Rapid daily and sub-daily temperature variations in an urban environment

Urban settlements induce major disturbances in the regional climate and generate particular living conditions for the population. The high heterogeneity of the urban environment gives rise to a corresponding mixture of intra-urban climate characteristics, depending on factors like meteorological context, urban geometry and land cover/land use. Intra-urban temperature variations may be quite large in time and space. Based on data provided by ground sensors of the standard meteorological stations, sensors placed in urban conditions and satellite remote sensing, this study investigates the daily and sub-daily thermal variations in Bucharest (Romania). Averaged across the city, the air temperature variations in Bucharest may reach 20 degrees C over 24 h, and can exceed 4 degrees C between consecutive hours, while the variations at individual locations may be larger, under the inflence of sensible heat conditions of the built urban zones. This study also reports on the utility of the remote sensing data of high temporal resolution (15 min) provided by the SEVIRI sensors in assessing the rapid thermal variations in an urban environment.