气候变化领域集成服务门户

Optimizing urban greenspace spatial pattern has been widely recommended to mitigate urban heat island (UHI) effect, mainly based on the statistically significant relationships between temperature and measurements of urban greenspace spatial pattern at local scale within a city. However, the scientific evidence at the city level is scarce, even though the importance of urban greenspace spatial pattern in mitigating UHI effect at the city level has been recognized. This study aims to fill this gap by investigating the relationship between the city level surface UHI intensity (SUHII) and a series of explanatory variables belonging to urban greenspace spatial pattern, urban morphology, and urban-rural difference of surface characteristics, using the region of Illinios-Indiana-Ohio in the USA as a case study. Results showed that urban greenspace spatial pattern variables were significantly correlated with SUHII, even after controlling for the impacts of urban-rural difference of surface characteristics (e.g., urban-rural difference of vegetation index) and urban morphology (e.g., urban size). SUHII was negatively correlated with patch density and mean patch shape of urban greenspace, and positively correlated with edge density of urban greenspace. Variance partitioning showed significant overlaps of the explanatory ability of these three groups of variables, which jointly explained 38% of the SUHII variation. Urban greenspace spatial pattern had a slightly larger independent role in explaining the SUHII variation than urban morphology (5% vs 2%), even though the urban-rural difference of surface characteristics was the major determinant (19%). Findings of this study extended our understanding of the impact of urban greenspace spatial pattern on SUHII from the local scale to the city scale and can help design effective urban planning and management strategies at the city scale to improve urban thermal environment.