1970-2020年黄土高原水蚀风蚀交错区极端降水时空变化研究及驱动因素分析OA北大核心CSTPCD

As a typical ecologically vulnerable area in northern China,the ecologically vulnerable area of the Loess Plateau is significantly affected by extreme rainfall events because of its unique topography and climatic conditions.Twenty-eight meteorological stations in the water-wind erosion crisscross region were selected,and eleven extreme precipitation indices were calculated using the RClimDex model.Linear correlation analysis,the Mann-Kendall trend test,and the wavelet crossing method were used to analyze the spatial-temporal distribution characteristics of extreme precipitation events in the water-wind erosion crisscross region of the Loess Plateau from 1970 to 2020.Driving factors for extreme precipitation events are discussed.The results are as follows:(1)The number of continuous dry days in the water and wind erosion interlacing zone from 1970 to 2020 shows a de-creasing trend,whereas the other 10 indices show an increasing trend,reflecting the increasing frequency,magni-tude,and intensity of extreme precipitation events in the study area during the past 50 years.There is a close rela-tionship between increases in annual precipitation and extreme precipitation events,and an increase in extreme precipitation events is mainly caused by the number of moderate and heavy rain days.(2)Extreme precipitation events show an increasing trend in the entire region from 1970 to 2020,with significant extreme precipitation events occurring in the central and southwest parts of the crisscross region.The extreme precipitation and intensi-ty in the Shaanxi section show a significant increasing trend,and the extreme degree is very significant.(3)The three extreme precipitation indices,total wet day precipitation,number of heavy rain days,and 5-day maximum precipitation,have varying degrees of influence from El Nino-Southern Oscillation,East Asian Summer Mon-soon,and sunspot number(SN),with cross wavelet transform with SN having the greatest influence.This shows that the correlation between SN and extreme precipitation index is the highest among the influencing factors,and SNs have the greatest influence on extreme precipitation events.