The impact of the impervious surfaces and the condition of vegetation on the land surface temperature in urban centers on the example of Wloclawek, Poland

Abstract

The increase in temperature means that public spaces in city centres should be adapted to climate change. Policies in this area conducted over the years were, however, largely focused on representative functions, where urban greenery receded into the background. The aim of this study was therefore to check which factors - represented by vegetation indices - have the greatest impact on high temperature in city centres and its increase in relation to the surroundings. The research area was the city of Wloclawek with 12 selected public spaces. For the analysis, we used Landsat 5 for 2000 and Landsat 8 for 2020. Based on sourced images, we calculated the LST, NDVI and NDISI. In the next step, we checked how NDVI and NDISI affect LST for two moments of time. In the last stage, we examined whether the change in deviations (from the city average) of the calculated spectral indices in selected public spaces had an impact on the increase or decrease in the deviation from the LST average in these areas. It turned out that high NDVI values have a greater impact on LST reduction than high NDISI values on its increase. The research also shows that the correlation of changes in deviations from the mean for LST and selected spectral indices does not show a significant impact of these variables. This is caused, among others, by changes in land cover taking place in the city, which significantly affect the average values of LST as well as NDVI and NDISI.