The Mechanism Of The Influence Of The Moving Speed Of Tropical Cyclones Landing In The South China Sea On China's Precipitatio

Interactions between tropical cyclones(TCs)and mid-latitude weather systems can lead to varying Predecessor Rain Events(PREs),which can result in severe disasters.This study focuses on TCs making landfall from the South China Sea with similar tracks but different translation speeds,leading to different PREs.Understanding the impact of landfalling TCs with varying translation speeds on precipitation in mainland China is crucial for improving operational forecasting of PREs.The key findings are as follows:Analysis of the factors influencing the translation speed of landfalling TCs reveals that the South Asian High(SAH)and the Western Pacific Sub-tropical High(WPSH)are the main systems affecting TCs’ translation speeds.The disparity in translation speeds between Fast West TCs(FW)and Slow West TCs(SW)is primarily attributed to variations in the form and intensity of the SAH and WPSH.The distribution of PREs from FW and SW TCs in North and Central China exhibits an inverse north-south phase pattern.FW TCs produce more precipitation in northern China,while SW TCs result in significantly higher rainfall in central China.The most pronounced differences in precipitation occur in the Jianghuai and Jiangnan regions.The disparities in PREs during landfalling of FW and SW TCs in mainland China are closely linked to mid-latitude systems.The shifting of the upper-level jet stream from north to south is the primary driver of the spatial distribution differences in precipitation.FW TCs influence precipitation directly through their impact on water vapor transport.SW TCs,on the other hand,affect the intensity of the SAH,subsequently influencing the evolution of midlatitude westerly troughs through topographic forcing.This indirect effect induces variations in PREs by altering dynamic configurations.