Evaluating the Cooling Efficacy of Urban Green Spaces during Extreme Heat Events

Cities are particularly vulnerable to climatic phenomena including extreme weather events, heatwaves, and the formation of urban heat islands. Urban Green Spaces (UGSs) play a significant role in mitigating the adverse impacts of these phenomena. This research delves into the assessment of UGSs and their cooling effects on the urban thermal environment by employing a combination of AI, remote sensing, and statistical techniques. A data set of 1,179 UGSs was extracted for the region of interest, i.e., Lahore, Pakistan. Landsat 8 imagery for the given area was utilized to extract four cooling parameters: mean land surface temperature, cooling extent, cooling strength, and cooling gradient as measures of cooling effect of green spaces. The findings of thermal and greenness assessment reveal that the vegetation density (measured through mean NDVI) and the presence of nearby green spaces significantly influence the cooling efficacy of the UGSs. Furthermore, the results indicated that the UGSs had an average LST ranging from 21.898° C to 29.396° C, a cooling extent in between 132 meters and 463 meters, a mean cooling strength of 0.419° C, and an average cooling gradient of 1.222°C per meter. Considering the severe health risks posed by urban heat islands, especially in megacities like Lahore, our research provides suitable measures to alleviate these effects through optimal utilization of UGSs.