Climatology of Saharan Dust Plume Height over North Atlantic Ocean Retrieved by EPIC/DSCOVR

Abstract:

Vertical distribution of aerosol is a significant parameter that can determine the magnitude and even the sign of the effects of aerosols on the radiative balance of the earth-atmosphere system. Based on the algorithm of retrieving AOD and aerosol layer height (ALH) using oxygen absorption bands from EPIC measurements, developed by Xu et al. (2017), which demonstrated the potential of global ALH retrieval on a daily basis, we retrieved the optical depth and altitude of Saharan dust plumes over subtropical North Atlantic Ocean for a long time period from June 2015 to June 2019. The monthly climatology of the retrieved ALH indicates that Saharan dust plumes over North Atlantic Ocean reach the highest altitude in July, while are lowest in February. Dust plume height is significantly higher in summer than that in winter. We also analyzed the hourly climatology of Saharan dust plume height, which shows that over North Atlantic Ocean, dust plumes are very low in the morning, keeping raising to noontime, and remain high altitudes until 15:00-16:00 UTC, then descend to a low altitude till sunset. We also validated the EPIC retrieval climatology with CALIOP and compared that with MERRA-2 data. Our work demonstrates the seasonal and diurnal variation of Saharan dust plume height over North Atlantic Ocean, and it may further help climate models to better estimate the aerosol radiative effects.