Based on NCEP 1°×1° reanalysis data,ground encryption hourly precipitation,FY-2E stationary satellite and Doppler radar data,the structural characteristics of precipitation clouds in Hunan Province and the effects of airplane precipitation operation were analyzed.The results show that under the effects of low-pressure system and southwest monsoon,Hunan was rich in water vapor,which was beneficial to the maintaining of precipitation clouds.During the process of the artificial precipitation operation over Hunan Province,convection developed vigorously,and precipitation was strong in the south of the province; embedded convective clouds were dominant and precipitation was weak in the east of the province.Cloud optical thickness correlated with ground precipitation positively.After catalyzing,echo at high altitudes responded firstly,and the echo intensity increased gradually; the response of low-altitude echo lagged behind that of high-altitude echo.It shows that catalysis could lead to increase of upper precipitation particles in size and quantity.As time goes on,upper precipitation particles descended to low altitudes,so that echo intensity increased at low altitudes.It is clearly seen that catalysis could lead to increase of echo intensity and prolong the lifetime of target clouds to improve the area of strong echo zone,showing obvious positive catalytic effect.At the same time,hourly average precipitation in the affected region tended to increase stably and was obviously more than that of the contrast region where hourly average precipitation reduced gradually with time.The changing trend of hourly average precipitation in the affected region correlated positively with the response of radar echo.
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