中国气象学会气象青年科技交流会暨2021年青年科学家论坛

The spatial and vertical distributions of aerosol optical properties associated with the aerosol types are very important in the estimation of climate forcing. Based on this, we investigate the global climatology of the distribution of different aerosol types, mainly total aerosols (All), desert dust (DD), polluted dust (PD), Elevated Smoke (ES) by using the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and Modern Era Retrospective-Analysis for Research MERRA-2 reanalysis data for the period 2007-2019. We found that the seasonal distribution of the global mean aerosol optical depth (AOD) of All aerosol types for the land samples are in the order JJA (0.1574)>MAM (0.1341)> DJF (0.1272) > SON (0.1242). This is attributed to the more frequent sand and dust activities over the Taklimakan Desert and the Sahara Desert in MAM and JJA. Owing to the transportation of DD, ES, and PD from the aerosol source, the ocean areas (especially for downwind regions) present the high AOD, and with the same seasonal distribution trend as in the land area. Also, the mean extinction coefficient (EC) for All aerosols decreases with the increase of height in all seasons for both the hemispheres. The maximum mean EC for All aerosols is 0.0102 km^-1 (0.0162 km^-1) during the day (night) in DJF (JJA) in the north hemisphere (NH), while the maximum is 0.0065km^-1 (0.0083 km^-1) during day (night) in JJA (SON) in the south hemisphere (SH). Moreover, the occurrence frequencies of DD, PD, and ES aerosols are dominant at all levels (from 0 to 12 km) in all seasons, but the clean marine (CM) and polluted continent (PC) are mostly below 3km.
 

CALIPSO; Global AOD; Aerosol types; Vertical structure; Spatiotemporal pattern.