Heavy Rain Storm Floods in China and their Estimation

Four heavy rainstorm systems resulted in extraordinary floods in China are presented. Each has its synoptic feature which are different from those of ordinary heavy rainstorms. There is a reason to believe that extraordinary floods and frequent and minor floods do not come from the same parent population. In addition to this, it is difficult to estimate the recurrence interval of historic floods. And therefore the outliers could hardly match the ordinary floods even if the historic floods are involved. Closely scrutinizing the features of the heavy rain storms, we find that Probable Maximum Precipitation and Flood (PMP/PMF) estimation is favorable compared with that of frequency analysis.