Greenspace coverage vs. enhanced vegetation index: Correlations with surface urban heat island intensity in different climate zones

Abstract

The two greenspace indicators, greenspace coverage (GC) and enhanced vegetation index (EVI), have been widely used in studies on surface urban heat island intensity (SUHII). However, GC, which is more practical for urban planning, has not been as extensively involved in cross-regional SUHII studies as EVI. This study investigated 233 Chinese cities spanning three climate zones to examine how the correlations between SUHII and GC differ from those between SUHII and EVI across different climate zones. Our findings reveal that SUHII is more closely associated with the urban-rural differences in greenspace (ΔGC and ΔEVI) than with the urban values of GC and EVI. ΔGC shows potential for inter-city SUHII studies and outperforms ΔEVI in mild temperate climate zones (Cw and Cf). In the snow with dry winter climate zone (Dw), the correlation between SUHII and ΔEVI peaks at −0.795, exceeding that of ΔGC at −0.653. The cooling effects of greenspace diminish progressively from Dw to Cw to Cf, with the same ΔGC corresponding to higher SUHII in Cf than in Cw and Dw. These results underscore the necessity to develop targeted acceptable SUHII standards and GC thresholds for different climate zones to guide greening-based cooling measures.