Urban Heat Island in the city of Kielce as derived from in-situ measurements and satellite imagery

Abstract

The intensity of the atmospheric Urban Heat Island (UHI) effect in the city of Kielce (central-southern Poland) was studied for the 2010–2018 period, in particular its diurnal and annual variability. The UHI is defined as a positive difference in hourly air temperature between the centre and outskirts of a city or town. Meanwhile, four LANDSAT 8 images were used to delimit the Surface Heat Island (SHI). The average annual intensity of the atmospheric UHI in Kielce is 0.5°C, while its maximum intensity was 8.3°C in the studied period. The highest average intensity of the UHI is recorded at night during the summer. The inverse state known as the “cold island” (when the air temperature is higher on the outskirts) often occurs in Kielce in the morning. A seasonal variability of the intensity of the UHI depends largely on the total cloudiness. SHI covered 34–70% of the area of Kielce. The highest intensity of SHI was found in areas where large low-rise industrial, commercial and storage buildings are located. The lowest Land Surface Temperature (LST) was found for forests, water bodies and green areas, especially in the area adjacent to the Silnica River