Statistical investigation of surface UHI analysis of five European cities using LCZ

The risk and frequency of heatwaves is rising due to anthropogenic climate change specifically for urban cities effected by urban heat island. Nature based solutions have been used as a mitigation strategy for various urban issues including urban heat island effect. The UPSURGE project aims to use Nature based solutions for regenerative development in five demonstration cities. The five cities are based in different climate zones, vary in population, consists of single to multiple demonstration sites, and are deploying various Nature based solutions based on the key challenges. The demonstration cities include Belfast, Breda, Budapest, Maribor, and Katowice. The demonstration sites are being Co-designed with stakeholders to address local concerns, diverse perspectives and involve citizens to address the longevity of Nature based solutions. The cities have selected Nature based solutions varying from green roof, green wall, Miyawaki forest, raingardens, agroecology community gardens, rewilded zones, meadows, climate arboretum, water gardens. The work aims to analyse the surface urban heat island effect of these five demo cities during heatwave. The local climate zone approach is used to understand the neighbourhoods within the demo cities. The variation in urban heat is analysed utilizing the probability distribution of land surface temperature. The LST data from Sentinel-3 and Ecostress have been used using Google Earth Engine. The LST data over the last 5 year during heatwaves have been analysed to understand the effect of Covid lockdowns. The Kullback- Leibler divergence statistics is estimated to determine the distance between the distributions of LST data. The most vulnerable neighbourhoods in each demo city have been highlighted having the highest probability and maximum statistical distance. The surface urban heat island significantly reduced during the Covid period.