Multiple factors’ diagnostic analysis of a heavy rainstorm process in Zhuanghe region, Liaoning province

Based on the conventional observation data, the automatic weather station data, Doppler radar data and NCEP 1°×1° data, a heavy rainstorm process on August 10-12, 2007 was analyzed with radar echo and physical vector diagnostic analysis methods in Zhuanghe, Liaoning province. The results indicate the heavy rainstorm process in Zhuanghe is generated by the conjunct actions of deeply warm-wet air current in subtropical high pressure back, west wind belt upper trough, shear line and cyclone inverse trough, but there is no strong thunderstorm. The main influencing system of this process is ground cyclone inverse trough. 700 hPa and 850 hPa lower vortex and shear line make the middle and lower levels convergence strong and come into being the dynamic lift and water vapor convergence. Zhuanghe is located in the strong and wide potential pseudo-equivalent temperature frontal zone, so the establishment of potential instability is indispensable conditions of this process. The water vapor causing the heavy rainstorm weather comes from (1) the Bay of Bengal and the weakened tropical depression, and (2) from the East China Sea.