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Surface reflectivity (Scenario)
Overview
This layer shows the change in surface reflectivity—a measure of how much sunlight surfaces reflect—under a modeled scenario where all roofs have their reflectivities increased to that of cool roofs. Surface reflectivity is expressed as a value between 0 and 100%, representing the proportion of incoming solar radiation reflected by a surface. Light-colored surfaces have higher reflectivities, while darker surfaces absorb more heat and have lower reflectivities. The data are derived from Sentinel-2 satellite imagery using the methods of Bonafoni and Sekertekin (2020) for calculating albedo, which represents reflectivity on a scale of 0 to 1, and downscaled to a higher spatial resolution.
Function
To demonstrate the change in surface reflectivity as a result of cool roof implementation.
Source
WRI
Data sources
Sentinel-2
Spatial resolution
1 meter downscaled from 10 meters
Spatial coverage
Global
Temporal resolution
static
Temporal coverage
2024 summertime median
Cautions
Albedo is estimated from satellite data which is affected by cloud cover, atmospheric conditions, and the angle and orientation of roofs. While we make every effort to minimize these effects, the data the data is not intended to serve as a tool for assessing the reflectivity of individual buildings. The scenario assumes that all roofs can be resurfaced with cool roofs and uses reflectivity values associated with widely available materials—0.28 for low slope (< 2/12 pitch) and 0.62 for high slope. Additionally, roof slope is only available in U.S. cities—outside of the U.S. roofs are all assumed to be low slope if the building footprint is greater than 821 square meters in area and high slope otherwise. This data useful for understanding where the highest gains are possible.The data is suitable for guiding assessments of heat and the potential for creating interventions.