## 4 Discussion
It is evident from the results that the heat island intensity in Zhengzhou was the strongest in autumn, and the summer nights had the highest heat island intensity. The results of this study show that with the rapid urbanization, the temperature of the land surface and heat island intensity has increased from 2012 to 2021. An apparent increasing trend can be seen in 2012. The heat island intensity was 0.88; in 2021, it was measured to be 2.06. Every type of land exhibits seasonal changes, and Zhengzhou's UHI effect has prominent seasonal characteristics. More water can be sprayed onto impervious surfaces such as roads in cities in the summer to reduce the surface temperature inside the city and thereby contribute to reducing the UHI, especially in construction areas where the surface temperature is at its highest in the summer. The thermal properties of various underlying surfaces in Zhengzhou were investigated using a statistical surface temperature analysis across different land use types (Figure 13). The temperature change patterns for each land use type remained consistent from 2012 to 2021, with urban areas displaying the highest surface temperatures. This can be attributed to replacing natural surfaces with concrete roads and buildings during urbanization, which results in increased heat absorption and, thus, elevated surface temperatures [43; 44]. Conversely, wetlands and water bodies exhibited the lowest surface temperatures, followed by woodlands. This is due to vegetation transpiration's cooling and dissipation of heat potential [45; 46]. These findings emphasize the importance of preserving natural land cover in urban areas to mitigate the UHI effect and improve the overall urban climate. The findings of this study reveal a clear trend of increasing warmth in the city of Zhengzhou due to urbanization, accompanied by a rise in the intensity of the urban heat island effect. While global warming plays a role in this phenomenon, the rate of urban warming surpasses that of suburban areas. The frequency of heat waves and extreme weather events in recent years underscores the urgency of taking proactive measures in urban planning and development to mitigate the urban heat island effect and counteract the escalating urban warming trend. Based on the findings of this study, we propose the following recommendations:  
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2. Emphasize policy guidance: In the future development of cities, urban planners and policymakers should prioritize the construction of cool cities. This entails implementing policies that focus on mitigating the urban heat island effect and promoting sustainable urban environments. 2. Enhance urban blue-green infrastructure: It is crucial to invest in the development of urban blue-green infrastructure, as it serves as an urban cool island. The presence of blue-green spaces and the evapotranspiration process they facilitate play a significant role in alleviating the urban thermal environment. 3. Increase surface greenery and reflectivity: Efforts should be made to enhance surface greenery, such as incorporating green roofs and vertical greening. Additionally, increasing surface reflectivity through the use of cooling pavement materials and cool infrastructure can help modify the thermal properties of urban areas, leading to a reduction in the urban heat island effect. 4. Implement urban heat island monitoring systems: Establish comprehensive urban heat island monitoring systems to continuously assess and analyze temperature variations across different urban zones. These data can provide valuable insights for urban planning and facilitate targeted interventions. By implementing these recommendations, we can actively work towards mitigating and minimizing the impacts of the urban heat island effect, thus fostering more sustainable and livable cities.