Urban heat island modelling based on MUKLIMO: examples from Slovakia

Abstract. Cities are generally expected to experience higher temperatures than surrounding rural areas due to the Urban Heat Island (UHI) effect. The aim of this paper is to document identification and delimitation of land cover/land use (LC/LU) classes based on Urban Atlas data in three cities in Slovakia: the capital Bratislava and two regional centres, Trnava and Žilina, in the years 1998–2016 and their effect on the temperature change. The concept of Local Climate Zones (replaced by LC/LU classes in this study) was used as an input for the UHI modelling by application of the Mikroskaliges Urbanes KLIma MOdell (MUKLIMO). The model MUKLIMO was validated by data taken in five stations in Bratislava, two in Trnava, and one in Žilina, while a good rate of agreement between the modelled and measured data was statistically proved. A single representative day (August 22, 2018) was chosen for which UHI was modelled with three inputs of LC/LU classes: situation in 1998, 2007, and 2016 to assess the effect of change of LC/LU classes on the distribution of temperatures. The spatial manifestation of UHI was assessed in the frame of LC/LU classes for 2016 at 21:00 of Central European Summer Time (CEST). The results indicate that UHI intensity trends are spatially correlated with LC/LU classes and their change pattern. Results of Bratislava show, regarding the size of the city and relief dissection, greater variability than smaller Trnava situated in flat terrain and Žilina situated in the river valley surrounded by the mountain ranges.