Heinl, Michael; Hammerle, Albin; Tappeiner, Ulrike; Leitinger, Georg (2015). Determinants of urban-rural land surface temperature differences - A landscape scale perspective. LANDSCAPE AND URBAN PLANNING, 134, 33-42.

Abstract
Urban areas are known to have a local climate different from that of surrounding rural landscapes and the temperature difference constitutes an urban heat island (UHI). Despite being described as 'heating islands', cities are not isolated from their environment. But only few studies respect the UHI as a relative measure and consider both the drivers of the temperature level of the urban area and of the surrounding landscape in their UHI assessments. A series of 124 Landsat satellite images spanning four decades were used to derive land surface temperatures (LST) of 77 urban areas (between 20 and 1 600 ha) and their surroundings in the Province of South Tyrol, northern Italy. These data were used to calculate urban-rural LST differences (Delta LSTUHI) and NDVI differences (Delta NDVI) for quantifying the urban heat island effect. Delta LSTUHI were recorded between 1.0K and 8.1 K, with a mean Delta LSTUHI of 4.2 K. The results show pronounced Delta LSTUHI effects already for small cities of less than 1 km(2), but suggest that the urban size is of only minor importance for the Delta LSTUHI magnitude in case of urban areas smaller than about 10 km(2). Urban-rural land surface temperature difference (Delta LSTUHI) was identified to be primarily driven by Delta NDVI, together with solar irradiance and land use. Threshold values for the occurrence of Delta AST(UHI) extremes are provided. Implications for landscape and urban planning are presented that underpin the crucial importance of considering the surrounding landscape for quantitative assessments of UHI intensity. (C) 2014 Elsevier B.V. All rights reserved.

DOI:
10.1016/j.landurbplan.2014.10.003

ISSN:
0169-2046