A correlative study on the relationship between modeled anthropogenic aerosol concentration and satellite-observed cloud properties over east Asia

Abstract

Vertically integrated anthropogenic aerosol mass concentration M a and low-level water cloud properties (optical depth τ, effective particle radius r e, and columnar droplet number N c) were correlated over east Asia to elucidate human-induced effects on low-cloud properties. Aerosol and cloud properties were obtained from numerical simulations and satellite observations, respectively. Monthly averages of geographical matches between collocated M a and cloud properties for three seasons showed that as M a increased, τ and N c increased and r e, decreased, which is consistent with the Twomey effect. Their changing rates became less steep when M a was large. However, the importance of a dynamical effect was also suggested. A comparison of different cloud top heights revealed that values of τ and r e of middle and lower clouds followed those of the total water cloud cases and reflected vertical characteristics. Copyright 2006 by the American Geophysical Union.