The Impact Of Anthropogenic Activities On Lake Surface Water Temperature Changes

As global climate change and rapid urbanization,the lake surface water temperature(LSWT)shows a rising trend commonly with significant spatial heterogeneity.The variations in lake surface water temperature are influenced by a combination of natural factors and human activities.While previous studies have primarily focused on quantifying the impact of natural factors,it is crucial to recognize the importance of assessing the effects of human activities on lake surface water temperature.Such an evaluation is of paramount importance in safeguarding lake ecosystems and fostering the sustainable development of lakeside cities.Human activities significantly alter the surface water temperature of lakes,primarily through urban thermal runoff and the effects of climate change.This study focuses on understanding the impact of human activities on different types of lakes(urban,semiurban,and natural)by examining 11 lakes in the Yunnan-Guizhou Plateau,China.Using the Air2 water physical model,we construct a comprehensive dataset of lake surface water temperature for major lakes in the Yunnan-Guizhou Plateau from 2001 to 2020.We propose an innovative method to quantify the contribution of human activities to lake surface water temperature and analyze the implications of anthropogenic effects on the warming of lake surface water temperature based on the type of lake.The research findings reveal the following insights:(1)Between 2001 and 2020,there was an overall warming trend in the surface water temperature of lakes in the Yunnan-Guizhou Plateau,with an average comprehensive warming rate of 0.17℃/decade.However,Caohai and Chenghai exhibited a cooling trend,with an average cooling rate of -0.05℃/decade,while the remaining nine lakes showed a warming trend,with an average rate of 0.22℃/decade.Significantly,Xingyun Lake displayed the most pronounced warming effect,with a rate of 0.50℃/decade.(2)Human activities during the same period contributed to the warming of the surface water temperature in the Yunnan-Guizhou Plateau lakes,resulting in an average increase of 0.46℃.Among the lakes,Xingyun Lake,Caohai,and Dianchi Lake experienced the most significant warming impact on their surface water temperature.(3)Human activities have the greatest average contribution to the warming of urban lakes(23%),followed by natural lakes,while semi-urban lakes exhibit a relatively weaker impact.(4)The response of lake surface water temperature to anthropogenic influences exhibits spatial heterogeneity.Lakes in the central region of the YunnanGuizhou Plateau,such as Dianchi Lake,Fuxian Lake,and Xingyun Lake,demonstrate significant warming effects.Conversely,lakes in the northern region,such as Lugu Lake,Qinghai Lake,and Caohai,display a cooling trend.On average,when human activities cause a 1℃ increase in lake surface water temperature,the average temperature rise is 2.98℃.With the emergence of global climate change and water scarcity issues,the impact of human activities on lake warming cannot be ignored.The development of appropriate lake conservation policies is crucial for the sustainable development of lake basin ecosystems.