Aerosol and Cloud Radiative Forcing in China: Preliminary Results from the EAST-AIRE Project

East Asia, and China in particular, is a region that can provide crucial and unique information concerning natural and anthropogenic aerosols and their impact on fundamental climate issues. Until very recently, few observational studies were conducted in this region of heavy aerosol loading and unique properties. The East Asian Study of Tropospheric Aerosols: an International Regional Experiment (EAST-AIRE) is an attempt to more fully characterize the physical, optical and chemical properties of these aerosols in different parts of China. Currently, three ground observation stations have been established under the aegis of this experiment. They include Xianghe (70 km southeast of Beijing), Liaozhong (50 km west of Shenyang), and Tai Lake (central to three mega-cities Shanghai, Hangzhou and Nanjing). Measurements have been taken continuously over different periods of time. The measurements include radiative quantities (for example, longwave and shortwave broadband and narrowband irradiances, etc.), the sky condition from a total sky imager, and aerosol quantities such as optical depth and single-scattering albedo. A preliminary analysis of the data with regards to the aerosol radiative forcing at the top of the atmosphere and at the surface will be presented. Critical to this analysis is the identification of clear skies, which is problematic in this region due to the ubiquitous presence of aerosol in the atmosphere. Another challenge is the discrimination between haze and cloud. The synergy of multiple data sources from the ground and from satellite is shown to help in identifying sky condition so that aerosol and cloud forcing can be determined.