Evidence of relieved urban heat island intensity during rapid urbanization through local climate zones

The mitigation strategy study of urban heat island (UHI) provides a key indicator for achieving sustainable development, particularly for cities enduring rapid urbanization. The spatial and temporal variations of land cover were investigated by analyzing the local climate zones (LCZs) in selected years (2008, 2013, 2018). The results demonstrated that the dominant type of built-up land cover LCZs changed from open mid-rise (LCZ 5) to open high-rise (LCZ 4). Additionally, almost all types of natural land cover LCZs presented a downward trend, except for "dense trees" (LCZ A). Comparing the land cover variations with the calculated UHI intensity in the corre-sponding years, an increased intensity in UHI (from 3.0 degrees C to 3.3 degrees C) was observed from 2008 to 2013. In contrast, the UHI intensity reduced to 3.1 degrees C from 2013 to 2018 with an even stronger urbanization process. The transition of land cover varied with the city's development goal, which changed from "building a modern city" to "forming a livable city." The evidence that the UHI intensity was relieved by promoting the open arrangement of LCZs and the recovering of "green" eco-system suggest a potential strategy to achieve sustainable development for rapid urbanization.