Fig. 1. Research area diagram

Fig. 2. Imaging parameters of the "three lakes" research area in Yuxi City. (a) 2015; (b) 2017; (c) 2019; (d) 2021

Fig. 3. Distribution of measured sample points. (a) Distribution of the measured sample points corresponding to the four phase images; (b) spatial distribution of the whole sample points

Fig. 4. Comparative analysis and accuracy verification of land surface temperature inversion results in the study area. (a) 2015; (b) 2017; (c) 2019; (d) 2021

Fig. 5. Analysis of standard deviation between retrieved and measured land surface temperature in the study area

Fig. 6. The inversion results of the changes in surface temperature grades in the study area from 2015 to 2021. (a) 2015; (b) 2017; (c) 2019; (d) 2021

Fig. 7. Proportion of areas with different surface temperature grades in the study area from 2019 to 2021

Fig. 8. Variation of land surface temperature in districts and counties releated to the "three lakes" during 2015–2021

Fig. 9. Water body extraction by maximum likelihood classification. (a) Modified normalized difference water index; (b) binary processing; (c) water zone extraction

Fig. 10. Variation characteristics of the influence range of cold island effect for different lakes from 2015 to 2021. (a) Fuxian Lake; (b) Xingyun Lake; (c) Qilu Lake

Fig. 11. Variation of cooling intensity and influence of cold island effect for different lakes from 2015 to 2021. (a) Fuxian Lake; (b) Xingyun Lake; (c) Qilu Lake

Fig. 12. Ridge trace map fitting by ridge regression analysis of influencing factors of cold island effect for different lakes. (a) Fuxian Lake; (b) Xingyun Lake; (c) Qilu Lake

Fig. 13. The distribution of sampling points for each lake. (a) Fuxian Lake; (b) Xingyun Lake; (c) Qilu Lake

Fig. 13. The fitting degree and accuracy test of model estimated values for different lakes. (a) Fuxian Lake; (b) Xingyun Lake; (c) Qilu Lake