The state of the Baltic Sea and North Sea within changing climate
Abstract
The North Sea and Baltic Sea are not well resolved in global climate and ocean models. Therefore, we here apply for additional computational resources for running regional CMIP5 ocean climate and nutrient scenarios. These are important to understand the impact of changing climate and other anthropogenic drivers to coastal regions and its environment. An ensemble of simulations will be performed using a high resolution regional ocean model that uses output from low resolution global climate models as forcing. In addition, some of our forcing at the lateral open boundary (e.g. wind driven sea level variability) of the regional ocean model is produced using machine learning methods.
Within the project, we will run an ocean climate scenario ensemble with 27 members using our ocean and biogeochemistry model NEMO-Nordic-SCOBI covering the North Sea and the Baltic Sea. This work is part of the Havsmiljöscenario project, which gathers much of the work of SMHI's oceanographic research group in the field of climate and marine environment research. The ensemble, which we apply computational resource for, is based on three global climate models, and includes three nutrient emission and three greenhouse gases emission scenarios. Preparatory simulations, mainly focussing on the ocean physics, where performed since year 2022 under the allocations SNIC 2022/5-77, SNIC 2022-3-39 and NAISS 2023/1-45. In addition, several test simulations have been performed on Tetralith and Bi to create biogeochemical forcing for running SCOBI with the three different nutrient emission scenarios. All biogeochemical forcing is now ready and the spin-up simulations for the three global climate models have been performed on Bi. The aim of this application is to perform a part of the ensemble member simulations on Tetralith’s updated system as our resources on Bi (later Freja) will not be sufficient to perform all members of the ensemble simulation in a reasonable time. The simulations, running from year 1971 until 2100, can start immediately from a possible medium allocation approval.
The results of the ensemble simulations will be the basis for scientific publications with focus on changes of ocean physics as well as the marine environment caused by climate change. Beside using the model results to inform stakeholders, they will also be made available to the general public through SMHI’s climate scenario service (https://www.smhi.se/klimat/framtidens-klimat/fordjupade-klimatscenarier/oce/-/temperature/rcp45/2071-2100/year/reference).
