Spatiotemporal evolution of the urban heat island effect in the middle reaches of the Yangtze River urban agglomeration

The rapid urban expansion has intensified the urban heat island (UHI) effect, posing substantial risks to human health. This study evaluates the surface thermal environment and its adaptive response, focusing on the urban agglomeration in the middle reaches of the Yangtze River, China. Using MODIS land surface temperature (LST) data (including clear-sky and all-sky) and enhanced vegetation index (EVI) data from 2001 to 2023 at 30-arc-second spatial resolution, we analyze the spatial distribution and variation trends of UHI across diurnal, seasonal, and interannual scales. Results indicate a regional average UHI intensity of 1.44°C, with daytime intensity generally exceeding nighttime, and summer intensity higher than winter. Interannually, UHI intensity shows an average growth rate of 0.44°C per decade, also following a pattern of higher values during daytime and in summer. Vegetation factors are identified as significant drivers of UHI variation. Based on these findings, intervention strategies for LST regulation are proposed. This study provides a scientific basis for UHI mitigation and sustainable urban development in the middle reaches of the Yangtze River.