The application of mesoscale weather chart analysis to short-duration heavy rain under the 500 hPa subtropical high of west Pacific in summer 2009

摘要

By using the synoptic chart, densified observation of precipitation and sounding data, the characteristic of the short-duration heavy rain which occurred over China mainland under the region which controlled by 500 hPa Subtropical High of west Pacific in summer 2009 are analyzed. Moreover, the typical examples are analyzed by mesoscale weather chart anaysis. Then the respect of mesoscale weather chart analysis would be given. Results demonstrate that the short-duration heavy rain is familiar in the region which controlled by 500 hPa Subtropical High of west Pacific in summer 2009. The occurrence days of short-duration heavy rain in the region which controlled by 500 hPa Subtropical High of west Pacific in summer 2009 are increased from June to August. The occurrence days of short-duration heavy rain in August are the most which are 95.7% of the Subtropical high control days. In summer the occurrence days of Short-duration heavy rain which controlled by Subtropical High are 71.4% of the Subtropical high control days. The short-duration heavy rain under the region which controlled by subtropical high occur in the forenoon more than in the afternoon. When we analyze the short-duration heavy rain under the 500 hPa subtropical high of west Pacific in summer 2009 by using the mesoscale weather chart analysis, we should pay attention to the significant moist region in the low level, the baroclinicity of Subtropical High, convergence of air flow in the low level, orographic uplift, 925 hPa level and convergence of water vapour etc..