Urban Heat Island effect by means of WRF simulations in future climate scenarios: the Bologna case study

The increasing frequency and intensity of extremeheat waves are currently causes of concern worldwide for their effects on several aspects of the natural ecosystems as well as on human health and comfort. These phenomena can be further exacerbated in urban areas in combination with the Urban Heat Island (UHI) effect that enhances the thermal discomfort. While such phenomena have been analyzed with regional models at local scales and with different urban canopy models, very few studies have been conducted on the evolution of the UHI in a climate change scenario. To this aim, a new dataset including global bias-corrected climate model output data suitable for WRF can be used. The new dataset deriving from version 1 of NCAR's Community Earth System Model allows us to estimate the potential effects of climate changes on the UHI phenomena under different future scenarios. This stud y will be conducted by means of WRF model simulating the UHI in a medium size city of the Po Valley, namely Bologna, spanning different seasons in the Mid Future (2045-2050) and in the far future (2075-2080) under the Representative Concentration Pathways 8.5 scenario (RCP8.5). The WRF model is driven by the Global 6-Hourly Bias-corrected Coupled Model Intercomparison Project, Phase 5 (CMIP5),Community Earth System Model (CESM) dataset over Europewith different resolution nested domains centered over the city of Bologna. In order to evaluate the performance of the model setup, it was also verified using reanalysis (ERA5) and CESM driven historical simulations. An analysisof the mean temperature and wind intensity in the inner domain of the city will be conducted together with a climatic analysis of the Emilia -Romagna region. This study mayassist to develop UHI mitigation strategies, mainly but not only restricted to the cities in the whole Po valley region, as well as to develop new policies aimed at improving the urban thermal comfort.