The Statistics And Analysis Of Weather Radar Echo Of Convective Clouds Merging Over AnHui In Summer

Doppler Weather Radar data in each summer (June to August) of 2003～2006 around Hefei were investigated to analyze the characteristics of convective clouds merger in Anhui. Results show a frequent occurrence and a typical spatial and temporal distribution characteristic of merger coinciding very well with the Severe Convections in summer. a) Cloud mergers often occur during late June and early August, with a prominent peak during late July. The diurnal variation of cloud mergers shows a peak during the period of 14:00～15:00 LST. b) Cloud mergers show a distinct spatial grouping associated to mesoscale topography. Three high frequency areas are Dabieshan mountain area, Huangshan mountain area and Jianghuai hilly area near Dingyuan. c) The frequence of small cloud merger is 75 %. d) Merging has a significant effect on cloud system developing. More than 77% merged clouds have apparent extension in intensity, area and lifetime. e) The merger frequence of new-born clouds within 10dBZ intensity is about 82%. Obvious changes of the merged cloud are found through analyzing two events of heavy rainfall and hailstorm.