Theory and procedure for measuring the solar reflectance of urban prototypes

•We propose a new method to measure the albedo of urban prototype.•The method can estimate the effectiveness of reflective walls and pavements.•The proposed method is compared with ASTM E 1918-06.•The error of the measurement is lower than 0.02.

Solar radiation on urban surfaces is subjected to multiple reflections, which increase the solar absorption of these surfaces. Measuring the albedo of an urban area is important in order to estimate the solar absorption of the area and find engineered solutions for urban heat island mitigation. This study proposes a new approach to measure the albedo of the urban prototype. The approach measures the albedo of an urban prototype by sequentially covering a target area with a white solar-opaque mask, a black solar-opaque mask, and a black urban prototype, and the measured urban prototype, and while simultaneously measuring the incident radiation and reflected radiation over the target area. The errors of the albedo measurement depend on the albedo of the black urban prototype. The smaller this albedo is, the less the error. The proposed method can be used to measure the albedo of urban prototypes with high-reflective walls and high-reflective pavements.