Evaluating Urban Green Spaces for Urban Heat Island Mitigation Effects in the Yangtze River Delta

The urban heat island (UHI) effect is a prominent environmental issue constraining the sustainable development of the Yangtze River Delta urban agglomeration (YRD), and green space construction is a critical approach to mitigating this effect. Based on panel data from 41 prefecture-level cities in the YRD across eight selected years between 2000 and 2020, this study constructs a multi-dimensional green space evaluation system encompassing scale, quality, and pattern, then employs a two-way fixed effects model to analyze its impact on UHI intensity. The findings reveal that green space coverage and vegetation quality exert significant negative effects on UHI mitigation, with each unit increase in green space coverage associated with an average reduction of approximately 0.54°C. In contrast, landscape pattern indicators (patch density and edge density) are positively correlated with UHI effects, indicating that, at the scale of the YRD urban agglomeration, the spatial aggregation and shape regularity of green spaces do not enhance cooling effects. This study provides a scientific basis for mitigating UHI effects through optimizing green space scale and vegetation quality in the Yangtze River Delta and similar highly urbanized regions, offering valuable insights for improving urban green space planning.