Abstract:
During 18-20, June and 17-18, September in 2014, there occurred two infrequent heavy rain in western Guizhou caused by Inverted Trough of Typhoon, which results in serious disaster. Based on observations and NCEP reanalysis data, the two heavy rain cases caused by inverted trough of typhoon in western Guizhou was analyzed. Analysis found that: The two typhoon trough heavy rains are produced under the condition that the stability of the subtropical high pressure of 588 line is in the western edge of Hunan. The typhoons weaken into the tropical depressions after landing. After the tropical depressions under the influence of easterly airflow on the south side of the subtropical high westbound to western Guangxi, rainstorms happen which the northeast of typhoon trough affects in Guizhou. The southeast jet from the periphery of typhoon depression brings abundant water vapor and unstable energy from the South China Sea to the rainstorm area. The typhoon trough rainstorm of Wimason (on July 19-20, 2014) is effect on the single typhoon trough. Although the thermal instability stratification lasted longer, both the ascending movement and convergence or divergence are not strong, corresponding to weak rainstorm intensity and the less and scattered sites. Both the low-level shear and the typhoon trough impact on the typhoon trough rainstorm of Seagull (on September 17-18, 2014). And the strong water vapor convergence is formed in the southerly airflow between the two systems. The ascending movement and convergence or divergence last longly, corresponding to the long time of rainstorm rainfall and the more and concentrated sites. The analysis of weather system configuration on forecast point over the western Guizhou and the distribution variation characteristics of water vapor flux and water vapor flux divergence have good indication function for the prediction and warning of typhoon trough in western Guizhou.