Spatial and temporal characteristics of severe precipitation in Hubei Province during the past 10 years and main weather conceptual model

Using hourly rainfall and wind field data of 78 meteorological stations in Hubei, reanalysis data from NCEP, Doppler-Radar data and satellite images, this paper investigated and analyzed spatial and temporal distribution, formation region and track of rain clusters, rainfall intensity and main circulation systems of 208 severe precipitation cases in Hubei from 1999 to 2009. The results indicate that formation region of severe precipitation in Hubei is mainly located in the western mountain area of Hubei and southern part of Jianghan Plain, and rain clusters moved with 6 tracks by effect of different steering flow. Meanwhile, severe precipitation high frequency areas are mainly located in Xiaogan, northern Huanggang and Yichang, and the high frequency center of severe precipitation in Hubei is in Xiaogan. Main synoptic systems caused severe precipitation include dry-line (named as dew-point front, the same as below), moist tongue, convergence area of warm-shear top, convergence area of cold-shear rear, airflow convergence zone, surge line and surface convergence line. According to the different role and influence of the dry-line, 180 severe precipitation cases with dry-line in Hubei have been classified into dry-intrusion type,dry-blending type, dry-frontogenesis type and warm and dry air type. By summary analysis of characteristics of dynamic, water vapor and instability conditions as well as severe precipitation distribution, the four types of weather conceptual model of dry-line severe precipitations are concluded.