Strong Precipitation Suppression by Aerosols in Marine Low Clouds
Chongxing Fan, Minghuai Wang, Daniel Rosenfeld, Yannian Zhu, Jihu Liu, Baojun Chen
Abstract
Abstract The adjustment of cloud amount to aerosol effects occurs to a large extent in response to the aerosol effect on precipitation. Here the marine boundary layer clouds were studied by analyzing the dependence of rain intensity measured by Global Precipitation Measurement on cloud properties. We showed that detectable rain initiates when the drop effective radius at the cloud top (r e ) exceeds 14 μm, and precipitation is strongly suppressed with increasing cloud drop concentration (N d ), which contributes to the strong dependence of cloud amount on aerosols. The rain rate increases sharply with cloud thickness (CGT) and r e when r e > 14 μm. The dependence of rain rate on r e and CGT presents a simple framework for precipitation susceptibility to aerosols, which explains other previously observed relationships. We showed that sorting data by CGT and using alternative cloud condensation nuclei proxy rather than aerosol optical depth are critical for studying aerosol‐cloud‐precipitation interactions.