Basin-scale ocean prediction with the hybrid coordinate ocean model

Eddy-resolving simulations of the Atlantic and Pacific Oceans were performed using the hybrid coordinate ocean model (HYCOM) at 1/12° (∼7 km midlatitude) resolution. HYCOM is isopycnal in the open, stratified ocean, but makes a dynamically smooth transition to a terrain-following coordinate in shallow water and to pressure coordinates in the mixed layer and/or unstratified regions via the layered continuity equation. This approach retains the advantages that each individual vertical coordinate system offers. After a series of free-running simulations, a data assimilative version of the 1/12° Atlantic HYCOM has been developed into a near real-time nowcast/forecast system. Sea surface height analyses of available satellite altimeter data are assimilated into the model. A nowcast and a 10-day forecast are produced each week. Near real-time results are available via the HYCOM consortium for data assimilative ocean modeling web page at http://hycom.rsmas.miami.edu.