The impact of thermal image spatial enhancement on the estimation of the urban green cooling effect

Remotely sensed thermal data are applied widely in ecology studies, although the resolution of them is usually low. The spatial enhancement of thermal images (TSE) will play an important role in ecological applications. This paper used emissivity modulation (EM) for the TSE, and then used the images to estimate the urban cooling effect with three popular approaches: the local climate regulation index (LCRI), cooling intensity (CI), and green cooling island (GCI). After TSE process, the results of LCRI and CI showed little statistical difference, although the spatial differences should not be overlooked. The GCI results changed clearly after the TSE, with a 38.1% decrease of the area of cooling extent. Therefore, the TSE is recommended for GCI and green patch level CI, and not for LCRI or regional CI.