Evaluation of urban green space in terms of thermal environmental benefits using geographical detector analysis

Urban green space (UGS) plays an indispensable role in urban spaces, providing important ecological services to compensate for natural environment functions damaged by rapid urbanization. Understanding the impact of the UGS landscape pattern on its environmental benefits in order to evaluate UGS quality is critical for increasing its use efficiency. Previous studies have frequently constructed evaluation indexes based on subjective assessment of UGS landscape patterns using principal component analysis, factor analysis, and other methods without combining the actual environmental benefits in a complex urban environment. We investigated the changes in land surface temperature (LST) under different UGS landscape patterns, which can help clarify the urban thermal environment effect of UGS, and constructed a comprehensive index, the Green Environmental Benefit Index (GEBI), for UGS evaluation. Our results show that: (1) spatial allocation and configuration of UGS impact LST at both landscape and class levels, and the impact varies significantly with different vegetation types and landscape patterns. (2) The influence of each pair of driving factors on UGS thermal environmental benefits is mutually enhanced, indicating that urban greening can be improved across multiple dimensions. (3) UGS evaluation based on GEBI is objective and compelling, where alleyways of the inner-city were identified as areas in need of greening optimization in the study area. Revealing more details of the UGS landscape pattern, this study can help to construct a scientific and objective evaluation model and provide a reference for urban greening optimization and planning.