Spatiotemporal Heterogeneity of Aerosol and Cloud Properties Over the Southeast Atlantic: An Observational Analysis

摘要

The southeast Atlantic has expansive aerosol plumes overlying clouds for a third of each year. Aerosol optical depths (AODs) were measured from the airborne Sun photometer and lidar during the 2016 NASA ObseRvations of Aerosols above CLouds and their intEractionS field campaign. We compare these measurements with one another and with collocated Moderate Resolution Imaging Spectroradiometer (MODIS) observations at native spatial resolutions using ＜ 15-min and 3-h temporal collocation criteria. We find better statistical relationships for the ＜ 15-min temporal resolution, indicating that AODs in the southeast Atlantic commonly vary below three-hourly temporal scales over MODIS spatial resolutions. We also use the airborne Solar Spectral Flux Radiometer (SSFR) to conduct the first comprehensive evaluation of attenuation-corrected below-aerosol cloud optical depths (CODs) from MODIS and the Spinning Enhanced Visible and Infrared Imager (SEVIRI). MODIS COD retrievals improve their agreement with the SSFR when accounting for overlying aerosol attenuation whereas SEVIRI CODs are mostly underestimated.