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J. Lenoble, D. Tanre, P. Y. Deschamps, and M. Herman

procedures areoutlined, as well as the influence of the main parameters: aerosol optical thickness, single scattering albedoand asymmetry factor, and sublayer albedo.The method is applied to compute the variation of the zonal albedo and the planetary radiation balancedue to a stratospheric aerosol layer of background H2S04 droplets and of volcanic ash. The resulting groundtemperature perturbation is evaluated, using a Budyko type climate model.1.IntroductionThe role of stratospheric aerosols in modifying

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Jacek Chowdhary, Brian Cairns, Michael I. Mishchenko, Peter V. Hobbs, Glenn F. Cota, Jens Redemann, Ken Rutledge, Brent N. Holben, and Ed Russell

(small) temporal difference between the low- and high-altitude measurements, the solar zenith angle θ 0 varied in this case study between 25° and 19°. 3. Methods a. Retrieval algorithm Chowdhary et al. (2002 , henceforth referred to as C2002 ) discuss the steps involved in inverting RSP data to retrieve aerosol properties. Their procedure takes advantage of the large difference in aerosol scattering optical thickness spectra for submicrometer- and micrometer-sized particles over the range of RSP

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Alexei Lyapustin, D. L. Williams, B. Markham, J. Irons, B. Holben, and Y. Wang

suitable for aerosol retrieval. The conventional 1D retrieval methods ignore the atmospheric blurring, and as a result, systematically overestimate the aerosol optical thickness over land. Lyapustin and Kaufman (2001) studied errors of 1D aerosol retrievals based on the accurate simulations for surfaces of different contrasts and scales of inhomogeneity. The main result is reproduced in Fig. 1 . It shows that the retrievals of aerosol optical thickness (AOT) at 30-m resolution are critically

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Pradeep Khatri, Tamio Takamura, Akihiro Yamazaki, and Yutaka Kondo

; Fioletov et al. 2002 ; Anton et al. 2008 ). The error induced by this assumption can be much larger at visible wavelengths than at UV wavelengths ( Grobner et al. 1996 ). The direct and diffuse irradiances observed by radiometers with horizontal surface detectors have been commonly used for aerosol research. For example, Petters et al. (2003) , Meloni et al. (2006) , Kassianov et al. (2007) , and Corr et al. (2009) retrieved key aerosol optical parameters, such as aerosol optical thickness ( τ

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Y. Fouquart, B. Bonnel, G. Brogniez, J. C. Buriez, L. Smith, J. J. Morcrette, and A. Cerf

. The ratio of infrared to visible optical thickness was ~14 ~zm)//~A (0.55 ~m) ~ 0.1, instead of 0.3 as calculated by Carlson and Benjamin. This discrexmncy is attributableto differences in size dislributions assumed. The radiative budget of the Sahelian aerosol hyer was determined for clear and dus~ conditions. The additionalaerosol shortwave heating was as much as 5 K day-~ for ~A (0.55 ~m) -- 1.5 and with the sun overhead, whereasthe additional cooling was close to I K day-L As a consequence

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Sundar A. Christopher, Xiang Li, Ronald M. Welch, Jeffrey S. Reid, Peter V. Hobbs, Thomas F. Eck, and Brent Holben

these calculations are performed at specific time periods during the day and therefore are termed “instantaneous DSWI.” No temporal averaging is performed on the datasets. Datasets and area of study Several datasets are used in this study, including aerosol microphysical properties from the University of Washington Convair 131-A (UW C-131A) research aircraft, aerosol optical thickness from ground-based sunphotometer measurements, and DSWI measurements from broadband Eppley Laboratory, Inc

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Jean-Louis Dufresne, Catherine Gautier, Paul Ricchiazzi, and Yves Fouquart

forcing at the TOA. These relative errors are almost independent of the aerosol optical thickness ( Fig. 3 ). Results are not very sensitive to the atmospheric vertical profile, the error ranging from 3 to 5 W m −2 ( Table 1 ). For winter conditions, and especially for arctic winter conditions, the aerosol forcing is also present in the spectral region around 20 μ m, and the relative error on longwave radiative forcing at the TOA when neglecting scattering jumps to 90%. Figure 4 illustrates how

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Zhengzhao Luo, William B. Rossow, Toshiro Inoue, and Claudia J. Stubenrauch

, ISCCP results suggest that the production of large amounts of stratospheric aerosol by Mt. Pinatubo is associated with a decrease in cirrus cloud amount by 0.02–0.04 and an increase in their average optical thickness ( Rossow and Schiffer 1999 ). How exactly did Mt. Pinatubo volcano affect cirrus properties? We explore this question by comparing the ISCCP products with two other cloud datasets derived from the split-window method and 3I cloud algorithm ( Stubenrauch et al. 1999a ). In the first half

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Yoram J. Kaufman and Teruyuki Nakajima

from satellite data it is impossible toderive all the parameters that influence cloud properties and smoke-cloud interaction (e.g., detailed aerosolparticles size distribution and chemistry, liquid water content, etc.); satellite data can be used to generate largescale statistics of the properties of clouds and surrounding aerosol (e.g., smoke optical thickness, cloud-dropsize, and cloud reflection of solar radiation) from which the interaction of aerosol with clouds can be surmised.- In order to

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F. E. Volz

) inthe western tropical Atlantic showed a minimum of aerosol optical thickness near 0.6 urn, which is probablytypical of a maritime aerosol. From 5-15 July, measurements at Puerto Rico showed highly variable andgenerally neutral aerosol attenuation in this wavelength range. Moreover, the skylight scattering functiondid not seem'to be typical of either a maritime or continental aerosol. During this period, transport ofSahara dust to the Caribbean was observed in satellite photographs and from BOMEX

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