Different characteristics of extreme precipitation in southern China

Based on the daily precipitation data of 206 stations in seven provinces of southern China from 1961 to 2020, the 95th percentile extreme precipitation of 20:00 BT-08:00 BT (nighttime), 08:00 BT-20:00 BT (daytime) and 20:00 BT- 20:00 BT (all-day) was extracted by percentile method, the temporal and spatial characteristics of 60 years' extreme precipitation, frequency, the earliest start time and the latest end time are analyzed. The results are as follows. (1) The spatial distribution characteristics of night, day and all-day extreme precipitation thresholds were similar, and the extreme precipitation at night was larger than that at day. (2) The long-term change of extreme precipitation and frequency in southern China are both increasing significantly. More than 70% of the stations with nighttime and daytime extreme precipitation and frequency are increasing; and nearly 80% of the stations with all-day extreme precipitation and frequency are also increasing. (3) The spatial distribution of extreme precipitation in southern China is uneven and varies between day and night.The high value area of the annual mean extreme precipitation in the south is in the southern part of Guangdong and Guangxi, the annual average extreme precipitation at night is larger than that at daytime; the large value distribution of the annual average extreme precipitation frequency is obviously different from that of extreme precipitation, high frequency area of extreme precipitation of daytime and all-day are located in the central and eastern parts of the Southern China, most of the regions with high frequency of night extreme precipitation at night are located in the northwest of the southern China. (4) The time period of extreme precipitation from beginning to end in southern China is lengthening. More than 60 percent of the stations had an earlier start and later end time trend for both nighttime and daytime extreme precipitation, and more than 67 percent had an earlier start and later end time trend for all-day extreme precipitation, overall, the start time was 2 days earlier on average in 10 years, and the end time was 2 days later on average in 10 years. The onset time of extreme precipitation is the earliest in the central part of South China, and the latest in the southwestern part of Guangdong and the western part of Guangxi and Guizhou; the end time of extreme precipitation is earliest in north Jiangxi and latest in east Zhejiang.