Satellite estimated cloud Radiative Forcing in the Presence of Aerosol events over the South of Portugal

Abstract

The present work aims to investigate the effects of Saharan desert dust storms on cloud properties and respective radiative forcing over the South of Portugal and nearby Atlantic Ocean, for a case study that occurred between 26 and 29 May 2006, using the MODerate Resolution Imaging Spectroradiometer (MODIS) satellite data. The determination of cloud properties in different regions subject to the presence of dust aerosols provides information on the possible alterations that these clouds may suffer due to the presence of an aerosol layer. Cloud effective radius, optical depth and water path retrieved values are considerably smaller for clouds developing in a dusty atmosphere than for clouds in a dust-free atmosphere. Due to these changes it was also possible to observe that the instantaneous cloud radiative forcing (ICRF) values at the top of the atmosphere (TOA) and at the surface are lower when dust aerosols are not present.