Variation in the Surface Urban Heat Island effect over Srinagar city in summer and winter seasons

This study aims to assess the change in land use and land cover (LULC) and its associated changes in Land Surface Temperature (LST) and Surface Urban Heat Island Intensity (SUHII) over Srinagar city in Jammu and Kashmir between 1993 and 2022 during summer and winter seasons. First, LULC maps were prepared for the years 1993 and 2022 using supervised classification technique and then it was analysed together with LST data obtained from Landsat 5 and Landsat 8 satellites for the corresponding years to detect changes in LULC pattern, LST and SUHII over the thirty-year period. It was observed that major changes took place over built-up area which increased by about 150% in 2022 compared to 1993 indicating increased urbanization of the city. In summer, LST has increased over all the classes, but the maximum increase was found over built-up areas. The increasing LST led to increase in SUHII too especially over areas that got converted to built-up or barren surfaces from vegetated surfaces or water bodies. Over such surfaces the SUHII increased by more than 4 °C. During the winter season, built-up areas exhibited marginally higher LST compared to vegetated areas in 1993, however, the SUHII over built-up areas had decreased. In 2022, persistent cold conditions resulted in marginally lower mean LST values (7.66 °C) for the built-up areas compared to the mean LST of vegetated surfaces (7.88 °C) which resulted in lower SUHII over built areas compared to vegetated surfaces. The overall LST in December 2022 was lower than the LST observed in December 1993. These results underscore the importance of vegetation in providing cooling effect in summer and in maintaining warmer temperatures during winter.