Astrid Kainz (Austria) 1; Maja Zuvela-Aloise (Austria) 1; Robert Goler (Austria) 1; Rosmarie De Wit (Austria) 1; Claudia Hahn (Austria) 1
1 - Zentralanstalt für Meteorologie und Geodynamik (ZAMG)
Urban areas and traffic infrastructure are particularly affected by climate change, thus raising the need for well-founded climate adaptation strategies. The project CLARITY, funded by EU Horizon 2020 Programme, aims at implementing a climate services information system (CSIS) specifically designed to address climate related hazards and to provide climate change adaptation strategies for supporting urban infrastructure development. The CSIS is tested and demonstrated on four study areas in different regional and climatological contexts. In this study, we focus on the Austrian demonstration case that addresses the compound effects of heat waves and urban heat islands in the city of Linz, which under climate change are expected to worsen.
The dynamical urban climate model MUKLIMO_3, developed by the Deutscher Wetterdienst (DWD), is used to investigate urban heat island effects and to carry out sensitivity simulations of climate adaptation measures for the city of Linz and its surrounding area. The model simulations, performed at a horizontal resolution of 100m, are based on Copernicus Urban Atlas land cover data combined with local data provided by the city administration of Linz to consider city-specific structures. A dynamical-statistical downscaling method is applied to derive climate indices for long-term historical and future climate periods by combining high-resolution model output with observational data and regional climate projections.
Model results are used to analyze the current and future climatic situation in the city of Linz in terms of urban heat load. Furthermore, several climate adaptation scenarios are tested with respect to their efficiency in reducing urban heat stress. These include, amongst others, roof greening, increased albedo of roofs and walls, unsealing of surfaces and increased vegetation cover. Depending on the scenario, moderate to strong cooling effects are found as indicated by a reduction in the mean annual number of summer days, hot days and tropical nights.
The main findings obtained in this study are used to demonstrate how urban climate models promote the efficiency assessment of different climate adaptation strategies and how they contribute to climate resilient urban planning.