Patch size and vegetation condition influence surface-temperature contrasts around urban green patches in a humid subtropical city
The study analyzed 456 urban and peri-urban green patches in Lucknow, India, using Landsat 8 land surface temperature (LST) and Sentinel-2 vegetation indicators from summer and winter scenes in 2019 and 2024. Green patches were cooler than surrounding built-up areas, showing a median warm-season temperature contrast of 0.6–0.8 °C, with cooling effects diminishing for patches larger than 8–10 hectares and flattening beyond a 100–200 meter buffer. Vegetation condition was a stronger predictor of summer cooling than patch shape, and peri-urban patches exhibited stronger temperature contrasts than urban ones.
Why it matters — It establishes specific spatial thresholds for park cooling in a humid subtropical context, demonstrating that cooling benefits plateau beyond 10 hectares and that temperature mitigation is concentrated within 200 meters of the green space boundary.
Caveat: The observed differences between urban and peri-urban patch cooling remain partially confounded by the varying characteristics of their surrounding built-up matrices.