Impacts of land cover change on cooling effect of waterbodies: Spatiotemporal variations and drivers in Wuhan from 1990 to 2022

Previous studies quantified the cooling effect of urban waterbodies with temperatures at one point in time, linking waterbodies’ characteristics and land cover to cooling effects. This study goes one step further by relating the impact of land cover changes within the waterfront to changes in the cooling effect. It quantifies the changes in waterbody size and shape and distinguishes between flowing and standing water and cooling effects in summer and winter. The city of Wuhan, China, is an interesting case to investigate the cooling effects of waterbodies because it is both highly urbanized and has numerous waterbodies. Land surface temperature (LST) and land use/cover data from 1990/91 and 2022 were utilized. Multiple regressions were employed to quantify the cooling effect and identify contributing factors. The results show that the cooling distances and cooling intensities of waterbodies vary considerably. Increasing the waterbody shape index and the mean shape index of surrounding cropland, so more irregular shapes with longer interfaces between water and land, both lead to increases in cooling effects. Unexpectedly, the changes in the size of the waterbodies, as such, are not significant. Regression models for the cooling effect of flowing water overall show higher explanatory value (adjusted R2 between 0.13 and 0.74) compared to standing water. These results can provide quantitative guidance for blue landscape planning for UHI effect mitigation.