The Seasonal Variations of Aerosols over East Asia as Jointly Inferred from MODIS and OMI

AbstractData on aerosol optical thickness (AOT) and single scattering albedo (SSA) derived from Moderate Resolution Imaging Spectrometer (MODIS) and Ozone Monitoring Instrument (OMI) measurements, respectively, are used jointly to examine the seasonal variations of aerosols over East Asia. The seasonal signals of the total AOT are well defined and nearly similar over the land and over the ocean. These findings indicate a natural cycle of aerosols that originate primarily from natural emissions. In contrast, the small-sized aerosols represented by the fine-mode AOT, which are primarily generated over the land by human activities, do not have evident seasonal-scale fluctuations. A persistent maximum of aerosol loadings centered over the Sichuan basin is associated with considerable amounts of fine-mode aerosols throughout the year. Most regions exhibit a general spring maximum. During the summer, however, the aerosol loadings are the most marked over north central China. This occurrence may result from anth...