Assessing Cool Roof Performance and Albedo Changes Across Multiple Sites Using Satellite Imagery

As the climate crisis intensifies, cities worldwide are increasingly adopting heat mitigation strategies to manage heat risks. Among these strategies, cool roofs have gained significant attention due to their ease of implementation and demonstrated efficiency. However, most existing research has been limited to small-scale field experiments that primarily focus on the physical cooling effects of cool roofs in outdoor and indoor environments or modeling studies that conduct ex-ante evaluations based on adjusted albedo values. Few studies have performed comprehensive ex-post evaluations across multiple sites, leaving a critical gap in evidence-based knowledge. This gap undermines decision-makers' confidence in the long-term effectiveness of cool roofs, leading to delayed implementation and hindering sustainable urban development.

To address this issue, we propose a universal satellite imagery monitoring methodology, combined with a Before-After-Control-Impact (BACI) design, to evaluate and compare the cooling effectiveness of cool roofs across various scales and locations. Additionally, we quantitatively analyze the degradation of cool roof albedo values over time and provide actionable recommendations for policymakers and practitioners. These findings enrich the existing body of knowledge by offering robust ex-post evaluation results, equipping decision-makers with practical guidelines for more effective heat mitigation and enabling researchers to enhance ex-ante modeling predictions by incorporating realistic assumptions.

 

This work was supported by Korea Environment Industry &Technology Institute (KEITI) through "Climate Change R&D Project for New Climate Regime.", funded by Korea Ministry of Environment (MOE) (RS-2022-KE002102)