Title: CHARACTERIZATION OF EXTREME RAINFALL IN AN EAST ASIAN MONSOON-CLIMATE CATCHMENT IN THE UPPER REACHES OF THE HUAI RIVER, CHINA
Abstract: A total of 200 heavy rainfall events with duration from 1 to 10 days were studied regarding maximum point depth, duration, areal extent, storm centre distribution, and seasonal distribution. The data base includes daily rainfall recordings from 78 stations in the Hongru River basin, an upper tributary to the Huai River, from 1955 to 1987. The 12 380 km2 large basin is situated on the outskirts of the North China Plain, and is controlled by the East Asian monsoon. The events were selected to include the largest daily point rainfalls in the data base. Each event thus includes at least one day with precipitation exceeding 79ċ 5 mm day−1 at any point. The 200 storms were divided into three categories depending on the isohyetal pattern formed by the accumulated rainfall; isolated convective rainfall, rainfall evenly distributed over the basin, and convective rainfall towering over a background rainfall. Rainfalls of the last two categories generally cover an area larger than the basin, and display several similarities, but also certain differences. Duration and average rainfall are comparable, but the category with convective components reaches much larger maximum point depths. The evenly distributed rainfalls often display a gradient in a predominant direction, and they seem to be connected more strongly with the occurrence of the Mei-Yu front. The storm centres of the two categories with convective features show a preference of occurrence at higher altitudes.