Attribution analysis of lake surface water temperature changing —taking China’s six main lakes as example

•The stepwise polynomial regression analysis was used to analyze factors impact LSWT.•LSWT is important for evaluating climate change and urbanization impacts on lakes.•Air temperature is still the most important factor affecting the change of LSWT.•The intensity of human disturbance varies among different types of lakes. Currently, lake surface water temperature (LSWT), as one of the most important indicators for evaluating lake health, is rapidly rising due to the influence of large-scale climate change and regional human activities in rapidly developing urban areas. The variety of LSWT will affect water environment problems such as lake water quality, aquatic organism growth and reproduction. Therefore, this study selected six lakes that play a crucial role in China’s economic and social development, and explored the causes and driving mechanisms of LSWT changes, which would provide support for the governance and protection of the ecological environment. Meanwhile, according to the fluctuation of lake boundary, the lakes were divided into two types, A and B. Based on the classification, the changing characteristics of LSWT from 2001 to 2018 were analyzed, and the stepwise polynomial regression analysis was used as new method to quantify the contribution from each driving factor to LSWT. Then, the driving mechanisms of natural and anthropogenic factors to LSWT was discussed. Results show that (1) the mean comprehensive change rates of LSWT-day and LSWT-night showed an upward trend in the past 18 years. The correlation between near surface air temperature (NSAT) and the annual average LSWT of the 6 lakes was higher than that of other factors, and this feature was most significant in spring, autumn and winter. The correlation between anthropogenic factors and annual average LSWT was affected by lake type, NSAT and precipitation in the basin. (2) Natural factors (especially NSAT) had higher contribution rates to LSWT. The contribution from anthropogenic factors to LSWT-night was higher than that in the daytime. For lakes classified in type B, the effect intensity of anthropogenic factors on LSWT-day was affected by NSAT, precipitation and lake area. The contribution rate to LSWT-night was related to the growth rate of the impervious surface area in the basin.