SPATIO-TEMPORAL ANALYSIS OF SURFACE URBAN HEAT ISLAND BASED ON LANDSAT ETM plus AND OLI/TIRS IMAGERY IN THE CITY OF KOSICE, SLOVAKIA

The availability of multispectral imagery including a thermal infrared band enabled monitoring the spatial pattern of land surface temperature (LST) and linking it with land cover properties. Multispectral data archives allow for assessing the dynamics of urban heat island (UHI) by the means of LST mapping for particular area. The research on UHI has been focused on large cities where the phenomenon is the most pronounced. However, UHI concerns also smaller cities which are more abundant and over a half of urban population lives in cities with less than a half of million inhabitants. Therefore, this paper focuses on assessing the pattern of the UHI in the city of Kosice as an example of a typical small post-communist Central European city after changes of urban landscape induced by transition to capitalism and modern trends in economy. We demonstrate the effect of urban greenery on the UHI phenomenon in Kosice using the Landsat 7 and Landsat 8 imagery and ground-based weather station data. We determine differences in the LST distribution in the city under various weather conditions in the vegetation season from 2013 to 2015. The results revealed the spatial pattern of the LST and UHI in Kosice which is unique from regional perspective. Globally, the results support the hypotesis that UHI poses problem even in such a small city. Expansion of urban fabric by construction of new residential, commercial and industrial estates and also building new traffic infrastructure in last few years amplified the UHI. Strong correlation was calculated between the LST and the amount of urban greenery in the city. Even narrow green alleys or small parks are capable of mitigating the UHI phenomenon which can be a usefull argument for officials in Kosice but also in other cities to support investments in development of green areas.