSTI)

Since as early as 1969, solar absorbing aerosols inside of cloud drops have been suggested to influence cloud radiative properties. The absorbing aerosols were invoked to help explain two “anomalies”: 1) the maximum visible albedo of thick ...

Carynelisa Erlick; Dana Schlesinger

2008-02-01T23:59:59.000Z

310

Assessment of Aerosol Modes Used in the MODIS Ocean Aerosol Retrieval  

Science Conference Proceedings (OSTI)

Coastal and island Aerosol Robotic Network (AERONET) sites are used to determine characteristic aerosol modes over marine environments. They are compared with the assumed modes used in the operational Moderate Resolution Imaging Spectroradiometer (...

Jiacheng Wang; Qiang Zhao; Shengcheng Cui; Chengjie Zhu

2012-12-01T23:59:59.000Z

311

ARM - Field Campaign - Two-Column Aerosol Project (TCAP)  

NLE Websites -- All DOE Office Websites (Extended Search)

govCampaignsTwo-Column Aerosol Project (TCAP) govCampaignsTwo-Column Aerosol Project (TCAP) Campaign Links TCAP website Related Campaigns Two-Column Aerosol Project (TCAP): Field Evaluation of Real-time Cloud OD Sensor TWST 2013.04.15, Scott, AMF Two-Column Aerosol Project (TCAP): Winter Aerosol Effects on Cloud Formation 2013.02.04, Cziczo, AMF Two-Column Aerosol Project (TCAP): CU GMAX-DOAS Deployment 2012.07.15, Volkamer, AMF Two-Column Aerosol Project (TCAP): Aerosol Light Extinction Measurements 2012.07.15, Dubey, AMF Two-Column Aerosol Project (TCAP): Aerial Campaign 2012.07.07, Berg, AAF Two-Column Aerosol Project (TCAP): Aerodynamic Particle Sizer 2012.07.01, Berg, AMF Two-Column Aerosol Project (TCAP): KASPRR Engineering Tests 2012.07.01, Mead, AMF Two-Column Aerosol Project (TCAP): Airborne HSRL and RSP Measurements

312

Using MODIS and AERONET to Determine GCM Aerosol Size  

Science Conference Proceedings (OSTI)

Aerosol size is still a poorly constrained quantity in general circulation models (GCMs). By using the modal radii of the coarse and fine mode retrieved from 103 stations in the Aerosol Robotic Network (AERONET) and the fine mode aerosol optical ...

Glen Lesins; Ulrike Lohmann

2006-04-01T23:59:59.000Z

313

Aerosol Remote Sensing over Clouds Using A-Train Observations  

Science Conference Proceedings (OSTI)

The detection of aerosol above clouds is critical for the estimate of both the aerosol and cloud radiative impacts. In this study, the authors present a new method to retrieve the aerosol properties over clouds that uses the multiangle ...

F. Waquet; J. Riedi; L. C. Labonnote; P. Goloub; B. Cairns; J-L. Deuzé; D. Tanré

2009-08-01T23:59:59.000Z

314

AEROSOL ANALYSIS FOR THE REGIONAL AIR POLLUTION STUDY - FINAL REPORT  

E-Print Network (OSTI)

Beta-Gauge Methods Applied to Aerosol Samples." Submitted toHusar and B.Y.H. Liu. "The Aerosol Size Distribution of LosAngeles Smog." In: Aerosols and Atmospheric Chemistry, G.M.

Jaklevic, J.M.

2010-01-01T23:59:59.000Z

315

Distinguishing Aerosol Impacts on Climate Over the Past Century  

E-Print Network (OSTI)

Table 1. Aerosol Characteristics Species Emissions Burdenc and h), IE (d, i) and BAE (e, f). List of Tables AerosolEmission of trace gases and aerosols from biomass burning,

Koch, Dorothy

2009-01-01T23:59:59.000Z

316

OH-initiated heterogeneous aging of highly oxidized organic aerosol  

E-Print Network (OSTI)

P. ; Jimenez, J. L. Aerosol Science and Technology 2004, 38,A. G. Highly dispersed aerosols; Halsted Press, New York,highly oxidized organic aerosol Sean H. Kessler 1 , Theodora

Kessler, Sean H.

2013-01-01T23:59:59.000Z

317

SPURIOUS SULFATE FORMATION ON COLLECTED AMBIENT AEROSOL SAMPLES  

E-Print Network (OSTI)

FORMATION ON COLLECTED AMBIENT AEROSOL SAMPLES B. W. Loo, R.FORMATION ON COLLECTED AMBIENT AEROSOL SAMPLES Billy W. Lao,ON COLLECTED AMBIENT AEROSOL SAMPLES* _B_il_l~y ___ W_. _L~o

Loo, B.W.

2011-01-01T23:59:59.000Z

318

The CALIPSO Automated Aerosol Classification and Lidar Ratio Selection Algorithm  

Science Conference Proceedings (OSTI)

Descriptions are provided of the aerosol classification algorithms and the extinction-to-backscatter ratio (lidar ratio) selection schemes for the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) aerosol products. One ...

Ali H. Omar; David M. Winker; Mark A. Vaughan; Yongxiang Hu; Charles R. Trepte; Richard A. Ferrare; Kam-Pui Lee; Chris A. Hostetler; Chieko Kittaka; Raymond R. Rogers; Ralph E. Kuehn; Zhaoyan Liu

2009-10-01T23:59:59.000Z

319

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

SciTech Connect

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 three 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 (NW) wet 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, especially in the activation parameterization, 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, and may do so with the reliability required for policy analysis.

Saide P. E.; Springston S.; Spak, S. N.; Carmichael, G. R.; Mena-Carrasco, M. A.; Yang, Q.; Howell, S.; Leon, D. C.; Snider, J. R.; Bandy, A. R.; Collett, J. L.; Benedict, K. B.; de Szoeke, S. P.; Hawkins, L. N.; Allen, G.; Crawford, I.; Crosier, J.

2012-03-29T23:59:59.000Z

320

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

SciTech Connect

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

Note: This page contains sample records for the topic "direct aerosol forcing" 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

Atmospheric Aerosols Aging Involving Organic Compounds and Impacts on Particle Properties  

E-Print Network (OSTI)

In the first part of this dissertation, we study the aging of soot, a representative type of primary aerosols, in the presence of OH-initiated oxidation products of toluene. Monodisperse soot particles are introduced into an environmental chamber where toluene is oxidized by OH radicals. The variations in soot particle properties are simultaneously monitored, including particle size, mass, organic mass faction, hygroscopicity, and optical properties. The changes in particle properties are found to be largely governed by the thickness of the organic coating that is closely related to reaction time and initial reactant concentrations. Derived from particle size and mass, the effective density increases while dynamic shape factor decreases as the organic coating grows, suggesting a compaction of the soot morphology. As the organic coating grows, the particles become more hygroscopic and have enhanced light scattering and absorption. The second part discusses the potential reactions between amines and some aerosol constituents and alteration of aerosol properties. The reactions between alkylamines and ammonium sulfate/bisulfate have been studied using a low-pressure fast flow reactor coupled to a mass spectrometer at 293 K. Alkylamines react with ammonium sulfate/bisulfate to form alkylaminium sulfates, suggesting the existence of alkylaminium salts in particle phase. We have extended our study to characterize the physicochemical properties of alkylaminium sulfates. The hygroscopicity, thermostability, and density of five representative alkylaminium sulfates have been measured by an integrated aerosol analytical system. All alkylaminium sulfate aerosols show monotonic size growth when exposed to increasing relative humidity. Mixing ammonium sulfate with alkylaminium sulfates lowers the deliquescence point corresponding to ammonium sulfate. Alkylaminium sulfates are thermally comparable to or more stable than ammonium sulfate. The densities of alkylaminium sulfate particles are lower than that of ammonium sulfate. Our results suggest that the organic compounds can effectively alter the composition and properties of atmospheric aerosols, considerably influencing the impacts of aerosols on air quality, climate forcing, and human health.

Qiu, Chong

2013-05-01T23:59:59.000Z

322

Forced Trench Waves  

Science Conference Proceedings (OSTI)

A general theory for forced barotropic long trench waves in the presence of linear bottom friction is presented. Two specific forcing mechanisms are considered: (i) transverse fluctuations in a western boundary current as it flows across a trench,...

Lawrence A. Mysak; Andrew J. Willmott

1981-11-01T23:59:59.000Z

323

New Chemical Aerosol Characterization Methods- Examples Using Agricultural and Urban Airborne Particulate Matter  

E-Print Network (OSTI)

This study explored different chemical characterization methods of agricultural and urban airborne particulate matter. Three different field campaigns are discussed. For the agricultural aerosols, measurement of the chemical composition of size-resolved agricultural aerosols collected from a ground site at the nominally downwind and upwind edge of a feedlot in West Texas were reported. High volume cascade impactor samplers were used for the collection of the particles, and two major analytical methods were applied to characterize different components of the aerosols, ion chromatography (IC ) was used to measure ionic composition with the main targets being ammonium (NH4 ), nitrate (NO3 -), and sulfate (SO4 2-), direct thermal desorption gas chromatography-mass spectrometry/flame ionization detection (GC-MS/FID) methodology was used to identify and quantify organic compounds in the aerosol particles. For the urban aerosols, I report the measurement of mass, and the chemical composition of size-resolved aerosols collected from two different locations in Houston, analyzed by the thermal desorption GC-MS/FID method. The investigation of single particle composition using RM is reported as well: RM and chemical mapping techniques have been applied for the qualitative analysis of components in the samples of air particulate matter collected in downtown Houston.

Zhou, Lijun

2010-08-01T23:59:59.000Z

324

SERVOMECHANISMS WITH FORCE FEEDBACK  

SciTech Connect

A class of linear proportional servomechanisms is examined in which an electrical signal proportional to output force is used to improve performance. The effect of this "force feedback" on a positional servomechanism is analyzed as well as the effect on a special type of servomechanism which reflects load forces back to the input. This latter type of servomechanism is called "force reflecting." Laboratory models of these servormechanisms were designed and constructed, and experimental data are presented in support of the analysis. (auth)

Arzbaecher, R.C.

1960-05-01T23:59:59.000Z

325

Calibrated Atomic Force Microscopy  

Science Conference Proceedings (OSTI)

... Vorburger, SL Tan, NG Orji, J. Fu, “Interlaboratory Comparison of Traceable Atomic Force Microscope Pitch Measurements,” SPIE Proceedings Vol. ...

2011-10-28T23:59:59.000Z

326

Composition and Reactions of Atmospheric Aerosol Particles  

NLE Websites -- All DOE Office Websites (Extended Search)

change. Tiny Specks with Large Effects Most people equate aerosols with hairspray and household cleaning products, but a large portion of these microscopic particles floating...

327

Radiative and climate impacts of absorbing aerosols  

E-Print Network (OSTI)

over the southwest summer monsoon region, Meteorol. Atmos.Absorbing aerosols and summer monsoon evolution over SouthK. M. Kim (2006), Asian summer monsoon anomalies induced by

Zhu, Aihua

2010-01-01T23:59:59.000Z

328

Micro Aerosol-based Decontamination System - Available ...  

Search PNNL. PNNL Home; About; Research; Publications; Jobs; News; Contacts; Micro Aerosol-based Decontamination System. Battelle Number(s): 15847. ...

329

Carbonaceous Aerosol Study Using Advanced Particle Instrumentation  

E-Print Network (OSTI)

range transport of biomass combustion aerosols. Environ.6 6.1 Introduction Biomass combustion emissions contributeparticles from the combustion of biomass fuels. Environ.

Qi, Li

2010-01-01T23:59:59.000Z

330

Aerosol Retrieval Using Remote-sensed Observations  

E-Print Network (OSTI)

electromagnetic solar radiation. The amount of atmosphericas the amount of solar radiation that aerosols scatter andbased on reflected solar radiation field measurements

Wang, Yueqing

2012-01-01T23:59:59.000Z

331

THERMOPHORESIS AND ITS THERMAL PARAMETERS FOR AEROSOL COLLECTION  

NLE Websites -- All DOE Office Websites (Extended Search)

THERMOPHORESIS AND ITS THERMAL PARAMETERS FOR AEROSOL COLLECTION Title THERMOPHORESIS AND ITS THERMAL PARAMETERS FOR AEROSOL COLLECTION Publication Type Journal Article LBNL Report...

332

Coupled aerosol-chemistry-climate twentieth century transient...  

NLE Websites -- All DOE Office Websites (Extended Search)

Coupled aerosol-chemistry-climate twentieth century transient model investigation: Trends in short-lived species and climate responses Title Coupled aerosol-chemistry-climate...

333

OLIGOMERIZATION OF LEVOGLUCOSAN IN PROXIES OF BIOMASS BURNING AEROSOLS.  

E-Print Network (OSTI)

??Biomass burning aerosols play an important role in the chemistry and physics of the atmosphere and therefore, affect global climate. Biomass burning aerosols are generally… (more)

Holmes, Bryan J.

334

Aerosol Jet® Material Deposition for High Resolution Printed ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Aerosol Jet printing, is finding wide use in a number of ... The Aerosol Jet systems deposit a wide variety of functional materials onto a wide ...

335

Characterizing the Formation of Secondary Organic Aerosols-Interim...  

NLE Websites -- All DOE Office Websites (Extended Search)

Characterizing the Formation of Secondary Organic Aerosols-Interim Report. Title Characterizing the Formation of Secondary Organic Aerosols-Interim Report. Publication Type Report...

336

Modeling Corrosion of a Metal under an Aerosol Droplet  

Science Conference Proceedings (OSTI)

Deposition of aerosol droplets produced either by marine or industrial activity on the ... The atmospheric corrosion caused by aerosols is a result of a complex ...

337

Raman Lidar Measurements of Aerosols and Water Vapor During the...  

NLE Websites -- All DOE Office Websites (Extended Search)

Raman Lidar Measurements of Aerosols and Water Vapor During the May 2003 Aerosol IOP R. A. Ferrare National Aeronautics and Space Administration Langley Research Center Hampton,...

338

Factors affecting the indoor concentrations of carbonaceous aerosols...  

NLE Websites -- All DOE Office Websites (Extended Search)

Factors affecting the indoor concentrations of carbonaceous aerosols of outdoor origin Title Factors affecting the indoor concentrations of carbonaceous aerosols of outdoor origin...

339

The Transformation of Outdoor Ammonium Nitrate Aerosols in the...  

NLE Websites -- All DOE Office Websites (Extended Search)

The Transformation of Outdoor Ammonium Nitrate Aerosols in the Indoor Environment Title The Transformation of Outdoor Ammonium Nitrate Aerosols in the Indoor Environment...

340

Retrieval of Aerosol Mass Concentration from Elastic Lidar Data.  

E-Print Network (OSTI)

??Agricultural aerosol sources can contribute significantly to air pollution in many regions of the country. Characterization of the aerosol emissions of agricultural operations is required… (more)

Marchant, Christian C.

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "direct aerosol forcing" 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

Studies of urban atmospheric aerosols using lidar and sky radiometer.  

E-Print Network (OSTI)

???This thesis discusses the remote sensing of atmospheric aerosols, the corresponding instrumental technology and inversion algorithm. The urban aerosol optical properties in Hong Kong have… (more)

Yang, Xun (??)

2008-01-01T23:59:59.000Z

342

Aerosol concentration and size distribution measured below, in, and above cloud from the DOE G-1 during VOCALS-REx  

SciTech Connect

During the VOCALS Regional Experiment, the DOE G-1 aircraft was used to sample a varying aerosol environment pertinent to properties of stratocumulus clouds over a longitude band extending 800 km west from the Chilean coast at Arica. Trace gas and aerosol measurements are presented as a function of longitude, altitude, and dew point in this study. Spatial distributions are consistent with an upper atmospheric source for O{sub 3} and South American coastal sources for marine boundary layer (MBL) CO and aerosol, most of which is acidic sulfate. Pollutant layers in the free troposphere (FT) can be a result of emissions to the north in Peru or long range transport from the west. At a given altitude in the FT (up to 3 km), dew point varies by 40 C with dry air descending from the upper atmospheric and moist air having a boundary layer (BL) contribution. Ascent of BL air to a cold high altitude results in the condensation and precipitation removal of all but a few percent of BL water along with aerosol that served as CCN. Thus, aerosol volume decreases with dew point in the FT. Aerosol size spectra have a bimodal structure in the MBL and an intermediate diameter unimodal distribution in the FT. Comparing cloud droplet number concentration (CDNC) and pre-cloud aerosol (D{sub p} > 100 nm) gives a linear relation up to a number concentration of {approx}150 cm{sup -3}, followed by a less than proportional increase in CDNC at higher aerosol number concentration. A number balance between below cloud aerosol and cloud droplets indicates that {approx}25 % of aerosol with D{sub p} > 100 nm are interstitial (not activated). A direct comparison of pre-cloud and in-cloud aerosol yields a higher estimate. Artifacts in the measurement of interstitial aerosol due to droplet shatter and evaporation are discussed. Within each of 102 constant altitude cloud transects, CDNC and interstitial aerosol were anti-correlated. An examination of one cloud as a case study shows that the interstitial aerosol appears to have a background, upon which is superimposed a high frequency signal that contains the anti-correlation. The anti-correlation is a possible source of information on particle activation or evaporation.

Kleinman L. I.; Daum, P. H.; Lee, Y.-N.; Lewis, E. R.; Sedlacek III, A. J.; Senum, G. I.; Springston, S. R.; Wang, J.; Hubbe, J.; Jayne, J.; Min, Q.; Yum, S. S.; Allen, G.

2012-01-04T23:59:59.000Z

343

"Radiative Closure Studies for Clear Skies During the ARM 2003 Aerosol Intensive Observation Period"  

SciTech Connect

The Department of Energy's Atmospheric Radiation Measurement (ARM) program sponsored a large intensive observation period (IOP) to study aerosol during the month of May 2003 around the Southern Great Plains (SGP) Climate Research Facility (CRF) in north central Oklahoma. Redundant measurements of aerosol optical properties were made using different techniques at the surface as well as in vertical profile with sensors aboard two aircraft. One of the principal motivations for this experiment was to resolve the disagreement between models and measurements of diffuse horizontal broadband shortwave irradiance at the surface, especially for modest aerosol loading. This paper focuses on using the redundant aerosol and radiation measurements during this IOP to compare direct beam and diffuse horizontal broadband shortwave irradiance measurements and models at the surface for a wide range of aerosol cases that occurred during 30 clear-sky periods on 13 days of May 2003. Models and measurements are compared over a large range of solar-zenith angles. Six different models are used to assess the relative agreement among them and the measurements. Better agreement than previously achieved appears to be the result of better specification of input parameters and better measurements of irradiances than in prior studies. Biases between modeled and measured direct irradiances are less than 1%, and biases between modeled and measured diffuse irradiances are less than 2%.

J. J. Michalsky, G. P. Anderson, J. Barnard, J. Delamere, C. Gueymard, S. Kato, P. Kiedron, A. McComiskey, and P. Ricchiazzi

2006-04-01T23:59:59.000Z

344

Spatial and Temporal Variability of Aerosol Particles in Arctic Spring  

SciTech Connect

The objective of this work is to investigate the variability in the particle number concentration that may affect climate change assessment for Arctic regions. The Indirect and Semi-Direct Aerosol Campaign (ISDAC) was conducted in April 2008, in the vicinities of Fairbanks and Barrow, Alaska. Measurements of particle number concentrations and size distributions were conducted using a Passive Cavity Aerosol Spectrometer Probe (PCASP-100X) mounted under the Convair-580 aircraft wing. Total number concentration of particles (Na) with diameters in the range 0.12-3 ?m was determined for polluted and clean air masses during times when the air was free of clouds and/or precipitation. Variability in Na was considered for both vertical profiles and constant altitude (horizontal) flight legs. This variability can have important implications for estimates of particle properties used in global climate model (GCM) simulations. When aerosol particle layers were encountered, Na rapidly increased from 25 cm-3 up to 550 cm-3 within relatively clean air masses, and reached up to 2200 cm-3 within polluted air masses, dominated by biomass burning pollution. When averaging Na over different distance scales, it was found that Na=140 cm-3 represent an average value for the majority of the encountered clean cases; while Na=720 cm-3 is a mean for polluted cases dominated by biomass burning plumes. These estimates, however, would not capture the details of particle layers encountered during most of the flights. Average aerosol particle characteristics can be difficult to interpret, especially during polluted cases, due to small-scale spatial and temporal variability.

Shantz, Nicole C.; Gultepe, Ismail; Liu, Peter; Earle, Michael; Zelenyuk, Alla

2012-10-01T23:59:59.000Z

345

Squeeze bottle apparatus with force multiplying pistons  

DOE Patents (OSTI)

The present invention comprises a spray bottle in which the pressure resulting from the gripping force applied by the user is amplified and this increased pressure used in generating a spray such as an aerosol or fluid stream. In its preferred embodiment, the invention includes a high pressure chamber and a corresponding piston which is operative for driving fluid out of this chamber at high pressure through a spray nozzle and a low pressure chamber, and a corresponding piston which is acted upon by the hydraulic pressure within the bottle resulting from the gripping force. The low pressure chamber and piston are of larger size than the high pressure chamber and piston. The pistons are rigidly connected so that the force created by the pressure acting on the piston in the low pressure chamber is transmitted to the piston in the high pressure chamber where it is applied over a more limited area, thereby generating greater hydraulic pressure for use in forming the spray.

Moss, Owen R. (Cary, NC); Gordon, Norman R. (Kennewick, WA); DeFord, Henry S. (Kennewick, WA); Eschbach, Eugene A. (Richland, WA)

1994-01-01T23:59:59.000Z

346

BNL | Mobile Aerosol Observing System (MAOS)  

NLE Websites -- All DOE Office Websites (Extended Search)

Mobile Aerosol Observing System (MAOS) Mobile Aerosol Observing System (MAOS) The Mobile Aerosol Observing System (MAOS) is a platform and instrument suite for Intensive Operation Periods (IOPs) to conduct in situ measurements of aerosols and their precursors. MAOS is part of the ARM Climate Research Facility. Physically MAOS is contained in two 20' SeaTainers custom adapted to provide a sheltered laboratory environment for operators and instruments even under harsh conditions. The two structures are designated MAOS-A and MAOS-C for Aerosol and Chemistry respectively. Although independent, with separate data systems, inlets and power distribution, the two structures are normally a single operating unit. The two enclosures comprising MAOS are designed for rapid deployment. All components (except for the Radar Wind Profiler) are transported internally

347

The Opposed Migration Aerosol Classifier (OMAC)  

NLE Websites -- All DOE Office Websites (Extended Search)

The Opposed Migration Aerosol Classifier (OMAC) The Opposed Migration Aerosol Classifier (OMAC) Speaker(s): Harmony Gates Date: February 22, 2007 - 12:00pm Location: 90-4133 Seminar Host/Point of Contact: Melissa Lunden A new differential mobility classifier will be described. The instrument classifies aerosol particles in a channel flow between porous (or screen) electrodes. The aerosol enters the channel parallel to the porous electrodes, while a larger, particle-free cross-flow enters through one of the porous electrode. A potential difference between electrodes causes the charged aerosol particles to migrate upstream against the cross-flow. Only particles whose upward migration velocity balances the cross flow will be transmitted along the path of the classifier. Simulations of the OMAC show that it should give the same resolution at the traditional

348

Number, Mass and Volume Distributions of Mineral Aerosol and Soils of the Sahara  

Science Conference Proceedings (OSTI)

A direct method will be described to determine the complete mineral size distribution in aerosol (xylene-insoluble component) and soils (water-insoluble component) covering a size range from 0.01 up to 100 ?m and 1000 ?m radius, respectively, by ...

Guillaume A. d'Almeida; Lothar Schütz

1983-02-01T23:59:59.000Z

349

AEROSOL PARTICLE COLLECTOR DESIGN STUDY  

Science Conference Proceedings (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

350

Aircraft Observations of Sub-cloud Aerosol and Convective Cloud Physical Properties  

E-Print Network (OSTI)

This research focuses on aircraft observational studies of aerosol-cloud interactions in cumulus clouds. The data were collected in the summer of 2004, the spring of 2007 and the mid-winter and spring of 2008 in Texas, central Saudi Arabia and Istanbul, Turkey, respectively. A set of 24 pairs of sub-cloud aerosol and cloud penetration data are analyzed. Measurements of fine and coarse mode aerosol concentrations from 3 different instruments were combined and fitted with lognormal distributions. The fit parameters of the lognormal distributions are compared with cloud droplet effective radii retrieved from 260 cloud penetrations. Cloud condensation nuclei (CCN) measurements for a subset of 10 cases from the Istanbul region are compared with concentrations predicted from aerosol size distributions. Ammonium sulfate was assumed to represent the soluble component of aerosol with dry sizes smaller than 0.5 mm and sodium chloride for aerosol larger than 0.5 mm. The measured CCN spectrum was used to estimate the soluble fraction. The correlations of the measured CCN concentration with the predicted CCN concentration were strong (R2 > 0.89) for supersaturations of 0.2, 0.3 and 0.6%. The measured concentrations were typically consistent with an aerosol having a soluble fraction between roughly 0.5 and 1.0, suggesting a contribution of sulfate or some other similarly soluble inorganic compound. The predicted CCN were found to vary by +or-3.7% when the soluble fraction was varied by 0.1. Cumulative aerosol concentrations at cutoff dry diameters of 1.1, 0.1 and 0.06 mm were found to be correlated with cloud condensation nuclei concentrations but not with maximum cloud base droplet concentrations. It is also shown that in some cases the predominant mechanisms involved in the formation of precipitation were altered and modified by the aerosol properties. This study suggests that CCN-forced variations in cloud droplet number concentration can change the effective radius profile and the type of precipitation hydrometeors. These differences may have a major impact on the global hydrological cycle and energy budget.

Axisa, Duncan

2009-12-01T23:59:59.000Z

351

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

Science Conference Proceedings (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

352

Why measure force?  

Science Conference Proceedings (OSTI)

... Automated industrial processes such as rolling mills require accurate force measurement to control roll pressure on bar steel, sheet metal, paper ...

2011-10-03T23:59:59.000Z

353

NUCLEAR PROXIMITY FORCES  

E-Print Network (OSTI)

One might summarize of nuclear potential energy has beendegree of freedom) for the nuclear interaction between anyUniversity of California. Nuclear Proximity Forces 'I< at

Randrup, J.

2011-01-01T23:59:59.000Z

354

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

355

Constraining the Influence of Natural Variability to Improve Estimates of Global Aerosol Indirect Effects in a Nudged Version of the Community Atmosphere Model 5  

SciTech Connect

Natural modes of variability on many timescales influence aerosol particle distributions and cloud properties such that isolating statistically significant differences in cloud radiative forcing due to anthropogenic aerosol perturbations (indirect effects) typically requires integrating over long simulations. For state-of-the-art global climate models (GCM), especially those in which embedded cloud-resolving models replace conventional statistical parameterizations (i.e. multi-scale modeling framework, MMF), the required long integrations can be prohibitively expensive. Here an alternative approach is explored, which implements Newtonian relaxation (nudging) to constrain simulations with both pre-industrial and present-day aerosol emissions toward identical meteorological conditions, thus reducing differences in natural variability and dampening feedback responses in order to isolate radiative forcing. Ten-year GCM simulations with nudging provide a more stable estimate of the global-annual mean aerosol indirect radiative forcing than do conventional free-running simulations. The estimates have mean values and 95% confidence intervals of -1.54 ± 0.02 W/m2 and -1.63 ± 0.17 W/m2 for nudged and free-running simulations, respectively. Nudging also substantially increases the fraction of the world’s area in which a statistically significant aerosol indirect effect can be detected (68% and 25% of the Earth's surface for nudged and free-running simulations, respectively). One-year MMF simulations with and without nudging provide global-annual mean aerosol indirect radiative forcing estimates of -0.80 W/m2 and -0.56 W/m2, respectively. The one-year nudged results compare well with previous estimates from three-year free-running simulations (-0.77 W/m2), which showed the aerosol-cloud relationship to be in better agreement with observations and high-resolution models than in the results obtained with conventional parameterizations.

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

2012-12-11T23:59:59.000Z

356

JGI - Directions  

NLE Websites -- All DOE Office Websites (Extended Search)

Map to JGI Directions from Directions from key local start points, public transit Home > About Us > Map to JGI UC logo DOE logo Contact Us Credits Disclaimer Access...

357

wong-99.PDF  

NLE Websites -- All DOE Office Websites (Extended Search)

Direct aerosol radiative forcing (ARF) is important in understanding the impact of aerosols on earth's climate (Schimel et al. 1996). Global distribution of ARF is usually...

358

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 burning events. It is found that the regional AAI data follow the regional tropospheric NO2 data well sensitive to desert dust aerosols (DDA) and biomass burning aerosols (BBA). See Figure 1. The AAI

Tilstra, Gijsbert

359

Evolution of organic aerosol mass spectra upon heating: implications for OA phase and partitioning behavior  

E-Print Network (OSTI)

and Seinfeld, J. H. : Organic aerosol formation from theJ. : A large organic aerosol source in the free troposphereand Worsnop, D. R. : Organic aerosol components observed in

Cappa, Christopher D.

2011-01-01T23:59:59.000Z

360

Aerosol effects on red blue ratio of clear sky images, and impact on solar forecasting  

E-Print Network (OSTI)

urban, and desert dust aerosols ." JOURNAL OF GEOPHYSICALand K. V. S. Badarinath. "Aerosol climatology: dependence ofUsing a Sky Imager for aerosol characterization."

Ghonima, Mohamed Sherif

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "direct aerosol forcing" 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

Emissions of trace gases and aerosols during the open combustion of biomass in the laboratory  

E-Print Network (OSTI)

in press), Organic aerosols in the earth's atmosphere,loss, and trace gas and aerosol emissions during laboratoryproperties of biomass burn aerosols, Geophysical Research

McMeeking, Gavin R.

2009-01-01T23:59:59.000Z

362

Secondary Organic Aerosol Formation from Primary Aliphatic Amines with Nitrate Radical  

E-Print Network (OSTI)

back- ground atmospheric aerosol in the UK determined inof secondary organic aerosols, Atmos. Environ. , 31, 3921–et al. : Secondary organic aerosol formation from amines

Malloy, Q G J; Qi, L; Warren, B; Cocker III, D R; Erupe, M E; Silva, P J

2009-01-01T23:59:59.000Z

363

Impacts of aerosol-cloud interactions on past and future changes in tropospheric composition  

E-Print Network (OSTI)

of gas-phase chemistry-aerosol interactions on directforcing by anthropogenic aerosols and ozone, J. Geophys.GCM to constrain the aerosol indirect effect, J. Geophys.

Menon, S.

2009-01-01T23:59:59.000Z

364

Correlations between Optical, Chemical and Physical Properties of Biomass Burn Aerosols  

E-Print Network (OSTI)

instruments and photoelectric aerosol sensors in source-sampling of black carbon aerosol and particle-bound PAHsAirborne minerals and related aerosol particles: Effects on

2008-01-01T23:59:59.000Z

365

Composition, sources, and formation of secondary organic aerosols from urban emissions  

E-Print Network (OSTI)

organonitrate functional groups in aerosol particles200 5.1v aerosol Chapter 3 Meteorological conditions during theSecondary organic aerosol formation from fossil fuel sources

Liu, Shang; Liu, Shang

2012-01-01T23:59:59.000Z

366

X-RAY METHODS FOR THE CHEMICAL CHARACTERIZATION OF ATMOSPHERIC AEROSOLS  

E-Print Network (OSTI)

Goulding Fine Particles: Aerosol Generation, Sampling andCHARACTERIZATION OF ATMOSPHERIC AEROSOLS J.M. Jaklevic andCHARACTERIZATION OF ATMOSPHERIC AEROSOLS J.M. Jaklevic and

Jaklevic, J.M.

2010-01-01T23:59:59.000Z

367

Characterization of the Molecular Composition of Secondary Organic Aerosols using High Resolution Mass Spectrometry  

E-Print Network (OSTI)

in secondary organic aerosol formation from isoprene, Proc.biogenic secondary organic aerosol, J. Phys. Chem. A, 112(in secondary organic aerosol, Environ. Sci. Technol. , 41(

Sellon, Rachel Elizabeth

2012-01-01T23:59:59.000Z

368

DETERMINATION OF CARBON IN ATMOSPHERIC AEROSOLS BY DEUTERON-INDUCED NUCLEAR REACTIONS  

E-Print Network (OSTI)

deuteron irradiation of an atmospheric aerosol sample.CARBON IN ATMOSPHERIC AEROSOLS BY DEUTERON-INDUCED NUCLEARCARBON IN ATMOSPHERIC AEROSOLS BY DEUTERON-INDUCED NUCLEAR

Clemenson, Mark

2013-01-01T23:59:59.000Z

369

Real time in situ detection of organic nitrates in atmospheric aerosols  

E-Print Network (OSTI)

Biogenic Secondary Organic Aerosol. J. Phys. Chem. A 2008,H. Secondary organic aerosol (SOA) formation from reactionsec- ondary organic aerosol yields. Atmospheric Chemistry

Rollins, Andrew W.

2011-01-01T23:59:59.000Z

370

Secondary Organic Aerosol Formation From Radical-Initiated Reactions of Alkenes: Development of Mechanisms  

E-Print Network (OSTI)

and Secondary Organic Aerosols in Southern California duringSources of Organic Carbon Aerosols in the Free Troposphere21 co-authors), 2005. Organic Aerosol and Global Climate

Matsunaga, Aiko

2009-01-01T23:59:59.000Z

371

ATMOSPHERIC AEROSOL RESEARCH FY-1979, CHAPTER IN THE ENERGY AND ENVIRONMENT ANNUAL REPORT, 1979  

E-Print Network (OSTI)

California atmospheric aerosols," Environ. Sci. Technol. ll•suspensions," in Atmospheric Aerosol Research Annual Report,formation," in Atmospheric Aerosol Research Annual Report,

Authors, Various

2013-01-01T23:59:59.000Z

372

ILC Citizens' Task Force  

NLE Websites -- All DOE Office Websites (Extended Search)

the Fermilab ILC Citizens' Task Force June 2008 Report of the Fermilab ILC Citizens' Task Force 3 Contents 1 Executive Summary 3 Chapter 1 Purpose 7 Chapter 2 Origins and Purpose of the Fermilab Citizens' Task Force 15 Chapter 3 Setting the Stage 19 Chapter 4 Current Status of High Energy Physics Research 25 Chapter 5 Bringing the Next-Generation Accelerator to Fermilab 31 Chapter 6 Learning from Past Projects 37 Chapter 7 Location, Construction and Operation of Facilities Beyond Fermilab's Borders 45 Chapter 8 Health and Safety 49 Chapter 9 Environment 53 Chapter 10 Economics 59 Chapter 11 Political Considerations 65 Chapter 12 Community Engagement 77 Chapter 13 Summary 81 Appendices Appendix A. Task Force Members Appendix B. Task Force Meetings and Topics

373

Aerosol characterization study using multi-spectrum remote sensing measurement techniques.  

SciTech Connect

A unique aerosol flow chamber coupled with a bistatic LIDAR system was implemented to measure the optical scattering cross sections and depolarization ratio of common atmospheric particulates. Each of seven particle types (ammonium sulfate, ammonium nitrate, sodium chloride, potassium chloride, black carbon and Arizona road dust) was aged by three anthropogenically relevant mechanisms: 1. Sulfuric acid deposition, 2. Toluene ozonolysis reactions, and 3. m-Xylene ozonolysis reactions. The results of pure particle scattering properties were compared with their aged equivalents. Results show that as most particles age under industrial plume conditions, their scattering cross sections are similar to pure black carbon, which has significant impacts to our understanding of aerosol impacts on climate. In addition, evidence emerges that suggest chloride-containing aerosols are chemically altered during the organic aging process. Here we present the direct measured scattering cross section and depolarization ratios for pure and aged atmospheric particulates.

Glen, Crystal Chanea; Sanchez, Andres L.; Lucero, Gabriel Anthony; Schmitt, Randal L.; Johnson, Mark S.; Tezak, Matthew Stephen; Servantes, Brandon Lee

2013-09-01T23:59:59.000Z

374

Effects of the El Chichon Volcanic Cloud on Direct and Diffuse Solar Irradiances  

Science Conference Proceedings (OSTI)

Direct normal and diffuse solar irradiances and 500 nm aerosol optical depths measured at the University of Michigan departed far from normal on 26 October 1982, when it is concluded that the main stratospheric cloud from the El Chichon volcanic ...

C. Bruce Baker; William R. Kuhn; Edward Ryznar

1984-03-01T23:59:59.000Z

375

Volcanic forcing improves Atmosphere-Ocean Coupled General Circulation Model scaling performance  

E-Print Network (OSTI)

Recent Atmosphere-Ocean Coupled General Circulation Model (AOGCM) simulations of the twentieth century climate, which account for anthropogenic and natural forcings, make it possible to study the origin of long-term temperature correlations found in the observed records. We study ensemble experiments performed with the NCAR PCM for 10 different historical scenarios, including no forcings, greenhouse gas, sulfate aerosol, ozone, solar, volcanic forcing and various combinations, such as it natural, anthropogenic and all forcings. We compare the scaling exponents characterizing the long-term correlations of the observed and simulated model data for 16 representative land stations and 16 sites in the Atlantic Ocean for these scenarios. We find that inclusion of volcanic forcing in the AOGCM considerably improves the PCM scaling behavior. The scenarios containing volcanic forcing are able to reproduce quite well the observed scaling exponents for the land with exponents around 0.65 independent of the station dista...

Vyushin, D; Havlin, S; Bunde, A; Brenner, S; Vyushin, Dmitry; Zhidkov, Igor; Havlin, Shlomo; Bunde, Armin; Brenner, Stephen

2004-01-01T23:59:59.000Z

376

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

Science Conference Proceedings (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

377

Emerging Technology for Measuring Atmospheric Aerosol Properties...  

NLE Websites -- All DOE Office Websites (Extended Search)

Brookhaven Laboratory and with funding from the DOE STTR program. DMT is developing a new technique for measuring aerosol size distributions in the sub-0.1 um size range. The...

378

Composition and Reactions of Atmospheric Aerosol Particles  

NLE Websites -- All DOE Office Websites (Extended Search)

Composition and Reactions of Composition and Reactions of Atmospheric Aerosol Particles Composition and Reactions of Atmospheric Aerosol Particles Print Wednesday, 29 June 2005 00:00 Microscopic aerosol particles in the atmosphere contain carbonaceous components from mineral dust and combustion emissions released from around the world. How long these tiny particles remain in the atmosphere can have a huge impact on the global climate. Measurements based on high-resolution scanning transmission x-ray images obtained at the ALS have revealed chemical reactions on and in atmospheric aerosol particles that caused particle growth while changing organic composition by 13 to 24% per day, an oxidation rate significantly slower than is currently used in atmospheric models. Since oxidation has a strong effect on particle lifetime in the atmosphere, these results will help climate scientists refine the computer models used to predict climate change.

379

ARM - Measurement - Aerosol particle size distribution  

NLE Websites -- All DOE Office Websites (Extended Search)

particle size distribution particle size distribution ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Aerosol particle size distribution The number of aerosol particles present in any given volume of air within a specificied size range Categories Aerosols Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments SMPS : Scanning mobility particle sizer TDMA : Tandem Differential Mobility Analyzer UHSAS : Ultra-High Sensitivity Aerosol Spectrometer Field Campaign Instruments

380

Composition and Reactions of Atmospheric Aerosol Particles  

NLE Websites -- All DOE Office Websites (Extended Search)

Composition and Reactions of Atmospheric Aerosol Particles Print Composition and Reactions of Atmospheric Aerosol Particles Print Microscopic aerosol particles in the atmosphere contain carbonaceous components from mineral dust and combustion emissions released from around the world. How long these tiny particles remain in the atmosphere can have a huge impact on the global climate. Measurements based on high-resolution scanning transmission x-ray images obtained at the ALS have revealed chemical reactions on and in atmospheric aerosol particles that caused particle growth while changing organic composition by 13 to 24% per day, an oxidation rate significantly slower than is currently used in atmospheric models. Since oxidation has a strong effect on particle lifetime in the atmosphere, these results will help climate scientists refine the computer models used to predict climate change.

Note: This page contains sample records for the topic "direct aerosol forcing" 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.


381

BNL | Two-Column Aerosol Program (TCAP)  

NLE Websites -- All DOE Office Websites (Extended Search)

Two-Column Aerosol Project (TCAP) Two-Column Aerosol Project (TCAP) There remain many key knowledge gaps despite advances in the scientific understanding of how aerosols and clouds evolve and affect climate. Many climatically important processes depend on particles that undergo continuous changes within a size range spanning a few nanometers to a few microns, and with compositions that consist of a variety of carbonaceous materials, soluble inorganic salts and acids and insoluble mineral dust. Primary particles, which are externally-mixed when emitted, are subject to coagulation and chemical changes associated with the condensation of semi-volatile gases to their surface resulting in a spectrum of compositions or mixing-states with a range of climate-affecting optical and hygroscopic properties. The numerical treatments of aerosol transformation

382

Exploring Atmospheric Aerosols by Twilight Photometry  

Science Conference Proceedings (OSTI)

The instrument twilight photometer was designed, developed, and installed at the Indian Institute of Tropical Meteorology (IITM), Pune, India (18°43?N, 73°51?E), to monitor the vertical distribution of atmospheric aerosols. The instrument, based ...

B. Padma Kumari; S. H. Kulkarni; D. B. Jadhav; A. L. Londhe; H. K. Trimbake

2008-09-01T23:59:59.000Z

383

ARM - Campaign Instrument - aerosol-tower-eml  

NLE Websites -- All DOE Office Websites (Extended Search)

govInstrumentsaerosol-tower-eml Comments? We would love to hear from you Send us a note below or call us at 1-888-ARM-DATA. Send Campaign Instrument : EML Tower based Aerosol...

384

Remote Sensing of Aerosol Properties during CARES  

SciTech Connect

One month of MFRSR data collected at two sites in the central California (USA) region during the CARES campaign are processed and the MFRSR-derived AODs at 500 nm wavelength are compared with available AODs provided by AERONET measurements. We find that the MFRSR and AERONET AODs are small ({approx}0.05) and comparable. A reasonable quantitative agreement between column aerosol size distributions (up to 2 um) from the MFRSR and AERONET retrievals is illustrated as well. Analysis of the retrieved (MFRSR and AERONET) and in situ measured aerosol size distributions suggests that the contribution of the coarse mode to aerosol optical properties is substantial for several days. The results of a radiative closure experiment performed for the two sites and one-month period show a favorable agreement between the calculated and measured broadband downwelling irradiances (bias does not exceed about 3 Wm-2), and thus imply that the MFRSR-derived aerosol optical properties are reasonable.

Kassianov, Evgueni I.; Barnard, James C.; Pekour, Mikhail S.; Flynn, Connor J.; Ferrare, R.; Hostetler, Chris A.; Hair, John; Jobson, Bertram Thomas

2011-10-01T23:59:59.000Z

385

The Life Cycle of Stratospheric Aerosol Particles  

Science Conference Proceedings (OSTI)

This paper describes the life cycle of the background (nonvolcanic) stratospheric sulfate aerosol. The authors assume the particles are formed by homogeneous nucleation near the tropical tropopause and are carried aloft into the stratosphere. The ...

Patrick Hamill; Eric J. Jensen; P. B. Russell; Jill J. Bauman

1997-07-01T23:59:59.000Z

386

On the Background Stratospheric Aerosol Layer  

Science Conference Proceedings (OSTI)

Balloonborne aerosol particle counter measurements are used in studying the stratospheric sulfate layer at Laramie, Wyoming, during 1978 and 1979, a 2-year volcanically quiescent period in which the layer appears to have been in a near ...

D. J. Hofmann; J. M. Rosen

1981-01-01T23:59:59.000Z

387

Study of Aerosol Indirect Effects in China  

NLE Websites -- All DOE Office Websites (Extended Search)

Aerosol Indirect Effects in China In 2008, the U.S. Department of Energy (DOE)'s Atmospheric Radiation Measurement (ARM) Climate Research Facility is providing the ARM Mobile...

388

Radiative and climate impacts of absorbing aerosols  

E-Print Network (OSTI)

during SHADE: 1. Solar spectrum, J. Geophys. Res . , 108(sensed data in the solar spectrum, J. Geophys. Res , 106 (a scattering aerosol in the solar spectrum with a SSA=1 and

Zhu, Aihua

2010-01-01T23:59:59.000Z

389

A New Method for Measuring Aerosol Absorption  

Science Conference Proceedings (OSTI)

A new technique has recently been developed to measure aerosol absorption by means of a microdensitometer. Black particulate material is collected into six spots on membrane filters by a laboratory-tested impaction/concentration technique. Follow-...

B. B. Murphey; S. I. Reynolds

1988-08-01T23:59:59.000Z

390

Aerosol Transport in the Southern Sierra Nevada  

Science Conference Proceedings (OSTI)

Aerosol transport and meteorology were investigated during 10 days in August 1985, at three elevations in the southern Sierra. Ground weather station and pilot balloon data revealed the diurnal variation of the topographic winds to be remarkably ...

D. M. Ewell; R. G. Flocchini; L. O. Myrup; T. A. Cahill

1989-02-01T23:59:59.000Z

391

Urban Aerosol Impacts on Downwind Convective Storms  

Science Conference Proceedings (OSTI)

The impacts of urban-enhanced aerosol concentrations on convective storm development and precipitation over and downwind of St. Louis, Missouri, are investigated. This is achieved through the use of a cloud-resolving mesoscale model, in which ...

Susan C. van den Heever; William R. Cotton

2007-06-01T23:59:59.000Z

392

Aerosol Best Estimate Value-Added Product  

Science Conference Proceedings (OSTI)

The objective of the Aerosol Best Estimate (AEROSOLBE) value-added product (VAP) is to provide vertical profiles of aerosol extinction, single scatter albedo, asymmetry parameter, and Angstroem exponents for the atmospheric column above the Central Facility at the ARM Southern Great Plains (SGP) site. We expect that AEROSOLBE will provide nearly continuous estimates of aerosol optical properties under a range of conditions (clear, broken clouds, overcast clouds, etc.). The primary requirement of this VAP was to provide an aerosol data set as continuous as possible in both time and height for the Broadband Heating Rate Profile (BBHRP) VAP in order to provide a structure for the comprehensive assessment of our ability to model atmospheric radiative transfer for all conditions. Even though BBHRP has been completed, AEROSOLBE results are very valuable for environmental, atmospheric, and climate research.

Flynn, C; Turner, D; Koontz, A; Chand, D; Sivaraman, C

2012-07-19T23:59:59.000Z

393

Composition and Reactions of Atmospheric Aerosol Particles  

NLE Websites -- All DOE Office Websites (Extended Search)

Composition and Reactions of Atmospheric Aerosol Particles Print Composition and Reactions of Atmospheric Aerosol Particles Print Microscopic aerosol particles in the atmosphere contain carbonaceous components from mineral dust and combustion emissions released from around the world. How long these tiny particles remain in the atmosphere can have a huge impact on the global climate. Measurements based on high-resolution scanning transmission x-ray images obtained at the ALS have revealed chemical reactions on and in atmospheric aerosol particles that caused particle growth while changing organic composition by 13 to 24% per day, an oxidation rate significantly slower than is currently used in atmospheric models. Since oxidation has a strong effect on particle lifetime in the atmosphere, these results will help climate scientists refine the computer models used to predict climate change.

394

ARM - Field Campaign - Aerosol Lidar Validation Experiment -...  

NLE Websites -- All DOE Office Websites (Extended Search)

govCampaignsAerosol Lidar Validation Experiment - ALIVE Campaign Links ALIVE Website Comments? We would love to hear from you Send us a note below or call us at 1-888-ARM-DATA....

395

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

Science Conference Proceedings (OSTI)

In the recent chemistry version (v3.3) of the Weather Research and Forecasting (WRF-Chem) model, we have coupled the Morrison double-moment microphysics scheme with interactive aerosols so that full two-way aerosol-cloud interactions are included in simulations. We have used this new WRF-Chem functionality in a study focused on assessing predictions of aerosols, marine stratocumulus clouds, and their interactions over the Southeast Pacific using measurements from the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) and satellite retrievals. This study also serves as a detailed analysis of our WRF-Chem simulations contributed to the VOCALS model Assessment (VOCA) project. The WRF-Chem 31-day (October 15-November 16, 2008) simulation with aerosol-cloud interactions (AERO hereafter) is also compared to a simulation (MET hereafter) with fixed cloud droplet number concentrations assumed by the default in Morrison microphysics scheme with no interactive aerosols. The well-predicted aerosol properties such as number, mass composition, and optical depth lead to significant improvements in many features of the predicted stratocumulus clouds: cloud optical properties and microphysical properties such as cloud top effective radius, cloud water path, and cloud optical thickness, and cloud macrostructure such as cloud depth and cloud base height. These improvements in addition to the aerosol direct and semi-direct effects, in turn, feed back to the prediction of boundary-layer characteristics and energy budgets. Particularly, inclusion of interactive aerosols in AERO strengths temperature and humidity gradients within capping inversion layer and lowers the MBL depth by 150 m from that of the MET simulation. Mean top-of-the-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 over the remote ocean) and aerosol quantities (e.g., overestimations of supermicron sea salt mass) might affect simulated stratocumulus and energy fluxes over the SEP, and require further investigations. Although not perfect, the overall performance of the regional model in simulating mesoscale aerosol-cloud interactions is encouraging and suggests that the inclusion of spatially varying aerosol characteristics is important when simulating marine stratocumulus over the southeastern Pacific.

Yang, Qing; Gustafson, William I.; Fast, Jerome D.; Wang, Hailong; Easter, Richard C.; Morrison, H.; Lee, Y.- N.; Chapman, Elaine G.; Spak, S. N.; Mena-Carrasco, M. A.

2011-12-02T23:59:59.000Z

396

Climatic Effects of 1950-2050 Changes in US Anthropogenic Aerosols -1 Part 1: Aerosol trends and radiative forcing2  

E-Print Network (OSTI)

Laboratory, Argonne, IL USA18 N. Kumar19 Electric Power Research Institute, Palo Alto, CA USA20 D. Rind21 anthropogenic sources over the 1950-2050 period, based on historical31 emission inventories and future declining post-2010 but at a41 much slower rate since US SO2 emissions have already declined by almost 60

Jacob, Daniel J.

397

ARM - Field Campaign - Aerosol Life Cycle IOP at BNL  

NLE Websites -- All DOE Office Websites (Extended Search)

govCampaignsAerosol Life Cycle IOP at BNL govCampaignsAerosol Life Cycle IOP at BNL Campaign Links Images Wiki 2011 ASR STM Presentation: Sedlacek 2011 ASR STM Presentation: Springston 2010 ASR Fall Meeting: Sedlacek News, June 14, 2011: Next-generation Aerosol-sampling Stations to Head for India Related Campaigns Aerosol Life Cycle: Chemical Ionization Mass Spectrometer - CIMS 2011.07.10, Lee, OSC Aerosol Life Cycle: HR-ToF-AMS 2011.06.15, Zhang, OSC Aerosol Life Cycle: ARM Mobile Facility 2 Aerosol Observing System 2011.06.15, Sedlacek, OSC Aerosol Life Cycle: UV-APS and Nano-SMPS 2011.06.10, Hallar, OSC Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Aerosol Life Cycle IOP at BNL 2011.06.01 - 2011.08.31 Lead Scientist : Arthur Sedlacek For data sets, see below.

398

ARM - Publications: Science Team Meeting Documents: A decade long aerosol  

NLE Websites -- All DOE Office Websites (Extended Search)

A decade long aerosol and cloud statistics and aerosol indirect effect at A decade long aerosol and cloud statistics and aerosol indirect effect at the ARM SGP site Min, Qilong State University of New York at Albany Duan, Minzheng State University of New York at Albany Harrison, Lee State University of New York Joseph, Everette Howard University Twelve-year data of MFRSR and MWR have been used to derive aerosol and cloud optical properties at the ARM SGP. Diurnal, monthly, seasonal and interannual variability of aerosol (optical depth and Angstrom coefficient) and cloud (optical depth and effective radius) have been analyzed. We specially focused on aerosol-cloud interactions. We found a signature of indirect aerosol effect for summer data: increased aerosol index has a statistically-significant anti-correlation with mean effective radius. No

399

DETERMINATION OF RADIAL MOMENTS OF AN AEROSOL  

NLE Websites -- All DOE Office Websites (Extended Search)

DETERMINATION OF RADIAL MOMENTS OF AN AEROSOL DETERMINATION OF RADIAL MOMENTS OF AN AEROSOL SIZE DISTRIBUTION FROM MEASUREMENTS OF LIGHT TRANSMITTANCE AND SCATTERING Ernie R. Lewis and Stephen E. Schwartz Brookhaven National Laboratory, Upton, NY 11933 ses@bnl.gov elewis@bnl.gov MOMENTS FROM MEASUREMENTS As each of the measured quantities is linear in the size distribution dn/dr, it is possible to construct linear combinations of measurements that yield

400

Apparatus for sampling and characterizing aerosols  

DOE Patents (OSTI)

Apparatus for sampling and characterizing aerosols having a wide particle size range at relatively low velocities may comprise a chamber having an inlet and an outlet, the chamber including: a plurality of vertically stacked, successive particle collection stages; each collection stage includes a separator plate and a channel guide mounted transverse to the separator plate, defining a labyrinthine flow path across the collection stage. An opening in each separator plate provides a path for the aerosols from one collection stage t

Dunn, P.F.; Herceg, J.E.; Klocksieben, R.H.

1984-04-11T23:59:59.000Z

Note: This page contains sample records for the topic "direct aerosol forcing" 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

Piezoresistive cantilever force-clamp system  

Science Conference Proceedings (OSTI)

We present a microelectromechanical device-based tool, namely, a force-clamp system that sets or ''clamps'' the scaled force and can apply designed loading profiles (e.g., constant, sinusoidal) of a desired magnitude. The system implements a piezoresistive cantilever as a force sensor and the built-in capacitive sensor of a piezoelectric actuator as a displacement sensor, such that sample indentation depth can be directly calculated from the force and displacement signals. A programmable real-time controller operating at 100 kHz feedback calculates the driving voltage of the actuator. The system has two distinct modes: a force-clamp mode that controls the force applied to a sample and a displacement-clamp mode that controls the moving distance of the actuator. We demonstrate that the system has a large dynamic range (sub-nN up to tens of {mu}N force and nm up to tens of {mu}m displacement) in both air and water, and excellent dynamic response (fast response time, instruments such as a microscope with patch-clamp electronics. We demonstrate the capabilities of the system by using it to calibrate the stiffness and sensitivity of an electrostatic actuator and to measure the mechanics of a living, freely moving Caenorhabditis elegans nematode.

Park, Sung-Jin; Petzold, Bryan C.; Pruitt, Beth L. [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Goodman, Miriam B. [Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305 (United States)

2011-04-15T23:59:59.000Z

402

Examination of the Effects of Sea Salt Aerosols on Southeast Texas Ozone and Secondary Organic Aerosol  

E-Print Network (OSTI)

Despite decades of study, we still do not fully understand aerosols and their interactions among gases or other aerosols in the atmosphere. Among their impacts, they influence radiative transfer in the atmosphere and contribute to cloud formation. There are many different types of aerosols, including dust particles, soot particles, and microscopic particles containing inorganic compounds such as sulfates. Most of these particles have natural origins, but many are anthropogenic. The eventual purpose of this research is to examine sea salt aerosols and their impact on polluted environments. Sea salt aerosols act as Cloud Condensation Nuclei (CCN) as well as providing a surface for heterogeneous reactions. Such reactions have implications for trace gases such as ozone, reactive nitrogen, mercury, and sulfur containing compounds. Urban areas are most impacted by these trace gases, which is a concern because ozone especially affects the health of citizens. Experiments have three basic parts. First we generate mono-disperse 3 aerosols. That aerosol is then injected into the aerosol chambers with sea salt aerosols and prescribed concentrations of trace gases to characterize relevant interactions. However, those chambers are still under construction and not used during my study. The processed aerosols are then analyzed with a tandem differential mobility analyzer (TDMA) and other equipment. Different concentrations of sea salt aerosols, Cl, NOx, and other gases were planned to be introduced during the experiments. Concentrations of other gases and intensity of solar radiation would mimic those outside. Because these reactions have proved to increase localized concentrations of ozone in other work, this could have important implications. Future work will be designed to find study these interactions. This is important because the EPA has considered tightening the standards for both ozone and particulate matter. Industries would then need to reduce emissions or move farther from current sources of Cl or NOx pollution.

Benoit, Mark David

2013-05-01T23:59:59.000Z

403

Constraint and Restoring Force  

E-Print Network (OSTI)

Long-lived sensor network applications must be able to self-repair and adapt to changing demands. We introduce a new approach for doing so: Constraint and Restoring Force. CRF is a physics-inspired framework for computing ...

Beal, Jacob

2007-08-24T23:59:59.000Z

404

Optical Bernoulli forces  

E-Print Network (OSTI)

By Bernoulli's law, an increase in the relative speed of a fluid around a body is accompanied by a decrease in the pressure. Therefore, a rotating body in a fluid stream experiences a force perpendicular to the motion of ...

Movassagh, Ramis

405

Reduction-in-Force  

Energy.gov (U.S. Department of Energy (DOE))

Reduction in force (RIF) is a set of regulations and procedures that are used to determine whether an employee keeps his or her present position, or whether the employee has a right to another...

406

Topographically Forced Convergence in Western Washington State  

Science Conference Proceedings (OSTI)

Several times a year when the low-level winds from off the Pacific Ocean are within a narrow range of speed and direction, air passes both north and south of the Olympic Mountains of Washington State and is forced to converge in Puget Sound by ...

Clifford Mass

1981-06-01T23:59:59.000Z

407

Weak nuclear forces cause the strong nuclear force  

E-Print Network (OSTI)

We determine the strength of the weak nuclear force which holds the lattices of the elementary particles together. We also determine the strength of the strong nuclear force which emanates from the sides of the nuclear lattices. The strong force is the sum of the unsaturated weak forces at the surface of the nuclear lattices. The strong force is then about ten to the power of 6 times stronger than the weak force between two lattice points.

E. L. Koschmieder

2007-12-11T23:59:59.000Z

408

Assessment of the global impact of aerosols on tropospheric oxidants  

E-Print Network (OSTI)

[1] We present here a fully coupled global aerosol and chemistry model for the troposphere. The model is used to assess the interactions between aerosols and chemical oxidants in the troposphere, including (1) the conversion from gas-phase oxidants into the condensed phase during the formation of aerosols, (2) the heterogeneous reactions occurring on the surface of aerosols, and (3) the effect of aerosols on ultraviolet radiation and photolysis rates. The present study uses the global three-dimensional chemical/ transport model, Model for Ozone and Related Chemical Tracers, version 2 (MOZART-2), in which aerosols are coupled with the model. The model accounts for the presence of

Xuexi Tie; Sasha Madronich; Stacy Walters; David P. Edwards; Paul Ginoux; Natalie Mahowald; Renyi Zhang; Chao Lou; Guy Brasseur

2005-01-01T23:59:59.000Z

409

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

Science Conference Proceedings (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

410

Forces on laboratory model dredge cutterhead  

E-Print Network (OSTI)

Dredge cutting forces produced by the movement of the cutterhead through the sediment have been measured with the laboratory dredge carriage located at the Haynes Coastal Engineering Laboratory. The sediment bed that was used for the dredging test was considered to be relatively smooth and the sediment used was sand with a d50=0.27 mm. Forces on the dredge carriage were measured using five 13.3 kN (3000 lb) one directional load cells placed on the dredge ladder in various places so the transmitted cutting forces could be obtained. The objectives for this study are to determine the vertical, horizontal, and axial forces that are produced by the cutterhead while testing. So, to find these cutter forces, a static analysis was performed on the carriage by applying static loads to the cutterhead in the vertical, horizontal, and axial directions, and for each load that was applied, readings were recorded for all five of the load cells. Then, static equilibrium equations were developed for the dredge carriage ladder to determine loads in the five load cells. Also, equilibrium equations can be applied to a dredging test to find the cutterhead forces by taking the measured data from the five load cells and applying the known forces to the equations, and the cutterhead forces can be determined. These static equilibrium equations have been confirmed by using a program called SolidWorks, which is modeling software that can be used to do static finite element analysis of structural systems to determine stresses, displacement, and pin and bolt forces. Data that were gathered from the experimental procedure and the theoretical calculations show that the force on the dredge cutterhead can be determined. However, the results from the static equilibrium calculations and the results from the SolidWorks program were compared to the experiment procedure results, and from the comparison the procedure results show irregularities when a force of approximately 0.889 kN (200 lb) or above is applied to the cutterhead in a north, south, west, or east orientation. The SolidWorks program was used to determine the results for displacements of the dredge carriage ladder system, which showed that large displacements were occurring at the location of the cutterhead, and when the cutterhead displaces it means that the carriage ladder is also moving, which causes false readings in the five load cells. From this analysis it was determined that a sixth force transducer was needed to produce more resistance on the ladder; and the cell #1 location needed to be redesigned to make the ladder system as rigid as possible and able to produce good testing results. The SolidWorks program was used to determine the best location where the sixth force transducer would give the best results, and this location was determined to be on the lower south-west corner oriented in the direction east to west. The static equilibrium equations were rewritten to include the new redesigned cell #1 location and the new location of the sixth load cell. From the new system of equations, forces on the cutterhead can be determined for future dredging studies conducted with the dredge carriage. Finally, the forces on the laboratory cuttersuction dredge model cutterhead were scaled up to the prototype 61 cm (24 in) cuttersuction dredge. These scaled up cutting forces on the dredge cutterhead can be utilized in the design of the swing winches, swing cable size, ladder supports, and ladder.

Young, Dustin Ray

2009-12-01T23:59:59.000Z

411

East Asian Studies of Tropospheric Aerosols and their Impact on Regional Climate (EAST-AIRC): An Overview  

Science Conference Proceedings (OSTI)

As the most populated region of the world, Asia is a major source of aerosols with potential large impact over vast downstream areas. Papers published in this special section describe the variety of aerosols observed in China and their effects and interactions with the regional climate as part of the East Asian Study of Tropospheric Aerosols and Impact on Regional Climate (EAST-AIRC). The majority of the papers are based on analyses of observations made under three field projects, namely, the Atmospheric Radiation Measurements (ARM) Mobile Facility mission in China (AMF10 China), the East Asian Study of Tropospheric Aerosols: an International Regional Experiment (EAST-AIRE), and the Atmospheric Aerosols of China and their Climate Effects (AACCE). The former two are US-China collaborative projects and the latter is a part of the China’s National Basic Research program (or often referred to as “973 project”). Routine meteorological data of China are also employed in some studies. The wealth of general and specialized measurements lead to extensive and close-up investigations of the optical, physical and chemical properties of anthropogenic, natural, and mixed aerosols; their sources, formation and transport mechanisms; horizontal, vertical and temporal variations; direct and indirect effects and interactions with the East Asian monsoon system. Particular efforts are made to advance our understanding of the mixing and interaction between dust and anthropogenic pollutants during transport. Several modeling studies were carried out to simulate aerosol impact on radiation budget, temperature, precipitation, wind and atmospheric circulation, fog, etc. In addition, impacts of the Asian monsoon system on aerosol loading are also simulated.

Li, Zhanqing; Li, C.; Chen, H.; Tsay, S. C.; Holben, B. N.; Huang, J.; Li, B.; Maring, H.; Qian, Yun; Shi, Guangyu; Xia, X.; Yin, Y.; Zheng, Y.; Zhuang, G.

2011-02-01T23:59:59.000Z

412

JGI - Directions  

NLE Websites -- All DOE Office Websites (Extended Search)

Directions Address DOE Joint Genome Institute 2800 Mitchell Drive Walnut Creek, CA 94598 From Oakland Airport Follow Airport exit signs onto AIRPORT DR. Turn RIGHT onto HEGENBERGER...

413

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

SciTech Connect

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 Chemistryâ??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 Earthâ??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

414

Directional Coarsening of Nickel Based Superalloys: Driving Force ...  

Science Conference Proceedings (OSTI)

Since plastic deformation is driven by the elastic energy stored in the .... channels , o, is the applied stress intensity, E, is the .... commercial superalloys [18], when the Orowan process .... dislocation building and contributing to a back-stress for.

415

Work Force Restructuring Activities  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Force Restructuring Activities Force Restructuring Activities December 10, 2008 Note: Current updates are in bold # Planned Site/Contractor HQ Approved Separations Status General * LM has finalized the compilation of contractor management team separation data for the end of FY07 actuals and end of FY08 and FY09 projections. LM has submitted to Congress the FY 2007 Annual Report on contractor work force restructuring activities. The report has been posted to the LM website. *LM conducted a DOE complex-wide data call to the Field and Operations offices for DOE Contractor Management teams to provide, by program, actual contractor separation data for the end of FY 2008 and projections for the end of FY 2009 and FY 2010. The data will be used to keep senior management informed of upcoming large WFR actions.

416

The Response of the Southern Hemisphere Atmospheric Circulation to an Enhanced Greenhouse Gas Forcing  

Science Conference Proceedings (OSTI)

The response of the atmospheric circulation to an enhanced radiative greenhouse gas forcing is investigated. It has been proposed that the response of the climate system to an enhanced forcing projects directly onto the preexisting natural modes ...

Jenny Brandefelt; Erland Källén

2004-11-01T23:59:59.000Z

417

Optical Properties of Atmospheric Aerosol in Maritime Environments  

Science Conference Proceedings (OSTI)

Systematic characterization of aerosol over the oceans is needed to understand the aerosol effect on climate and on transport of pollutants between continents. Reported are the results of a comprehensive optical and physical characterization of ...

Alexander Smirnov; Brent N. Holben; Yoram J. Kaufman; Oleg Dubovik; Thomas F. Eck; Ilya Slutsker; Christophe Pietras; Rangasayi N. Halthore

2002-02-01T23:59:59.000Z

418

ARM - Field Campaign - Carbonaceous Aerosol and Radiative Effects Study  

NLE Websites -- All DOE Office Websites (Extended Search)

govCampaignsCarbonaceous Aerosol and Radiative Effects Study (CARES) govCampaignsCarbonaceous Aerosol and Radiative Effects Study (CARES) Campaign Links CARES Website Related Campaigns Carbonaceous Aerosol and Radiation Effects Study (CARES) - Surface Meteorological Sounding 2010.05.26, Zaveri, OSC Carbonaceous Aerosol and Radiation Effects Study (CARES) Photo-Acoustic Aerosol Light Absorption and Scattering 2010.05.26, Arnott, OSC Carbonaceous Aerosol and Radiative Effects Study (CARES): SMPS & CCN counter deployment during CARES/Cal-NEx 2010.05.04, Wang, OSC Carbonaceous Aerosol and Radiative Effects Study (CARES) Ground Based Instruments 2010.04.01, Cziczo, OSC Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Carbonaceous Aerosol and Radiative Effects Study (CARES)

419

Optical Properties of Aerosol Particles over the Northeast Pacific  

Science Conference Proceedings (OSTI)

In July 2002, atmospheric aerosol measurements were conducted over the northeast Pacific Ocean as part of the Subarctic Ecosystem Response to Iron Enhancement Study (SERIES). The following aerosol quantities were measured: particle number size ...

Julia Marshall; Ulrike Lohmann; W. Richard Leaitch; Nicole Shantz; Lisa Phinney; Desiree Toom-Sauntry; Sangeeta Sharma

2005-08-01T23:59:59.000Z

420

Experimental investigation of aerosol deposition on slot-and...  

NLE Websites -- All DOE Office Websites (Extended Search)

Experimental investigation of aerosol deposition on slot-and joint-type leaks Title Experimental investigation of aerosol deposition on slot-and joint-type leaks Publication Type...

Note: This page contains sample records for the topic "direct aerosol forcing" 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

ARM - Field Campaign - Two-Column Aerosol Project (TCAP): Aerial...  

NLE Websites -- All DOE Office Websites (Extended Search)

Facility (AMF) and the Mobile Aerosol Observing System (MAOS) will be deployed on Cape Cod (MA) for a 12-month period starting in the summer of 2012 in order to quantify aerosol...

422

Dynamical Effects of Aerosol Perturbations on Simulated Idealized Squall Lines  

Science Conference Proceedings (OSTI)

The dynamical effects of increased aerosol loading on the strength and structure of numerically simulated squall lines are explored. Results are explained in the context of RKW theory. Changes in aerosol loading lead to changes in rain drop size ...

Zachary J. Lebo; Hugh Morrison

423

Light Extinction by Aerosols during Summer Air Pollution  

Science Conference Proceedings (OSTI)

In order to utilize satellite measurements of optical thickness over land for estimating aerosol properties during air pollution episodes the optical thickness was measured from the surface and investigated. Aerosol optical thicknesses have been ...

Yoram J. Kaufman; Robert S. Fraser

1983-10-01T23:59:59.000Z

424

Overview of the Cumulus Humilis Aerosol Processing Study  

Science Conference Proceedings (OSTI)

The primary goal of the Cumulus Humilis Aerosol Processing Study (CHAPS) was to characterize and contrast freshly emitted aerosols below, within, and above fields of cumuli, and to study changes to the cloud microphysical structure within these ...

Larry K. Berg; Carl M. Berkowitz; John M. Hubbe; John A. Ogren; Chris A. Hostetler; Richard A. Ferrare; Johnathan W. Hair; Manvendra K. Dubey; Claudio Mazzoleni; Elisabeth Andrews; Richard L. Coulter; Yin-Nan Lee; Jasono Olfert; Stephen R. Springston

2009-11-01T23:59:59.000Z

425

Aerosol Impacts on the Microphysical Growth Processes of Orographic Snowfall  

Science Conference Proceedings (OSTI)

The Regional Atmospheric Modeling System was used to simulate four winter snowfall events over the Park Range of Colorado. For each event, three hygroscopic aerosol sensitivity simulations were performed with initial aerosol profiles representing ...

Stephen M. Saleeby; William R. Cotton; Douglas Lowenthal; Joe Messina

2013-04-01T23:59:59.000Z

426

A Critical Examination of the Observed First Aerosol Indirect Effect  

Science Conference Proceedings (OSTI)

The relative change in cloud droplet number concentration with respect to the relative change in aerosol number concentration, ?, is an indicator of the strength of the aerosol indirect effect and is commonly used in models to parameterize this ...

Hongfei Shao; Guosheng Liu

2009-04-01T23:59:59.000Z

427

Wave-Induced Drift Force in the Marginal Ice Zone  

Science Conference Proceedings (OSTI)

Wind waves are commonly ignored when modeling the ice motion in the marginal ice zone. In order to estimate the importance of the wave forcing, an expression for the second-order wave-induced drift force on a floe exposed to a full directional ...

Diane Masson

1991-01-01T23:59:59.000Z

428

Evaluation of the carbon content of aerosols from the burn- ing of biomass in the Brazilian Amazon using thermal, op- tical and thermal-optical analysis methods  

E-Print Network (OSTI)

Crutzen, P. : Atmospheric Aerosols: Biogeochemical sourcesof optically active aerosol particles over the Amazonproperties of Amazonian aerosol particles: Rev. Geophys. ,

Soto-Garcia, Lydia L.

2012-01-01T23:59:59.000Z

429

A Barotropic Stability Study of Free and Forced Planetary Waves  

Science Conference Proceedings (OSTI)

The stability of free and forced planetary waves in a ? plane channel is investigated with a barotropic model. The equilibrium flows that are considered have the gravest possible scale in the meridional direction and a zonal wavenumber of either ...

John Fyfe; Jacques Derome

1986-10-01T23:59:59.000Z

430

Stratospheric Forcing of Surface Climate in the Arctic Oscillation  

Science Conference Proceedings (OSTI)

Diagnostic results are presented indicating that during the Arctic oscillation surface climate variations are directly forced by changes in the strength of the stratospheric polar vortex. To be specific, large-scale potential vorticity anomalies ...

Robert X. Black

2002-02-01T23:59:59.000Z

431

Electron Diamagnetic Effect on Axial Force in an Expanding Plasma: Experiments and Theory  

SciTech Connect

The axial force imparted from a magnetically expanding current-free plasma is directly measured for three different experimental configurations and compared with a two-dimensional fluid theory. The force component solely resulting from the expanding field is directly measured and identified as an axial force produced by the azimuthal current due to an electron diamagnetic drift and the radial component of the magnetic field. The experimentally measured forces are well described by the theory.

Takahashi, Kazunori [Space Plasma, Power and Propulsion Laboratory, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia); Department of Electrical Engineering and Computer Science, Iwate University, Morioka 020-8551 (Japan); Lafleur, Trevor; Charles, Christine; Alexander, Peter; Boswell, Rod W. [Space Plasma, Power and Propulsion Laboratory, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia)

2011-12-02T23:59:59.000Z

432

Observations of Saharan Aerosols: Results of ECLATS Field Experiment. Part I: Optical Thicknesses and Aerosol Size Distributions  

Science Conference Proceedings (OSTI)

A series of ground-based and airborne observations of desert aerosols, the ECLATS experiment was carried out in December 1980 in the vicinity of Niamey (Niger). This paper deals with aerosol optical thicknesses and size distributions derived from ...

Y. Fouquart; B. Bonnel; M. Chaoui Roquai; R. Santer; A. Cerf

1987-01-01T23:59:59.000Z

433

Emission-Induced Nonlinearities in the Global Aerosol System: Results from the ECHAM5-HAM Aerosol-Climate Model  

Science Conference Proceedings (OSTI)

In a series of simulations with the global ECHAM5-HAM aerosol-climate model, the response to changes in anthropogenic emissions is analyzed. Traditionally, additivity is assumed in the assessment of the aerosol climate impact, as the underlying ...

Philip Stier; Johann Feichter; Silvia Kloster; Elisabetta Vignati; Julian Wilson

2006-08-01T23:59:59.000Z

434

Possible Aerosol Effects on Ice Clouds via Contact Nucleation  

Science Conference Proceedings (OSTI)

The indirect effect of aerosols on water clouds, whereby aerosol particles change cloud optical properties, is caused by aerosol-induced changes of the size and number of cloud droplets. This affects the lifetime of the water clouds as well as ...

Ulrike Lohmann

2002-02-01T23:59:59.000Z

435

Discrete-element modeling of particulate aerosol flows  

Science Conference Proceedings (OSTI)

A multiple-time step computational approach is presented for efficient discrete-element modeling of aerosol flows containing adhesive solid particles. Adhesive aerosol particulates are found in numerous dust and smoke contamination problems, including ... Keywords: Aerosols, Aggregation, Particle adhesion, Particulate flow

J. S. Marshall

2009-03-01T23:59:59.000Z

436

Researchers Model Impact of Aerosols Over California  

NLE Websites -- All DOE Office Websites (Extended Search)

Researchers Model Researchers Model Impact of Aerosols Over California Researchers Model Impact of Aerosols Over California Research may clarify the effectiveness of regional pollution controls May 28, 2013 | Tags: Climate Research, Hopper Contact: Linda Vu, lvu@lbl.gov, (510) 495-2404 LosAngelesSmogv1.jpg Smog over downtown Los Angeles. Aerosols are microscopic particles-like dust, pollen and soot-that ubiquitously float around in our atmosphere. Despite their tiny stature, these particles can have a huge impact on human health, climate and the environment. So scientists from the Pacific Northwest National Laboratory (PNNL), Colorado State University and the California Air Resources Board have set out to characterize the roles of various particles as atmospheric change agents on a regional scale.

437

Morphology effects on polydispersed aerosol deposition rates  

Science Conference Proceedings (OSTI)

In the analysis of severe nuclear accidents, accurate prediction of aerosol deposition is important since, among other things, this influences the distribution of radioactive decay heat within the primary system and containment compartments. The fact that the aerosol cloud is not comprised of dense isolated spherical particles of only one size inevitably complicates such calculations but must be taken into account. Some particle deposition mechanisms are more sensitive to particle size and morphology than others so that simplifying assumptions valid for one mechanism [such as particle thermophoresis (notoriously size and morphology insensitive)] may be seriously in error for others (e.g., convective Brownian diffusion or eddy impaction). This paper deals with aggregate aerosol deposition.

Rosner, D.E.; Tandon, P. [Yale Univ., New Haven, CT (United States); Khalil, Y.F. [Northeast Utilities Service Co., Berlin, CT (United States)

1997-12-01T23:59:59.000Z

438

Can aerosols be trapped in open flows?  

E-Print Network (OSTI)

The fate of aerosols in open flows is relevant in a variety of physical contexts. Previous results are consistent with the assumption that such finite-size particles always escape in open chaotic advection. Here we show that a different behavior is possible. We analyze the dynamics of aerosols both in the absence and presence of gravitational effects, and both when the dynamics of the fluid particles is hyperbolic and nonhyperbolic. Permanent trapping of aerosols much heavier than the advecting fluid is shown to occur in all these cases. This phenomenon is determined by the occurrence of multiple vortices in the flow and is predicted to happen for realistic particle-fluid density ratios.

Rafael D. Vilela; Adilson E. Motter

2007-06-10T23:59:59.000Z

439

Omni-directional railguns  

DOE Patents (OSTI)

This invention is comprised of a device for electromagetically accelerating projectiles. The invention features two parallel conducting circular plates, a plurality of electrode connections to both upper and lower plates, a support base, and a projectile magazine. A projectile is spring-loaded into a firing position concentrically located between the parallel plates. A voltage source is applied to the plates to cause current to flow in directions defined by selectable, discrete electrode connections on both upper and lower plates. Repulsive Lorentz forces are generated to eject the projectile in a 360 degree range of fire.

Shahinpoor, M.

1994-12-31T23:59:59.000Z

440

A multi-sensor approach for assessing the impacts of ultraviolet-absorbing aerosols on top of atmosphere radiative fluxes  

Science Conference Proceedings (OSTI)

One year (June 2006-May 2007) of the Clouds and the Earth's Radiant Energy System (CERES) top of atmosphere (TOA) shortwave (SW) and longwave (LW) fluxes are used with Ozone Monitoring Instrument-Aerosol Index (OMI-AI) data to assess the direct radiative ...

Thomas A. Jones; Sundar A. Christopher

2011-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "direct aerosol forcing" 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

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

Science Conference Proceedings (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

442

between Photolytic Aerosols and Solar Radiation  

E-Print Network (OSTI)

Since the early 70’s chemistry and transport models (ChTMs) have been proposed and improved. Tropospheric ChTMs for trace species are detailed numerical formulations intended to represent the atmospheric system as a whole, accounting for all the individual processes and phenomena that influence climate changes. The development of computer resources and the retrieval of emission inventories and observational data of the species of interest have enhanced the model evolution towards three-dimensional global models that account for more complicated chemical mechanisms, wet and dry deposition phenomena, and interactions and feedback mechanisms between meteorology and atmospheric chemistry. The purpose of this study is to ascertain the sensitivity of the solar radiative field in the atmosphere to absorption and scattering by aerosols. This effort is preliminary to the study of feedback mechanisms between photolytic processes that create and destroy aerosols and the radiation field itself. In this study, a cloud of water-soluble aerosols, randomly distributed in space within hypothetical 1-cm cubes of atmosphere, is generated. A random radius is assigned to each aerosol according to a lognormal size distribution function. The radiative field characterization is analyzed using a Mie scattering code to determine the scattering phase function and the absorption and scattering coefficients of sulfate aerosols, and a Monte Carlo ray-trace code is used to evaluate the radiative exchange. The ultimate goal of the effort is to create a tool to analyze the vertical distribution of absorption by aerosols in order to determine whether or not feedback between photolytic processes and the radiation field needs to be included in a Third Generation Chemistry and Transport model. ii

María Santa; María Iruzubieta; María Santa; María Iruzubieta

2001-01-01T23:59:59.000Z

443

Spatial and temporal variations of aerosols around Beijing in summer 2006: 2. Local and column aerosol optical properties  

SciTech Connect

Weather Research and Forecasting (WRF)-chem model calculations were conducted to study aerosol optical properties around Beijing, China, during the Campaign of Air Quality Research in Beijing and Surrounding Region 2006 (CAREBeijing-2006) period. In this paper, we interpret aerosol optical properties in terms of aerosol mass concentrations and their chemical compositions by linking model calculations with measurements. In general, model calculations reproduced observed features of spatial and temporal variations of various surface and column aerosol optical parameters in and around Beijing. Spatial and temporal variations of aerosol absorption, scattering, and extinction coefficient corresponded well to those of elemental carbon (primary aerosol), sulfate (secondary aerosol), and the total aerosol mass concentration, respectively. These results show that spatial and temporal variations of the absorption coefficient are controlled by local emissions (within 100 km around Beijing during the preceding 24 h), while those of the scattering coefficient are controlled by regional-scale emissions (within 500 km around Beijing during the preceding 3 days) under synoptic-scale meteorological conditions, as discussed in our previous study of aerosol mass concentration. Vertical profiles of aerosol extinction revealed that the contribution of secondary aerosols and their water uptake increased with altitude within the planetary boundary layer, leading to a considerable increase in column aerosol optical depth (AOD) around Beijing. These effects are the main factors causing differences in regional and temporal variations between particulate matter (PM) mass concentration at the surface and column AOD over a wide region in the northern part of the Great North China Plain.

Matsui, Hitoshi; Koike, Makoto; Kondo, Yutaka; Takegawa, Nobuyuki; Fast, Jerome D.; Poschl, U.; Garland, R. M.; Andreae, M. O.; Wiedensohler, A.; Sugimoto, N.; Zhu, T.

2010-11-23T23:59:59.000Z

444

Apparatus for sampling and characterizing aerosols  

DOE Patents (OSTI)

Apparatus for sampling and characterizing aerosols having a wide particle size range at relatively low velocities may comprise a chamber having an inlet and an outlet, the chamber including: a plurality of vertically stacked, successive particle collection stages; each collection stage includes a separator plate and a channel guide mounted transverse to the separator plate, defining a labyrinthine flow path across the collection stage. An opening in each separator plate provides a path for the aerosols from one collection stage to the next. Mounted within each collection stage are one or more particle collection frames.

Dunn, Patrick F. (Downers Grove, IL); Herceg, Joseph E. (Naperville, IL); Klocksieben, Robert H. (Park Forest, IL)

1986-01-01T23:59:59.000Z

445

Near-Real-Time Measurement of Sea-Salt Aerosol during the SEAS Campaign: Comparison of Emission-Based Sodium Detection with an Aerosol Volatility Technique  

Science Conference Proceedings (OSTI)

The first deployment of an emission-based aerosol sodium detector (ASD), designed to chemically characterize marine aerosols on a near-real-time basis, is reported. Deployment occurred as part of the Shoreline Environment Aerosol Study (SEAS) ...

P. Campuzano-Jost; C. D. Clark; H. Maring; D. S. Covert; S. Howell; V. Kapustin; K. A. Clarke; E. S. Saltzman; A. J. Hynes

2003-10-01T23:59:59.000Z

446

Radially Classified Aerosol Detector for Aircraft-Based Submicron Aerosol Measurements  

Science Conference Proceedings (OSTI)

A radially classified aerosol detector (RCAD) for fast characterization of fine particle size distributions aboard aircraft has been designed and implemented. The measurement system includes a radial differential mobility analyzer and a high-flow,...

Lynn M. Russell; Shou-Hua Zhang; Richard C. Flagan; John H. Seinfeld; Mark R. Stolzenburg; Robert Caldow

1996-06-01T23:59:59.000Z

447

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

448

Force Modulator System  

SciTech Connect

Many metal parts manufacturers use large metal presses to shape sheet metal into finished products like car body parts, jet wing and fuselage surfaces, etc. These metal presses take sheet metal and - with enormous force - reshape the metal into a fully formed part in a manner of seconds. Although highly efficient, the forces involved in forming metal parts also damage the press itself, limit the metals used in part production, slow press operations and, when not properly controlled, cause the manufacture of large volumes of defective metal parts. To date, the metal-forming industry has not been able to develop a metal-holding technology that allows full control of press forces during the part forming process. This is of particular importance in the automotive lightweighting efforts under way in the US automotive manufacturing marketplace. Metalforming Controls Technology Inc. (MC2) has developed a patented press control system called the Force Modulator that has the ability to control these press forces, allowing a breakthrough in stamping process control. The technology includes a series of hydraulic cylinders that provide controlled tonnage at all points in the forming process. At the same time, the unique cylinder design allows for the generation of very high levels of clamping forces (very high tonnages) in very small spaces; a requirement for forming medium and large panels out of HSS and AHSS. Successful production application of these systems testing at multiple stamping operations - including Ford and Chrysler - has validated the capabilities and economic benefits of the system. Although this technology has been adopted in a number of stamping operations, one of the primary barriers to faster adoption and application of this technology in HSS projects is system cost. The cost issue has surfaced because the systems currently in use are built for each individual die as a custom application, thus driving higher tooling costs. This project proposed to better marry the die-specific Force Modulator technology with stamping presses in the form of a press cushion. This system would be designed to operate the binder ring for multiple parts, thus cutting the per-die cost of the technology. This study reports the results of technology field application. This project produced the following conclusions: (1) The Force Modulator system is capable of operating at very high tempos in the stamping environment; (2) The company can generate substantial, controlled holding tonnage (binder ring pressure) necessary to hold high strength steel parts for proper formation during draw operations; (3) A single system can be designed to operate with a family of parts, thus significantly reducing the per-die cost of a FM system; (4) High strength steel parts made with these systems appear to show significant quality improvements; (5) The amounts of steel required to make these parts is typically less than the amounts required with traditional blank-holding technologies; and (6) This technology will aid in the use of higher strength steels in auto and truck production, thus reducing weight and improving fuel efficiency.

Redmond Clark

2009-04-30T23:59:59.000Z

449

ARMY SERVICE FORCES  

Office of Legacy Management (LM)

ARMY SERVICE FORCES ARMY SERVICE FORCES ' -, 1 MANHATTAN ENGINEER DISTRICT --t 4 IN "LPLI RC,' LR io EIDM CIS INTELLIGENCE AND SECURITY DIVISION CHICAGO BRANCH OFFICE i ., -,* - P. 0. Box 6770-A I ' 1 .' CHICAGO 80. ILLINOIS /lvb 15 February 1945 Subject: shipment Security Survey at &Uinckrodt Chemical Works. MEMORANDUM to the Officer in Charge. 1. The Mallinckrodt Chemical Works, St. Louis, Missouri, was contacted by the undersigned on 16 November 1944, for the purpose of -king an investigation to determine security provided shipments of interest to the Manhattan Engineer District. The investigation in- cluded shipments of vital materials originating with the Mallinckrodt Company and those received by them. Particular attention has been given to the future production and shipment schedules of these materials.

450

Anthropogenic NO2 in the Atmosphere: Estimates of the Column Content and Radiative Forcing  

NLE Websites -- All DOE Office Websites (Extended Search)

Anthropogenic NO Anthropogenic NO 2 in the Atmosphere: Estimates of the Column Content and Radiative Forcing A. N. Rublev Institution of Molecular Physics Russian Research Center Kurchatov Institute Moscow, Russia N Chubarova Meteorological Observatory of Moscow State University Moscow, Russia G. Gorchakov Obukhov Institute of Atmospheric Physics Russian Academy of Sciences Moscow, Russia Introduction The work summarizes the different methodical aspects, firstly, the use of atmosphere optical depths presented in Aerosol Robotic Network (AERONET) data for NO 2 column retrievals, and, secondly, its radiative forcing calculated as difference between integral solar fluxes absorbed in the atmosphere with and without NO 2 under given air mass or the sun zenith angle.

451

Understanding Brown Carbon Aerosols and Their Role in Climate Change  

NLE Websites -- All DOE Office Websites (Extended Search)

Brown Carbon Aerosols Brown Carbon Aerosols Tiny aerosol particles in the atmosphere are a possible cause of climate change. Among the many contributors to climate change are aerosols in the atmosphere. These tiny particles suspended in the air come from many sources, some natural and some man-made. Some aerosols are organic (containing carbon), while others are inorganic (such as sea salt and sulfates). Most aerosols reflect sunlight, and some also absorb it. Many of these nanoparticles have severe health effects in addition to climate effects. Human activities that produce aerosols include transportation, industry, and agriculture. Black carbon particles (a component of soot) originating from combustion processes have been known for some time to absorb sunlight and warm the

452

Response of California temperature to regional anthropogenic aerosol  

NLE Websites -- All DOE Office Websites (Extended Search)

Response of California temperature to regional anthropogenic aerosol Response of California temperature to regional anthropogenic aerosol changes Title Response of California temperature to regional anthropogenic aerosol changes Publication Type Journal Article Year of Publication 2008 Authors Novakov, Tihomir, Thomas W. Kirchstetter, Surabi Menon, and Jeffery Aguiar Journal Geophysical Research Letters Volume 35 Issue 19 Abstract In this paper, we compare constructed records of concentrations of black carbon (BC) - an indicator of anthropogenic aerosols - with observed surface temperature trends in California. Annual average BC concentrations in major air basins in California significantly decreased after about 1990, coincident with an observed statewide surface temperature increase. Seasonal aerosol concentration trends are consistent with observed seasonal temperature trends. These data suggest that the reduction in anthropogenic aerosol concentrations contributed to the observed surface temperature increase. Conversely, high aerosol concentrations may lower surface temperature and partially offset the temperature increase of greenhouse gases.

453

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

SciTech Connect

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

454

THE LIFETIME OF AEROSOL DROPLETS IN AMBIENT AIR: CONSIDERATION OF THE EFFECTS OF SURFACTANTS AND CHEMICAL REACTIONS  

E-Print Network (OSTI)

of various urban sulfate aerosol production mechanisms.radius of an evaporating aerosol droplet in which oxidationEnvironment THE LIFETIME OF AEROSOL DROPLETS IN AMBIENT AIR:

Toossi, R.

2013-01-01T23:59:59.000Z

455

The radiative influence of aerosol effects on liquid-phase cumulus clouds based on sensitivity studies with two climate models  

E-Print Network (OSTI)

A global black carbon aerosol model. J Geophys Res 101:of interactions between aerosols and cloud microphysics overby anthropogenic sulfate aerosol. J Geophys Res 106: 5279-

Menon, Surabi; Rotstayn, Leon

2005-01-01T23:59:59.000Z

456

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.

457

Scavenging of Aerosol Particles by Precipitation  

Science Conference Proceedings (OSTI)

Airborne measurements have been made of aerosol particle size distributions (>0.01 ?m) in aged air masses, in the plumes from several coal power plants and a large Kraft paper mill, and in the emissions from a volcano, before and after rain or ...

Lawrence F. Radke; Peter V. Hobbs; Mark W. Eltgroth

1980-06-01T23:59:59.000Z

458

Scanning 6-Wavelength 11-Channel Aerosol Lidar  

Science Conference Proceedings (OSTI)

A transportable multiple-wavelength lidar is presented, which is used for the profiling of optical and physical aerosol properties. Two Nd:YAG and two dye lasers in combination with frequency-doubling crystals emit simultaneously at 355, 400, 532,...

Dietrich Althausen; Detlef Müller; Albert Ansmann; Ulla Wandinger; Helgard Hube; Ernst Clauder; Steffen Zörner

2000-11-01T23:59:59.000Z

459

Secondary Ion Mass Spectrometry of Environmental Aerosols  

Science Conference Proceedings (OSTI)

Atmospheric particles influence many aspects of climate, air quality and human health. Understanding the composition, chemistry and behavior of atmospheric aerosols is a key remaining challenge in improving climate models. Furthermore, particles may be traced back to a particular source based on composition, stable isotope ratios, or the presence of particular surface chemistries. Finally, the characterization of atmospheric particles in the workplace plays an important role in understanding the potential for exposure and environmental and human health effects to engineered and natural nanoscale particles. Secondary ion mass spectrometry (SIMS) is a useful tool in determining any of several aspects of the structure, composition and chemistry of these particles. Often used in conjunction with other surface analysis and electron microscopy methods, SIMS has been used to determine or confirm reactions on and in particles, the presence of particular organic species on the surface of atmospheric aerosols and several other interesting and relevant findings. Various versions of SIMS instruments – dynamic SIMS, time of flight secondary ion mass spectrometry or TOF-SIMS, nanoSIMS – have been used to determine specific aspects of aerosol structure and chemistry. This article describes the strengths of each type of SIMS instrument in the characterization of aerosols, along with guidance on sample preparation, specific characterization specific to the particular information sought in the analysis. Examples and guidance are given for each type of SIMS analysis.

Gaspar, Daniel J.; Cliff, John B.

2010-08-01T23:59:59.000Z

460

Aerosol Condensational Growth in Cloud Formation  

E-Print Network (OSTI)

A code for the quasi-stationary solution of the coupled heat and mass transport equations for aerosols in a finite volume was developed. Both mass and heat are conserved effectively in the volume, which results in a competitive aerosol condensation growth computational model. A further model that couples this competitive aerosol condensation growth computational model with computational fluid dynamics (CFD) software (ANSYS FLUENT) enables the simulation of the realistic atmospheric environment. One or more air parcels, where the aerosols reside, are placed in a very big volume in order to mimic the large atmospheric environment. Mass (water vapor) and heat transportat between the air parcels and the environment facilitates the growth and prevents the parcels from unrealistically overheating. The suppression of cloud condensation nuclei (CCN) growth by high number densities was quantified by our model study. Model