Statistical analysis of climatological characteristics of spring rainstorm in Anhui province

Based on daily precipitation data collected at 80 stations in Anhui province during 1961-2012, and NCEP/NCAR daily reanalysis data with 2.5°×2.5° resolution, the climatological characteristics and circulation features of spring rainstorm in Anhui were analyzed. In particular, this study puts emphasis on discussing the relationship between rainstorm and coastal height denoted with CH₅₀₀ (geopotential height on 500 hPa at 120°E, 30°N, unit: dagpm). Results are shown as follows. (1) The total precipitation of spring rainstorm varied small from year to year, and had obvious decadal change for temporal characteristics. For spatial distribution of occurrence, spring rainstorm varied with latitude, basically, decreased from the south to the north with relatively homogeneous average precipitation. (2) CH₅₀₀ is a key factor to forecasting spring rainstorm. Generally, higher CH₅₀₀ leads to more spring rainstorms, but the probability of occurrence varies in different months and regions. Thus, the following threshold of CH₅₀₀ can be used in forecasting operations: Huaibei rainstorm on March (568, 580), April (572, 584), May (576, 588), Jianghuai rainstorm on March (568, 580), April (568, 584), May (568, 588), and Jiangnan rainstorm on March (564, 580), April (564, 584), May (568, 588).