Abstract
The first rainy season (April-May-June) of South China includes the phases before and after the onset of South China Sea Summer Monsoon (hereafter SCSSM). Abundant moisture supply is the key dynamic process for precipitation formation. Thus, we employ the FLEXPART model to explore the corresponding moisture sources for the two phases. Before the onset of SCSSM, land regions contribute more moisture to the precipitation over South China than the ocean sources. The main source regions are Southeastern Asia (27.01%), South China Sea (25.96%), South China (11.12), and southern part of northwestern Pacific (10.23%). Land sources (66.87%) play a more important role than ocean sources (33.13%) in the interannual variations, with the contributions mainly from Southeastern Asia (47.56%) and South China Sea (28.79%). After the onset of SCSSM, the climatological contribution of ocean sources is larger than that of land regions, and the main source regions are South China Sea (20.78%), Southeastern Asia (17.51%), Bay of Bengal (13.76%), and South China (11.21%). For the interannual variations, the contributions of land sources and ocean regions are comparable, and mainly from Southeastern Asia (33.53%) and the Bay of Bengal (32.26%). The moisture transports for the interannual variations in FRS precipitation over South China before and after the onset of SCSSM are significantly correlated with the east-west contrast of sea surface temperature anomalies over northern part of North Pacific and the uniform warming over Indian Ocean, respectively. This study provides important guidance in improving the regional precipitation predictions and understanding the water resources changes.
Impact of parameterizing the turbulent orographic form drag on convection-permitting simulations of winds and precipitation over South China during the 2019 pre-summer rainy season
