近60a黄河上游流域不同强度降水及大气湿润指数变化的新特征OA北大核心CSTPCD

An in-depth study of precipitation and atmospheric humidity in the upper reaches of the Yellow River Basin aims to provide a scientific basis for its ecological environment protection.Data on precipitation,air pres-sure,air temperature,wind speed,and relative humidity from 36 meteorological stations in the upper Yellow Riv-er Basin from 1961 to 2020 were selected to analyze the variation characteristics of precipitation,rain days,and atmospheric humidity index of different intensities over the past 60 years.The analysis employed the least square method,Mann-Kendall mutation test,and correlation analysis.The results reveal the following:(1)Annual precip-itation in the upper reaches of the Yellow River Basin is higher in the southwest and lower in the northeast,in-creasing at a rate of 4.9 mm·(10a)-1 over the past 60 years,especially in summer.(2)Except for a decrease in light rain days,light rainfall,moderate rain days,moderate rainfall,and heavy rain days,heavy rainfall all showed an increasing trend,with moderate rainfall increasing most significantly in the flow-producing region dur-ing summer.(3)The humidity index of the upper reaches of the Yellow River consistently showed a downward trend,with the largest decline in the headwater region.This mutation occurred in 1989.(4)With the warming cli-mate,the potential evapotranspiration in the upper reaches of the Yellow River Basin has increased at a faster rate than precipitation,resulting in increased water loss in the air,decreased atmospheric humidity,and heightened po-tential risks to vegetation growth.