金沙江流域1961-2020年干湿日时空演变特征分析OA北大核心CSTPCD

[Background]Accurate observation of precipitation data is crucial in revealing the spatio-temporal evolution characteristics of the dry and wet spell index,as well as the influencing factors.As one of the most sensitive and vulnerable regions to climate change,the Jinsha River Basin is subjected to potential errors in precipitation measurements using standard rainfall gauges.Factors such as wind speed,humidity,and evaporation losses may result in an underestimation of the observed precipitation.The accuracy of precipitation data directly affects the analysis and simulation research of hydrological processes in the Jinsha River Basin.[Methods]The spatio-temporal variations of dry and wet day indices in the Jinsha River Basin from 1961 to 2020 were identified using corrected Mann-Kendall,spatial field significance test.[Results]1)There were differences in the values of dry and wet day indices identified by observed precipitation(Po)and corrected precipitation(Pc),but their spatial distribution was similar.Compared to Po,the trend of dry and wet day indices identified by Pc decreased mainly in the upper reaches of the Jinsha River,increased mainly in the middle and lower reaches,and decreased(increased)in the Yalong River section.2)The spatial field significance test results showed that the significant changes in dry and wet day indices identified by Po and Pc were mainly caused by internal variability of the climate system,this indicates that the change trend of the dry and wet day indices in the Jinsha River Basin is mainly driven by climate change,making it highly sensitive to climate variations.[Conclusions]Based on the above analysis,it is evident that there are significant spatial differences in identifying dry and wet indices in the Jinsha River Basin between observed precipitation(Po)and corrected precipitation(Pc).Therefore,in order to ensure accurate hydrological research and simulation in this basin,the application of corrected precipitation data should be considered.The findings also indicate that the simultaneous occurrence of extreme dry and wet indices could pose a serious threat to agricultural production and ecosystems in the Jinsha River Basin,and thus,should be given sufficient attention.Furthermore,the study's investigation into the evolving characteristics of dry and wet days based on Po and Pc identification can serve as a scientific reference for the prevention of landslides,debris flows,water resource security planning,and soil conservation deployment in the region.