Albedo Quantification Using Remote Sensing Techniques. Cool Roof in the Metropolitan Area of Mendoza-Argentina

Abstract

The presence of cities raises air temperature. The growth of sealed urban surfaces and anthropogenic heat modifies the natural energy balance increasing the CO2 emissions of a city. A strategy to reduce urban temperatures and energy consumption is the widespread application of cool materials -with high albedo and high emissivity- in the urban envelope. Roofs are the horizontal opaque surfaces most exposed to solar radiation and are therefore the ones that absorb the highest thermal load of a building. The objective of this research is to design a procedure that allows the discrimination the different roofing materials within the Metropolitan Area of Mendoza, Argentina, to determine the possible energy savings and improvements in urban microclimatic conditions associated with the increase of albedo in the roofs of the city. The methodology is based on a supervised classification of roof materials using spectral signatures with QGIS 3.2 'Bonn' software. For this purpose, images from the Sentinel 2a platform were used and 3 series of spectral signatures were obtained from built urban areas. The results show that the materials mainly used in the roofs of the city of Mendoza are membranes (74%), zinc sheet (14%) and traditional tiles (13%). These findings represent an efficient tool to quantify the energy and environmental effects of regulating albedo values in urban roof.