北流河电导率与水文气象要素多时间尺度关联性分析OA

Taking the Beiliu River belonging to the Xunjiang River system within the Xijiang River Basin as the research object,this paper discusses the impacts of hydrometeorological factors on water quality under climate change.Electrical conductivity(EC)was selected as the representative parameter reflecting river water quality.Hydrological statistical methods and cross wavelet transform were adopted to conduct multi-timescale correlation analysis on electrical conductivity and hydrometeorological elements(precipitation,runoff,water temperature)of the Beiliu River from January to December 2023.The results show that in 2023,local precipitation generally presented a decreasing trend,water temperature showed an upward trend,while runoff tended to increase.The river electrical conductivity experienced four successive variation stages:rising → declining → rising→sustained significant reduction.The significant effect of runoff on electrical conductivity mainly occurred from mid-May to August,on the 16-30 d period.During this period,river water quality was predominantly controlled by hydrological conditions,and variations in runoff preceded changes in electrical conductivity.On the short timescale(5-10 d period),local precipitation was positively correlated with electrical conductivity.This is because rainfall scours and dissolves surface materials,transporting abundant ions into the river and raising electrical conductivity.On the long timescale(16-45 d period),the dilution effect of runoff on river ions became dominant,and the scouring and transport effect of rainfall weakened.Variations in electrical conductivity preceded local precipitation changes.The influence of water temperature on electrical conductivity of the Beiliu River is complex,which is related to the climate feature of synchronized high temperature and rainy season in South China.Throughout the flood season,water temperature and runoff varied synchronously,and electrical conductivity decreased as water temperature rose.