气象干旱对朔州市水文连通性季节异质性的响应OA

Studying the response of meteorological drought to seasonal heterogeneity of hydrological connectivity aids in understanding the evolution law of regional drought and provides new insight for optimal allocation of water resources and dynamic adjustment of agricultural water use in arid areas.Based on Sentinel-2 satellite remote sensing data,precipitation(P)data and potential evapotranspiration(PET)data from 2019 to 2023,this paper takes Shuozhou City,Shanxi Province,which has been affected by meteorological drought for a long time,as the research object.The hydrological connectivity comprehensive index method is used to quantify the surface hydrological connectivity(C),and the meteorological drought level is divided by the Moisture Index(MI)to explore the response characteristics of meteorological drought to the seasonal heterogeneity of hydrological connectivity.The results show that:① The water body area of Shuozhou City fluctuates significantly,reaching a peak of 93.12 km2 in 2019,plummeting to 40.24 km2 in 2020,and recovering to 67.76 km2 in 2021 due to ecological engineering.The water distribution is scattered and the shortage of water resources is prominent.The composite water body area in winter is 4.9 times that in summer,and the seasonal difference is significant.② The comprehensive index of surface hydrological connectivity in Shuozhou City from 2019 to 2023 is between 0.014 and 0.227,with an average value of 0.058,showing significant seasonal fluctuation characteristics.Affected by the increase of evapotranspiration in spring and summer,the C value from April to August is at the lowest level in the whole year(average 0.035).The low temperature in winter inhibits evapotranspiration,which leads to the peak value of C value from November to January of the next year(average 0.099).Evapotranspiration intensity is the core factor driving the seasonal heterogeneity of hydrological connectivity in Shuozhou City.③ The response of meteorological drought to hydrological connectivity in Shuozhou City exhibits significant seasonal heterogeneity.In winter,hydrological connectivity was strongly negatively correlated with relative humidity index(r=-0.53).In summer(r=-0.31)and autumn(r=-0.25),it decreased in turn.In spring,there was no significant positive correlation(r=0.16).The risk of meteorological drought increased with the increase of surface hydrological connectivity.The results of this study provide a new idea for arid and semi-arid regions to use the seasonal heterogeneity of hydrological connectivity to cope with meteorological drought.