THE CHARACTERS AND NUMERICAL DIAGNOSTIC ANALYSIS ON TORRENTIAL RAIN ON 23 MAY,2009 IN GUANGDONG

Guangdong suffered a torrential rain on 23 May,2009.Diagnostic analysis was made with U.S.National Centers for Environmental Protection reanalysis data and meteorological observations.Results show that a monsoon disturbance moved north along a stationary subtropical high and affected Pearl River Delta and western Guangdong.The divergence at high levels provided advantageous background field for the heavy rain.The primary influencing systems are the low-level jet and the monsoon disturbance which are related to the torrential rain closely.A linear diagnostic model for local Hadley circulation was used in simulation and quantitatively diagnosed,results show that the term of latent heat plays an important role in this process,and temperature advection due to the westerly system has indirection contribution.