Björn Maronga
StadtKlimaNDS is a project funded by the state of Lower Saxony through the Lower Saxony Competence Center for Climate Change (NIKO). The purpose of this project is to contribute significant supplemental information on the adaptation of Lower Saxony cities to climate change, with a focus on increasing temperatures and periods of heat and drought. For this purpose, the urban climate model PALM will be coupled to the weather forecast model ICON-D2 from the German Weather Service. This coupling will create a high-resolution urban weather model for the operational warning of heat and drought stress. In addition, model simulations will be used to investigate adaptation and mitigation strategies for urban areas.
Before the system is transferred to operational use, simulation results will be validated using hindcast simulations. Initially, the model domain and prediction system will be limited to the city of Hannover. Forecasts will be extended to a second city or municipality depending on data availability. The simulation results will provide high-resolution predictions for wind, temperature, and humidity distribution for a forecast period up to several days. Additional biometeorological indices (Heat Index, Physiological Equivalent Temperature, Universal Thermal Comfort Index) will be output to compliment the forecast results. To reduce computational requirements but maintain level of detail and domain extent, a resolution on the order of 50 m is anticipated for the whole of Hannover. An additional nested domain of 4 km2 at a resolution of 5 m or finer will be included for ultra-high-resolution results. In addition, it should be possible to forecast the energy demand generated by building services to a first approximation. A module for predicting water availability and drought stress will be implemented to assess the impact of weather on the urban green. The predictions of the model system will be made available to the public automatically through the project home page (www.stadtklima-hannover.de). To investigate possible adaptation strategies regarding heat and drought in the context of climate change, predictions will be made with the actual state of the urban surface structure. These predictions will be compared to scenarios under various adaptation strategies. Simulations of existing buildings retrofit with adaptation strategies are envisaged (e.g., energetic refurbishment, highly reflective facade and roof colors, photovoltaic systems and building greening). Simulations of unsealing and renaturation strageties will also be conducted. To investigate the response of the urban area to higher temperatures and corresponding mitigation strategies, supplementary simulations for climate change scenarios will be carried out for both the actual state and the adaptation scenarios.
