Numerical experiment on the spreading of Mediterranean water in the North Atlantic

The Princeton Ocean General Circulation model (OGCM) is used to simulate the circulation in the Atlantic Ocean between 80°N and 15°S. Horizontal resolution is Δφ = Δλ = 2°, and the computations are carried out at 12 levels. The model is initialized with Levitus's (1982) data. Robust diagnostic and prognastic experiments with prescribed Mediterranean outflow are carried out to study the gross features of the North Atlantic circulation, and in particular the Mediterranean water tongue. The model simulates westward and west-southwestward flow in the area where Mediterranean water is usually observed. The positive temperature and salinity anomalies extend westward. The simulated water masses and their general features agree well with Levitus's (1982) data. Horizontal density gradients due to temperature and salinity anomalies compensate each other in the Mediterranean water tongue, and the buoyancy signal originating from the Strait of Gibraltar does not substantially affect the general circulation in the interior Atlantic Ocean.