A new method for evaluate the cold island effect in cities

Building urban parks is one of the important ways to alleviate the Urban Heat Island Effect, and the cold island effect is a commonly used indicator to characterize the cooling effect of urban parks on surrounding areas. This study takes the Olympic Park in Beijing as an example and combines remote sensing data with measured data from meteorological stations to propose a new method for evaluating the urban cold island effect based on the superposition of multiple remote sensing images. The research results show that: The magnitude of PCI(Park Cold Island)values has a highly significant correlation with the highest temperature of the day, and the two show a linear correlation. The higher the temperature, the greater the PCI; From 2013 to 2021, the difference between the highest temperature and the lowest temperature in the study area is 23 times, and the difference between the maximum and minimum PCI value is 19 times. The PCImix assessment method can better contain the extreme value, reduce the instability of temperature with seasonal changes and the impact of temperature variation differences between years, and reduce the contingency of assessment research; This new method is systematic, continuous, and statistically significant. The method proposed in this study for evaluating the urban cold island effect based on multi-phase image overlay can provide guidance for the future construction of urban parks and open up new ideas for evaluating the cooling effect of urban parks.