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R. Pedrós, J.L. Gómez-Amo, C.R. Marcos, M.P. Utrillas, S. Gandía, F. Tena, and J.A. Martinez Lozano

the lower part of the stratosphere. On the other hand, aerosols experience physical and chemical transformations in the time they spend in the atmosphere, known as aging, which modifies their optical properties. In particular, aerosols change their mixing state as they age. Aerosols can be externally mixed, which means that different aerosol components exist separately. In other words, there is no physical or chemical interaction between the aerosol components. Alternatively, aerosols can be

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M. Hess, P. Koepke, and I. Schult

The software package OPAC (Optical Properties of Aerosols and Clouds) is described. It easily provides optical properties in the solar and terrestrial spectral range of atmospheric particulate matter. Microphysical and optical properties of six water clouds, three ice clouds, and 10 aerosol components, which are considered as typical cases, are stored as ASCII files. The optical properties are the extinction, scattering, and absorption coefficients, the single scattering albedo, the asymmetry parameter, and the phase function. They are calculated on the basis of the microphysical data (size distribution and spectral refractive index) under the assumption of spherical particles in case of aerosols and cloud droplets and assuming hexagonal columns in case of cirrus clouds. Data are given for up to 61 wavelengths between 0.25 and 40 μm and up to eight values of the relative humidity. The software package also allows calculation of derived optical properties like mass extinction coefficients and Ångström coefficients.

Real aerosol in the atmosphere always is a mixture of different components. Thus, in OPAC it is made possible to get optical properties of any mixtures of the basic components and to calculate optical depths on the base of exponential aerosol height profiles. Typical mixtures of aerosol components as well as typical height profiles are proposed as default values, but mixtures and profiles for the description of individual cases may also be achieved simply.

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Z. Q. Li, H. Xu, K. T. Li, D. H. Li, Y. S. Xie, L. Li, Y. Zhang, X. F. Gu, W. Zhao, Q. J. Tian, R. R. Deng, X. L. Su, B. Huang, Y. L. Qiao, W. Y. Cui, Y. Hu, C. L. Gong, Y. Q. Wang, X. F. Wang, J. P. Wang, W. B. Du, Z. Q. Pan, Z. Z. Li, and D. Bu

, chemical, and radiative properties. The Sun–Sky Radiometer Observation Network (SONET; ) is a ground-based Cimel radiometer network with the extension of multiwavelength polarization measurement capability to provide long-term columnar atmospheric aerosol properties over China. In this paper, an overview of SONET infrastructure and data products is briefly introduced and then a climatology study is presented, focusing on aerosol optical, physical, chemical, and radiative properties

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Juan Carlos Antuña Marrero, René Estevan Arredondo, and Boris Barja González

derive the optical and geometrical properties of CCs were implemented; the preliminary results showed very encouraging performances for measurements of CCs conducted by both CEILAP in Argentina and CLS in Cuba ( Lavorato et al. 2008 ). During Antuña's visit, in the late 2005, to the Grupo de Óptica Atmosférica (Optics Atmospheric Group) at the University of Valladolid (GOA-UVA), Spain, a letter of agreement was signed with Dr. Angel de Frutos-Baraja, chair of GOA-UVA. The goal was to establish

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X. Y. Zhang, Y. Q. Wang, W. L. Lin, Y. M. Zhang, X. C. Zhang, S. Gong, P. Zhao, Y. Q. Yang, J. Z. Wang, Q. Hou, X. L. Zhang, H. Z. Che, J. P. Guo, and Y. Li

Before and during the 2008 Beijing Olympics from June to September, ground-based and satellite monitoring were carried out over Beijing and its vicinity (BIV) in a campaign to quantify the outcomes of various emission control measures. These include hourly surface PM10 and PM2.5 and their fraction of black carbon (BC), organics, nitrate, sulfate, ammonium, and daily aerosol optical depth (AOD), together with hourly reactive gases, surface ozone, and daily columnar NO2 from satellite. The analyses, excluding the estimates from weather contributions, demonstrate that after the control measures, including banning ~300,000 “yellow-tag” vehicles from roads, the even–odd turn of motor vehicles on the roads, and emission reduction aiming at coal combustion, were implemented, air quality in Beijing improved substantially. The levels of NO, NO2, NOx, CO, SO2, BC, organics, and nitrate dropped by about 30%–60% and the ozone moderately increased by ~40% while the sulfate and ammonium exhibited different patterns during various control stages. Weather conditions have a great impact on the summertime secondary aerosol (~80% of total PM) and O3 formations over BIV. During the Olympic Game period, various atmospheric components decreased dramatically at Beijing compared to the same period in the previous years. This decrease was related not only to the implementation of rigorous control measures, but also to the favorable weather processes. The subtropical high was located to the south so that Beijing's weather was dominated by the interaction between a frequently eastward shifting trough in the westerlies and a cold continental high with clear to cloudy days or showery weather.

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Laura Fierce, Nicole Riemer, and Tami C. Bond

et al. 2009 ) coupled to the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC; Zaveri et al. 2008 ) to simulate the evolution of diverse particle populations under a range of atmospheric conditions. For different stages of aerosol evolution, we quantified the errors in optical properties and CCN concentrations from simplified mixing-state representations. PartMC–MOSAIC is uniquely suited for benchmarking approximations of particle composition because it is the only model that

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Jinyuan Xin, Yuesi Wang, Yuepeng Pan, Dongsheng Ji, Zirui Liu, Tianxue Wen, Yinghong Wang, Xingru Li, Yang Sun, Jie Sun, Pucai Wang, Gehui Wang, Xinming Wang, Zhiyuan Cong, Tao Song, Bo Hu, Lili Wang, Guiqian Tang, Wenkang Gao, Yuhong Guo, Hongyan Miao, Shili Tian, and Lu Wang

CARE-China is the first comprehensive attempt to assess the physical, chemical, and optical properties of atmospheric aerosols across China and their impact on climate change. Aerosols represent an important component of Earth's atmosphere and are composed of solid and liquid particles of varying chemical complexity, size, and phase. The main components of anthropogenic aerosols are sulfate, nitrate, ammonium salt, black carbon (EC), and organic carbon (OC) ( Prather et al. 2008 ). Aerosols

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C. J. Stubenrauch, W. B. Rossow, S. Kinne, S. Ackerman, G. Cesana, H. Chepfer, L. Di Girolamo, B. Getzewich, A. Guignard, A. Heidinger, B. C. Maddux, W. P. Menzel, P. Minnis, C. Pearl, S. Platnick, C. Poulsen, J. Riedi, S. Sun-Mack, A. Walther, D. Winker, S. Zeng, and G. Zhao

(e.g., optically thin clouds over heterogeneous land areas or clouds over winter land areas). Sensor types for retrieving cloud properties. Multi-spectral imagers are radiometers measuring in only a limited number of discrete bands, usually from the solar to thermal infrared wavelengths. Nadir viewing with cross-track scanning capabilities, they have a spatial resolution from about 0.25–7 km (at nadir) and are the only sensors that exist aboard both geostationary weather satellites and polar

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Ralph A. Kahn, Tim A. Berkoff, Charles Brock, Gao Chen, Richard A. Ferrare, Steven Ghan, Thomas F. Hansico, Dean A. Hegg, J. Vanderlei Martins, Cameron S. McNaughton, Daniel M. Murphy, John A. Ogren, Joyce E. Penner, Peter Pilewskie, John H. Seinfeld, and Douglas R. Worsnop

solely from remote sensing data. Mass extinction efficiencies (MEEs) are required to translate between remote sensing–derived particle optical properties and aerosol mass, the fundamental quantity tracked in air quality, aerosol transport, and climate models. However, MEEs must be derived from in situ particle composition and size distribution measurements; otherwise, they are estimated by modeling these factors, or simply assumed. Lacking direct measurements for validation in most cases, only very

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Laura D. Riihimaki, Connor Flynn, Allison McComiskey, Dan Lubin, Yann Blanchard, J. Christine Chiu, Graham Feingold, Daniel R. Feldman, Jake J. Gristey, Christian Herrera, Gary Hodges, Evgueni Kassianov, Samuel E. LeBlanc, Alexander Marshak, Joseph J. Michalsky, Peter Pilewskie, Sebastian Schmidt, Ryan C. Scott, Yolanda Shea, Kurtis Thome, Richard Wagener, and Bruce Wielicki

detailed information of aerosol and cloud microphysical and optical properties that serve as the foundation for exploring the processes that introduce the largest uncertainties into climate predictions such as cloud phase, its impact on cloud formation, development, and radiative properties; cloud liquid water and its relationship to precipitation formation; and properties of aerosol and cloud in the clear–cloudy transition zone, the radiative effects of the transition zone, and their relationship to

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