Characteristics of Extremely Daily Precipitation Events in the Mid-Eastern Tibetan Plateau during the Summer of 1980~2019

Based on the daily observation data of the National Meteorological Stations of China Meteorological Administration, the extreme daily precipitation events in the middle and eastern Tibetan Plateau during the summer of 1980-2019 were defined by the percentile method, and the climatic distribution characteristics of extreme daily precipitation events in different quantiles were analyzed. The results show that: (1) The summer precipitation in the central and eastern Tibetan Plateau was characterized by an antiphase distribution of more in the east than that in the west, and more in the middle than that in the north and south, and there were obvious interannual and interdecadal variations. (2) 99 % quantile precipitation thresholds were generally above 24 mm / d, 95 % and 90 % quantile precipitation thresholds were maintained at 12~20 mm / d, and 75 % quantile precipitation thresholds were further decreased to 7~9 mm / d. (3) From the perspective of long-term change trend, the frequency of extreme daily precipitation at 99 % quantiles in the central and eastern Tibetan Plateau showed an obvious upward trend, while the other quantiles showed a downward trend. (4) Compared with the 99% and 90% quantiles, the 95% quantile extreme daily precipitation events had a more important contribution to the summer precipitation in the mid-eastern Tibetan Plateau, and the contribution of the 99% quantile was increasing in recent 40 years. (5) The daily precipitation values in mid-eastern Tibetan Plateau ranged from 0.1 mm to 10.5 mm, but the positions of the frequency peaks of daily precipitation and the total precipitation peaks were different. The daily precipitation of 2.4~5.1 mm played an important role in the precipitation in the mid-eastern Tibetan Plateau.