Analyzing radiative effect of dust and its impact on energy budget and cloudiness over Cabo Verde

Dust is a dominant aerosol type over Cabo Verde, sourced via long-range transport from Sahara and Sahel. Understanding the effects of the dust on surface energy balance, and thus temperature and precipitation has important implications for predicting the weather and climate in the region. Although such studies have been conducted over west Africa, their findings cannot be applied to Cabo Verde, where the meteorological regime is dominated by the Atlantic Ocean, with local effects of island topography and a distinct interaction between ITCZ migration and large-scale dust transport compared to that over continental Africa.  Here, we analyze how the interaction between dust and radiation influences the radiative energy at the Top of Atmosphere (TOA) and at the surface, and how it affects cloudiness over Cabo Verde from 2018 to 2022. The Aerosol Optical Depth (AOD) data are from a ground-based sunphotometer AERONET and from the spaceborne CERES instruments. Saharan dust loading peaks in the Summer. June shows the highest AOD values with monthly mean reaching 1.4. Direct radiative effect (DRE) and indirect radiative effect (IRE) are calculated from CERES CRS1deg-Hour Ed4A, which includes clear sky, pristine and all sky conditions. Results showed that DRE in all seasons presents a net cooling at surface and at the TOA. The IRE shows net cooling on the surface and warming at the TOA. We also investigate how dust events are associated with the mean temperature (reanalysis data), liquid water path, precipitable water and the cloud amount (all three datasets are from CERES and geostationary satellite) combined with the height at which the dust is present (vertical profiles from spaceborne lidar). Further research aims to understand the changes in precipitation over Cabo Verde associated with large-scale dust transport.