Simulations of the Sea Surface Temperature over the North Atlantic

Simulations of the Sea Surface Temperature (SST) (left) and the air temperature at 2m over the North Atlantic by the global ultra-high resolution EC-Earth (http://www.ec-earth.org). The simulation shows a full year at daily resolution, with a horizontal resolution of about 16 km for both the ocean and atmosphere. The video shows the Gulfstream in the left panel, detaching from the American continent at Cape Hatteras and meandering into the open ocean. The Gulfstream is visualized by the sharp gradient in SST, from hot (red/yellow) to cold (blue/purple). In the right panel, you see that the temperature contrast over the Gulfstream is reflected in a sharp boundary between warm air and cold air in the overlying atmosphere - the so-called polar front (note that the continents are presented somewhat differently in both figures).

The video demonstrates the simulation of small-scale structures in the ocean (water motions in the ocean, called eddies and fronts). These small-scale structures directly influence the temperature of the overlying air, and hence the surface circulation of the atmosphere.

A striking example of this interaction is the cold eddy detaching from the Gulfstream southward. This blob of cold water drifts southward (the greenblobs), surrounded by warmer water and influences the temperature of the overlying air. In the right panel, a similar small structure in the air temperature of the atmosphere is visible (near 0.06-0.07 and 0.48-0.49 in the video). In a coarse resolution atmosphere model, such ocean-atmosphere feedback would not be visible. This demonstrates the importance of having high resolution in both ocean and atmosphere components of the coupled model.

Simulations with climate model ORCA12-T1279 are carried out on the MareNostrum supercomputer, at the Barcelona Supercomputing Center in the context of PRIMAVERA work package #6.