Comparative study on short-duration designed storm patterns of different weather systems in Chongqing

In this paper, using 1-minute precipitation data from 1961 to 2017 at the national basic meteorological station of Shapingba in Chongqing, regional and convective designed storm patterns calculated by the method of Pilgrim&Cordery are comparatively studied, which are classified according to weather system. The results show that regional storm samples account for 52.6%. Regional designed storm pattern for 60-minute single-peak pattern and uniform distribution account for 36.7% and 26.7%, respectively. The 120-minute is also single-peak, but the peak was in the middle. The 180-minute is single-peak and the peak is in the front. The convective storm samples account for 47.4%. The Short-duration convective designed storm patterns are mainly single-peak and the peaks are in the front. By comparison, the convective designed storm pattern's peak occurs in advance, the intensity is stronger and the rainfall accumulates more quickly. The peak occurs 5 minutes earlier for 60-minute, 35 minutes for 120-minute and 20 minutes for 180-minute. Under a 10-year recurrence period, the peak intensity is 0.5 mm·min^-1 higher for 60-minute, 0.9 mm·min^-1 higher for 120-minute and 0.9 mm·min^-1 higher for 180-minute. With the same designed rainfall, the convective designed storm pattern results in longer waterlogging time, more accumulated water and more severe flooding.