Abstract:
From the aspects of unstable energy sources for convective development, uplifting mechanism, and vertical shear of environmental wind, this work studies how the monsoon flow affects the intensity and distribution of typhoon precipitation. For this, CMORPH (CPC morphing technique) satellite data product obtained from the CPC’s (Climate Prediction Center) morphing technique, JRA-55 (55-year-old Japanese reanalysis products), and TBB (blackbody brightness temperature) data from the FY-2E (FengYun-2E) satellite were used, and the strong monsoon-influenced case 0604 “Bilis” and weak monsoon-influenced case 0708 “Sepat”, which have similar paths and cause heavy precipitation in the southern area of the Hunan Province after landfall, were selected. The analysis showed that with a similar underlying surface and topography, the main causes of heavy precipitation of the two cases are different. This is mainly reflected in the factors that induce and maintain convection. The strong convergent updraft and convective instability under the strong monsoon background were the main factors leading to the heavy rain of “Bilis”, while the rainstorm of “Sepat” was mainly due to the local orographic lift and baroclinic instability under the weak monsoon background. Moreover, the precipitation of “Bilis” was obviously asymmetric, which indicated that the monsoon flow could lead to asymmetric precipitation by changing the vertical shear of the environmental wind indirectly.