Impacts of Mesoscale Cloud Organization on Aerosol‐Induced Cloud Water Adjustment and Cloud Brightness

Abstract

Abstract The role of mesoscale cellular convection (MCC) in regulating aerosol‐induced cloud brightness remains unaddressed. Using 7 years of satellite‐based observations of cloud water adjustment to aerosol‐induced perturbations for closed MCCs across different sizes (8, 16, 32, and 64 km) over the North Atlantic Ocean, we show that MCC cell‐size plays a nontrivial role in regulating aerosol‐induced cloud brightness via cloud water adjustment. In cells that are primarily non‐precipitating, the adjustment in small‐scale MCCs can be 10 times more negative than in large‐scale MCCs, consistent with stronger evaporation via cloud top entrainment. Consequently, the response of cloud brightness is significantly stronger for large‐scale MCCs. We also find notable intra‐cell co‐variability between cloud liquid water path (LWP) and drop concentration (Nd) within MCCs that varies with cell size. Erroneously considering such co‐variability as a LWP response to Nd can lead to a significant positive bias, especially for small scale MCCs.