UHI ESTIMATION BASED ON ASTER AND MODIS SATELLITE IMAGERY: FIRST RESULTS ON STRASBOURG CITY, FRANCE

Abstract. The increase in urbanization of cities coupled with some effects of climate change is leading to the emergence of urban microclimates. The rising temperatures in cities create the phenomenon known as Urban Heat Island (UHI). This is a difference between the temperature of urban and rural areas that intensifies more during the night and varies according to the season of the year. This paper focuses on the estimation of the UHI and its variations in and around the city of Strasbourg. To this end, thermal remote sensing data from different satellite has been used to isolate and analyse this phenomenon, specifically, Land Surface Temperatures (LSTs) provided by ASTER and MODIS. The LST provided by these sensors has been compared to air temperatures of the last 15 years from meteorological stations distributed throughout the city that have served as ground truth. Forty-seven meteorological stations spread throughout the area of interest provided measurements of air humidity and temperature. This valuable data base has allowed the assessment of the correlations between LST from satellite and ground truth air temperature. Based on satellite data resampled at different spatial units, this work led to the creation of the first UHI map of Strasbourg.