Spatial and temporal variations of short-duration heavy precipitation in Jiangxi during 1961-2015

Using the hourly rainfall data from 83 national weather stations in Jiangxi from 1961 to 2015, combined with Empirical Orthogonal Function (EOF) and Morlet wavelet analysis, we have analyzed the temporal and spatial distribution characteristics of short-duration heavy precipitation (i.e. larger than or equal to 20 mm per hour) in Jiangxi, and discussed the relation between rainstorm and short-duration heavy precipitation. The results show that both the maximum and frequency of short-duration heavy precipitation show a spatial distribution of high in the eastern and low in the western Jiangxi. Consistent anomaly distribution is a main spatial mode of short-duration heavy precipitation frequency in Jiangxi, whose anomalous sensitive area is located in the places along Zhejiang-Jiangxi railway. In recent 55 years, the frequency of short-duration heavy precipitation has an obvious increasing trend which is positively responding to regional warming of Jiangxi, and it presents two inter-decadal variation periods of about 21 and 14 years. The short-duration heavy precipitation often happens between April and September, and it is the most frequent in June. The diurnal variation of short-duration heavy precipitation shows double-peak distribution between April to July, while single-peak distribution between August and September. The short-duration heavy precipitation occurs the most frequently between 16:00 and 17:00 every day. The high frequency area of short-duration heavy precipitation is similar to that of rainstorm, and their space similarity coefficient reaches 0.98. The short-duration heavy precipitation accompanied with the rainstorm accounts for 54.6%. Especially, the probability of rainstorm is 69.2% to 76.9% from early morning to midday at the day when short-duration heavy precipitation occurs.