REMOTE SENSING: Aerosols
Professor Li and his students work on the consolidation of various satellite based monthly mean aerosol products as derived from measurements made by the AVHRR and TOMS satellite sensors. The two products differ in many regards. The AVHRR retrievals are confined to dark oceans, while the TOMS retrievals are insensitive to aerosols at low altitudes. Based on the AVHRR and TOMS aerosol optical thickness (AOT), the AVHRR Angstrom exponent and TOMS aerosol index (AI), global aerosols are classified into different types: dust, biomass burning, sulfate/pollution, sea-salt, and their mixtures.
Global seasonal maps of dominant aerosol types.
East Asia is a major source of aerosol emissions due in part to the rapid economic development of the area and special environmental conditions. Aerosol characteristics and climatic effects are poorly known. The physical properties and chemical composition in this region may differ considerably from those found elsewhere. Not only is the magnitude of aerosol forcing large, the mechanisms by which aerosols interact with energy and water cycles may differ from those identified in relatively clean environments elsewhere. China is thus an ideal test-bed for examining both existing aerosol-climate paradigms and exploring new ones. Dr. Li is leading an experiment dubbed the “East Asian Study of Tropospheric Aerosols: an International Regional Experiment” (EAST-AIRE), in collaboration with scientists from NASA, NOAA and the Chinese Academy of Sciences. Under this project, three instrument-intensive sites will be established, as well as a national network measuring aerosol optical depth and total irradiance.