The towering buildings and crisscrossing roads in the city form a huge heat source, which leads to higher temperatures in urban areas than in surrounding rural areas. How to alleviate this urban heat island effect? On the 7th, it was learned from Southeast University that a research team led by Professor Cao Shijie from the School of Architecture, in collaboration with a team from Concordia University in Canada and the University of Surrey in the UK, has found that the urban heat island effect can be alleviated through rural land in neighboring cities. The relevant achievements were recently published in the international academic journal Nature City and selected as the cover paper. Previously, there have been studies attempting to alleviate the heat island effect by regulating green, blue, or gray infrastructure within cities. But the urban space is limited and the effect is not significant The first author of the paper, Yang Miao, a doctoral student at Southeast University, told reporters that this study proposes using rural land in neighboring cities as a potential cooling source to alleviate urban heat island effects through heat absorption and circulation processes. The rural land in this study refers to land types such as forests, cultivated land, water bodies, grasslands, and impermeable surfaces in non urban areas Yang Miao explained. To analyze the mitigating effect of rural land on urban heat islands, the team collected temperature and land cover data from 30 cities in China from 2000 to 2020. Researchers divided cities into five gradients based on development intensity indicators, and rural areas into four gradients based on their distance from the city boundary, constructing a hierarchical structure between urban and rural areas. The team utilized various machine learning regression models to extract and quantify the degree and scope of the impact of rural land on urban heat islands. Through interpretable machine learning models, they identified the key factors that rural land plays in mitigating urban heat islands and revealed their rules of action on urban heat islands. According to the corresponding author of the paper, Cao Shijie, the research results show that when the distance that rural land extends outward from the urban boundary is about half of the equivalent diameter of the city, its mitigation effect on urban heat island is most significant, and the mitigation degree of urban center heat island changes can reach 30%. We suggest that in the process of rural land planning, while avoiding land fragmentation as much as possible, the complexity and distribution uniformity of land types should be increased Yang Miao explained that this can effectively absorb urban heat in rural areas, thereby reducing heat accumulation in urban centers. Cao Shijie believes that this study provides a new way to alleviate urban heat waves, that is, by optimizing land use in the urban-rural interface, effectively alleviating the urban heat island effect without occupying limited land resources in the city. At the same time, this also helps to promote urban-rural integration and regional coordinated development, achieving harmonious coexistence between cities and nature. (New Society)