Abstract
<jats:p>Urban areas are heavily modified in terms of surface temperatures (UHI: Urban Heat Island) relative to their rural environment. By means of airborne or satellite-based Earth observation, it is possible to find out changes in radiation and energy flux densities in the mesoclimate of the city. Land cover utilization and sealing aspects play a significant role in the modification of surface temperatures in a city. In the present work, the surface temperature data, derived from the thermal scanner surveys of the years 1986, 2004, 2011 and 2021 as well as the degree of sealing, the land use, the land cover and the climatopes, were summarized in a geodatabase. With this GIS based information, it is possible to analyze the thermal behavior of different inner courtyards according to their underlying surfaces as well as their size. In addition to the description of the climatological features of the Graz urban area, a part of the paper is dedicated to the data preparation and methodology development, following by the analysis of results based primarily on statistical evaluations. After successful creation of the database, the results indicate a strong correlation between sealing degree and thermal behavior of inner courtyards. The temperature increases with higher sealing degrees whereas the opposite greener areas lower temperature was recognized as well. Additionally, thermal characteristics vary depending on their location within the city according to climate conditions. Almost no strong correlation referring to their size was identified.</jats:p>