Multiscale analysis as a central component of urban physics modeling

Abstract

Urban physics is seeking its place between two better structured scales, that of environmental physics and that of building physics. The intermediate level of the city and the urban district is particularly difficult to appreciate, because it involves huge geometries that must however be precisely detailed and finelymeshed. It has become very important to simulate on this scale, principally energy exchanges, because the urban environment, with its rapid worldwide growth, has become a complex dynamic interface for both top-down problems (generation of urban microclimates) and bottom-up ones (influence of urban morphology on the final consumption of the entire city), and even properly multiscale applications (involvement of cities in global warming). This paper provides a starting point (the shortwave radiative exchange), a process of cross-validation between measurements and simulations (with emphasis on the contribution of satellite imagery) and three main objectives: energy balance, urban planning and participation to global climate models.