鄂东南一次农业致灾暴雨的成因分析

利用常规观测和物理量场资料,从环流背景、水汽条件、动力条件和不稳定机制等方面对2010年4月21日鄂东南出现的农业致灾暴雨进行分析,结果表明,此次暴雨过程是在高空低槽、西南低涡、切变线、低空急流和地面暖倒槽的共同作用下发生的。低层充沛的水汽和源源不断的水汽输送为暴雨发生发展提供了有利的水汽条件;低层辐合、高层辐散和强烈的垂直上升运动为暴雨发生提供了有利的动力条件。850 hPa的温度露点差(T-Td)≤4℃的区域能提前12 h预告暴雨落区;1 000和925 hPa流场的中尺度辐合线能较好地预报出未来6 h强降水的落区。

Causal Analysis of An Agricultural Hazard Rainstorm Process in Southeast Hubei

Conventional observation and physical quantities field data was used to analyze the causes of an agricultural hazard rainstorm on April 21,2010 in Southeast of Hubei Province from the aspects of circulation,water vapor condition,kinetic condition and instability mechanism.The results showed that the heavy rainfall happened under the combine action of low trough,southwest low vortex,shear line,low-level southwest jet and ground warm inverted trough.Abundant low level water vapor and continual water vapor transfer provided advantageous vapor condition.Low level convergence,high level divergence and intense vertical ascent movement provided the dynamic conditions.Zone of which the dew point deficit was lower than 4 ℃ at 850 hPa was the indication of heavy rain area 12 h ahead.The mesoscale flow field convergence line at 1 000 and 925 hPa could forecast the heavy rainstorm area 6 h in advance.