The stratiform and convective components of surface precipitation

Abstract

One year of precipitation records taken from a subset of the World Meteorological Organization (WMO) global rain gauge network has been analyzed. This analysis has shown that the distribution of accumulation of precipitation with the rainfall rate is characterized by an exponential law. This relationship seems to be universal and is present regardless of the averaging interval considered. The data structure suggests that this exponential distribution can be used as a basic state to partition surface precipitation into stratiform and convective components. The physical basis of this approach is investigated and discussed using Monte Carlo simulations based on a simple cloud model. The methodology is validated using a Fourier analysis in time, and average global monthly maps of convective and stratiform precipitation are presented to illustrate the feasibility of the technique.