The CALIPSO retrieved spatiotemporal and vertical distributions of AOD and extinction coefficient for different aerosol types during 2007-2019: A recent perspective over global and regional scales

In the present study, we investigated the global climatology of the spatiotemporal and vertical distributions of aerosol optical properties for different aerosol types, mainly including total aerosols (All), desert dust (DD), polluted dust (PD), and elevated smoke (ES). The data used for the study is derived from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) for Research and Application. We found that the seasonal distribution of the global mean aerosol optical depth (AOD) of All type in the land area are in the order JJA (0.157) > MAM (0.134) > DJF (0.127) > SON (0.124). 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 hemispheres. The maximum mean EC for All aerosols is 0.0102 km(-1) (0.016 km(-1)) during the day (night) in DJF (JJA) in the northern hemisphere, while the maximum is 0.006 km(-1) (0.008 km(-1)) during the day (night) in JJA (SON) in the southern hemisphere. Also, the occurrence of frequencies of DD, PD, and ES aerosols are distributed throughout the entire troposphere in all seasons, but the clean marine (CM) and polluted continent (PC) are mostly below 3 km.

Automated summary

This study investigated the global distribution of aerosol optical properties for different aerosol types, including total aerosols, desert dust, polluted dust, and elevated smoke. The study found that the seasonal distribution of aerosol optical depth varied in different regions. Sand and dust activities in certain deserts contributed to higher aerosol optical depth in specific seasons. The study also observed high aerosol optical depth in ocean areas due to the transportation of aerosols from land sources. The extinction coefficient for all aerosols decreased with height in all seasons. Aerosols such as desert dust, polluted dust, and elevated smoke were found throughout the entire troposphere, while clean marine and polluted continent aerosols were mostly below 3 km.