Influence of convection and aerosol pollution on ice cloud particle effective radius

Abstract

Satellite observations show that ice cloud effective radius (<i>r</i>_e) increases with ice water content (IWC) but decreases with aerosol optical thickness (AOT). Using least-squares fitting to the observed data, we obtain an analytical formula to describe the variations of <i>r</i>_e with IWC and AOT for several regions with distinct characteristics of <i>r</i>_e-IWC-AOT relationships. As IWC directly relates to convective strength and AOT represents aerosol loading, our empirical formula provides a means to quantify the relative roles of dynamics and aerosols in controlling <i>r</i>_e in different geographical regions, and to establish a framework for parameterization of aerosol effects on <i>r</i>_e in climate models.