Albedo quantification using remote sensing techniques: Cool roof in the metropolitan area of Mendoza- Argentina

Abstract

The presence of cities raises the air temperature, because natural energetic balance is modified and CO2 emissions are increased, due to a growth of the sealed surfaces urban and to anthropogenic heat. A strategy to decrease urban temperatures and energy consumption is the extended application of cool materials -high albedo and thermal emittance- in the urban-building envelope. In particular, roofs are the horizontal opaque surfaces most exposed to solar radiation, and therefore, are those that absorb the highest thermal load of a building structure. The scope of this research is to design a procedure that allows discriminating the different albedo level of the surfaces of the urban envelope of Mendoza Metropolitan Area, Argentina, with final goal is to determine the energy saving (at building scale) and thermal comfort (at neighborhood scale) derived from to regulate the albedo values in the urban roofs. The methodology is based on performing a supervised classification of roofing materials using spectral signatures with the QGIS 3.2 ´Bonn´ software. For this purpose, images of the Sentinel 2a platform were used and 3 series of spectral signatures of built-up urban areas were obtained. The results show that the materials used mainly in the roofs of the city of Mendoza are membranes (74%), metal sheets (14%) and traditional tiles (13%). This knowledge is an efficient tool to quantify the energy and environmental effects derived from the regulation of albedo values in urban roofs.