Spatio-Temporal Dynamic Characteristics and Landscape Connectivity of Heat Islands in Xiamen in the Face of Rapid Urbanization

With the acceleration of urbanization, urban heat waves have become a major problem affecting the lives of citizens. In this context, the accurate identification of the key patches and nodes of urban heat islands is important for improving the urban environment. This study examined the Landsat image data from Xiamen city in 2001, 2011, and 2021 to analyze the construction of the urban heat island (UHI) network. A morphological spatial pattern analysis (MSPA) and landscape connectivity model were utilized to identify the central thermal landscape patches and key nodes of UHI and their spatial and temporal evolution characteristics in the urban development process. The ultimate goal of this research is to provide valuable insights that can contribute to the enhancement of the urban environment. The results showed that (1) there was a significant increase in the heat island area (HIA) of Xiamen from 2001 to 2021, and the heat island patches show a concentrated trend. The temperature contrast between the urban area and the surrounding countryside was more distinct, indicating the urban construction land has a tendency to gather and spread. (2) The core area of the heat island accounted for the largest proportion of the thermal landscape area during the study period, and its proportion increased significantly. And the rate of increase was first rapid and then slow. The areas of the edge, branch, islet, bridge, loop, and perforation classes all showed different degrees of a decreasing trend. This indicates an increasing degree of aggregation between heat island patches. (3) The top 20 thermal landscape patches with high landscape connectivity importance values were identified. Among them, the importance value and area of the first four patches are relatively large, and belong to the three importance classes of extremely important, important, and generally important heat island core patches, which deserve focused attention and optimization. (4) Cooling measures can be prioritized for core areas of heat islands with high importance values. Connections between hot and cold islands can be interrupted or connected to mitigate the heat island effect throughout the region. The results of this study have important practical guidance for urban planning and sustainable development.