For ocean regions closer to Norway («our waters»), we use a nested system consisting of the models «Nordic-4» and «NorKyst-800».
Nordic-4 is currently our main model for forecasts of water level (tides and storm surge), currents and hydrography near Norway. It covers the Norwegian Sea, the Barents Sea and the North Sea including Skagerrak/Kattegat (sett inn bilde). This model, based on ROMS, has a horizontal grid resolution of about 4 km and has 35 terrain-following vertical layers. It uses an assimilation system similar to that of Arctic-20 and produces estimates of the ocean state and a 3-day forecasts every day. At 4 km horizontal resolution, Nordic-4 is much more 'eddy permitting' than both TOPAZ and Arctic-20. These eddies, equivalent to synoptic high and low pressure systems in the atmosphere, are an important mechanism for spreading of water masses between e.g. the Norwegian Coastal Current (NCC) and the Norwegian Atlantic Current (NAC) along the continental slope.
Norkyst-800 is our newest coupled ice-ocean model for Norwegian near-shore waters (sett inn bilde). It has been developed in collaboration with the Institute for Marine Research (IMR) and the Norwegian Institute for Water Research (NIVA). This model, also based on ROMS, has a horizontal grid resolution of about 800 m and has 35 terrain-following vertical layers. At five times the horizontal resolution of Nordic-4, this model is able to much better reproduce currents and hydrography for near-shore areas. It is currently in a test phase, but will gradually evolve into our primary forecast model for near-shore forecasts.
Forecasts of surface gravity waves in near-shore regions is done with the «WAM» model at 4 km horizontal resolution (WAM4.00; sett inn bilde). It is nested into the coarser WAM model for the northern North Atlantic described above. For particular regions, e.g. Trondheimsleia, we also run the «SWAN» model at 500 m resolution (sett inn bilde) nested into WAM4.