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CR prepress abstract   -  DOI:

Extreme precipitation changes over the Yangtze River Basin in 1901-2020

Siqi Zhang, Guoyu Ren*, Yunjian Zhan, Cunjie Zhang, Yuyu Ren

*Corresponding author:

ABSTRACT: In order to understand the characteristics of the long-term change and variability in regional extreme precipitation, and the possible regional response to global climate warming, we analyzed the temporal and spatial patterns of precipitation value and extreme precipitation index changes over the Yangtze River Basin (YRB) during the last 120 years. Based on the China Meteorological Administration Daily precipitation dataset of 60 city stations in China mainland from 1901 to 2020, we found that the total annual precipitation and daily precipitation intensity of the Upper Reaches (UR) experienced a downward trend, but those of the Middle and Lower Reaches (MLR) showed an upward trend. The precipitation amount and intensity increased, and the number of precipitation days slightly decreased over the YRB during 1901–2020. Most of the extreme precipitation indices showed a decreasing trend in the first 60 years, which reversed after 1961, with slightly upward trends, except for consecutive dry days and wet days in the YRB during 1901–2020. There were significant downward trends for consecutive dry days and maximum one- and five-day precipitation during the first 60 years, and significant upward trends for maximum one-day precipitation, total extreme heavy precipitation, and very heavy precipitation days in the last 60 years. The trends for extreme precipitation in the UR were lower than those in the MLR during 1901−2020, particularly in the last 60 years, whereas the trends in the UR were higher than those in the MLR during 1901–1960. The fluctuations of extreme precipitation indices in the UR were more dramatic than those in the MLR, and the extreme precipitation indices all showed 5−10 year or 20 year periodic variabilities. The analysis also showed that the observed changes in regional extreme events were directly related to the rapid urbanization around the stations and multi-decadal variability of the East Asian monsoon.