Budget Analysis Of Precipitation And Energetics Associated With Torrential Rainfall Events Over Zhejiang,Fujian And Jiangxi

The statistical results show that there is a significant precipitation center in the Zhejiang-Fujian-Jiangxi region during the East Asian summer monsoon advancement.This paper analyzes 4 torrential rainfall events in the Zhejiang-Fujian-Jiangxi region during early summer.Meteorology and dynamic diagnostics results shows that the intensity and location of the west Pacific subtropical high(WPSH)has profoundly affected torrential rainfall events.The system directly causing precipitation is the front between the warm and humid East Asian summer air mass and the dry and cold continental air mass and related systems.The front exists in the large gradient area of the pseudo-equivalent temperature.The main source of water vapor for precipitation comes from the South China Sea and the Bay of Bengal brought by the southwesterly wind.The southerly airflow is the strongest.The results of cloud resolving model show that water vapor convergence(QWVE)is paramount in the water vapor related surface rainfall budget,while heat divergence(SHF)contributes the most in the heat related surface rainfall budget.Linear correlation between water vapor related precipitation efficiency(PEWV)and heat related precipitation efficiency(PEH)is excellent.This correlation stems from similarity between QWVF and SHF.Precipitation efficiency increases with rainfall development and stays high during mature stage.A new energy conversion efficiency can be conducted by regarding convective available potential energy(CAPE)as the source of perturbation kinetic energy(K')after vertical integration.The relationship between surface rainfall rate,precipitation efficiency and energy conversion efficiency is decided by dynamical process and water vapor transportation simultaneously.Daily rainfall peak appears in the afternoon at local time.The heat effect of ice cloud contains two parts:latent heat effect and radiation effect.By altering the vertical structure of atmosphere,the heat effect of ice cloud changes net condensation of the whole atmosphere,causing the fluctuation of rainfall finally.The phrase of daily rainfall trend advances lightly due to the heat effect of ice cloud.