Land Surface Temperature Comparison of Green and Cool Roofs in Seoul: Seasonal Variations and Implications

Sojin Jun*
Department of Landscape Architecture and Rural System Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
*Corresponding Author: Sojin Jun, Department of Landscape Architecture and Rural System Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea.

Published: July 08, 2025

View Pdf

Abstract  

This study compares the land surface temperature (LST) of green roofs and cool roofs in Seoul to assess their effectiveness in mitigating urban heat islands and enhancing resilience to cold waves. Using Sentinel-2 imagery for rooftop classification and Landsat-8 thermal data for LST estimation, we analyzed 169 green roofs and 338 cool roofs, matched by area and location. Results show that green roofs consistently maintain lower LSTs during summer (mean 39.83°C, SD 3.52) compared to cool roofs (mean 40.88°C, SD 2.19), with a statistically significant difference (t = -22.04, p < 0.001, Cohen's d = -0.39). In winter, the difference is smaller but still significant (green roofs: mean 3.13°C, SD 1.63; cool roofs: mean 3.33°C, SD 1.40; t = -8.49, p < 0.001, Cohen's d = -0.14). These findings are consistent with previous studies showing that both green and cool roofs can reduce rooftop and ambient temperatures and provide important energy savings, though the degree of effectiveness varies by climate and building characteristics [1-5]. Green roofs are particularly effective in providing stable thermal performance and reducing summer heat in humid climates, while cool roofs can offer substantial cooling and energy benefits, especially in hot, dry regions [2-4, 6, 7].

Keywords: Green roof; Cool roof; Land surface temperature; Urban heat island; Sentinel-2; Landsat-8; Seoul

.