Contribution of the main moisture sources to precipitation during extreme peak precipitation months

Abstract

A worldwide study is presented to understand the role of major global moisture source regions in the occurrence of extreme monthly precipitation over the continents. The Lagrangian model FLEXPART v9.0 was used to analyse the moisture transport for precipitation, and the extreme precipitation was calculated for each grid point (at 0.25°) using the Multi-Source Weighted-Ensemble Precipitation (MSWEP) monthly precipitation dataset. Although the eventual aim of this work is to show the link between the contributions from the sources to their sinks during months of extreme rainfall, we provide, for the first time, much-needed information on these contributions at a monthly scale – previously this information was only available at an annual scale. We also provide maps showing global monthly moisture sources, together with the identification of the peak precipitation month (PPM) and of the preferred moisture source for precipitation in that month.