Powered by Deep Web Technologies
Note: This page contains sample records for the topic "aerosol radiative 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.


1

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

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

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

4

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

5

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.

6

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

7

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

8

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

9

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

10

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

11

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

12

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

13

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 0.45ş×0.4ş 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

14

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

15

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

16

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

17

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

18

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

19

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

20

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

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

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

22

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

23

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

24

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

25

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

26

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

27

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

28

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

29

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

30

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

31

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

32

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

33

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

34

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

35

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

36

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

37

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

38

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

39

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

40

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

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

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

42

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.

43

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

44

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...

45

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 Joăo Costa; Ana Maria Silva; Vincenzo Levizzani

2004-12-01T23:59:59.000Z

46

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

47

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

48

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

49

Investigation of Aerosol Sources, Lifetime and Radiative Forcing through Multi-Instrument Data Assimilation  

E-Print Network (OSTI)

as clouds reflect solar radiation and trap outgoing CHAPTEReffectively scatter solar radiation, such as sulfate, reduceF o = 1361W/m 2 (Solar Radiation and Climate Experiement (

Rubin, Juli Irene

2012-01-01T23:59:59.000Z

50

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

51

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

52

Role of aerosols in radiative forcing of climate change: Global mean and uncertainties  

SciTech Connect

Anthropogenically induced climate change is of great current interest because of increases in atmospheric loading of infrared active (greenhouse) gases over the past 150 years and the inferred resultant increase in infrared radiation flux in the troposphere. However, the climate change ascribed to such increases, not to mention predictions of future climate change in response to prospective changes in the earth`s radiation budget, is based virtually entirely on climate model simulations of how the earth`s climate would respond to changes in radiation rather than on empirically established relationships between changes in the earth`s radiation budget and climate change. There is thus an urgent need to evaluate the performance of climate models to ascertain the accuracy with which they represent the changes in temperature and other indicia of climate that have been observed over the industrial period. Such an evaluation, however, requires an accurate assessment of the totality of changes in the earth`s radiation budget in both the longwave (thermal infrared) and shortwave (solar) spectral regions, not just of changes in the longwave due to increased concentrations of long-lived greenhouse gases.

Schwartz, S.E.

1998-10-01T23:59:59.000Z

53

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

54

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, Ĺngström 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

55

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

56

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

57

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

58

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

59

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

60

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

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

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

62

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

63

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

64

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

65

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

66

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

67

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)

68

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

69

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

70

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

71

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

72

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

73

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

74

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...

75

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...

76

ARM - Field Campaign - MArine Stratus Radiation Aerosol and Drizzle  

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

govCampaignsMArine Stratus Radiation Aerosol and Drizzle (MASRAD) IOP govCampaignsMArine Stratus Radiation Aerosol and Drizzle (MASRAD) IOP Campaign Links Science Plan AMF Point Reyes Website AMF Point Reyes Data Plots Related Campaigns MASRAD: Pt. Reyes Stratus Cloud and Drizzle Study 2005.07.07, Coulter, AMF MASRAD: Cloud Condensate Nuclei Chemistry Measurements 2005.07.01, Berkowitz, AMF MASRAD - Aerosol Optical Properties 2005.06.29, Strawa, AMF MASRAD:Sub-Micron Aerosol Measurements 2005.06.20, Wang, AMF MASRAD: Cloud Study from the 2NFOV at Pt. Reyes Field Campaign 2005.06.02, Wiscombe, AMF Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : MArine Stratus Radiation Aerosol and Drizzle (MASRAD) IOP 2005.03.14 - 2005.09.14 Website : http://www.arm.gov/sites/amf/pye/ Lead Scientist : Mark Miller

77

Attractive Optical Forces from Blackbody Radiation  

E-Print Network (OSTI)

Blackbody radiation around hot objects induces ac Stark shifts of the energy levels of nearby atoms and molecules. These shifts are roughly proportional to the fourth power of the temperature and induce a force decaying with the third power of the distance from the object. We explicitly calculate the resulting attractive blackbody optical dipole force for ground state hydrogen atoms. Surprisingly, this force can surpass the repulsive radiation pressure and actually pull the atoms against the radiation energy flow towards the surface with a force stronger than gravity. We exemplify the dominance of the "blackbody force" over gravity for hydrogen in a cloud of hot dust particles. This overlooked force appears relevant in various astrophysical scenarios, in particular, since analogous results hold for a wide class of other broadband radiation sources.

Matthias Sonnleitner; Monika Ritsch-Marte; Helmut Ritsch

2013-02-13T23:59:59.000Z

78

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

79

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

80

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

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

ARM - Field Campaign - Shortwave Radiation and Aerosol Intensive  

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

govCampaignsShortwave Radiation and Aerosol Intensive Observation govCampaignsShortwave Radiation and Aerosol Intensive Observation Periods Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Shortwave Radiation and Aerosol Intensive Observation Periods 1998.08.03 - 1998.08.28 Lead Scientist : Warren Wiscombe For data sets, see below. Summary Wednesday, August 5, 1998: IOP Opening Activities: The IOP updates for the Shortwave/Aerosol/BDRF will be composed from notes taken during briefing sessions lead by Don Cahoon and company each night at the Marland Mansion in Ponca City. IOP Status as of 8/4/98 Weather forecasts indicate that cloudy conditions will prevail for the next few days. The Helicopter is on standby for clear sky conditions. Model output indicates clear sky's may move in later this week.

82

Radiative Forcing of Stationary Planetary Waves  

Science Conference Proceedings (OSTI)

The stationary wave components of the planetary-scale circulation are maintained by topographic forcing and by latent and sensible heat transfers and radiation. These waves have a potential vorticity balance mainly due to vertically differential ...

Leo J. Donner; Hsiao-Lan Kuo

1984-10-01T23:59:59.000Z

83

Radiative Forcing Due to Reactive Gas Emissions  

Science Conference Proceedings (OSTI)

Reactive gas emissions (CO, NOx, VOC) have indirect radiative forcing effects through their influences on tropospheric ozone and on the lifetimes of methane and hydrogenated halocarbons. These effects are quantified here for the full set of ...

T. M. L. Wigley; S. J. Smith; M. J. Prather

2002-09-01T23:59:59.000Z

84

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

85

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

86

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

87

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

88

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

89

Development of Aerosol Models for Radiative Flux Calculations at ARM Sites: Utility of Trajectory Clustering for Characterizing Aerosol Climatology  

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

Development of Aerosol Models for Radiative Flux Development of Aerosol Models for Radiative Flux Calculations at ARM Sites: Utility of Trajectory Clustering for Characterizing Aerosol Climatology E. Andrews Cooperative Institute for Research in the Environment University of Colorado Boulder, Colorado E. Andrews, J. A. Ogren, P. J. Sheridan, and J. M. Harris Climate Monitoring and Diagnostics Laboratory National Oceanic and Atmospheric Administration Boulder, Colorado P. K. Quinn Pacific Marine Environmental Laboratory National Oceanic and Atmospheric Administration Seattle, Washington Abstract The uncertainties associated with assumptions of generic aerosol properties in radiative transfer codes are unknown, which means that these uncertainties are frequently invoked when models and

90

Effects of Aerosols on the Radiative Properties of Clouds  

Science Conference Proceedings (OSTI)

The influence of anthropogenic aerosols, in the form of ship exhaust effluent, on the microphysics and radiative properties of marine stratocumulus is studied using data gathered from the U.K. Met. Office C-130 and the University of Washington C-...

Jonathan P. Taylor; Martin D. Glew; James A. Coakley Jr.; William R. Tahnk; Steven Platnick; Peter V. Hobbs; Ronald J. Ferek

2000-08-01T23:59:59.000Z

91

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

92

Radiative and climate impacts of absorbing aerosols  

E-Print Network (OSTI)

resolved Radiative Transfer Model: MODTRAN……….131 APMEXModerate Imaging Spectroradiometer MODTRAN MODerate spectralprovide by MODTRAN…………………………………………………………………………133 Table 4.2

Zhu, Aihua

2010-01-01T23:59:59.000Z

93

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.

94

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

95

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

96

Reduction of photosynthetically active radiation under extreme stratospheric aerosol loads  

Science Conference Proceedings (OSTI)

The recently published hypothesis that the Cretaceous-Tertiary extinctions might be caused by an obstruction of sunlight is tested by model calculations. First we compute the total mass of stratospheric aerosols under normal atmospheric conditions for four different (measured) aerosol size distributions and vertical profiles. For comparison, the stratospheric dust masses after four volcanic eruptions are also evaluated. Detailed solar radiative transfer calculations are then performed for artificially increased aerosol amounts until the postulated darkness scenario is obtained. Thus we find that a total stratospheric aerosol mass between 1 and 4 times 10/sup 1/ g is sufficient to reduce photosynthesis to 10/sup -3/ of normal. We also infer from this result tha the impact of a 0.4- to 3-km-diameter asteroid or a close encounter with a Halley-size comet may deposit that amount of particulates into the stratosphere. The darkness scenario of Alvarez et al. is thus shown to be a possible extinction mechanism, even with smaller size asteroids of comets than previously estimated.

Gerstl, S.A.W.; Zardecki, A.

1981-08-01T23:59:59.000Z

97

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

98

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

99

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

100

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

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

Influence of cloud-radiative forcing on tropical cyclone structure  

Science Conference Proceedings (OSTI)

We demonstrate how and why cloud-radiative forcing (CRF), the interaction of hydrometeors with longwave and shortwave radiation, can influence tropical cyclone structure through “semi-idealized” integrations of the Hurricane Weather Research and ...

Yizhe Peggy Bu; Robert G. Fovell; Kristen L. Corbosiero

102

Longwave Cloud Radiative Forcing as Determined from Nimbus-7 Observations  

Science Conference Proceedings (OSTI)

Collocated and coincident cloud and outgoing longwave radiation observations taken by experiments on board the Nimbus-7 satellite have been used to infer the daytime longwave cloud-radiative forcing. Through the specification of a time-series of ...

Philip E. Ardanuy; Larry L. Stowe; Arnold Gruber; Mitchell Weiss; Craig S. Long

1989-08-01T23:59:59.000Z

103

Influence of Absorbing Aerosols on the Inference of Solar Surface Radiation Budget and Cloud Absorption  

Science Conference Proceedings (OSTI)

This study addresses the impact of absorbing aerosols on the retrieval of the solar surface radiation budget (SSRB) and on the inference of cloud absorption using multiple global datasets. The data pertain to the radiation budgets at the top of ...

Zhanqing Li

1998-01-01T23:59:59.000Z

104

The Effect of Tropospheric Aerosols on the Earth's Radiation Budget: A Parameterization for Climate Models  

Science Conference Proceedings (OSTI)

Guided by the results of doubling-adding solutions to the equation of radiative transfer, we develop a simple technique for incorporating in climate models the effect of the background tropospheric aerosol on solar radiation. Because the ...

James A. Coakley Jr.; Robert D. Cess; Franz B. Yurevich

1983-01-01T23:59:59.000Z

105

Radiative forcing for changes in tropospheric O{sub 3}  

Science Conference Proceedings (OSTI)

We have evaluated the radiative forcing for assumed changes in tropospheric O{sub 3} in the 500-1650 cm{sup {minus}1} wavenumber range. The radiative forcing calculations were performed as a function of latitude as well as for a globally and seasonally averaged model atmosphere, both in a clear sky approximation and in a model containing a representative cloud distribution. The scenarios involved radiative forcing calculations for O{sub 3} at normal atmospheric abundance and at a tropospheric abundance depleted by 25 ppbv, at each altitude, for all northern hemisphere latitudes. Normal abundances of H{sub 2}O, CO{sub 2}, CH{sub 4}, and N{sub 2}O were included in the calculations. The IR radiative forcing was calculated using a correlated k-distribution radiative transfer model. The tropospheric radiative forcing values are compared to the IPCC formulae for ozone tropospheric forcing as well as other published values to determine the validity of the correlated k-distribution approach to the radiative forcing calculations. The results for the global average atmosphere show agreement with previous results to the order of 10 percent. We conclude that the O{sub 3} forcing is linear in the background abundance and that the radiative forcing for ozone for the globally averaged atmosphere and the latitude averaged radiative forcing in the clear sky approximation are in agreement to within 10 percent. For the case of an atmosphere in which the tropospheric ozone has been depleted by 25 ppbv at all altitudes in the northern hemisphere, the mid latitude zone contributes {approximately}50 percent of the forcing, tropic zone contributes {approximately}37 percent of the forcing and the polar zone contributes {approximately}13 percent of the total forcing.

Grossman, A.S.; Wuebbles, D.J.; Grant, K.E.

1994-06-01T23:59:59.000Z

106

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

107

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

108

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; Michčle Forichon; Olivier Boucher; Zhao-Xin Li

1998-07-01T23:59:59.000Z

109

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

110

Climate Forcing by Changing Solar Radiation  

Science Conference Proceedings (OSTI)

By how much does changing radiation from the sun influence the earth’s climate, presently and in the recent past, compared with other natural and anthropogenic processes? Current knowledge of the amplitudes and timescales of solar radiative ...

Judith Lean; David Rind

1998-12-01T23:59:59.000Z

111

Aerosol Radiative Effects and Single-Scattering Properties in the Tropical Western Pacific  

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

Effects and Single-Scattering Properties Effects and Single-Scattering Properties in the Tropical Western Pacific A. M. Vogelmann and P. J. Flatau Center for Atmospheric Sciences Scripps Institution of Oceanography University of California San Diego, California M. A. Miller, M. J. Bartholomew, and R. M. Reynolds Brookhaven National Laboratory Upton, New York P. J. Flatau University Corporation for Atmospheric Research Naval Research Laboratory Monterey, California K. M. Markowicz Institute of Geophysics University of Warsaw Warsaw, Poland Introduction The Atmospheric Radiation Measurement (ARM) Tropical Western Pacific (TWP) sites are downwind from Southeast Asia where biomass burning occurs and can advect over the tropical warm pool. Previous research (Vogelmann 2001, 2002, 2003) indicates that aerosol forcing was particularly large

112

Vertical Profiles of Aerosol and Radiation and the Influence of a Temperature Inversion: Measurements and Radiative Transfer Calculations  

Science Conference Proceedings (OSTI)

The results of an airborne experiment performed near Mönchengladbach (Germany) in November 1993 are reported. Besides meteorological data, vertical profiles of aerosol properties (number concentration, size distribution) and radiation (...

M. Wendisch; S. Mertes; A. Ruggaber; T. Nakajima

1996-10-01T23:59:59.000Z

113

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

DOE Data Explorer (OSTI)

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

Art Sedlacek

114

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

Science Conference Proceedings (OSTI)

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

Art Sedlacek

2011-08-30T23:59:59.000Z

115

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

116

A Parametric Radiative Forcing Model for Contrail Cirrus  

Science Conference Proceedings (OSTI)

A new parameterized analytical model is presented to compute the instantaneous radiative forcing (RF) at the top of the atmosphere (TOA) produced by an additional thin contrail cirrus layer (called “contrail” below). The model calculates the RF ...

U. Schumann; B. Mayer; K. Graf; H. Mannstein

2012-07-01T23:59:59.000Z

117

Global Relationships among the Earth's Radiation Budget, Cloudiness, Volcanic Aerosols, and Surface Temperature  

Science Conference Proceedings (OSTI)

The analyses of Cess are extended to consider global relationships among the earth's radiation budget (including solar insulation and changes in optically active gass), cloudiness, solar constant, volcanic aerosols, and surface temperature. ...

Philip E. Ardanuy; H. Lee Kyle; Douglas Hoyt

1992-10-01T23:59:59.000Z

118

A Model of the Radiative Properties of the EL Chichon Stratospheric Aerosol Layer  

Science Conference Proceedings (OSTI)

An accurate multiple-scattering model has been employed to examine the effect of an aerosol layer at 25 mb, corresponding to the EL Chichon observations, on the reflection, transmission and absorption of radiation by the stratosphere as a ...

Michael D. King; Harshvardhan; Albert Arking

1984-07-01T23:59:59.000Z

119

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

120

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.

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

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.

122

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...

123

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

124

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

125

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

126

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

127

Radiative Forcing of Simulated Tropical Cloud Clusters  

Science Conference Proceedings (OSTI)

A number of field experiments and subsequent studies in the 1970s and 1980s have led to the belief that radiative processes play a more significant role in the evolution of tropical mesoscale convective systems (MCSS) than was once thought. In ...

Rosemary Auld Miller; William M. Frank

1993-02-01T23:59:59.000Z

128

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

129

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

130

Apparatus having reduced background for measuring radiation activity in aerosol particles  

DOE Patents (OSTI)

Apparatus having reduced background for measuring radiation activity in aerosol particles. A continuous air monitoring sampler is described for use in detecting the presence of alpha-emitting aerosol particles. An inlet fractionating screen has been demonstrated to remove about 95% of freshly formed radon progeny from the aerosol sample, and approximately 33% of partially aged progeny. Addition of an electrical condenser and a modified dichotomous virtual impactor are expected to produce considerable improvement in these numbers, the goal being to enrich the transuranic (TRU) fraction of the aerosols. This offers the possibility of improving the signal-to-noise ratio for the detected alpha-particle energy spectrum in the region of interest for detecting TRU materials associated with aerosols, thereby enhancing the performance of background-compensation algorithms for improving the quality of alarm signals intended to warn personnel of potentially harmful quantities of TRU materials in the ambient air.

Rodgers, John C. (Santa Fe, NM); McFarland, Andrew R. (College Station, TX); Oritz, Carlos A. (Bryan, TX); Marlow, William H. (College Station, TX)

1992-01-01T23:59:59.000Z

131

ARM - Publications: Science Team Meeting Documents: Cloud Radiative Forcing  

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

Cloud Radiative Forcing at the ARM Climate Research Facility: Part 2. The Cloud Radiative Forcing at the ARM Climate Research Facility: Part 2. The Vertical Redistribution of Radiant Energy by Clouds. Mace, Gerald University of Utah Benson, Sally University of Utah Kato, Seiji Hampton University/NASA Langley Research Center Documentation with data of the effects of clouds on the radiant energy balance of the surface and atmosphere represent a critical shortcoming in the set of observations that are needed to ascertain the validity of model simulations of the earth's climate. While clouds are known to cool the climate system from TOA radiation budget studies, the redistribution of energy between the surface and atmosphere and within the atmosphere by clouds has not been examined in detail. Using data collected at the Atmospheric Radiation Measurement Program (ARM) Southern Great Plains (SGP)

132

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

Science Conference Proceedings (OSTI)

Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic) emissions in the production and transformation of atmospheric aerosol and the resulting impact on climate change. The U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program's Carbonaceous Aerosol and Radiative Effects Study (CARES) carried out in June 2010 in Central Valley, California, was a comprehensive effort designed to improve this understanding. The primary objective of the field study was to investigate the evolution of secondary organic and black carbon aerosols and their climate-related properties in the Sacramento urban plume as it was routinely transported into the forested Sierra Nevada foothills area. Urban aerosols and trace gases experienced significant physical and chemical transformations as they mixed with the reactive biogenic hydrocarbons emitted from the forest. Two heavily-instrumented ground sites - one within the Sacramento urban area and another about 40 km to the northeast in the foothills area - were set up to characterize the evolution of meteorological variables, trace gases, aerosol precursors, aerosol size, composition, and climate-related properties in freshly polluted and 'aged' urban air. On selected days, the DOE G-1 aircraft was deployed to make similar measurements upwind and across the evolving Sacramento plume in the morning and again in the afternoon. The NASA B-200 aircraft, carrying remote sensing instruments, was also deployed to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties within and around the plume. This overview provides: a) the scientific background and motivation for the study, b) the operational and logistical information pertinent to the execution of the study, c) an overview of key observations and initial results from the aircraft and ground-based sampling platforms, and d) a roadmap of planned data analyses and focused modeling efforts that will facilitate the integration of new knowledge into improved representations of key aerosol processes in climate models.

Zaveri, Rahul A.; Shaw, William J.; Cziczo, D. J.; Schmid, Beat; Ferrare, R.; Alexander, M. L.; Alexandrov, Mikhail; Alvarez, R. J.; Arnott, W. P.; Atkinson, D.; Baidar, Sunil; Banta, Robert M.; Barnard, James C.; Beranek, Josef; Berg, Larry K.; Brechtel, Fred J.; Brewer, W. A.; Cahill, John F.; Cairns, Brian; Cappa, Christopher D.; Chand, Duli; China, Swarup; Comstock, Jennifer M.; Dubey, Manvendra K.; Easter, Richard C.; Erickson, Matthew H.; Fast, Jerome D.; Floerchinger, Cody; Flowers, B. A.; Fortner, Edward; Gaffney, Jeffrey S.; Gilles, Mary K.; Gorkowski, K.; Gustafson, William I.; Gyawali, Madhu S.; Hair, John; Hardesty, Michael; Harworth, J. W.; Herndon, Scott C.; Hiranuma, Naruki; Hostetler, Chris A.; Hubbe, John M.; Jayne, J. T.; Jeong, H.; Jobson, Bertram T.; Kassianov, Evgueni I.; Kleinman, L. I.; Kluzek, Celine D.; Knighton, B.; Kolesar, K. R.; Kuang, Chongai; Kubatova, A.; Langford, A. O.; Laskin, Alexander; Laulainen, Nels S.; Marchbanks, R. D.; Mazzoleni, Claudio; Mei, F.; Moffet, Ryan C.; Nelson, Danny A.; Obland, Michael; Oetjen, Hilke; Onasch, Timothy B.; Ortega, Ivan; Ottaviani, M.; Pekour, Mikhail S.; Prather, Kimberly A.; Radney, J. G.; Rogers, Ray; Sandberg, S. P.; Sedlacek, Art; Senff, Christoph; Senum, Gunar; Setyan, Ari; Shilling, John E.; Shrivastava, ManishKumar B.; Song, Chen; Springston, S. R.; Subramanian, R.; Suski, Kaitlyn; Tomlinson, Jason M.; Volkamer, Rainer M.; Wallace, Hoyt A.; Wang, J.; Weickmann, A. M.; Worsnop, Douglas R.; Yu, Xiao-Ying; Zelenyuk, Alla; Zhang, Qi

2012-08-22T23:59:59.000Z

133

Surface Solar Radiation Flux and Cloud Radiative Forcing for the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP): A Satellite, Surface Observations, and Radiative Transfer Model Study  

Science Conference Proceedings (OSTI)

This study presents surface solar radiation flux and cloud radiative forcing results obtained by using a combination of satellite and surface observations interpreted by means of a simple plane-parallel radiative transfer model called 2001. This ...

Catherine Gautier; Martin Landsfeld

1997-05-01T23:59:59.000Z

134

Sensitivity of Clear-Sky Diffuse Radiation to In Situ Aerosol Scattering Parameters  

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

Sensitivity of Clear-Sky Diffuse Radiation to In Situ Sensitivity of Clear-Sky Diffuse Radiation to In Situ Aerosol Scattering Parameters P. J. Ricchiazzi and C. Gautier University of California Santa Barbara, California Introduction Recent studies of clear-sky radiation indicate that current radiative transfer (RT) models underestimate atmospheric absorption when standard aerosol properties are used. This so-called clear-sky anomaly is manifested in predicted levels of diffuse radiation significantly below those observed at Southern Great Plains (SGP) and other sites in the continental United States (e.g., Halthore et al. 1998 GRL). Other observations at pristine sites do not show a discrepancy (Barnard and Powell 2001, 2001; Kato et al. 1997; Halthore 1998). These results may indicate that the clear-sky anomaly is only observed at sites

135

Solar radiative heating in the presence of aerosols  

Science Conference Proceedings (OSTI)

A theoretical study is carried out to evaluate the effects of aerosols on the shortwave flux divergence in the lower troposphere (0-2 km) by using four computational methods: Gauss-Seidel iteration, a reference method by which all orders of scattering ...

P. Halpern; K. L. Coulson

1978-03-01T23:59:59.000Z

136

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

137

"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

138

The Link between Summertime Cloud Radiative Forcing and Extratropical Cyclones in the North Pacific  

Science Conference Proceedings (OSTI)

This paper examines the role of extratropical cyclones in determining the cloud radiative forcing over the North Pacific during summer. Specifically, this study uses daily and monthly ERBE cloud radiative forcing, monthly ISCCP cloud-type ...

C. P. Weaver; V. Ramanathan

1996-09-01T23:59:59.000Z

139

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

140

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

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

Radiative Forcing of Climate By Ice-Age Atmospheric Dust  

E-Print Network (OSTI)

During glacial periods, dust deposition rates and inferred atmospheric concentrations were globally much higher than present. According to recent model results, the large enhancement of atmospheric dust content at the last glacial maximum (LGM) can be explained only if increases in the potential dust source areas are taken into account. Such increases are to be expected, due to e#ects of low precipitation and low atmospheric (CO 2 ) on plant growth. Here the modelled three-dimensional dust fields from Mahowald et al. and modelled seasonally varying surface-albedo fields derived in a parallel manner, are used to quantify the mean radiative forcing due to modern (non-anthropogenic) and LGM dust. The e#ect of mineralogical provenance on the radiative properties of the dust is taken into account, as is the range of optical properties associated with uncertainties about the mixing state of the dust particles. The high-latitude (poleward of 45#) mean change in forcing (LGM minus modern) is estimated to be small (--0.9 to +0.2 W m ), especially when compared to nearly --20 W m due to reflection from the extended ice sheets. Although the net e#ect of dust over ice sheets is a positive forcing (warming), much of the simulated high-latitude dust was not over the ice sheets, but over unglaciated regions close to the expanded dust source region in central Asia. In the tropics the change in forcing is estimated to be overall negative, and of similarly large magnitude (--2.2 to --3.2 W m ) to the radiative cooling e#ect of low atmospheric (CO 2 ). Thus, the largest long-term climatic e#ect of the LGM dust is likely to have been a cooling of the tropics. Low tropical sea-surface temperatures, low atmospheric (CO 2 ) and high atmospheric dust loading may be mutually reinforcin...

T. Claquin; C. Roelandt; K.E. Kohfeld; S.P. Harrison; I. Tegen; I.C. Prentice; Y. Balkanski; Prentice Ć Y. Balkanski; G. Bergametti; Ć N. Mahowald; Ć M. Schulz; M. Schulz; Ć K. E. Kohfeld; Ć K. E. Kohfeld; C. Roelandt; C. Roelandt; Ć S. P. Harrison; Ć S. P. Harrison; Ć S. P. Harrison; G. Bergametti; H. Rodhe; Ć H. Rodhe; M. Hansson; M. Hansson; N. Mahowald; N. Mahowald

2003-01-01T23:59:59.000Z

142

Impact of Shortwave Radiative Effects of Dust Aerosols on the Summer Season Heat Low over Saudi Arabia  

Science Conference Proceedings (OSTI)

A two-stream scattering scheme based on the delta-Eddington approximation is incorporated into the Florida State University Limited Area Model for computing the shortwave radiative fluxes due to dust aerosols over the Saudi Arabian region and to ...

Saad Mohalfi; H. S. Bedi; T. N. Krishnamurti; Steven D. Cocke

1998-12-01T23:59:59.000Z

143

Final report. [Impact of tropospheric aerosols on the past surface radiation income: Calibration with ARM site data  

DOE Green Energy (OSTI)

This work involved a comparison of surface solar radiation observations from the SOCMET-DATA BASE from 1960-1990 and results from a General Circulation Model to test and evaluate the effects of tropospheric aerosols on clouds.

Kukla, George

2001-03-15T23:59:59.000Z

144

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

145

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

146

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

147

Measurement and Modeling of Vertically Resolved Aerosol Optical Properties and Radiative Fluxes Over the ARM SGP Site During the May 2003 Aerosol IOP  

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

Measurement and Modeling Measurement and Modeling of Vertically Resolved Aerosol Optical Properties and Radiative Fluxes Over the ARM SGP Site During the May 2003 Aerosol IOP B. Schmid and J. Redemann Bay Area Environmental Research Institute National Aeronautics and Space Administration Ames Research Center Moffett Field, California W. P. Arnott Desert Research Institute Reno, Nevada A. Bucholtz and J. Reid Naval Research Laboratory Monterey, California P. Colarco Earth System Science Interdisciplinary Center University of Maryland College Park, Maryland D. Covert and R. Elleman University of Washington Seattle, Washington J. Eilers, P. Pilewskie, and A. Strawa National Aeronautics and Space Administration Ames, Research Center Moffett Field, California R. A. Ferrare

148

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

149

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

150

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.

151

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

152

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

153

Transport and Mixing Patterns over Central California during the Carbonaceous Aerosol and Radiative Effects Study (CARES)  

SciTech Connect

We describe the synoptic and regional-scale meteorological conditions that affected the transport and mixing of trace gases and aerosols in the vicinity of Sacramento, California during June 2010 when the Carbonaceous Aerosol and Radiative Effects Study (CARES) was conducted. The meteorological measurements collected by various instruments deployed during the campaign and the performance of the chemistry version of the Weather Research and Forecasting model (WRF-Chem) are both discussed. WRF-Chem was run daily during the campaign to forecast the spatial and temporal variation of carbon monoxide emitted from 20 anthropogenic source regions in California to guide aircraft sampling. The model is shown to reproduce the overall circulations and boundary-layer characteristics in the region, although errors in the upslope wind speed and boundary-layer depth contribute to differences in the observed and simulated carbon monoxide. Thermally-driven upslope flows that transported pollutants from Sacramento over the foothills of the Sierra Nevada occurred every afternoon, except during three periods when the passage of mid-tropospheric troughs disrupted the regional-scales flow patterns. The meteorological conditions after the passage of the third trough were the most favorable for photochemistry and likely formation of secondary organic aerosols. Meteorological measurements and model forecasts indicate that the Sacramento pollutant plume was likely transported over a downwind site that collected trace gas and aerosol measurements during 23 periods; however, direct transport occurred during only eight of these periods. The model also showed that emissions from the San Francisco Bay area transported by intrusions of marine air contributed a large fraction of the carbon monoxide in the vicinity of Sacramento, suggesting that this source likely affects local chemistry. Contributions from other sources of pollutants, such as those in the Sacramento Valley and San Joaquin Valley, were relatively low. Aerosol layering in the free troposphere was observed during the morning by an airborne Lidar; WRF-Chem forecasts showed that mountain venting processes contributed to aged pollutants aloft in the valley atmosphere which then can be entrained into the growing boundary layer the subsequent day.

Fast, Jerome D.; Gustafson, William I.; Berg, Larry K.; Shaw, William J.; Pekour, Mikhail S.; Shrivastava, ManishKumar B.; Barnard, James C.; Ferrare, R.; Hostetler, Chris A.; Hair, John; Erickson, Matthew H.; Jobson, Tom; Flowers, Bradley; Dubey, Manvendra K.; Springston, Stephen R.; Pirce, Bradley R.; Dolislager, Leon; Pederson, J. R.; Zaveri, Rahul A.

2012-02-17T23:59:59.000Z

154

Transport and mixing patterns over Central California during the carbonaceous aerosol and radiative effects study (CARES)  

SciTech Connect

We describe the synoptic and regional-scale meteorological conditions that affected the transport and mixing of trace gases and aerosols in the vicinity of Sacramento, California during June 2010 when the Carbonaceous Aerosol and Radiative Effects Study (CARES) was conducted. The meteorological measurements collected by various instruments deployed during the campaign and the performance of the chemistry version of the Weather Research and Forecasting model (WRF-Chem) are both discussed. WRF-Chem was run daily during the campaign to forecast the spatial and temporal variation of carbon monoxide emitted from 20 anthropogenic source regions in California to guide aircraft sampling. The model is shown to reproduce the overall circulations and boundary-layer characteristics in the region, although errors in the upslope wind speed and boundary-layer depth contribute to differences in the observed and simulated carbon monoxide. Thermally-driven upslope flows that transported pollutants from Sacramento over the foothills of the Sierra Nevada occurred every afternoon, except during three periods when the passage of mid-tropospheric troughs disrupted the regional-scale flow patterns. The meteorological conditions after the passage of the third trough were the most favorable for photochemistry and likely formation of secondary organic aerosols. Meteorological measurements and model forecasts indicate that the Sacramento pollutant plume was likely transported over a downwind site that collected trace gas and aerosol measurements during 23 time periods; however, direct transport occurred during only eight of these periods. The model also showed that emissions from the San Francisco Bay area transported by intrusions of marine air contributed a large fraction of the carbon monoxide in the vicinity of Sacramento, suggesting that this source likely affects local chemistry. Contributions from other sources of pollutants, such as those in the Sacramento Valley and San Joaquin Valley, were relatively low. Aerosol layering in the free troposphere was observed during the morning by an airborne Lidar. WRF-Chem forecasts showed that mountain venting processes contributed to aged pollutants aloft in the valley atmosphere that are then entrained into the growing boundary layer the subsequent day.

Fast J. D.; Springston S.; Gustafson Jr., W. I.; Berg, L. K.; Shaw, W. J.; Pekour, M.; Shrivastava, M.; Barnard, J. C.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. A.; Erickson, M.; Jobson, B. T.; Flowers, B.; Dubey, M. K.; Pierce, R. B.; Dolislager, L.; Pederson, J.; Zaveri, R. A.

2012-02-17T23:59:59.000Z

155

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

156

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

157

Aerosol Optical Properties in the Iranian Region Obtained by Ground-Based Solar Radiation Measurements in the Summer Of 1991  

Science Conference Proceedings (OSTI)

Solar radiation measurements were made using sun photometers and pyranometers during 31 May-7 June 1991 at several places in Iran and during 12 June-17 September 1991 at a fixed place, Bushehr, Iran. In the first period the aerosol optical ...

Teruyuki Nakajima; Tadahiro Hayasaka; Akiko Higurashi; Gen Hashida; Naser Moharram-Nejad; Yahya Najafi; Hamzeh Valavi

1996-08-01T23:59:59.000Z

158

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

159

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

160

DOE/SC-ARM-10-018 CARES: Carbonaceous Aerosol and Radiative  

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

8 8 CARES: Carbonaceous Aerosol and Radiative Effects Study Operations Plan June 2010 RA Zaveri Principal Investigator WJ Shaw DJ Cziczo DISCLAIMER This report was prepared as an account of work sponsored by the U.S. Government. Neither the United States nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or

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

Wave–Current Interaction: A Comparison of Radiation-Stress and Vortex-Force Representations  

Science Conference Proceedings (OSTI)

The vortex-force representation of the wave-averaged effects on currents is compared to the radiation-stress representation in a scaling regime appropriate to coastal and shelf waters. Three-dimensional and vertically integrated expressions for ...

E. M. Lane; J. M. Restrepo; J. C. McWilliams

2007-05-01T23:59:59.000Z

162

Simulations of Contrail Optical Properties and Radiative Forcing for Various Crystal Shapes  

Science Conference Proceedings (OSTI)

The aim of this study is to investigate the sensitivity of radiative-forcing computations to various contrail crystal shape models. Contrail optical properties in the shortwave and longwave ranges are derived using a ray-tracing geometric method ...

Krzysztof M. Markowicz; Marcin L. Witek

2011-08-01T23:59:59.000Z

163

The Role of Longwave Radiation and Boundary Layer Thermodynamics in Forcing Tropical Surface Winds  

Science Conference Proceedings (OSTI)

This paper reveals major deficiencies of the existing intermediate climate models for tropical surface winds and elaborates the important roles of cloud-longwave radiational forcing and boundary layer thermodynamics in driving the tropical ...

Xiouhua Fu; Bin Wang

1999-04-01T23:59:59.000Z

164

Reproducibility by Climate Models of Cloud Radiative Forcing Associated with Tropical Convection  

Science Conference Proceedings (OSTI)

In this study, cloud radiative forcing (CRF) associated with convective activity over tropical oceans is analyzed for monthly mean data from twentieth-century simulations of 18 climate models participating in phase 3 of the Coupled Model ...

Hiroki Ichikawa; Hirohiko Masunaga; Yoko Tsushima; Hiroshi Kanzawa

2012-02-01T23:59:59.000Z

165

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

166

Developments in the CSU-RAMS Aerosol Model: Emissions, Nucleation, Regeneration, Deposition, and Radiation  

Science Conference Proceedings (OSTI)

The Colorado State University – Regional Atmospheric Modeling System (RAMS) has undergone development focused upon improving the treatment of aerosols in the microphysics model, with the goal of examining the impacts of aerosol characteristics, ...

Stephen M. Saleeby; Susan C. Van Den Heever

167

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

168

Abstract Aerosols can affect the cloud-radiation feedback and the precipitation over the Indian monsoon region. In this paper, we propose that another pathway by  

E-Print Network (OSTI)

monsoon region. In this paper, we propose that another pathway by which aerosols can modulate the multi-scale aspect of Indian monsoons is by altering the land­atmosphere interactions. The nonlinear feedbacks due to aerosol/diffuse radiation on coupled interactions over the Indian monsoon region are studied by: (1

Niyogi, Dev

169

Demonstrating the Potential for First-Class Research in Underdeveloped Countries: Research on Stratospheric Aerosols and Cirrus Clouds Optical Properties, and Radiative Effects in Cuba (1988–2010)  

Science Conference Proceedings (OSTI)

Optical properties of stratospheric aerosols and cirrus clouds and their radiative effects are currently important subjects of research worldwide. Those investigations are typical of developed countries, conducted by several highly specialized groups ...

Juan Carlos Antuńa Marrero; René Estevan Arredondo; Boris Barja González

2012-07-01T23:59:59.000Z

170

An Ultralight Aircraft as Platform for Research in the Lower Troposphere: System Performance and First Results from Radiation Transfer Studies in Stratiform Aerosol Layers and Broken Cloud Conditions  

Science Conference Proceedings (OSTI)

The ultraviolet actinic radiation flux governing the photochemical reactions in the atmosphere is dependent on the optical properties of atmospheric aerosols and reflective surfaces of ground and clouds. Theoretical models exist for horizontal ...

Wolfgang Junkermann

2001-06-01T23:59:59.000Z

171

Using Surface Remote Sensors to Derive Mixed-Phase Cloud Radiative Forcing:  

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

Using Surface Remote Sensors to Derive Mixed-Phase Cloud Radiative Forcing: Using Surface Remote Sensors to Derive Mixed-Phase Cloud Radiative Forcing: An Example from M-PACE Title Using Surface Remote Sensors to Derive Mixed-Phase Cloud Radiative Forcing: An Example from M-PACE Publication Type Journal Article Year of Publication 2011 Authors de Boer, Gijs, William D. Collins, Surabi Menon, and Charles N. Long Journal Atmospheric Chemistry and Physics Volume 11 Start Page 11937 Pagination 11937-11949 Abstract Measurements from ground-based cloud radar, high spectral resolution lidar and microwave radiometer are used in conjunction with a column version of the Rapid Radiative Transfer Model (RRTMG) and radiosonde measurements to derive the surface radiative properties under mixed-phase cloud conditions. These clouds were observed during the United States Department of Energy (US DOE) Atmospheric Radiation Measurement (ARM) Mixed-Phase Arctic Clouds Experiment (M-PACE) between September and November of 2004. In total, sixteen half hour time periods are reviewed due to their coincidence with radiosonde launches. Cloud liquid (ice) water paths are found to range between 11.0-366.4 (0.5-114.1) gm-2, and cloud physical thicknesses fall between 286-2075 m. Combined with temperature and hydrometeor size estimates, this information is used to calculate surface radiative flux densities using RRTMG, which are demonstrated to generally agree with measured flux densities from surface-based radiometric instrumentation. Errors in longwave flux density estimates are found to be largest for thin clouds, while shortwave flux density errors are generally largest for thicker clouds. A sensitivity study is performed to understand the impact of retrieval assumptions and uncertainties on derived surface radiation estimates. Cloud radiative forcing is calculated for all profiles, illustrating longwave dominance during this time of year, with net cloud forcing generally between 50 and 90 Wm-2.

172

Estimation and Model Validation of Surface Solar Radiation and Cloud Radiative Forcing Using TOGA COARE Measurements  

Science Conference Proceedings (OSTI)

The Tropical Ocean and Global Atmosphere Coupled Ocean–Atmosphere Response Experiment (TOGA COARE) radiation measurements in the western Pacific warm pool are used to estimate surface solar radiation budgets and to validate radiation model ...

Ming-Dah Chou; Wenzhong Zhao

1997-04-01T23:59:59.000Z

173

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

174

Aerosol-Cloud-Radiation Interaction Studies with GEOS-4 Model and Comparison with Observations .  

E-Print Network (OSTI)

??Increasing human population and rapid urbanization in the last two decades have caused a sharp rise in anthropogenic aerosols particularly over South and East Asia.… (more)

Bhattacharjee, Partha Sarathi

2011-01-01T23:59:59.000Z

175

Aerosol-Cloud-Radiation Interaction Studies with GEOS-4 model and Comparison with Observations.  

E-Print Network (OSTI)

?? Increasing human population and rapid urbanization in the last two decades have caused a sharp rise in anthropogenic aerosols particularly over South and East… (more)

Bhattacharjee, Partha Sarathi

2011-01-01T23:59:59.000Z

176

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.

177

A Climatology of Midlatitude Continental Clouds from the ARM SGP Central Facility. Part II: Cloud Fraction and Surface Radiative Forcing  

Science Conference Proceedings (OSTI)

Data collected at the Department of Energy Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Central Facility (SCF) are analyzed to determine the monthly and hourly variations of cloud fraction and radiative forcing between ...

Xiquan Dong; Baike Xi; Patrick Minnis

2006-05-01T23:59:59.000Z

178

The Significance of Cloud–Radiative Forcing to the General Circulation on Climate Time Scales—A Satellite Interpretation  

Science Conference Proceedings (OSTI)

Cloud–radiative forcing calculations based on Nimbus-7 radiation budget and cloudiness measurements reveal that cloud-induced longwave (LW) warming (cloud greenhouse influence) is dominant over the tropics, whereas cloud-induced shortwave (SW) ...

Byung-Ju Sohn; Eric A. Smith

1992-05-01T23:59:59.000Z

179

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

180

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

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

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

182

RCP4.5: A Pathway for Stabilization of Radiative Forcing by 2100  

SciTech Connect

Representative Concentration Pathway (RCP) 4.5 is a scenario that stabilizes radiative forcing at 4.5 W m{sup -2} in the year 2100 without ever exceeding that value. Simulated with the Global Change Assessment Model (GCAM), RCP4.5 includes long-term, global emissions of greenhouse gases, short-lived species, and land-use-land-cover in a global economic framework. RCP4.5 was updated from earlier GCAM scenarios to incorporate historical emissions and land cover information common to the RCP process and follows a cost-minimizing pathway to reach the target radiative forcing. The imperative to limit emissions in order to reach this target drives changes in the energy system, including shifts to electricity, to lower emissions energy technologies and to the deployment of carbon capture and geologic storage technology. In addition, the RCP4.5 emissions price also applies to land use emissions; as a result, forest lands expand from their present day extent. The simulated future emissions and land use were downscaled from the regional simulation to a grid to facilitate transfer to climate models. While there are many alternative pathways to achieve a radiative forcing level of 4.5 W m{sup -2}, the application of the RCP4.5 provides a common platform for climate models to explore the climate system response to stabilizing the anthropogenic components of radiative forcing.

Thomson, Allison M.; Calvin, Katherine V.; Smith, Steven J.; Kyle, G. Page; Volke, April C.; Patel, Pralit L.; Delgado Arias, Sabrina; Bond-Lamberty, Benjamin; Wise, Marshall A.; Clarke, Leon E.; Edmonds, James A.

2011-07-29T23:59:59.000Z

183

Numerical Simulation of Transient Boundary-Forced Radiation. Part II: The Modon Regime  

Science Conference Proceedings (OSTI)

In Part I of the present work we studied the transient Rossby wave radiation excited in the far field by a northern boundary forcing. We proposed as a possible mechanism responsible for transient pulses of Rossby waves the sudden growth to finite ...

Paola Malanotte-Rizzoli; Roberta E. Young; Dale B. Haidvogel

1988-11-01T23:59:59.000Z

184

Absorption of Visible Radiation by Atmospheric Aerosol Particles Fog and Cloud Water Residues  

Science Conference Proceedings (OSTI)

Light absorption by samples of atmospheric aerosol particles as a function of size was studied using the integrating sphere method. In addition, the optical properties of fog and cloud-water residues were determined. The samples were taken at two ...

Karl Andre; Ralph Dlugi; Gottfried Schnatz

1981-01-01T23:59:59.000Z

185

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

186

Aerosol Indirect Effects on Tropical Convection Characteristics under Conditions of Radiative–Convective Equilibrium  

Science Conference Proceedings (OSTI)

The impacts of enhanced aerosol concentrations such as those associated with dust intrusions on the trimodal distribution of tropical convection have been investigated through the use of large-domain (10 000 grid points), fine-resolution (1 km), ...

Susan C. van den Heever; Graeme L. Stephens; Norman B. Wood

2011-04-01T23:59:59.000Z

187

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

E-Print Network (OSTI)

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

Cziczo, Daniel James

188

Dynamic Effects on the Tropical Cloud Radiative Forcing and Radiation Budget  

Science Conference Proceedings (OSTI)

Vertical velocity is used to isolate the effect of large-scale dynamics on the observed radiation budget and cloud properties in the tropics, using the methodology suggested by Bony et al. Cloud and radiation budget quantities in the tropics show ...

Jian Yuan; Dennis L. Hartmann; Robert Wood

2008-06-01T23:59:59.000Z

189

Investigation of Aerosol Sources, Lifetime and Radiative Forcing through Multi-Instrument Data Assimilation  

E-Print Network (OSTI)

and D.C. Robertson. Modtran: A moderate resolution model forradiative transfer code, MODTRAN, which allows insertion ofproperties inserted into MODTRAN, a dataset with hundreds of

Rubin, Juli Irene

2012-01-01T23:59:59.000Z

190

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

191

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

192

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

193

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

194

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

195

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.

196

Aerosol Characteristics and Radiative Impacts over the Arabian Sea during the Intermonsoon Season: Results from ARMEX Field Campaign  

Science Conference Proceedings (OSTI)

During the second phase of the Arabian Sea Monsoon Experiment (ARMEX-II), extensive measurements of spectral aerosol optical depth, mass concentration, and mass size distribution of ambient aerosols as well as mass concentration of aerosol black ...

K. Krishna Moorthy; S. Suresh Babu; S. K. Satheesh

2005-01-01T23:59:59.000Z

197

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

198

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

199

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.

200

Implications of Representative Concentration Pathway 4.5 Methane Emissions to Stabilize Radiative Forcing  

SciTech Connect

Increases in the abundance of methane (CH4) in the Earth’s atmosphere are responsible for significant radiative forcing of climate change (Forster et al., 2007; Wuebbles and Hayhoe, 2002). Since 1750, a 2.5 fold increase in atmospheric CH4 contributed 0.5 W/m2 to direct radiative forcing and an additional 0.2 W/m2 indirectly through changes in atmospheric chemistry. Next to water and carbon dioxide (CO2), methane is the most abundant greenhouse gas in the troposphere. Additionally, CH4 is significantly more effective as a greenhouse gas on a per molecule basis than is CO2, and increasing atmospheric CH4 has been second only to CO2 in radiative forcing (Forster et al., 2007). The chemical reactivity of CH4 is important to both tropospheric and stratospheric chemistry. Along with carbon monoxide, methane helps control the amount of the hydroxyl radical (OH) in the troposphere where oxidation of CH4 by OH leads to the formation of formaldehyde, carbon monoxide, and ozone.

Emanuel, William R.; Janetos, Anthony C.

2013-02-01T23:59:59.000Z

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

Antarctic Cloud Radiative Forcing at the Surface Estimated from the AVHRR Polar Pathfinder and ISCCP D1 Datasets, 1985–93  

Science Conference Proceedings (OSTI)

Surface cloud radiative forcing from the newly extended Advanced Very High Resolution Radiometer (AVHRR) Polar Pathfinder (APP-x) dataset and surface cloud radiative forcing calculated using cloud and surface properties from the International ...

Michael J. Pavolonis; Jeffrey R. Key

2003-06-01T23:59:59.000Z

202

Multi-Dimensional Effects in Longwave Radiative Forcing of PBL Clouds  

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

Multi-Dimensional Effects in Longwave Radiative Forcing of PBL Clouds D. B. Mechem and Y. L. Kogan Cooperative Institute for Mesoscale Meteorological Studies University of Oklahoma Norman, Oklahoma M. Ovtchinnikov Pacific Northwest National Laboratory Richland, Washington K. F. Evans University of Colorado Boulder, Colorado A. B. Davis Los Alamos National Laboratory Los Alamos, New Mexico R. F. Cahalan National Aeronautic and Space Administration Goddard Space Flight Center Greenbelt, Maryland E. E. Takara and R. G. Ellingson Florida State University Tallahassee, Florida 1. Introduction Numerical cloud models nearly universally employ one-dimensional (1D) treatments of radiative transfer (RT). Radiative transfer is typically implemented as a 2- or 4-stream approximation to the

203

The Sensitivity of Latent Heat Flux to Changes in the Radiative Forcing: A Framework for Comparing Models and Observations  

Science Conference Proceedings (OSTI)

A climate model must include an accurate surface physics scheme in order to examine the interactions between the land and atmosphere. Given an increase in the surface radiative forcing, the sensitivity of latent heat flux to available energy ...

Jonathan M. Winter; Elfatih A. B. Eltahir

2010-05-01T23:59:59.000Z

204

Arctic Ocean Radiative Fluxes and Cloud Forcing Estimated from the ISCCP C2 Cloud Dataset, 1983?1990  

Science Conference Proceedings (OSTI)

Radiative fluxes and cloud forcings for the ocean areas of the Arctic are computed from the monthly cloud product of the International Satellite Cloud Climatology Project (ISCCP) for 1983?90. Spatially averaged short-wave fluxes compare well with ...

Axel J. Schweiger; Jeffrey R. Key

1994-08-01T23:59:59.000Z

205

The Interactions among Cyclone Dynamics, Vertical Thermodynamic Structure, and Cloud Radiative Forcing in the North Atlantic Summertime Storm Track  

Science Conference Proceedings (OSTI)

This study investigates the changes in the vertical thermodynamic structure of the troposphere associated with the passage of cyclones and the corresponding influence on cloud radiative forcing (CRF). The focus is the synoptic-scale evolution of ...

C. P. Weaver

1999-08-01T23:59:59.000Z

206

The Sensitivity of Latent Heat Flux to Changes in the Radiative Forcing: A Framework for Comparing Models and Observations  

E-Print Network (OSTI)

A climate model must include an accurate surface physics scheme in order to examine the interactions between the land and atmosphere. Given an increase in the surface radiative forcing, the sensitivity of latent heat flux ...

Winter, Jonathan (Jonathan Mark)

207

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...

208

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

209

Role of radiation reaction forces in the dynamics of centrifugally accelerated particles  

Science Conference Proceedings (OSTI)

In this paper we study the influence of radiation reaction (RR) forces on the dynamics of centrifugally accelerated particles. It is assumed that the particles move along magnetic field lines anchored in the rotating central object. The common 'bead-on-the-wire' approximation is used. The solutions are found and analyzed for cases when the form of the prescribed trajectory (rigidly rotating field line) is approximated by: (a) straight line, and (b) Archimedes spiral. Dynamics of neutral and charged particles are compared with the emphasis on the role of RR forces in the latter case. It is shown that for charged particles there exist locations of stable equilibrium. It is demonstrated that for particular initial conditions RR forces cause centripetal motion of the particles: their 'falling' on the central rotating object. It is found that in the case of Archimedes spiral both neutral and charged particles can reach infinity where their motion has asymptotically force-free character. The possible importance of these processes for the acceleration of relativistic, charged particles by rotating magnetospheres in the context of the generation of nonthermal, high-energy emission of AGN and pulsars is discussed.

Dalakishvili, G. T.; Rogava, A. D.; Berezhiani, V. I. [Eugene Kharadze Georgian National Astrophysical Observatory, 2a Kazbegi Avenue, Tbilisi-0160(Georgia); Ivane Javakhishvili Tbilisi State University, Faculty of Natural and Exact Sciences, Physics Department, 3, Chavchavadze Avenue, 0128 Tbilisi (Georgia); Centre for Plasma Astrophysics, K.U. Leuven, Celestijnenlaan 200B, 3001 Leuven (Belgium) and Abdus Salam International Centre for Theoretical Physics, Trieste I-34014 (Italy); Graduate School of Frontier Sciences, University of Tokyo, 5-1-5-Kashiwanoha, Kashiwa-shi, Chiba 277-8561 (Japan); Institute of Physics, 6 Tamarashvili Street., 0177 Tbilisi (Georgia)

2007-08-15T23:59:59.000Z

210

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...

211

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

212

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

213

Aerosol Retrievals from Individual AVHRR Channels. Part I: Retrieval Algorithm and Transition from Dave to 6S Radiative Transfer Model  

Science Conference Proceedings (OSTI)

The present second-generation aerosol retrieval algorithm over oceans used at NOAA/National Environmental Satellite, Data, and Information Service (NESDIS) separately retrieves two values of aerosol optical depth, ?1 and ?2, from Advanced Very ...

Alexander Ignatov; Larry Stowe

2002-02-01T23:59:59.000Z

214

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

215

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

216

Thermal correction to the Casimir force, radiative heat transfer, and an experiment  

E-Print Network (OSTI)

The low-temperature asymptotic expressions for the Casimir interaction between two real metals described by Leontovich surface impedance are obtained in the framework of thermal quantum field theory. It is shown that the Casimir entropy computed using the impedance of infrared optics vanishes in the limit of zero temperature. By contrast, the Casimir entropy computed using the impedance of the Drude model attains at zero temperature a positive value which depends on the parameters of a system, i.e., the Nernst heat theorem is violated. Thus, the impedance of infrared optics withstands the thermodynamic test, whereas the impedance of the Drude model does not. We also perform a phenomenological analysis of the thermal Casimir force and of the radiative heat transfer through a vacuum gap between real metal plates. The characterization of a metal by means of the Leontovich impedance of the Drude model is shown to be inconsistent with experiment at separations of a few hundred nanometers. A modification of the impedance of infrared optics is suggested taking into account relaxation processes. The power of radiative heat transfer predicted from this impedance is several times less than previous predictions due to different contributions from the transverse electric evanescent waves. The physical meaning of low frequencies in the Lifshitz formula is discussed. It is concluded that new measurements of radiative heat transfer are required to find out the adequate description of a metal in the theory of electromagnetic fluctuations.

V. B. Bezerra; G. Bimonte; G. L. Klimchitskaya; V. M. Mostepanenko; C. Romero

2007-08-18T23:59:59.000Z

217

Observed Perturbations of the Earth's Radiation Budget: A Response to the El Chichón Stratospheric Aerosol Layer?  

Science Conference Proceedings (OSTI)

The Earth Radiation Budget experiment, launched aboard the Nimbus-7 polar-orbiting spacecraft in late 1978, has now taken over seven years of measurements. The dataset, which is global in coverage, consists of the individual components of the ...

Philip E. Ardanuy; H. Lee Kyle

1986-04-01T23:59:59.000Z

218

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

219

State-Space Realization of the Wave-Radiation Force within FAST: Preprint  

DOE Green Energy (OSTI)

Several methods have been proposed in the literature to find a state-space model for the wave-radiation forces. In this paper, four methods were compared, two in the frequency domain and two in the time domain. The frequency-response function and the impulse response of the resulting state-space models were compared against the ones derived by the numerical code WAMIT. The implementation of the state-space module within the FAST offshore wind turbine computer-aided engineering (CAE) tool was verified, comparing the results against the previously implemented numerical convolution method. The results agreed between the two methods, with a significant reduction in required computational time when using the state-space module.

Duarte, T.; Sarmento, A.; Alves, M.; Jonkman, J.

2013-06-01T23:59:59.000Z

220

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

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

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

222

The effect of horizontal resolution on cloud radiative forcing in the ECMWF model. PCMDI report No. 22  

SciTech Connect

With expanding computer capability and capacity there has been considerable interest in increasing the resolution in GCMs. The primary driving force behind this are two fold: (1) increased resolution may reduce the systematic errors inherent in parameterization of sub-grid scale processes, and (2) higher resolution may improve confidence in regional scale studies of climatic features that are orographically influenced -- such as the effect of the Tibetan Plateau on the East Asian Monsoon. This study focuses on the effect of horizontal resolution on the spatial and temporal systematic errors of cloud radiative forcing and its components. In this paper, the top-of-the-atmosphere radiation fields are taken from a series of simulations using the European Centre for Medium Range Forecasts (ECMWF) general circulation model (cycle 33), run at four different horizontal resolutions. Section 2 discusses the concept of cloud radiative forcing and describes the simulations from the ECMWF model. The observed global field of cloud forcing from ERBE is presented in section 3 along with the model-produced fields of the net solar and longwave cloud forcing. The seasonal effect of forcing is described in section 4, and the results are summarized in section 5.

Potter, G.L.

1995-05-01T23:59:59.000Z

223

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

224

Relating Secondary Organic Aerosol Characteristics with Cloud Condensation Nuclei Activity  

E-Print Network (OSTI)

and absorb solar and terrestrial radiation, influence cloudand absorb solar and terrestrial radiation, influence cloudand absorption of solar and thermal radiation by aerosol

Tang, Xiaochen

2013-01-01T23:59:59.000Z

225

Periodicity, Thermal Effects, and Vacuum Force: Rotation in Random Classical Zero-Point Radiation  

E-Print Network (OSTI)

We show that for a detector rotating in a random classical zero-point electromagnetic or massless scalar field at T=0 thermal effects exist. The rotating reference system is constructed as an infinite set of Frenet-Seret tetrads defined so that the detector is at rest in a tetrad at each proper time. Correlation functions, more exactly their frequency spectrum, contain the Planck thermal factor, and the energy density the rotating detector observes is proportional to the sum of energy densities of Planck's spectrum at the temperature T_rot = \\hbar \\Omega / (2 \\pi k_B) and zero-point radiation. The proportionality factor is (2/3)(4\\gamma^2 - 1) for an electromagnetic field and (2/9)(4\\gamma^2 - 1) for a massless scalar field, where \\gamma = (1 - (\\Omega r/c)^2)^(-1/2), and r is a detector rotation radius. The origin of these thermal effects is the periodicity of the correlation functions and their discrete spectrum, both following rotation with angular velocity \\Omega. The thermal energy can also be interpreted as a source of a vacuum force, f_vac, applied to the rotating detector from the vacuum field. The f_vac depends on the size of neither the charge nor the mass, like the force in the Casimir model for a charged particle, but, contrary to the last one, it is directed to the center of the circular orbit. The f_vac infinitely grows by magnitude when r \\to r_0 = c/\\Omega, with a fixed \\Omega. The orbits with a radius greater than r_0 do not exist simply because the returning vacuum force becomes infinite. On the uttermost orbit with the radius r_0, a linear velocity of the rotating particle would have become c. The f_vac becomes very small and proportional to r when r is small, r << c/\\aOmega. Such vacuum force dependence on radius, at large and small r, can be associated respectively with so called confinement and asymptotic freedom, known in QCD, and provide a new explanation for them.

Yefim Semenovitch Levin

2010-03-22T23:59:59.000Z

226

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

227

Periodicity, Thermal Effects, and Vacuum Force: Rotation in Random Classical Zero-Point Radiation  

E-Print Network (OSTI)

We show that, for a detector rotating in a random classical zero-point electromagnetic or massless scalar field at zero temperature, thermal effects exist. The rotating reference system is constructed as an infinite set of Frenet-Seret tetrads so that the detector is at rest in a tetrad at each proper time. Frequency spectrum of correlation functions contains the Planck thermal factor with temperature $T_{rot} = \\frac{\\hbar \\Omega}{2 \\pi k_B} $. The energy density the rotating detector observes is proportional to the sum of energy densities of Planck's spectrum at the temperature $T_{rot}$ and zero-point radiation. The proportionality factor is $2/3 (4 \\gamma^2 -1)$ for an EMF and $2/9 (4 \\gamma^2 -1)$ for a MSF, where $\\gamma = (1 - (\\frac{\\Omega r}{c})^2)^{-1/2}$, and r is a rotation radius. The origin of these thermal effects is the periodicity of the correlation functions and their discrete spectrum, both following rotation with angular velocity $\\Omega$. The thermal energy can also be interpreted as a source of a vacuum force (VF) applied to the rotating detector from the vacuum field. The VF depends on the size of neither the charge nor the mass, like the force in the Casimir model for a charged particle, but, contrary to the last one, VF is attractive and directed to the center of the circular orbit. VF infinitely grows in magnitude with orbit radius. The orbits with a radius greater than $c/ \\Omega$ do not exist because the returning VF becomes infinite. On the uttermost orbit with the radius $c / \\Omega$, a linear velocity of the rotating particle would have become c. The VF becomes very small and proportional to radius when r is very small. Such VF dependence on radius, at large and small radii, can be associated respectively with so called confinement and asymptotic freedom, known in quantum chromodynamics, and provide a new explanation for them.

Yefim Semenovitch Levin

2010-03-23T23:59:59.000Z

228

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

229

Evaluation of Cloud Type Occurrences and Radiative Forcings Simulated by a Cloud Resolving Model Using Observations from Sa...  

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

Cloud Type Occurrences Cloud Type Occurrences and Radiative Forcings Simulated by a Cloud Resolving Model Using Observations from Satellite and Cloud Radar Y. Luo and S. K. Krueger University of Utah Salt Lake City, Utah Introduction Because of both the various effects clouds exert on the earth-atmospheric system and the cloud feedback, correct representations of clouds in numerical models are critical for accurate climate modeling and weather forecast. Unfortunately, determination of clouds and their radiative feedback processes is still the weakest component of current general circulation models (e.g., Senior and Mitchell 1993, Cess et al. 1996). Using radiative fluxes at the top of atmosphere (TOA) available from satellite observations made by the Earth Radiation Budget Experiment (ERBE; Barkstrom 1984), one could assess cloud radiative effects

230

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

231

Modeling Tropical Pacific Sea Surface Temperature with Satellite-Derived Solar Radiative Forcing  

Science Conference Proceedings (OSTI)

Two independent datasets for the solar radiation at the surface derived from satellites are compared. The data derived from the Earth Radiation Budget Experiment (ERBE) is for the net solar radiation at the surface whereas the International ...

Richard Seager; M. Benno Blumenthal

1994-12-01T23:59:59.000Z

232

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...

233

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

234

EOS Terra Aerosol and Radiative Flux Validation: An Overview of the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) Experiment  

Science Conference Proceedings (OSTI)

NASA developed an Earth Observing System (EOS) to study global change and reduce uncertainties associated with aerosols and other key parameters controlling climate. The first EOS satellite, Terra, was launched in December 1999. The Chesapeake ...

W. L. Smith Jr.; T. P. Charlock; R. Kahn; J. V. Martins; L. A. Remer; P. V. Hobbs; J. Redemann; C. K. Rutledge

2005-04-01T23:59:59.000Z

235

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

236

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

237

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

238

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

239

The Competition of Freshwater and Radiation in Forcing the Ocean during El Nińo  

Science Conference Proceedings (OSTI)

The relative roles of heat and freshwater fluxes in forcing the tropical Pacific on interannual timescales are investigated using sophisticated atmospheric and oceanic general circulation models.

Niklas Schneider; Tim P. Barnett

1995-05-01T23:59:59.000Z

240

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.

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

The impact of detailed urban-scale processing on the composition, distribution, and radiative forcing of anthropogenic aerosols  

E-Print Network (OSTI)

Detailed urban-scale processing has not been included in global 3D chemical transport models due to its large computational demands. Here we present a metamodel for including this processing, and compare it with the use ...

Cohen, Jason Blake

242

Validation of aerosol extinction and water vapor profiles from routine Atmospheric Radiation Measurement Climate Research Facility measurements  

Science Conference Proceedings (OSTI)

The accuracy with which vertical profiles of aerosol extinction ?ep(?) can be retrieved from ARM Climate Research Facility (ACRF) routine measurements was assessed using data from two airborne field campaigns, the ARM Aerosol Intensive Operation Period (AIOP, May 2003), and the Aerosol Lidar Validation Experiment (ALIVE, September 2005). This assessment pertains to the aerosol at its ambient concentration and thermodynamic state (i.e. ?ep(?) either free of or corrected for sampling artifacts) and includes the following ACRF routine methods: Raman Lidar, Micro Pulse Lidar (MPL) and in-situ aerosol profiles (IAP) with a small aircraft. Profiles of aerosol optical depth ?p(???, from which the profiles of ?ep(???are derived through vertical differentiation, were measured by the NASA Ames Airborne Tracking 14-channel Sunphotometer (AATS-14); these data were used as truth in this evaluation. The ACRF IAP ?ep(550 nm) were lower by 16% (during AIOP) and higher by 10% (during ALIVE) when compared to AATS-14. The ACRF MPL ?ep(523 nm) were higher by 24% (AIOP) and 19%-21% (ALIVE) compared to AATS-14 but the correlation improved significantly during ALIVE. In the AIOP a second MPL operated by NASA showed a smaller positive bias (13%) with respect to AATS-14. The ACRF Raman Lidar ?ep(355 nm) were higher by 54% (AIOP) and higher by 6% (ALIVE) compared to AATS-14. The large bias in AIOP stemmed from a gradual loss of the sensitivity of the Raman Lidar starting about the end of 2001 going unnoticed until after AIOP. A major refurbishment and upgrade of the instrument and improvements to a data-processing algorithm led to the significant improvement and very small bias in ALIVE. Finally we find that during ALIVE the Raman Lidar water vapor densities ?w are higher by 8% when compared to AATS-14, whereas comparisons between AATS-14 and in-situ measured ?w aboard two different aircraft showed small negative biases (0 to -3%).

Schmid, Beat; Flynn, Connor J.; Newsom, Rob K.; Turner, David D.; Ferrare, Richard; Clayton, Marian F.; Andrews, Elisabeth; Ogren, John A.; Johnson, Roy R.; Russell, P. B.; Gore, W.; Dominguez, Roseanne

2009-11-26T23:59:59.000Z

243

Using an AGCM to diagnose historical effective radiative forcing and mechanisms of recent decadal climate change  

Science Conference Proceedings (OSTI)

An atmospheric general circulation model is forced with observed monthly sea-surface-temperature and sea-ice boundary conditions, as well as forcing agents that vary in time, for the period 1979-2008. The simulations are then repeated with various ...

Timothy Andrews

244

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

245

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

246

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

247

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

248

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

249

A scattering approach to Casimir forces and radiative heat transfer for nanostructured surfaces out of thermal equilibrium  

E-Print Network (OSTI)

We develop an exact method for computing Casimir forces and the power of radiative heat transfer between two arbitrary nanostructured surfaces out of thermal equilibrium. The method is based on a generalization of the scattering approach recently used in investigations on the Casimir effect. Analogously to the equilibrium case, we find that also out of thermal equilibrium the shape and composition of the surfaces enter only through their scattering matrices. The expressions derived provide exact results in terms of the scattering matrices of the intervening surfaces.

Giuseppe Bimonte

2009-09-11T23:59:59.000Z

250

Comparison of Aerosol Single Scattering Albedos Derived by Diverse Techniques in Two North Atlantic Experiments  

Science Conference Proceedings (OSTI)

Aerosol single scattering albedo ? (the ratio of scattering to extinction) is important in determining aerosol climatic effects, in explaining relationships between calculated and measured radiative fluxes, and in retrieving aerosol optical ...

P. B. Russell; J. Redemann; B. Schmid; R. W. Bergstrom; J. M. Livingston; D. M. McIntosh; S. A. Ramirez; S. Hartley; P. V. Hobbs; P. K. Quinn; C. M. Carrico; M. J. Rood; E. Öström; K. J. Noone; W. von Hoyningen-Huene; L. Remer

2002-02-01T23:59:59.000Z

251

Application of Sun/star photometry to derive the aerosol optical depth  

Science Conference Proceedings (OSTI)

Atmospheric aerosols play a crucial role in the radiative transfer and chemical processes that control the Earth's climate. Aerosol optical depth and other related aerosol characteristics are widely known during daytime through Sun photometers, and so ...

D. Perez-Ramirez; B. Ruiz; J. Aceituno; F. J. Olmo; L. Alados-Arboledas

2008-09-01T23:59:59.000Z

252

Tropospheric Aerosol Optical Thickness from the GOCART Model and Comparisons with Satellite and Sun Photometer Measurements  

Science Conference Proceedings (OSTI)

The Georgia Institute of Technology–Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model is used to simulate the aerosol optical thickness ? for major types of tropospheric aerosols including sulfate, dust, organic carbon ...

Mian Chin; Paul Ginoux; Stefan Kinne; Omar Torres; Brent N. Holben; Bryan N. Duncan; Randall V. Martin; Jennifer A. Logan; Akiko Higurashi; Teruyuki Nakajima

2002-02-01T23:59:59.000Z

253

Relationship between Cloud Radiative Forcing and Sea Surface Temperatures over the Entire Tropical Oceans  

Science Conference Proceedings (OSTI)

Satellite measurements from January 1985 to December 1989 show that warmer tropical oceans as a whole are associated with less longwave greenhouse effect of clouds and less cloud reflection of solar radiation to the space. The regression slopes ...

M. H. Zhang; R. D. Cess; S. C. Xie

1996-06-01T23:59:59.000Z

254

Radiation Control Coatings Installed on Federal Buildings at Tyndall Air Force Base  

DOE Green Energy (OSTI)

The technical objectives of this CRADA comprise technology deployment and energy conservation efforts with the radiation control coatings industry and the utility sector. The results of this collaboration include a high-level data reporting, analysis and management system to support the deployment efforts. The technical objectives include successfully install, commission, operate, maintain and document the performance of radiation control coatings on roofs at Tyndall AFB and the Buildings Technology Center at the Oak Ridge National Laboratory; determine the life cycle savings that can be achieved by using radiation control coatings on entire roofs at Tyndall AFB, based on documented installed cost and operating maintenance costs with and without the coatings; determine if any specific improvements are required in the coatings before they can be successfully deployed in the federal sector; determine the most effective way to facilitate the widespread and rapid deployment of radiation control coatings in the federal sector; and clearly define any barriers to deployment.

Kaba, R.L.; Petrie, T.W.

1999-03-16T23:59:59.000Z

255

Use of the ARM Measurement of Spectral Zenith Radiance For Better Understanding Of 3D Cloud-Radiation Processes and Aerosol-Cloud Interaction  

Science Conference Proceedings (OSTI)

Our proposal focuses on cloud-radiation processes in a general 3D cloud situation, with particular emphasis on cloud optical depth and effective particle size. We also focus on zenith radiance measurements, both active and passive. The proposal has three main parts. Part One exploits the �¢����solar-background�¢��� mode of ARM lidars to allow them to retrieve cloud optical depth not just for thin clouds but for all clouds. This also enables the study of aerosol cloud interactions with a single instrument. Part Two exploits the large number of new wavelengths offered by ARM�¢����s zenith-pointing ShortWave Spectrometer (SWS), especially during CLASIC, to develop better retrievals not only of cloud optical depth but also of cloud particle size. We also propose to take advantage of the SWS�¢���� 1 Hz sampling to study the �¢����twilight zone�¢��� around clouds where strong aerosol-cloud interactions are taking place. Part Three involves continuing our cloud optical depth and cloud fraction retrieval research with ARM�¢����s 2NFOV instrument by, first, analyzing its data from the AMF-COPS/CLOWD deployment, and second, making our algorithms part of ARM�¢����s operational data processing.

D. Jui-Yuan Chiu

2010-10-19T23:59:59.000Z

256

Gravity Wave Radiation and Mean Responses to Local Body Forces in the Atmosphere  

Science Conference Proceedings (OSTI)

The authors determine the spectral linear solutions that arise in response to local 3D body forces and heatings in an idealized environment that turn on and off smoothly but not necessarily slowly over a finite interval in time. The solutions ...

Sharon L. Vadas; David C. Fritts

2001-08-01T23:59:59.000Z

257

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

258

A research program on radiative, chemical, and dynamical feedback progresses influencing the carbon dioxide and trace gases climate effects: Annual progress report, September 1, 1986--July 15, 1989  

SciTech Connect

This report summarizes the up-to-date progress. The program includes two tasks: atmospheric radiation and climatic effects and their objective is to link quantitatively the radiation forcing changes and the climate responses caused by increasing greenhouse gases. Here, the objective and approach are described. We investigate the combined atmospheric radiation characteristics of the greenhouse gases (H/sub 2/O, CO/sub 2/, CH/sub 4/, N/sub 2/O, CFCs, and O/sub 3/), aerosols and clouds. Since the climatic effect of increasing atmospheric greenhouse gases is initiated by perturabtion to the longwave thermal radiation, it is critical to understand better the radiation characteristics of the greenhouse gases and their relationship to radiatively-important aerosols and clouds; the latter reflect solar radiation (a cooling of the surface) and provide a greenhouse effect (a warming to the surface). Therefore, aerosol and cloud particles are an integral part of the radiation field in the atmosphere. 9 refs.

1989-07-01T23:59:59.000Z

259

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

260

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

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

On the Theory of Continuous-Spin Particles: Helicity Correspondence in Radiation and Forces  

E-Print Network (OSTI)

We have recently shown that continuous-spin particles (CSPs) have covariant single-emission amplitudes with the requisite properties to mediate long-range forces. CSPs, the most general massless particle type consistent with Lorentz symmetry, are characterized by a scale \\rho. Here, we demonstrate a helicity correspondence at CSP energies larger than \\rho, in which these amplitudes are well approximated by the familiar ones for particles of helicity 0, 1, or 2. These properties follow from Lorentz invariance. We also construct tree-level multi-emission and CSP-exchange amplitudes that are unitary, appropriately analytic, and consistent with helicity-0 correspondence. We propose sewing rules from which these amplitudes and others can be obtained. We also exhibit a candidate CSP-graviton matrix element, which shows that the Weinberg-Witten theorem does not apply to CSPs. These results raise the surprising possibility that the known long-range forces might be mediated by CSPs with very small \\rho, rather than by...

Schuster, Philip

2013-01-01T23:59:59.000Z

262

On the Theory of Continuous-Spin Particles: Helicity Correspondence in Radiation and Forces  

E-Print Network (OSTI)

We have recently shown that continuous-spin particles (CSPs) have covariant single-emission amplitudes with the requisite properties to mediate long-range forces. CSPs, the most general massless particle type consistent with Lorentz symmetry, are characterized by a scale \\rho. Here, we demonstrate a helicity correspondence at CSP energies larger than \\rho, in which these amplitudes are well approximated by the familiar ones for particles of helicity 0, 1, or 2. These properties follow from Lorentz invariance. We also construct tree-level multi-emission and CSP-exchange amplitudes that are unitary, appropriately analytic, and consistent with helicity-0 correspondence. We propose sewing rules from which these amplitudes and others can be obtained. We also exhibit a candidate CSP-graviton matrix element, which shows that the Weinberg-Witten theorem does not apply to CSPs. These results raise the surprising possibility that the known long-range forces might be mediated by CSPs with very small \\rho, rather than by helicity 1 and 2 particles.

Philip Schuster; Natalia Toro

2013-02-06T23:59:59.000Z

263

Self-Force in the Radiation Reaction Formula -- Adiabatic Approximation of a Metric Perturbation and an Orbit --  

E-Print Network (OSTI)

We propose a new metric perturbation scheme under a possible constraint of the gauge conditions in which we obtain a physically expected prediction of the orbital evolution caused by the MiSaTaQuWa self-force. In this new scheme of a metric perturbation, an adiabatic approximation is applied to both the metric perturbation and the orbit. As a result, we are able to predict the gravitational evolution of the system in the so-called radiation reaction time scale, which is longer than the dephasing time scale. However, for gravitational wave detection by LISA, this may still be insufficient. We further consider a gauge transformation in this new metric perturbation scheme, and find a special gauge condition with which we can calculate the gravitational waveform of a time scale long enough for gravitational wave detection by LISA.

Yasushi Mino

2005-05-31T23:59:59.000Z

264

Two MODIS Aerosol Products over Ocean on the Terra and Aqua CERES SSF Datasets  

Science Conference Proceedings (OSTI)

Understanding the impact of aerosols on the earth’s radiation budget and the long-term climate record requires consistent measurements of aerosol properties and radiative fluxes. The Clouds and the Earth’s Radiant Energy System (CERES) Science ...

Alexander Ignatov; Patrick Minnis; Norman Loeb; Bruce Wielicki; Walter Miller; Sunny Sun-Mack; Didier Tanré; Lorraine Remer; Istvan Laszlo; Erika Geier

2005-04-01T23:59:59.000Z

265

A Simple Method to Compute the Change in Earth-Atmosphere Radiative Balance Due to a Stratospheric Aerosol Layer  

Science Conference Proceedings (OSTI)

A simple three-layer model of the earth-atmosphere system, including the ground, troposphere and stratosphere, with their interactions, is developed. The model permits the radiative characteristics of both the troposphere and stratosphere to be ...

J. Lenoble; D. Tanre; P. Y. Deschamps; M. Herman

1982-11-01T23:59:59.000Z

266

Improved Sea Ice Shortwave Radiation Physics in CCSM4: The Impact of Melt Ponds and Aerosols on Arctic Sea Ice  

Science Conference Proceedings (OSTI)

The Community Climate System Model, version 4 has revisions across all components. For sea ice, the most notable improvements are the incorporation of a new shortwave radiative transfer scheme and the capabilities that this enables. This scheme ...

Marika M. Holland; David A. Bailey; Bruce P. Briegleb; Bonnie Light; Elizabeth Hunke

2012-03-01T23:59:59.000Z

267

Indirect Impact of Atmospheric Aerosols in Idealized Simulations of Convective–Radiative Quasi Equilibrium. Part II: Double-Moment Microphysics  

Science Conference Proceedings (OSTI)

This paper extends the previous cloud-resolving modeling study concerning the impact of cloud microphysics on convective–radiative quasi equilibrium (CRQE) over a surface with fixed characteristics and prescribed solar input, both mimicking the ...

Wojciech W. Grabowski; Hugh Morrison

2011-04-01T23:59:59.000Z

268

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

269

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

270

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

271

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 :...

272

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...

273

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

274

ARM AOS Processing Status and Aerosol Intensive Properties VAP  

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

Andrews, and P. J. Sheridan National Oceanic and Atmospheric Administration Boulder, Colorado Abstract The Atmospheric Radiation Measurement (ARM) Aerosol Observing System (AOS)...

275

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

276

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

277

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...

278

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

279

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

280

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

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

Stratospheric Aerosol and Gas Experiment II CD-ROM Atlas of Global Monthly Aerosols, Ozone, NO2, Water, Vapor, and Relative Humitidy (1985–1993)  

Science Conference Proceedings (OSTI)

Individual profile measurements from the Stratospheric Aerosol and Gas Experiment II (SAGE II) instrument aboard the Earth Radiation Budget Satellite have been used to create latitude-longitude maps of monthly mean aerosols, ozone, water vapor, ...

D. Rind; X. Liao

1997-01-01T23:59:59.000Z

282

Greenhouse impact due to the use of combustible fuels: Life cycle viewpoint and relative radiative forcing commitment  

SciTech Connect

Extensive information on the greenhouse impacts of various human actions is important in developing effective climate change mitigation strategies. The greenhouse impacts of combustible fuels consist not only of combustion emissions but also of emissions from the fuel production chain and possible effects on the ecosystem carbon storages. It is important to be able to assess the combined, total effect of these different emissions and to express the results in a comprehensive way. In this study, a new concept called relative radiative forcing commitment (RRFC) is presented and applied to depict the greenhouse impact of some combustible fuels currently used in Finland. RRFC is a ratio that accounts for the energy absorbed in the Earth system due to changes in greenhouse gas concentrations (production and combustion of fuel) compared to the energy released in the combustion of fuel. RRFC can also be expressed as a function of time in order to give a dynamic cumulative picture on the caused effect. Varying time horizons can be studied separately, as is the case when studying the effects of different climate policies on varying time scales. The RRFC for coal for 100 years is about 170, which means that in 100 years 170 times more energy is absorbed in the atmosphere due to the emissions of coal combustion activity than is released in combustion itself. RRFC values of the other studied fuel production chains varied from about 30 (forest residues fuel) to 190 (peat fuel) for the 100-year study period. The length of the studied time horizon had an impact on the RRFC values and, to some extent, on the relative positions of various fuels.

Kirkinen, J.; Palosuo, T.; Holmgren, K.; Savolainen, I. [VTT Technical Research Center Finland, Espoo (Finland)

2008-09-15T23:59:59.000Z

283

Ionizing Radiation Dosimetry  

Science Conference Proceedings (OSTI)

Ionizing Radiation Dosimetry. ... OH. US Air Force Radiation Dosimetry Laboratory, Wright-Patterson - Base, OH [100548- 0] PA. ...

2013-09-06T23:59:59.000Z

284

Observed Impact of Atmospheric Aerosols on the Surface Energy Budget  

Science Conference Proceedings (OSTI)

Atmospheric aerosols scatter and potentially absorb incoming solar radiation, thereby reducing the total amount of radiation reaching the surface and increasing the fraction that is diffuse. The partitioning of incoming energy at the surface into ...

Allison L. Steiner; Dori Mermelstein; Susan J. Cheng; Tracy E. Twine; Andrew Oliphant

2013-09-01T23:59:59.000Z

285

Observed impact of atmospheric aerosols on the surface energy budget  

Science Conference Proceedings (OSTI)

Atmospheric aerosols scatter and potentially absorb incoming solar radiation, thereby reducing the total amount of radiation reaching the surface and increasing the fraction that is diffuse. The partitioning of incoming energy at the surface into ...

Allison L. Steiner; Dori Mermelstein; Susan J. Cheng; Tracy E. Twine; Andrew Oliphant

286

Climate Studies with a Multilayer Energy Balance Model. Part III: Climatic Impact of Stratospheric Volcanic Aerosols  

Science Conference Proceedings (OSTI)

The radiative and climatic effects of stratospheric volcanic aerosols are studied with a multilayer energy balance model. The results show that the latitudinal distribution of aerosols has a significant effect on climate sensitivity. When ...

Ming-Dah Chou; Li Peng; Albert Arking

1984-03-01T23:59:59.000Z

287

Different Approaches for Constraining Global Climate Models of the Anthropogenic Indirect Aerosol Effect  

Science Conference Proceedings (OSTI)

Assessments of the influence of aerosol emissions from human activities on the radiation budget, in particular via the modification of cloud properties, have been a challenge. In light of the variability to both aerosol properties and ...

U. Lohmann; J. Quaas; S. Kinne; J. Feichter

2007-02-01T23:59:59.000Z

288

Aerosol Effects on Cloud Emissivity and Surface Longwave Heating in the Arctic  

Science Conference Proceedings (OSTI)

Increases in anthropogenic aerosols in the atmosphere tend to increase the reflectance of solar (shortwave) radiation from water clouds, which can lead to lower surface temperatures. Here an opposing effect whereby aerosols increase the longwave ...

Timothy J. Garrett; Lawrence F. Radke; Peter V. Hobbs

2002-02-01T23:59:59.000Z

289

A Model Investigation of Aerosol-Induced Changes in Tropical Circulation  

Science Conference Proceedings (OSTI)

This study investigates how anthropogenic aerosols, alone or in conjunction with radiatively active gases, affect the tropical circulation with an atmosphere/mixed layer–ocean general circulation model. Aerosol-induced cooling gives rise to a ...

Yi Ming; V. Ramaswamy

2011-10-01T23:59:59.000Z

290

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

E-Print Network (OSTI)

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

Li, Guohui

291

A modeling study on the climate impacts of black carbon aerosols  

E-Print Network (OSTI)

The role of black carbon (BC) aerosols in climate change is important because of its strong capability in causing extinction of solar radiation. A three-dimensional interactive aerosol-climate model has been used to study ...

Wang, Chien.

292

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

293

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

294

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...

295

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, ...

296

Testing for the Possible Influence of Unknown Climate Forcings upon Global Temperature Increases from 1950-2000  

SciTech Connect

Global-scale variations in the climate system over the last half of the twentieth century, including long-term increases in global-mean near-surface temperatures, are consistent with concurrent human-induced emissions of radiatively active gases and aerosols. However, such consistency does not preclude the possible influence of other forcing agents, including internal modes of climate variability or unaccounted for aerosol effects. To test whether other unknown forcing agents may have contributed to multidecadal increases in global-mean near-surface temperatures from 1950 to 2000, data pertaining to observed changes in global-scale sea surface temperatures and observed changes in radiatively active atmospheric constituents are incorporated into numerical global climate models. Results indicate that the radiative forcing needed to produce the observed long-term trends in sea surface temperatures—and global-mean near-surface temperatures—is provided predominantly by known changes in greenhouse gases and aerosols. Further, results indicate that less than 10% of the long-term historical increase in global-mean near-surface temperatures over the last half of the twentieth century could have been the result of internal climate variability. In addition, they indicate that less than 25%of the total radiative forcing needed to produce the observed long-term trend in global-mean near-surface temperatures could have been provided by changes in net radiative forcing from unknown sources (either positive or negative). These results, which are derived from simple energy balance requirements, emphasize the important role humans have played in modifying the global climate over the last half of the twentieth century.

Anderson, Bruce T.; Knight, Jeff R.; Ringer, Mark A.; Yoon, Jin-Ho; Cherchi, Annalisa

2012-10-15T23:59:59.000Z

297

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

298

Transmission of Solar Radiation by Clouds over Snow and Ice Surfaces. Part II: Cloud Optical Depth and Shortwave Radiative Forcing from Pyranometer Measurements in the Southern Ocean  

Science Conference Proceedings (OSTI)

Downward solar irradiance at the sea surface, measured on several voyages of an icebreaker in the Southern Ocean, is used to infer transmittance of solar radiation by clouds. Together with surface albedo estimated from coincident hourly sea ice ...

Melanie F. Fitzpatrick; Stephen G. Warren

2005-11-01T23:59:59.000Z

299

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

300

The Influence of the 1998 El Nińo upon Cloud-Radiative Forcing over the Pacific Warm Pool  

Science Conference Proceedings (OSTI)

Clouds cool the climate system by reflecting shortwave radiation and warm it by increasing the atmospheric greenhouse. Previous studies have shown that in tropical regions of deep convection there is a near cancellation between cloud-induced ...

Robert D. Cess; Minghua Zhang; Bruce A. Wielicki; David F. Young; Xue-Long Zhou; Yuri Nikitenko

2001-05-01T23:59:59.000Z

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


301

Annual Forcing of the Surface Radiation Balance Diurnal Cycle Measured from a High Tower near Boulder, Colorado  

Science Conference Proceedings (OSTI)

The radiation balance consisting of upward and downward components of solar and thermal infrared broadband irradiances is continuously measured from the top of a 300-m tower situated on the Colorado high plains. The data are representative of a ...

Ellsworth G. Dutton

1990-12-01T23:59:59.000Z

302

The Influence of Solar Zenith Angle and Cloud Type on Cloud Radiative Forcing at the Surface in the Arctic  

Science Conference Proceedings (OSTI)

Measurements of the long- and shortwave incident radiation taken from the USCGC Polar Sea during a research cruise to the Northeast Water Polynya during the summer of 1993 are analyzed together with observations of cloud type and amount to ...

Peter J. Minnett

1999-01-01T23:59:59.000Z

303

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

SciTech Connect

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

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

2011-11-04T23:59:59.000Z

304

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

305

Robustness of Dynamical Feedbacks from Radiative Forcing: 2% Solar versus 2 × CO2 Experiments in an Idealized GCM  

Science Conference Proceedings (OSTI)

Despite the differences in the spatial patterns of the external forcing associated with a doubling CO2 and with a 2% solar variability, the final responses in the troposphere and at the surface in a three-dimensional general circulation model ...

Ming Cai; Ka-Kit Tung

2012-07-01T23:59:59.000Z

306

Final Report for Research Conducted at The Scripps Institution of Oceanography, University of California San Diego from 2/2002 to 8/2003 for ''Aerosol and Cloud-Field Radiative Effects in the Tropical Western Pacific: Analyses and General Circulation Model Parameterizations''  

SciTech Connect

OAK-B135 Final report from the University of California San Diego for an ongoing research project that was moved to Brookhaven National Laboratory where proposed work will be completed. The research uses measurements made by the Atmospheric Radiation Measurement (ARM) Program to quantify the effects of aerosols and clouds on the Earth's energy balance in the climatically important Tropical Western Pacific.

Vogelmann, A. M.

2004-01-27T23:59:59.000Z

307

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

308

Influence of the Upper-Tropospheric Wind Shear upon Cloud Radiative Forcing in the Asian Monsoon Region  

Science Conference Proceedings (OSTI)

Using the top-of-the-atmosphere radiative flux and cloud data from satellites, as well as atmospheric data from NCEP–NCAR reanalysis, this paper investigates the reason for the unusually large high-cloud amount in the Asian monsoon region during ...

V. Sathiyamoorthy; P. K. Pal; P. C. Joshi

2004-07-01T23:59:59.000Z

309

Arctic Stratus Cloud Properties and Radiative Forcing Derived from Ground-Based Data Collected at Barrow, Alaska  

Science Conference Proceedings (OSTI)

A record of single-layer and overcast low-level Arctic stratus cloud properties has been generated using data collected from May to September 2000 at the Atmospheric Radiation Measurement (ARM) North Slope of Alaska (NSA) (71.3°N, 156.6°W) site ...

Xiquan Dong; Gerald G. Mace

2003-02-01T23:59:59.000Z

310

Electron acceleration and emission in a field of a plane and converging dipole wave of relativistic amplitudes with the radiation reaction force taken into account  

SciTech Connect

A comparative analysis is performed of the electron emission characteristics as the electrons move in laser fields with ultra-relativistic intensity and different configurations corresponding to a plane or tightly focused wave. For a plane travelling wave, analytical expressions are derived for the emission characteristics, and it is shown that the angular distribution of the radiation intensity changes qualitatively even when the wave intensity is much less than that in the case of the radiation-dominated regime. An important conclusion is drawn that the electrons in a travelling wave tend to synchronised motion under the radiation reaction force. The characteristic features of the motion of electrons are found in a converging dipole wave, associated with the curvature of the phase front and nonuniformity of the field distribution. The values of the maximum achievable longitudinal momenta of electrons accelerated to the centre, as well as their distribution function are determined. The existence of quasi-periodic trajectories near the focal region of the dipole wave is shown, and the characteristics of the emission of both accelerated and oscillating electrons are analysed. (extreme light fields and their applications)

Bashinov, Aleksei V; Gonoskov, Arkady A; Kim, A V; Marklund, Mattias; Mourou, G; Sergeev, Aleksandr M

2013-04-30T23:59:59.000Z

311

THE PLUTONIUM AEROSOL MONITORING PROGRAM AT ANL-IDAHO FACILITIES  

SciTech Connect

The physical and radiation characteristics of plutonium aerosols are reviewed briefly. A number of detecting and sampling devices and techniques are discussed for application to plutonium aerosols under conditions of reactor operations. The monitoring program and the Pu-fueled reactors at ANL-Idaho are described. (D.L.C.)

Stoddart, P.G.

1963-07-01T23:59:59.000Z

312

Design and Implementation of the Radioactive Aerosol's Concentration Measurement System Based on Virtual Training  

Science Conference Proceedings (OSTI)

A Virtual Training System of radioactive aerosol 's concentration measurement is constructed based on Virtual Reality. Firstly, 3-d geometric models about radioactive aerosol's outer environment, detector, intelligent scaler and air sampling pump etc. ... Keywords: Virtual Training, Radioactivity, Aerosol, Radiation Field component

Hui Wei-hua; Huang Chang-qiang; Ding Da-li

2011-07-01T23:59:59.000Z

313

Aerosol Optical Depth and the Global Brewer Network: A Study Using U.K.- and Malaysia-Based Brewer Spectrophotometers  

Science Conference Proceedings (OSTI)

Aerosols play an important role in attenuating solar radiation reaching the earth's surface and are thus important inputs to climate models. Aerosol optical depth is routinely measured in the visible range but little data in the ultraviolet (UV) ...

Wilawan Kumharn; John S. Rimmer; Andrew R. D. Smedley; Toh Ying Ying; Ann R. Webb

2012-06-01T23:59:59.000Z

314

Spatial Gradients in Aerosol-Induced Atmospheric Heating and Surface Dimming over the Oceanic Regions around India: Anthropogenic or Natural?  

Science Conference Proceedings (OSTI)

Making use of the extensive shipboard and aircraft measurements of aerosol properties over the oceanic regions surrounding the Indian peninsula, under the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) field experiment during ...

Vijayakumar S. Nair; S. Suresh Babu; K. Krishna Moorthy; S. S. Prijith

2013-10-01T23:59:59.000Z

315

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

316

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

317

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

318

Some Results of Joint Measurements of Aerosol Extinction of Solar...  

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

Results of Joint Measurements of Aerosol Extinction of Solar Radiation on Horizontal and Slant Paths S. M. Sakerin, D. M. Kabanov, Yu. A. Pkhalagov, and V. N. Uzhegov Institute of...

319

Influence of Urban Aerosol on Spectral Solar Irradiance  

Science Conference Proceedings (OSTI)

From a dataset of spectral distribution of global and disuse solar irradiances measured in Barcelona during the last three years, the influence of turbidity caused by urban aerosol on spectral composition of solar radiation and transmissivity of ...

J. Lorente; A. Redań; X. De Cabo

1994-03-01T23:59:59.000Z

320

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

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

Attachment of radon progeny to cigarette-smoke aerosols  

SciTech Connect

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

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

1995-05-01T23:59:59.000Z

322

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

323

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

324

ARM - Measurement - Backscattered radiation  

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

govMeasurementsBackscattered radiation govMeasurementsBackscattered 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 : 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, Cloud Properties 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 IAP : In-situ Aerosol Profiles (Cessna Aerosol Flights)

325

Radiators  

SciTech Connect

A heat-exchange radiator is connected to a fluid flow circuit by a connector which provides one member of an interengageable spigot and socket pair for push-fit, fluid-tight, engagement between the connector and the radiator, with latching formations at least one of which is resilient. Preferably the connector carries the spigot which tapers and engages with a socket of corresponding shape, the spigot carrying an O-ring seal and either latching fingers or a resilient latching circlip.

Webster, D. M.

1985-07-30T23:59:59.000Z

326

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

327

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

328

The Surface Radiation Budget over Oceans and Continents  

Science Conference Proceedings (OSTI)

An updated evaluation of the surface radiation budget in climate models (1994–96 versions; seven datasets available, with and without aerosols) and in two new satellite-based global datasets (with aerosols) is presented. All nine datasets capture ...

J. R. Garratt; A. J. Prata; L. D. Rotstayn; B. J. McAvaney; S. Cusack

1998-08-01T23:59:59.000Z

329

Aerosol Single-Scattering Albedo in the Arctic, Determined from Ground-Based Nonspectral Solar Irradiance Measurements  

Science Conference Proceedings (OSTI)

The single-scattering albedo of atmospheric aerosol is a crucial parameter in realistic radiative transfer calculations. Various attempts have been undertaken to determine this variable.

J. Freund

1983-11-01T23:59:59.000Z

330

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

331

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

332

Production Mechanism, Number Concentration, Size Distribution, Chemical Composition, and Optical Properties of Sea Spray Aerosols Workshop, Summer 2012  

SciTech Connect

The objective of this workshop was to address the most urgent open science questions for improved quantification of sea spray aerosol-radiation-climate interactions. Sea spray emission and its influence on global climate remains one of the most uncertain components of the aerosol-radiation-climate problem, but has received less attention than other aerosol processes (e.g. production of terrestrial secondary organic aerosols). Thus, the special emphasis was placed on the production flux of sea spray aerosol particles, their number concentration and chemical composition and properties.

Meskhidze, Nicholas [NCSU] [NCSU

2013-10-21T23:59:59.000Z

333

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

334

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.

335

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

336

Kingdom of Saudi Arabia Solar Radiation Atlas  

DOE Green Energy (OSTI)

This atlas provides a record of monthly mean solar radiation generated by a Climatological Solar Radiation model, using quasi-climatological inputs of cloud cover, aerosol optical depth, precipitable water vapor, ozone, surface albedo, and atmospheric pressure.

NREL

1998-12-16T23:59:59.000Z

337

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

338

Atmospheric Aerosol Limb Scanning Based on the Lunar Eclipses Photometry  

E-Print Network (OSTI)

The work is devoted to the analysis of the surface photometric observations of two total lunar eclipses in 2004. The lunar surface relative brightness distribution inside the umbra was used to retrieve the vertical distribution of aerosol extinction of the solar radiation expanding by a tangent path and its dependence on the location at the limb of the Earth. The upper altitude of troposphere aerosol layer was estimated for different latitude zones. The correlation between additional aerosol extinction in the upper troposphere and cyclones was investigated.

O. S. Ugolnikov; I. A. Maslov

2005-10-06T23:59:59.000Z

339

A Numerical Sensitivity Study of Aerosol Influence on Immersion Freezing  

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

Numerical Sensitivity Study of Aerosol Influence on Immersion Freezing Numerical Sensitivity Study of Aerosol Influence on Immersion Freezing in Mixed-Phase Stratiform Clouds Gijs de Boer, Tempei Hashino, Edwin W. Eloranta and Gregory J. Tripoli The University of Wisconsin - Madison (1) Introduction (1) Introduction Mixed-phase stratiform clouds are commonly observed at high latitudes (Shupe et al., 2006; de Boer et al., 2009a). These clouds significaly impact the atmospheric radiative

340

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?

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

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

342

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

343

Application of Improved Radiation Modeling to General Circulation Models  

SciTech Connect

This research has accomplished its primary objectives of developing accurate and efficient radiation codes, validating them with measurements and higher resolution models, and providing these advancements to the global modeling community to enhance the treatment of cloud and radiative processes in weather and climate prediction models. A critical component of this research has been the development of the longwave and shortwave broadband radiative transfer code for general circulation model (GCM) applications, RRTMG, which is based on the single-column reference code, RRTM, also developed at AER. RRTMG is a rigorously tested radiation model that retains a considerable level of accuracy relative to higher resolution models and measurements despite the performance enhancements that have made it possible to apply this radiation code successfully to global dynamical models. This model includes the radiative effects of all significant atmospheric gases, and it treats the absorption and scattering from liquid and ice clouds and aerosols. RRTMG also includes a statistical technique for representing small-scale cloud variability, such as cloud fraction and the vertical overlap of clouds, which has been shown to improve cloud radiative forcing in global models. This development approach has provided a direct link from observations to the enhanced radiative transfer provided by RRTMG for application to GCMs. Recent comparison of existing climate model radiation codes with high resolution models has documented the improved radiative forcing capability provided by RRTMG, especially at the surface, relative to other GCM radiation models. Due to its high accuracy, its connection to observations, and its computational efficiency, RRTMG has been implemented operationally in many national and international dynamical models to provide validated radiative transfer for improving weather forecasts and enhancing the prediction of global climate change.

Michael J Iacono

2011-04-07T23:59:59.000Z

344

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

345

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

346

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

347

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

348

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

349

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

350

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

351

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

352

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

353

Implementation of a lidar system and its usage in characterization of aerosols in the atmospheric column  

Science Conference Proceedings (OSTI)

Light Detection and Ranging (LIDAR) is a recent remote sensing system which has been gradually expanding as a network among the countries actively concerned about the atmospheric contaminants, earth radiation budget, rain variations, clean air index, ... Keywords: AERONET station, Lidar system, aerosol optical depth, aerosol size distribution, air quality index, planetary boundary layer

Javier Mčndez-Rodríguez; Hamed Parsiani

2009-06-01T23:59:59.000Z

354

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

355

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

356

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

357

A New Assessment of the Aerosol First Indirect Effect  

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

New Assessment of the Aerosol First Indirect Effect New Assessment of the Aerosol First Indirect Effect Shao, Hongfei Florida State University Liu, Guosheng Florida State University Category: Aerosols The aerosol first indirect effect is known to cool the Earth radiatively. However, its magnitude is very uncertain; large discrepancies exist among the observed values published in the literature. In this study, we first survey the published values of those parameters used for describing the first indirect effect. By analyzing the discrepancies among these values, we show that the first indirect effect has been overestimated by many investigators due to an improper parameter being used. Therefore, we introduce a more meaningful parameter to measure this effect. We estimated the first indirect effect using the new parameter based on observational

358

Discrimination between thin cirrus and and tropospheric aerosol using  

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

Discrimination between thin cirrus and and tropospheric aerosol using Discrimination between thin cirrus and and tropospheric aerosol using multiple measurements from Darwin ARCS Mitchell, Ross CSIRO Category: Aerosols Thin cirrus cloud occurs frequently in the tropics, and is often difficult to distinguish from tropospheric aerosol on the basis of temporal variations in ground based measurements, since both can be rather spatially uniform. In this study we investigate their discrimination by combining data from three instruments at the Darwin Atmospheric Radiation and Cloud Station (ARCS): the Cimel sun photometer (CSP), the micropulse lidar (MPL), and the total sky imager (TSI). The study was carried out over the dry season of 2005, with the usual widespread burning of tropical savanna leading to extensive smoke plumes. It is shown that the locus of data in

359

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

SciTech Connect

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

Kmetyk, L.N.

1991-09-01T23:59:59.000Z

360

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

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

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

362

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...

363

Observations and Calculations of Aerosol Heating over the Arabian Sea during MONEX  

Science Conference Proceedings (OSTI)

Radiation flux observations were obtained during a flight of the NCAR Electra over the Arabian Sea during MONEX when aerosols were present, and these observations have been compared with theoretical calculations based upon simultaneously observed ...

Robert O. Ellingson; George N. Serafino

1984-02-01T23:59:59.000Z

364

Scientific Objectives, Measurement Needs, and Challenges Motivating the PARAGON Aerosol Initiative  

Science Conference Proceedings (OSTI)

Aerosols are involved in a complex set of processes that operate across many spatial and temporal scales. Understanding these processes, and ensuring their accurate representation in models of transport, radiation transfer, and climate, requires ...

John H. Seinfeld; Ralph A. Kahn; Theodore L. Anderson; Robert J. Charlson; Roger Davies; David J. Diner; John A. Ogren; Stephen E. Schwartz; Bruce A. Wielicki

2004-10-01T23:59:59.000Z

365

The CALIPSO Mission: A Global 3D View of Aerosols and Clouds  

Science Conference Proceedings (OSTI)

Aerosols and clouds have important effects on Earth's climate through their effects on the radiation budget and the cycling of water between the atmosphere and Earth's surface. Limitations in our understanding of the global distribution and ...

D. M. Winker; J. Pelon; J. A. Coakley Jr.; S. A. Ackerman; R. J. Charlson; P. R. Colarco; P. Flamant; Q. Fu; R. M. Hoff; C. Kittaka; T. L. Kubar; H. Le Treut; M. P. McCormick; G. Mégie; L. Poole; K. Powell; C. Trepte; M. A. Vaughan; B. A. Wielicki

2010-09-01T23:59:59.000Z

366

Fully Automated Detection of Cloud and Aerosol Layers in the CALIPSO Lidar Measurements  

Science Conference Proceedings (OSTI)

Accurate knowledge of the vertical and horizontal extent of clouds and aerosols in the earth’s atmosphere is critical in assessing the planet’s radiation budget and for advancing human understanding of climate change issues. To retrieve this ...

Mark A. Vaughan; Kathleen A. Powell; David M. Winker; Chris A. Hostetler; Ralph E. Kuehn; William H. Hunt; Brian J. Getzewich; Stuart A. Young; Zhaoyan Liu; Matthew J. McGill

2009-10-01T23:59:59.000Z

367

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

SciTech Connect

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

Meskhidze, Nicholas; Zhang, Yang; Kamykowski, Daniel

2012-03-28T23:59:59.000Z

368

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

Science Conference Proceedings (OSTI)

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

Meskhidze, Nicholas; Zhang, Yang; Kamykowski, Daniel

2012-03-28T23:59:59.000Z

369

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.

370

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

371

ARM - Field Campaign - 2006 MAX-Mex-Megacity Aerosol eXperiment - Mexico  

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

6 MAX-Mex-Megacity Aerosol eXperiment - Mexico City 6 MAX-Mex-Megacity Aerosol eXperiment - Mexico City Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : 2006 MAX-Mex-Megacity Aerosol eXperiment - Mexico City 2006.03.03 - 2006.03.28 Lead Scientist : Jeffrey Gaffney For data sets, see below. Description A 4-week field campaign was conducted in and downwind of Mexico City during March 2006. The Megacity Aerosol eXperiment - MEXico City (MAX-MEX) characterized aerosol formation and changes in aerosol composition, size distribution, light scattering coefficient, absorption coefficient, optical depth, soot-specific absorption, and radiative fluxes at selected vertical and horizontal locations in the outflow from a well-characterized urban core. Detailed analyses were made of the meteorological conditions during

372

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

373

Surface Forcing of the Infrared Cooling Profile over the Tibetan Plateau. Part I: Influence of Relative Longwave Radiative Heating at High Altitude  

Science Conference Proceedings (OSTI)

The role of the Tibetan Plateau on the behavior of the surface longwave radiation budget is examined, and the behavior of the vertical profile of longwave cooling over the plateau, including its diurnal variation, is quantified. The investigation ...

Eric A. Smith; Lei Shi

1992-05-01T23:59:59.000Z

374

The Vertical Structure of Cloud Occurrence and Radiative Forcing at the SGP ARM Site as Revealed by 8 Years of Continuous Data  

Science Conference Proceedings (OSTI)

Data collected at the Atmospheric Radiation Measurement (ARM) Program ground sites allow for the description of the atmospheric thermodynamic state, cloud occurrence, and cloud properties. This information allows for the derivation of estimates ...

Gerald G. Mace; Sally Benson

2008-06-01T23:59:59.000Z

375

Long-term impacts of aerosols on vertical development of cloud and precipitation  

Science Conference Proceedings (OSTI)

Aerosols alter cloud density and the radiative balance of the atmosphere. This leads to changes in cloud microphysics and atmospheric stability, which can either suppress or foster the development of clouds and precipitation. The net effect is largely unknown, but depends on meteorological conditions and aerosol properties. Here, we examine the long-term impact of aerosols on the vertical development of clouds and rainfall frequencies, using a 10-year dataset of aerosol, cloud and meteorological variables collected in the Southern Great Plains in the United States. We show that cloud-top height and thickness increase with aerosol concentration measured near the ground in mixed-phase clouds-which contain both liquid water and ice-that have a warm, low base. We attribute the effect, which is most significant in summer, to an aerosol-induced invigoration of upward winds. In contrast, we find no change in cloud-top height and precipitation with aerosol concentration in clouds with no ice or cool bases. We further show that precipitation frequency and rain rate are altered by aerosols. Rain increases with aerosol concentration in deep clouds that have a high liquid-water content, but declines in clouds that have a low liquid-water content. Simulations using a cloud-resolving model confirm these observations. Our findings provide unprecedented insights of the long-term net impacts of aerosols on clouds and precipitation.

Li Z.; Liu Y.; Niu, F.; Fan, J.; Rosenfeld, D.; Ding, Y.

2011-11-13T23:59:59.000Z

376

Radiation and Ozone  

Science Conference Proceedings (OSTI)

Radiation is the driving force for the general circulation of the atmosphere and controls the Earth's climate. Ozone is responsible for the warm stratosphere and protects life on Earth from harmful solar ultraviolet radiation. In July 1959, the ...

G. Ohring; R. D. Bojkov; H-J. Bolle; R. D. Hudson; H. Volkert

2009-11-01T23:59:59.000Z

377

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

378

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

379

Radiative and climate impacts of absorbing aerosols  

E-Print Network (OSTI)

Enhancement of Atmospheric Solar Heating from Forest FiresScale dependence of solar heating rates in convective cloudScale Dependence of Solar Heating Rates in Convective Cloud

Zhu, Aihua

2010-01-01T23:59:59.000Z

380

Radiative and climate impacts of absorbing aerosols  

E-Print Network (OSTI)

strong northwesterly offshore wind [Pease et al. , 1998],dusty air moves offshore blown by the easterly winds, it is

Zhu, Aihua

2010-01-01T23:59:59.000Z

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

Radiative and climate impacts of absorbing aerosols  

E-Print Network (OSTI)

fuel, biofuel and biomass combustion, organic carbon hasefficient combustion processes such as biomass burning haveincomplete combustion of fossil fuel and biomass burning. BC

Zhu, Aihua

2010-01-01T23:59:59.000Z

382

Radiative and climate impacts of absorbing aerosols  

E-Print Network (OSTI)

wind carries warm marine air mass from the Southern Hemisphere northward and brings moisture and precipitation over India

Zhu, Aihua

2010-01-01T23:59:59.000Z

383

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

384

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)

385

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

386

The Global Character of the Flux of Downward Longwave Radiation  

Science Conference Proceedings (OSTI)

Four different types of estimates of the surface downwelling longwave radiative flux (DLR) are reviewed. One group of estimates synthesizes global cloud, aerosol, and other information in a radiation model that is used to calculate fluxes. Because ...

Graeme L. Stephens; Martin Wild; Paul W. Stackhouse Jr.; Tristan L’Ecuyer; Seiji Kato; David S. Henderson

2012-04-01T23:59:59.000Z

387

Radiative Energy Budget Estimates for the 1979 Southwest Summer Monsoon  

Science Conference Proceedings (OSTI)

Obsemations of temperature moisture, cloud amount, cloud height and soil-derived aerosols are incorporated into radiative transfer models to yield estimates of the tropospheric and surface radiative energy budgets for the summer Monsoon of 1979. ...

Steven A. Ackerman; Stephen K. Cox

1987-10-01T23:59:59.000Z

388

A Radiation Fog Model with a Detailed Treatment of the Interaction between Radiative Transfer and Fog Microphysics  

Science Conference Proceedings (OSTI)

A one-dimensional radiation fog model is presented which includes a detailed description of the interaction between atmospheric radiative transfer and the microphysical structure of the fog. Aerosol particles and activated cloud droplets are ...

A. Bott; U. Sievers; W. Zdunkowski

1990-09-01T23:59:59.000Z

389

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

390

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

391

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

392

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

393

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

394

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

395

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

396

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

397

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

398

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

399

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

400

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

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

Effects of Aerosol Size Distribution and Vertical Profile on the Effects of Aerosol Size Distribution and Vertical Profile on the Polarization in the Oxygen A-Band Duan, Minzheng State University of New York at Albany Min, Qilong State University of New York at Albany A vector radiative transfer code with successive order of scattering method was used to simulate the high-resolution polarization spectra in the oxygen A-band. The effects of aerosol size distribution and vertical profile on the radiance and polarization at the top and bottom of the atmosphere were analyzed. The impacts of instrument specification on information content are also analyzed. Polarized radiances were dominated (>95%) by the first and second orders of scattering. The contributions of scattering from different levels to the TOA and surface observation are analyzed. The

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

Analyzing Surface Solar Flux Data in Oregon for Changes Due to Aerosols Laura D. Riihimaki1, Frank E. Vignola1, Charles N. Long2, James A. Coakley Jr.3 1 University of Oregon Solar Radiation Monitoring Lab 2 Pacific Northwest National Laboratory 3 Oregon State University, College of Oceanic and Atmospheric Sciences  

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

76 76 1980 1984 1988 1992 1996 2000 2004 2008 100 150 200 250 Direct Normal Irradiance (W/m 2 ) Eugene Hermiston Burns 3. All-sky direct normal irradiance increases 5% per decade Eppley NIP Conclusions Annual average all-sky total and direct normal irradiance measurements show an overall increase in Oregon between 1980 and 2007. Two measurement sites show statistically significant increases in clear- sky direct normal irradiance in background periods before and after the eruption of Mt. Pinatubo [6] (1987- 2008), consistent with the hypothesis that a reduction in anthropogenic aerosols may contribute to the increase in surface irradiance. References 1. Long, C.N. and T. P. Ackerman, 2000: J. Geophys. Res., 105(D12), 15,609-15,626. 2. Long, C.N., and K.L. Gaustad, 2004: Atmospheric Radiation

402

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...

403

Radiation dose reconstruction US occupation forces in Hiroshima and Nagasaki, Japan, 1945-1946. Final report 1 March-6 August 80  

Science Conference Proceedings (OSTI)

Upper limit dose estimates (internal and external) are determined for those units of the U.S. occupation forces assigned to Hiroshima or Nagasaki following the detonations of atomic weapons in those two cities. In the absence of specific maneuver and patrol data, these dose estimates are based on the maximum recorded activity levels with exposure over the entire stay period for each unit. The upper limit external dose is .03 rem for Hiroshima and .08 rem for Nagasaki. For the Nishiyama area, the upper limit is 0.63 rem. The dose from internal emitters (inhalation and ingestion) is considerably less. There is no basis for assuming that any individual in the occupation units received these upper limit doses.

McRaney, W.; McGahan, J.

1980-08-06T23:59:59.000Z

404

The dependence of cloud particle size and precipitation probability on non-aerosol-loading related variables  

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

Explaining and reducing the uncertainties in the first aerosol i Explaining and reducing the uncertainties in the first aerosol i Explaining and reducing the uncertainties in the first aerosol indirect effect ndirect effect Hongfei Shao and Guosheng Liu Meteorology Department, Florida State University INTRODUCTION INTRODUCTION Anthropogenic aerosols enhance cloud reflectance of solar radiation by increasing the cloud droplet number concentrations. This so-called first Aerosol Indirect Effect (AIE) has a potentially large cooling tendency on our planet. However, discrepancies of more than a factor of 2 have been reported among observations 1 as well as model simulations 2 of the AIE. Our recent study 3 shows that the discrepancies will be reduced greatly if the entrainment-mixing evaporation of cloud drops is taken into account.

405

The Uncertainty of Dosimetry of Radioactive and Non-Radiactive Aerosols  

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

The Uncertainty of Dosimetry of Radioactive and Non-Radiactive Aerosols The Uncertainty of Dosimetry of Radioactive and Non-Radiactive Aerosols Speaker(s): Lev Ruzer Date: September 27, 2001 - 12:00pm Location: Bldg. 90 Seminar Host/Point of Contact: David Faulkner Radioactive aerosols are a substantial risk factor in radiation safety in the atomic industry, mining industry, nuclear warhead depository and nuclear waste storage, as well as the natural radioactivity in houses. Assessment of the exposure, dose and health effect is very important for workers and the general population. In the last 5-10 years the problem of dosimetry of non-radioactive aerosols has become a "hot" topic in environmental health science with emphasis on submicron and even nanometer-sized particles. Both radioactive and non-radioactive aerosols

406

Examining the Effects of Dust Aerosols on Satellite Sea Surface Temperatures in the Mediterranean Sea Using the Medspiration Matchup Database  

Science Conference Proceedings (OSTI)

Dust aerosol plumes from the Sahara cover the Mediterranean Sea regularly during the summer months (June–August) and occasionally during other seasons. Dust can absorb infrared longwave radiation, thus causing a drop in sea surface temperature (...

Ana B. Ruescas; Manuel Arbelo; Jose A. Sobrino; Cristian Mattar

2011-05-01T23:59:59.000Z

407

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....

408

About ÂŤEffectiveÂŽ Height of the Aerosol Atmosphere in Visible and IR Wavelength Range  

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

"Effective" Height of the Aerosol Atmosphere in "Effective" Height of the Aerosol Atmosphere in Visible and IR Wavelength Range V. N. Uzhegov, D. M. Kabanov, M. V. Panchenko, Yu. A. Pkhalagov, and S. M. Sakerin Institute of Atmospheric Optics Tomsk, Russia Introduction Aerosol component of the atmosphere is one of the important factors affecting the radiation budget of the space - atmosphere - underlying surface system in visible and infrared (IR) wavelength ranges. It is extremely important to take into account the contribution of this component into the extinction of solar radiation under cloudless sky conditions. Sometimes it is important to know not only the total value of the aerosol component of extinction, but also to have the possibility to estimate the "effective" height of

409

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

410

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

SciTech Connect

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

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

2011-02-15T23:59:59.000Z

411

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

412

Toward the Development of Multi-Year Total and Special Solar Radiation Budgets at the Three ARM Locales  

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

the Development of Multi-Year Total and Special the Development of Multi-Year Total and Special Solar Radiation Budgets at the Three ARM Locales Z. Li and M. C. Cribb Earth System Science Interdisciplinary Center University of Maryland College Park, Maryland A. P. Trishchenko Canada Centre for Remote Sensing Ottawa, Ontario, Canada Introduction Over the past decade, an unprecedented amount of high-quality observational data pertaining to atmospheric and surface parameters has been collected at Atmospheric Radiation Measurement (ARM) locales around the globe. These data have been critical in the development and validation of models used to study the complex interaction of cloud, aerosols, and the surface on the solar radiative budget (SRB), the primary force driving atmospheric circulation. As the next step forward, the challenge of

413

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

414

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

415

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

416

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

417

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

418

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

419

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

420

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

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

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

422

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

423

Climate Feedbacks in CCSM3 under Changing CO2 Forcing. Part II: Variation of Climate Feedbacks and Sensitivity with Forcing  

Science Conference Proceedings (OSTI)

Are equilibrium climate sensitivity and the associated radiative feedbacks a constant property of the climate system, or do they change with forcing magnitude and base climate? Using the radiative kernel technique, feedbacks and climate ...

Alexandra K. Jonko; Karen M. Shell; Benjamin M. Sanderson; Gokhan Danabasoglu

2013-05-01T23:59:59.000Z

424

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

425

Observations and Modeling of Downward Radiative Fluxes (Solar and Infrared) in Urban/Rural Areas  

Science Conference Proceedings (OSTI)

Pollutants (gaseous and aerosol) contained in urban atmospheres alter radiative fluxes at the surface.Numerous radiative models have been developed, and while few experimental data are available, results areoften contradictory. We have taken ...

Claude Estournel; Raoul Vehil; Daniel Guedalia; Jacques Fontan; Aimé Druilhet

1983-01-01T23:59:59.000Z

426

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

427

Evidence that the spectral dependence of light absorption by aerosols is  

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

Evidence that the spectral dependence of light absorption by aerosols is Evidence that the spectral dependence of light absorption by aerosols is affected by organic carbon Title Evidence that the spectral dependence of light absorption by aerosols is affected by organic carbon Publication Type Journal Article LBNL Report Number LBNL-55056 Year of Publication 2004 Authors Kirchstetter, Thomas W., Tihomir Novakov, and Peter V. Hobbs Journal Journal of Geophysical Research: Atmospheres Volume 109 Issue D21 Keywords aerosol light absorption, biomass burning, organic carbon Abstract The wavelength dependence of light absorption by aerosols collected on filters is investigated throughout the near-ultraviolet to near-infrared spectral region. Measurements were made using an optical transmission method. Aerosols produced by biomass combustion, including wood and savanna burning, and by motor vehicles, including diesel trucks, are included in the analysis. These aerosol types were distinguished by different wavelength (λ) dependences in light absorption. Light absorption by the motor vehicle aerosols exhibited relatively weak wavelength dependence; absorption varied approximately as λ-1, indicating that black carbon (BC) was the dominant absorbing aerosol component. By contrast, the biomass smoke aerosols had much stronger wavelength dependence, approximately λ-2. The stronger spectral dependence was the result of enhanced light absorption at wavelengths shorter than 600 nm and was largely reduced when much of the sample organic carbon (OC) was extracted by dissolution in acetone. This indicates that OC in addition to BC in the biomass smoke aerosols contributed significantly to measured light absorption in the ultraviolet and visible spectral regions and that OC in biomass burning aerosols may appreciably absorb solar radiation. Estimated absorption efficiencies and imaginary refractive indices are presented for the OC extracted from biomass burning samples and the BC in motor vehicle-dominated aerosol samples. The uncertainty of these constants is discussed. Overall, results of this investigation show that low-temperature, incomplete combustion processes, including biomass burning, can produce light-absorbing aerosols that exhibit much stronger spectral dependence than high-temperature combustion processes, such as diesel combustion.

428

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

429

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

430

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...

431

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

432

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

433

Measurements of the effects of humidity on radio-aerosol penetration through ultrafine capillaries  

SciTech Connect

The purpose of this research was to examine the effects of humidity on radio-aerosol penetration through ultrafine capillaries. A number of tests were conducted at relative humidities of 20%, 50%, and 80%, with sampling times of 20, 40, and 60 min. The radio-aerosol consisted of polystyrene particles with a diameter of 0.1 {micro}m. The ultrafine capillaries had a diameter of 250 {micro}m. The data from these tests varied significantly. These results made the identification of radio-aerosol penetration trends inconclusive. The standard deviation for all penetration data ranged from 3% to 30%. The results of this study suggest that a better control of the experimental parameters was needed to obtain more accurate data from experiments associated with radio-aerosol penetration in the presence of moisture. The experimental parameters that may have contributed to the wide variance of data, include aerosol flow, radio-aerosol generation, capillary characteristics, humidity control, and radiation measurements. It was the uncertainty of these parameters that contributed to the poor data which made conclusive deductions about radio-aerosol penetration dependence on humidity difficult. The application of this study is to ultrafine leaks resulting from stress fractures in high-level nuclear waste transportation casks under accident scenarios.

Cullen, C.

1996-08-01T23:59:59.000Z

434

Model simulations of the first aerosol indirect effect and comparison of cloud susceptibility fo satellite measurements  

DOE Green Energy (OSTI)

Present-day global anthropogenic emissions contribute more than half of the mass in submicron particles primarily due to sulfate and carbonaceous aerosol components derived from fossil fuel combustion and biomass burning. These anthropogenic aerosols modify the microphysics of clouds by serving as cloud condensation nuclei (CCN) and enhance the reflectivity of low-level water clouds, leading to a cooling effect on climate (the Twomey effect or first indirect effect). The magnitude of the first aerosol indirect effect is associated with cloud frequency as well as a quantity representing the sensitivity of cloud albedo to changes in cloud drop number concentration. This quantity is referred to as cloud susceptibility [Twomey, 1991]. Analysis of satellite measurements demonstrates that marine stratus clouds are likely to be of higher susceptibility than continental clouds because of their lower number concentrations of cloud drops [Platnick and Twomey, 1994]. Here, we use an improved version of the fully coupled climate/chemistry model [Chuang et al., 1997] to calculate the global concentrations Of sulfate, dust, sea salt, and carbonaceous aerosols (biomass smoke and fossil fuel organic matter and black carbon). We investigated the impact of anthropogenic aerosols on cloud susceptibility and calculated the associated changes of shortwave radiative fluxes at the top of the atmosphere. We also examined the correspondence between the model simulation of cloud susceptibility and that inferred from satellite measurements to test whether our simulated aerosol concentrations and aerosol/cloud interactions give a faithful representation of these features.

Chuang, C; Penner, J E; Kawamoto, K

2002-03-08T23:59:59.000Z

435

Global and regional decreases in tropospheric oxidants from photochemical effects of aerosols  

E-Print Network (OSTI)

[1] We evaluate the sensitivity of tropospheric OH, O3, and O3 precursors to photochemical effects of aerosols not usually included in global models: (1) aerosol scattering and absorption of ultraviolet radiation and (2) reactive uptake of HO2,NO2, and NO3. Our approach is to couple a global 3-D model of tropospheric chemistry (GEOS-CHEM) with aerosol fields from a global 3-D aerosol model (GOCART). Reactive uptake by aerosols is computed using reaction probabilities from a recent review (gHO2 = 0.2, gNO2 =10 4, gNO3 =10 3). Aerosols decrease the O3! O ( 1 D) photolysis frequency by 5–20 % at the surface throughout the Northern Hemisphere (largely due to mineral dust) and by a factor of 2 in biomass burning regions (largely due to black carbon). Aerosol uptake of HO2 accounts for 10–40 % of total HOx radical ( OH + peroxy) loss in the boundary layer over polluted continental regions (largely due to sulfate and organic carbon) and for more than 70 % over tropical biomass burning regions (largely due to organic carbon). Uptake of NO2 and NO3 accounts for 10–20 % of total HNO3 production over biomass burning regions and less elsewhere. Annual mean OH concentrations decrease by 9 % globally and by 5–35 % in the boundary layer over the Northern

All V. Martin; Daniel J. Jacob; Robert M. Yantosca; Mian Chin; Paul Ginoux

2003-01-01T23:59:59.000Z

436

Radiation Stress Estimators  

Science Conference Proceedings (OSTI)

The radiation stresses Sij associated with the propagation of wind-generated waves are principal driving forces for several important surf-zone processes. The accurate estimation of the onshore flux of longshore-directed mean momentum Syx, using ...

S. S. Pawka; D. L. Inman; R. T. Guza

1983-09-01T23:59:59.000Z

437

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

438

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

439

Gordon Research Conference on Radiation & Climate in 2009, July 5 -10  

SciTech Connect

The 2009 Gordon Research Conference on Radiation and Climate will present cutting-edge research on the outstanding issues in global climate change with focus on the radiative forcing and sensitivity of the climate system and associated physical processes. The Conference will feature a wide range of topics, including grand challenges in radiation and climate, radiative forcing, climate feedbacks, cloud processes in climate system, hydrological cycle in changing climate, absorbing aerosols and Asian monsoon, recent climate changes, and geo-engineering. The invited speakers will present the recent most important advances and future challenges in these areas. The Conference will bring together a collection of leading investigators who are at the forefront of their field, and will provide opportunities for scientists especially junior scientists and graduate students to present their work in poster format and exchange ideas with leaders in the field. The collegial atmosphere of this Conference, with programmed discussion sessions as well as opportunities for informal gatherings in the afternoons and evenings, provides an avenue for scientists from different disciplines to brainstorm and promotes cross-disciplinary collaborations in the various research areas represented.

Quiang Fu

2009-07-10T23:59:59.000Z

440

Particles and People: Aerosol Movement Into and Around the Human Body  

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

Particles and People: Aerosol Movement Into and Around the Human Body Particles and People: Aerosol Movement Into and Around the Human Body Speaker(s): Miriam Byrne Date: April 14, 2006 - 12:00pm Location: Bldg. 90 Miriam Byrne is a participating guest in the Airflow and Pollutant Transport Group at LBL. She is an academic member of staff in the Physics Department at the National University of Galway, Ireland. Her research interests, primarily funded by European Commission radiation protection programs, focus on the mechanisms of aerosol transport to and from human body surfaces. Over the last ten years, she has been involved in tracer aerosol experiments to determine rates of particle deposition and resuspension from skin, hair and clothing, as well as studying particle transport into skin pores and hair follicles, and contact transfer from

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

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

Science Conference Proceedings (OSTI)

Scanning transmission x-ray microscopy (STXM) combines x-ray microscopy and near edge x-ray absorption fine structure spectroscopy (NEXAFS). This combination provides spatially resolved bonding and oxidation state information. While there are reviews relevant to STXM/NEXAFS applications in other environmental fields (and magnetic materials) this chapter focuses on atmospheric aerosols. It provides an introduction to this technique in a manner approachable to non-experts. It begins with relevant background information on synchrotron radiation sources and a description of NEXAFS spectroscopy. The bulk of the chapter provides a survey of STXM/NEXAFS aerosol studies and is organized according to the type of aerosol investigated. The purpose is to illustrate the current range and recent growth of scientific investigations employing STXM-NEXAFS to probe atmospheric aerosol morphology, surface coatings, mixing states, and atmospheric processing.

Moffet, Ryan C.; Tivanski, Alexei V.; Gilles, Mary K.

2011-01-20T23:59:59.000Z

442

A Solar Radiation Model for Use in Climate Studies  

Science Conference Proceedings (OSTI)

A solar radiation routine has been developed for use in climate studies. It includes the absorption and scattering due to ozone, water vapor, oxygen, carbon dioxide, clouds, and aerosols. Rayleigh scattering is also included. The UV and visible ...

Ming-Dah Chou

1992-05-01T23:59:59.000Z

443

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 68ş 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

444

Impact of Cloud-Nucleating Aerosols in Cloud-Resolving Model Simulations of Warm-Rain Precipitation in the East China Sea  

Science Conference Proceedings (OSTI)

Cloud-nucleating aerosols emitted from mainland China have the potential to influence cloud and precipitation systems that propagate through the region of the East China Sea. Both simulations from the Spectral Radiation-Transport Model for ...

Stephen M. Saleeby; Wesley Berg; Susan van den Heever; Tristan L’Ecuyer

2010-12-01T23:59:59.000Z

445

Sensitivity of the Residual Circulation Diagnosed from the UARS Data to the Uncertainties in the Input Fields and to the Inclusion of Aerosols  

Science Conference Proceedings (OSTI)

The simultaneous measurements of temperature, aerosol extinction, and concentrations of radiatively active gases by several instruments aboard the Upper Atmosphere Research Satellite permit an assessment of the uncertainties in the diagnosed ...

Janusz Eluszkiewicz; David Crisp; R. G. Grainger; Alyn Lambert; A. E. Roche; J. B. Kumer; J. L. Mergenthaler

1997-07-01T23:59:59.000Z

446

Boundary-Forced Nonlinear Planetary Radiation  

Science Conference Proceedings (OSTI)

In recent years there has been renewed interest in the Gulf Stream system and its interaction with the mesoscale oceanic eddy field. An important question, not yet adequately addressed, concern the possible generation mechanisms of the mesoscale ...

Paola Malanotte-Rizzoli

1984-06-01T23:59:59.000Z

447

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

448

Investigations of the Absorption Properties of Near-Ground Aerosol by the Methods of Optical-Acoustic Spectrometry and Diff...  

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

Investigations of the Absorption Properties of Investigations of the Absorption Properties of Near-Ground Aerosol by the Methods of Optical-Acoustic Spectrometry and Diffuse Extinction V. S. Kozlov, M. V. Panchenko, A. B. Tikhomirov, and B. A. Tikhomirov Institute of Atmospheric Optics Tomsk, Russia Introduction Aerosol absorption is an important factor in the formation of non-selective radiation extinction in the visible wavelength range, and plays a great role in solving many radiative and climatic problems. The principal absorbing substance in atmospheric aerosol is soot (crystal carbon), which strongly affects the atmospheric transparency, albedo of clouds, and snow cover. The non-selective absorption by finely dispersed soot aerosol is considered to be one of the most plausible reasons for the appearance of

449

Techniques and Methods Used to Determine the Aerosol Best Estimate Value-Added Product at SGP Central Facility  

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

Determine the Aerosol Best Estimate Value-Added Product at SGP Central Facility C. Sivaraman, D. D. Turner, and C. J. Flynn Pacific Northwest National Laboratory Richland, Washington Objective Profiles of aerosol optical properties are needed for radiative closure exercises such as the broadband heating rate profile (BBHRP) project (Mlawer et al. 2002) and the Shortwave Quality Measurement Experiment (QME). Retrieving cloud microphysical properties using radiation measurements in the shortwave, such as the spectral retrieval technique described in Daniel et al. (2002), also require the optical properties of the aerosols so that they can be accounted for in the retrieval process. The objective of the aerosol best estimate (ABE) value-added procedure (VAP) is to provide profiles of

450

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

451

Multi-year Satellite and Surface Observations of AOD in support of Two-Column Aerosol Project (TCAP) Field Campaign  

SciTech Connect

We use combined multi-year measurements from the surface and space for assessing the spatial and temporal distribution of aerosol properties within a large (~400x400 km) region centered on Cape Cod, Massachusetts, along the East Coast of the United States. The ground-based Aerosol Robotic Network (AERONET) measurements at Martha’s Vineyard Coastal Observatory (MVCO) site and Moderate Resolution Imaging Spectrometer (MODIS) sensors on board the Terra and Aqua satellites provide horizontal and temporal variations of aerosol optical depth, while the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) offers the altitudes of aerosol-layers. The combined ground-based and satellite measurements indicated several interesting features among which were the large differences in the aerosol properties observed in July and February. We applied the climatology of aerosol properties for designing the Two-Column Aerosol Project (TCAP), which is supported by the U.S. Department of Energy’s (DOE’s) Atmospheric Radiation Measurement (ARM) Program. The TCAP field campaign involves 12-month deployment (started July 1, 2012) of the ground-based ARM Mobile Facility (AMF) and Mobile Aerosol Observing System (MAOS) on Cape Cod and complimentary aerosol observations from two research aircraft: the DOE Gulfstream-1 (G-1) and the National Aeronautics and Space Administration (NASA) B200 King Air. Using results from the coordinated G-1 and B200 flights during the recent (July, 2012) Intensive Observation Period, we demonstrated that the G-1 in situ measurements and B200 active remote sensing can provide complementary information on the temporal and spatial changes of the aerosol properties off the coast of North America.

Kassianov, Evgueni I.; Chand, Duli; Berg, Larry K.; Fast, Jerome D.; Tomlinson, Jason M.; Ferrare, R.; Hostetler, Chris A.; Hair, John

2012-11-01T23:59:59.000Z

452

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

453

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

454

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.