Thermal behavior and its seasonal and diurnal variability of urban green infrastructure in a mid-latitude city - Berlin

Land surface temperature (LST) is a key variable in characterizing the surface energy and water balance at the land surface-atmosphere interface [1], [2]. Vegetation reduces the LST by providing shade and absorbing radiation energy via transpiration and photosynthesis [3], [4]. A review of research on urban green spaces recommended that future research should incorporate functional, structural, and configurational parameters of urban vegetation in order to more fully assess the thermal effect of green spaces [5]. This study aims to fill this research gap by considering satellite-derived LST (Landsat 8), biotope types and 3D vegetation data in a study of LST across diurnal and seasonal temporal scales in a mid-latitude city (Berlin). Four cloud-free Landsat 8 scenes representing each season were analyzed. Day and night summer scenes with comparable air temperatures were used to assess the day/ night difference in LST. Kruskall-Wallis tests and Dunn’s post-hoc tests were applied to assess the significance of difference between LST of biotope classes and subclasses. Overall, LST varied significantly between the majority of biotope classes and subclasses. The relative coolness of each biotope class differed based on the season. The lowest and highest day/night LST variation could be noted for water biotope classes and dwarf shrub heaths, respectively. Vegetation height was significantly negatively correlated with LST (p-value<0.001) for all day scenes. Our results contribute to an enhanced understanding of how biotope types influence LST in an urban environment, which will be vital to urban planning in light of climate change.