Climatological characteristics of night rain in Yunnan Province

Based on the hourly precipitation data at 124 stations from 1977 to 2017, the basic climatological characteristics of night rainfall rate, frequency and intensity in Yunnan province are analyzed by using the statistical methods such as time and space averaging. The results show that: (1) Night rain accounts for a large proportion of daily precipitation in Yunnan, which can exceed 50% in most areas for all seasons, and has significant regional differences. The annual variation of night rainfall rate has a complex and special three-peak pattern. (2) The annual frequency of night rain in Yunnan is more in the east and west than in the middle, which mainly comes from the contribution of the typical high frequency area of night rain in the east and west of Yunnan in spring and winter. In winter and spring, the high frequency area of night rain in eastern and western Yunnan is affected by the southwesterly wind system, Kunming quasi-stationary front and Yunnan topography. (3) The northern and southern margins of Yunnan province are the high value areas of night rainfall intensity in most of the year, while the middle part is relatively weak. In most areas of Yunnan, the intensity of night rain in summer and autumn is higher than that in spring and winter, but the intensity of night rain in winter and spring in northwest margins of Yunnan is higher than that in summer and autumn.