Influence of land cover change on spatio-temporal distribution of urban heat island -a case in Wuhan main urban area

In this study, the relationship between land cover (LC) characteristics and urban heat island (UHI) intensity in the main urban area of Wuhan City are investigated. The effects of LC change on green space and land surface temperature (LST) was investigated, along with the relationship among LST, LC, and normalised differential vegetation index (NDVI). The land was divided into five categories, namely, built-up area, agricultural land, water, forest, and bare land. LST was determined using the infrared band image from the same period. The area of built-up areas accounted for only 32.81% in 2007, and it increased to 46.01% in 2020, while agricultural land decreased by 12.14%, which is the primary reason for the increase in built-up areas. The average LST in the study area increased from 25.92 degrees C to 31.71 degrees C, and the range of LST moved forward to high-temperature range. The high-temperature areas (>32 degrees C) expanded from point distribution to plane distribution and its expansion direction was consistent with the urbanisation direction. The water and forest have the strongest mitigation capacity for UHI and should be protected. Urban managers should avoid the increase of bare land due to the degradation of agricultural land and forest because the increase in LST caused by this type of LC change is obvious. LST was negatively correlated with NDVI, indicating that fewer vegetation resulted in higher LST.