Assessment of aerosol-cloud interactions over the Northern Indian Ocean

Abstract

The interaction between aerosol and cloud causes one of the largest uncertainties in external forcing to our climate system, highlighting the importance of additional extensive research on aerosol - cloud interaction (ACI). Thus, in this study nearly two-decades (2000?2021) of Moderate Resolution Imaging Spectroradiometer (MODIS) derived aerosol and cloud dataset have been analysed to examine the warm cloud sensitivity to aerosols over the Northern Indian Ocean (NIO). We found a statistically significant anti-Twomey effect in warm clouds for lower liquid water path (< 70 gm?2) throughout all seasons, except for a pronounced Twomey effect during the monsoon season in the northern region. Nonetheless, limitations in satellite retrievals of cloud droplets prevent definitive conclusions on cloud droplet sensitivity. On other hand, albedo susceptibility indicates existence of cloud brightening in cleaner equatorial oceanic regions. Our results emphasize the importance of considering the distinctness of ACI at regional scale in global climate models which is essential for effectively constraining associated forcing mechanisms and enhancing the reliability of future predictions.