Polarimetric radar analysis of rain drop size variability in maritime and continental clouds

The focus of this paper is to examine the natural variability of the drop size distribution. The primary finding is that there are two basic rain drop size evolutions, one associated with continental air masses characterized by relatively high aerosol concentrations and long air trajectories over land and the other with maritime air masses with lower aerosol concentrations.

The size evolution difference is during the growth stage of the radar echoes. The differential radar reflectivity in the growing continental clouds is dominated by large rain drops, whereas in the maritime clouds differential reflectivity is dominated by small rain drops and drizzle. The drop size evolution in many of the maritime air masses was very similar to those observed in the maritime air of the Caribbean observed with the NCAR S-band polarimetric radar (S-Pol) during the Rain In Cumulus over the Ocean (RICO) experiment.