Search

Urban shape determines the absorption and emission of radiation. Urban fabrics are characterized by the solar trapping effect due to multiple reflections of radiation within the geometry, in turn generating increased energy absorption that contributes to the urban heat island. Interactions between urban radiative properties and urban shape are studied through an analytical development. A simplified solar balance model is developed based on morphological indicators. A processing chain is performed within OrbisGIS Geographic Information System (GIS) to characterize urban shapes from geographic data supplied by the French IGN. The studied territories are partitioned from the road network into elementary areas of city blocks. The processing chain also includes the production of 3D block models that are used in the SOLENE solar simulation model to perform detailed radiative simulations. The incident and absorbed solar radiations are estimated on 440 actual city blocks from the simplified solar balance model and then compared to the SOLENE computations. The relationships between the simplified solar balance model and the SOLENE simulations are investigated using linear regression analysis. The comparisons show significant correlations and that the simplified solar balance model developed is consistent with the simulations. This contribution produces simple and accurate radiative parametrizations that can be used in urban microclimate models to represent solar trapping and to evaluate radiation availability. [ABSTRACT FROM AUTHOR]