Radiative Effects on Precipitation: A South China Storm Case Study

Abstract

In this paper the effects of radiation on a meso-scale precipitating system is investigated during a severe storm in South China on June 8, 1998. This was done by using the Pennsylvania State University (PSU)/National Center for Atmospheric Research (NCAR)/Meso-scale Model 5 Version 3 (MM5_V3) after the introduction of radiative transfer schemes that are able to treat water clouds, ice crystals, snow, and groupel. The results suggest that the rainfall patterns do not differ too much for the various radiation schemes used in the numerical calculations, but rather influence the rainfall intensity in the central areas. The radiative effects on precipitation are more significant during daytime, as compared to nighttime. The diurnal variation of rainfall is enhanced by the radiative processes. Computed precipitation intensities, and radiative cooling/heating rates, are dependent on the specific radiative transfer scheme used. The results suggest that model improvement of daytime cloud radiative processes is crucial for a better representation of such effects on meso-scale precipitating system.