The Spatial and Temporal Distributions of Absorbing Aerosols over East Asia

Absorbing aerosols can strongly absorb solar radiation and have a profound impact on the global and regional climate. Black carbon (BC), organic carbon (OC) and dust are three major types of absorbing aerosols. In order to deepen the overall understanding of absorbing aerosols over East Asia and provide a basis for further investigation of its role in enhanced warming in drylands, the spatial-temporal distribution of absorbing aerosols over East Asia for the period of 2005-2016 was investigated based on the Ozone Monitoring Instrument (OMI) satellite retrievals. Overall, high values of Aerosol Absorption Optical Depth (AAOD) mainly distribute near dust sources as well as BC and OC sources. AAOD reaches its maximum during spring over East Asia as a result of dust activity and biomass burning. Single-scattering albedo (SSA) is comparatively high (>0.96) in the most part of East Asia in the summer, indicating the dominance of aerosol scattering. Hyper-arid regions have the highest Aerosol Optical Depth (AOD) and AAOD among the five climatic regions, with springtime values up to 0.72 and 0.04, respectively. Humid and sub-humid regions have relatively high AOD and AAOD during the spring and winter and the highest SSA during the summer. AAOD in some areas shows significant upward trends, which is likely due to the increase of BC and OC emission. SSA shows overall downward trends, indicating the enhancement of the aerosol absorption. Analysis of emission inventory and dust index data shows that BC and OC emissions mainly come from the humid regions, while dust sources mainly distribute in drylands.