Drizzle correlations with giant nuclei

Abstract

Giant nuclei (GN) concentrations (N GN) below RICO small cumulus clouds were substantially correlated with drizzle drop concentrations (N d), especially at higher cloud altitudes. The N GN -N d correlation coefficients (R) progressively increased with altitude whereas R for CCN concentrations with N d were negative with mostly decreasing magnitudes at increasing altitudes. These results indicate that the positive influence of GN [or CCN with low critical supersaturations (S c)] on N d is greater than the negative influence of high S c CCN on N d at high cloud altitudes where there are more drizzle drops. This work has implications not only for fundamental cloud physics but also for climate change; i.e., global warming and the indirect aerosol effect as well as geoengineering and hygroscopic cloud seeding. Copyright 2011 by the American Geophysical Union.