Analysis of spatiotemporal characteristics of extreme precipitation in the Yellow River basin based on CMIP6

Under the background of global warming, the risk of extreme precipitation disasters has increased, which has seriously affected people's life safety and caused a serious threat to regional economic development. The Yellow River Basin is the mother river of China. It is an important ecological barrier and economic zone. Promoting the ecological protection and high-quality development of the Yellow River basin has become China's national strategy. Therefore, we studied the past and future characteristics of extreme precipitation events in the Yellow River basin. The results show that:: (1) From 1975 to 2014, all extreme precipitation indices showed decreasing trends from southeast to northwest. On the temporal scale, except for Annual total wet-day precipitation, Number of heavy precipitation days and Max 5-day precipitation amount, other extreme precipitation indices showed increasing trends but are not significant. There are few extreme precipitation events; (2) From 2015 to 2100, the extreme precipitation index showed a significant upward trend, and the spatial distribution pattern of the multi-annual mean value of the extreme precipitation index was similar to that of the historical period. With the increase of emission, the greater the radiation force, the area of the extreme precipitation index showed a significant increase continued to expand. Under SSP1-2.6 and SSP2-4.5 scenarios, the area of the Yellow River Basin with a significant increase was concentrated in the southwest, while under SSP3-7.0 and SSP5-8.5 scenarios, the extreme precipitation in most of the eastern region except the southwest region showed a significant increase. In addition to annual precipitation, the other extreme precipitation index showed a significant decreasing trend with the increase of emission, which gradually concentrated in Gansu and Qinghai provinces; (3) The annual average precipitation of the Yellow River basin in four seasons shows an increasing trend, and there is a trend of wetting in different seasons. In addition to Ningxia, the two indexes of Max 1-day precipitation amount and Max 5-day precipitation amount in other regions show an increasing trend in different degrees in the four seasons. The maximum values of the two indexes of Max 1-day precipitation amount and Max 5-day precipitation amount in each region are concentrated in July. It is estimated that the rainstorm and flood disasters in the Yellow River basin in the future will mainly occur in summer. This study can provide effective basis for the prevention of extreme precipitation in the Yellow River basin and scientific reference for the high-quality development of the Yellow River basin.