Sensitivity of adaptation strategies in diverse European cities

There is a need to assess the effect of urban adaptation measures on city scale and micro-scale phenomena, such as the urban heat island (UHI) effect and thermal comfort, to make cities climate resilient. The impact of vegetation on the urban climate has been investigated by using observations and/or modelling sensitivity experiments. During model sensitivity experiments for adaptation measures, an urban climate model is run multiple times with different adaptation strategies. For several cities or neighborhoods such studies were performed to explore the impact of urbanization and/or greening scenarios. Among these studies different scenarios and models were however used, which makes a comparison of the effectiveness of these measures over the different cities impossible. There is thus a need for a general applicable method with pre-defined urban vegetation scenarios for all cities to assess the impact of adaptation measures.
We examined for a decade the sensitivity of several adaptation measures, such as implementing 40% urban vegetation or 50% green roofs, at kilometric resolution over more than 20 European cities that have diverse urban and climatic characteristics. The scenarios were produced by changing parameters in the land surface model SURFEX, which was driven by the atmospheric forcing of ALARO-SURFEX. By keeping the scenarios identical for every city, sensitivity differences in temperature, UHI and thermal comfort between cities are due to urban or climatic characteristics. The results of this research will be incredibly important for applied sciences, such as urban design, since it will improve our knowledge on the effectiveness of urban greening across different types of cities and climatic zones.