Successful coupling of RCA4 with the ocean model NEMO

The new version of the Rossby Centre regional atmospheric model (RCA4) has successfully been coupled with the ocean model NEMO. Recent evaluations show that the coupled system is stable.

We are currently developing the RCA4_NEMO model which is an interactive flux coupled regional atmosphere-ocean model. This coupled model system combines two well-known components, the Rossby Center regional climate model (RCA4) and the ocean model NEMO, using the OASIS4 coupler. This coupling introduces the interaction between the atmosphere and ocean into climate simulations in a sophisticated manner.

To build up this coupled modelling system, the OASIS4 coupler is applied to bridge the atmosphere model RCA4 and ocean model NEMO together as described in figure 1.

Figure 1. Description of RCA4-NEMO coupling.
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This coupler works in a sequential manner which synchronous couples different model components at reasonable time interval.

Up to date, the technical modification has been implemented into RCA4 and NEMO, and this fully coupled model system has been run without sea ice model for one year integration. Preliminary evaluation shows that this coupled system is stable. The fully coupled atmosphere-ocean-ice model system is still under further testing.