**6. Conclusions**

This study used a comprehensive method to investigate the urban heat island phenomenon of Zhengzhou city in China. Using the radiative transfer equation (RTE) method to retrieve the LST and we analyzed the relation of particular factors to park LST and park cooling effect. The results of this paper give a reference to characterize the complex correlation between UHI and other factors in the expanding capital city of Henan province in China. The practical results can imply urban planners and stakeholders by providing scientific guidance for future urbanization and urban management. First, the results showed that parks have a cooling effect in the city, the mean LST of the park is 0.79 ◦C lower than in the city. Different park types have different cooling intensity. The theme park category in Zhengzhou has the highest cooling intensity with the PCI reaching 2.76 ◦C. The cooling intensity of the street park and linear parks is lower; with the PCI only reaching 0. 8 ◦C and 0.64 ◦C, respectively. From the results of the park cooling effect analysis and its internal characteristics, we can recognize that the park LST depends mainly on the vegetation cover, waterbody and impervious surfaces in the park. Vegetation and water surface are the main factors of the park's cooling effect in Zhengzhou, but the impervious surface increases park LST. The study also shows a different linear correlation between the park LST and park patch metrics of Zhengzhou city. Park size and fractal dimension, perimeter area ratio affect park LST, while other geometric indicators such as shape index have no significant relation to the LST. Thus, we recommend for planners to maximize the park size and minimize perimeter area ratio to reduce the UHI effect.

The PCI is influenced by the park itself and its surrounding area:


We recommend additional planning consideration and construction of more parks in built-up urban areas among tall buildings and within large areas of impervious surfaces. Park types, such as theme parks and larger urban parks, should be considered with higher priority than above other park types.

Urban parks play an important role in the urban ecological environment. Targeted research on the cooling effect of parks has practical significance in urban planning and design. Parks with stronger cooling effects can help to reduce the adverse impacts of UHI problems. This study can provide a reference for urban planners and landscape architects as well as stakeholders and decision-makers.

**Author Contributions:** Data curation, H.L., G.T. and S.J.; Investigation, S.J.; Methodology, H.L.; resources, G.W.; software, H.L. and S.J.; supervision, S.J.; writing—original draft, H.L.; writing—review & editing, G.T. and S.J. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by "Henan Overseas Expertise Introduction Center for Discipline Innovation" and the APC was funded by Szent István University.

**Acknowledgments:** First, we would thank the Stipendium Hungaricum Programme founding for supporting my study and research. Second, we would also thank the colleagues in the Department of Landscape Planning and Regional Development, Szent István University. Third, thanks for the 6th Fábos Conference and land journal to organize this special issue. In addition, we would also like to thank the referees and the editors for their valuable comments for improving this manuscript. Finally, I would like to especially thank Malcolm Douglas Lambson and Eleanor Jessie Potgieter from the University of the Witwatersrand (South Africa), Kelvin Andrew Lasko from Montgomery Co. Public Schools (U.S.) for helping with the English revision of this article, Thank you very much for all your efforts.

**Conflicts of Interest:** The authors declare no conflict of interest.
