Diurnal contrast of urban park cooling effects in a “Furnace city” using multi-source geospatial data and optimal parameters-based geographical detector model

Urban parks serve as key nature-based solutions to alleviate the urban heat island phenomenon. Studies have examined park cooling effects (PCEs) from various perspectives. However, the diurnal impacts of environmental factors and their contributions to PCEs, specifically the cooling indicators that comprehensively characterize PCEs, are not well understood. To fill the gap, we constructed a new PCE index, park cooling composite index, based on principal components analysis and six cooling indicators. We selected 68 parks to explore the diurnal variations of PCEs in a “furnace city” using multi-source geospatial data and an optimal parameters-based geographical detector (OPGD) model. PCEs were not affected by park spatial distribution, and urban parks typically exhibited enhanced PCEs in daytime. Correlations between environmental factors and PCEs varied diurnally, with variations among PCEs. Park area and park perimeter were significantly correlated with all PCEs at nighttime. The OPGD revealed that the majority of the internal and external interactive factors of parks enhanced PCEs, regardless of the time. Additionally, balancing strategies for daytime and nighttime PCEs of different park types were developed. These findings provide a comprehensive understanding of the daily variations in PCEs, aiding in the design and planning of parks to adapt to extreme heat.