COSTRICE – three model online coupling using OASIS: problems and solutions

• Main Authors: Ho, H. T. M., Rockel, B., Kapitza, H., Geyer, B., Meyer, E.
• Format: Text
• Language: English
• Published: 2018
• Subjects: Kattegat; Sea ice
• Online Access: https://doi.org/10.5194/gmdd-5-3261-2012; https://gmd.copernicus.org/preprints/gmd-2012-90/

The coupled system COSTRICE is developed for the first time in order to reproduce the interactions and feedbacks between atmosphere, ocean and sea-ice in a two-way online coupled model system containing three component models for regional climate simulations over Baltic Sea and North Sea regions. The regional climate model CCLM 1 is coupled to the regional ocean model TRIMNP 1 and the sea ice model CICE 1 via the coupler OASIS3. In this study, CCLM is setup with a horizontal grid mesh size of 50 km and 32 vertical atmosphere layers and driven by the 6-h ERA-interim reanalysis data as initial and boundary conditions. TRIMNP is setup with a horizontal grid mesh size of 12.8 km and 50 vertical ocean levels. CICE calculates ice in 5 categories and runs with the same horizontal resolution as TRIMNP but only over the Baltic Sea and the Kattegat Bay of the North Sea. In a two-way online coupling process, CCLM is linked to TRIMNP through sea surface temperature (SST) as lower boundary condition every 3 h and TRIMNP is driven by 1-h atmospheric state variables and fluxes of CCLM. The data exchange processes between TRIMNP and CICE as well as from CCLM to CICE take place with an interval of 3 h. The coupled model is applied in a study for climate simulations over Baltic Sea and North Sea regions in 1997. The coupled system is set up to run in parallel on the super computing system IBM-power 6 at the German Climate Computing Center (DKRZ). 1 See Table A1.