EGU2020-18908, updated on 12 Jun 2020
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Climate scenarios of the Gulf of Bothnia using a high-resolution regional ocean model (NEMO-SCOBI)

Sam Fredriksson1,2, Simo Siiriä3, Annu Oikkonen3, Petra Roiha3, Jani Särkkä3, Robinson Hordoir4,5, Anders Höglund1, Jenny Hieronymus1, Kari Eilola1, Itzel Ruvalcaba Baroni1, and Lars Arneborg1,2
Sam Fredriksson et al.
  • 1Swedish Meteorological and Hydrological Institute, SMHI, Research department, Oceanography, Vastra Frolunda, Sweden (
  • 2University of Gothenburg, Department of Marine Sciences, Gothenburg, Sweden
  • 3Finnish Meteorological Institute, Helsinki, Finland
  • 4Institute of Marine Research, Bergen, Norway
  • 5Bjerknes Centre for Climate Research, Bergen, Norway

How will the Gulf of Bothnia be impacted by future climate change? A changing climate will, in addition to warming, reduce the ice-season, change the salinity, sea level, and wave and current conditions. This will in turn have implications for eco systems, habitats, biodiversity, as well as human activities such as fishing, aquaculture, and wind parks. The SmartSea project aims to estimate the climate change impacts in this area. This study, which is part of the project SmartSea, assesses the changing physical and biogeochemical properties up to year 2059 using numerical experiments with forcing from two different Representative Concentration Pathways (RCP 4.5 and RCP 8.5) and four different global climate models. Here NEMO3.6 with LIM3 sea ice model is coupled to the biogeochemical model SCOBI. The model comprises the Gulf of Bothnia with a horizontal resolution of approximately one nautical mile.

The preliminary results comparing periods 1975-2005 and 2030-2059 and the pathway RCP4.5 and RCP8.5 show significant changes in sea ice conditions including a decrease of the ice season length, annual maximum ice volume, and extent of ice cover. In addition, the annual maximum ice volume is seen to arise earlier in the season. The temperature increases consistently, although the actual increase between the different simulations varies considerably. A general trend of decreasing salinity can also be seen. This is, however, less systematic than for ice conditions and temperature. The simulations indicate that the changes in both temperature and salinity are not spread evenly, but some areas will be affected more than others. The flow speed trends have been studied by comparing simulations for the period 1980-2005 and the pathway RCP4.5 and RCP8.5 for 2040-2059. The simulations indicate a rise in both local maximum flow speeds, as in average flow speeds, both in surface currents and depth averaged currents (barotropic currents).

How to cite: Fredriksson, S., Siiriä, S., Oikkonen, A., Roiha, P., Särkkä, J., Hordoir, R., Höglund, A., Hieronymus, J., Eilola, K., Ruvalcaba Baroni, I., and Arneborg, L.: Climate scenarios of the Gulf of Bothnia using a high-resolution regional ocean model (NEMO-SCOBI), EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18908,, 2020

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Display material version 1 – uploaded on 30 Apr 2020
  • AC1: Comment on EGU2020-18908, Sam Fredriksson, 07 May 2020

    For further details the Nemo setup is based on the Nemo-Nordic 1.0 setup

    Hordoir, R., Axell, L., Höglund, A., Dieterich, C., Fransner, F., Gröger, M., . . . Haapala, J. (2019). Nemo-Nordic 1.0: a NEMO-based ocean model for the Baltic and North seas – research and operational applications. Geosci. Model Dev., 12(1), 363-386. doi:10.5194/gmd-12-363-2019

  • CC1: Comment on EGU2020-18908, Matt Lewis, 07 May 2020

    Many thanks for this presentation, perhaps it is in the paper () but (1) are rivers included in your boundary conditions, and (2) in the climate model runs: for each RCP scenario, you have 4 climate models, but do each of these models have only dataseries to them (i.e. the mean vlaue in a PPE or no PPE - perturbed parameter approach)? Many thanks in advance. 

    • AC2: Reply to CC1, Sam Fredriksson, 11 May 2020

      Thanks for your interest. 1) Yes, rivers including nutrient loadings are included. 2) One dataserie for each RCP and climate model run.