Application of weather data morphing for calibration of urban ENVI-met microclimate models. Results and critical issues

The detailed analysis of the urban microclimate calls for the use of Computational Fluid Dynamics (CFD) tools able to model complex heat and mass transfer mechanisms. ENVI-met is one of the most used and reliable tools for microclimate analysis if an accurate calibration is performed. The calibration process is fundamental to have a reliable model in order to perform microclimate analysis, but requires accurate on-site measurements of urban weather data and it is usually difficult to have urban meteorological data of the required granularity because of the lack of on- site stationary weather stations. To overcome such an issue, this paper explores the use of weather data retrieved from suburban meteorological stations and morphed for the urban context under study through the Urban Weather Generator (UWG) tool. UWG generates an urban weather file in the hourly .epw format that is eventually used for forcing the ENVI-met model of the investigated area. This approach is validated against on-site measurements at different times for various points located in a district of the city center of Catania (Italy). The validation process presented a very good correlation for most of the study points in the district during nighttime, while during daytime some discrepancies may occur.