An Investigation of the Impact of Cloud Diurnal Cycle on Aerosol Direct Radiative Effect over the SE Atlantic Region Using SEVIRI and CALIPSO Data

The objective of this study is to understand how the diurnal cycle of cloud properties influences the direct aerosol radiative forcing (DARF). We focus on the southeast Atlantic region where transported smoke is often observed above low-level water clouds during burning seasons. We use the CALIPSO observations to derive the optical properties of aerosols and cloud observations from the SEVIRI to derive the high-temporal frequency cloud diurnal variation. Based on the collocated CALIPSO and SEVIRI observations, we first derive a DARF that accounts for the cloud dirunal cycle (DARF-dirunal). We also derive another set of DARF beased on the cloud properties observed at 1:30PM local time, which cooresponds to the A-train crossing time (DARF-0130pm). We will present a comparison between the two data sets to reveal the how the diurnal cycle of cloud properties influences the DARF.