A study on the strategies of Park City construction of Chengdu from the perspective of urban heat island mitigation

In the process of urbanization, various urban problems have become increasingly prominent, and the heat island effect is one of them. The expansion of urban land, the increase in construction intensity and the increase in population make the urban heat island effect even worse. The construction of park cities improves the ecological environment of the city and is considered to have a positive effect on alleviating the heat island effect, but it is not clear whether it has such an effect or not. This article explores whether the construction of Park City can help to improve the urban thermal environment effectively, and also, seek solutions for how to improve the construction of park cities so that the heat island effect can be better mitigated. Landsat8 remote sensing images in 2014 and 2019 were used to estimate the fractional vegetation cover (FVC) and land surface temperature (LST) in the Third Ring Road of Chengdu. Land use data were also introduced into the study to analyze LST changes in different surfaces and FVC.The results indicate that: (1) the area of the heat island zone in the Third Ring Road of Chengdu decreased by 0.91% from 2014 to 2019, and the area of the cold island zone increased by 17.89% ; (2) the urban blue-green space is conductive to mitigating the urban heat island effect, in which the water provides the best mitigation, while impervious surface and bare land may aggravate the urban heat island effect; (3) the FVC in the area of the Third Ring Road in Chengdu is on the rise as a whole, and there is a significant negative correlation between FVC and LST (p < 0.01). Based on the above results, this paper shows that Park City construction is beneficial to alleviate the urban heat island effect, and more attention should be paid to blue-green space layout and quality, along with urban ventilation and FVC control. Our results provide useful input for green space planning and the construction of Park City in the future.