Jorge H. Amorim (Sweden) 1; David Segersson (Sweden) 1; Christina Wikberger (Sweden) 2; Christer Johansson (Sweden) 2; Isabel Ribeiro (Sweden) 1; Lena Strömbäck (Sweden) 1
1 - Swedish Meteorological and Hydrological Institute (SMHI); 2 - Stockholm City
While the urban population in Europe is projected to exceed 80% by 2050, augmented extreme weather events will push the resilience of citizens to its limits and call for efficient adaptation measures. In this path, ‘climate services have the potential to become the intelligence behind the transition to a climate-resilient society’, as stated by the European Commission.
Within the scope of the co-creation of a Climate Services Information System (CSIS) in the Horizon2020 project CLARITY, and with the support of the Swedish Civil Contingency Agency, SMHI has been cooperating with Stockholm municipality in the calculation and visualization of the effects of heat-waves. The city’s growing need of housing and roads demands for the citizens’ wellbeing and health to be safeguarded, while the resilience to climate hazards is strengthened. For this purpose, the impacts of urban development scenarios are investigated, namely the construction of 140,000 new homes by 2030, including one of Europe’s largest urban development areas: the ‘Stockholm Royal Seaport’. The implementation of urban green infrastructure as an adaptation tool is also being assessed through different scenarios.
High resolution climate simulations are carried out at 1 km grid space using a dynamical downscaling technique. The Numerical Weather Prediction system HARMONIE-AROME is applied with lateral boundary data provided by the UERRA-ALADIN reanalysis and surface observations retrieved from the ECMWF MARS archive. Surface/atmosphere fluxes over the city are computed by the Town Energy Balance (TEB) model. This method has been developed and validated in the Copernicus Climate Change Service UrbanSIS.
The summer of 2014, which encompassed a heat wave in the period 5-10 July with daily average air temperature above 26oC, was selected as baseline for the study. Results show that average temperature increases by 0.45oC in 2030, with larger differences found in urbanized forest lands. Also, the average cooling currently induced by urban vegetation in Stockholm was estimated as 0.4oC. In parks (e.g., Observatorietlunden), a strong diurnal cycle leads to night-/daytime average cooling ranging between 3.5 and 0.9oC, respectively, in the simulated summer period.
Co-created climate services that include user-tailored downscaled urban climate data, in the example of Stockholm, provide new insights for urban planning and development, including landscape architecture and the use of Nature-based Solutions. CLARITY is therefore targeted at delivering innovative and efficient solutions for the adaptation of cities to climate change.