Spatiotemporal characteristics of urban land surface temperature and UHI formation: a case study of Tehran, Iran

Abstract

Urban heat island (UHI) is one of the adverse effects of densely populated cities. Therefore, studying the causes of temperature variations and UHI formation in urban area has become more important as a significant stage in improving urban health and development. Toward this end, impacts of urban Land Use/Land Cover (LULC) characteristics and spatiotemporal pattern of Land Surface Temperature (LST) under different weather conditions were investigated for determining the area with high potential of UHI formation in Tehran. Furthermore, LST of six different land covers was recorded with 15-min time intervals using 2channel-thermocouples with six PT100 sensors. In addition, SHRP model that can effectively predict LST using air temperature were developed for different weather conditions. Then, the accuracy of the model was determined by actual measured LST. Results indicate that temperature of land surface corresponds exactly to the distinct LULC types. The temperature of water bodies and vegetated area ranges between 12–14 °C and 8–10 °C lower than the surface temperature of roads and built-up areas in summer and winter times, respectively. Hence, bare lands, built-up areas and roads with average surface temperature of 48.5, 47.2, and 46.1 °C are the hottest places of the city with high potential of UHI formation. Also, results illustrate that SHRP model has high degree of accuracy for estimating the LST using air temperature when direct observations and measurement of LST are unavailable (r = 0.95).