Towards the numerical simulation of the summer circulation in Todos Santos Bay, Ensenada, B.C. Mexico

The general circulation of Todos Santos Bay was studied using the ROMS numerical model for the summer season. The model was forced with the California Current System and by synoptic winds, which are mainly towards the equator. The circulation is characterized by two systems: one at the exterior with a strong southward flow that enters to the bay but limited by the ∼35 m isobath and the other at the rest of the bay. The circulation in the interior oscillates between two spatial structures: one in which the general circulation is anticyclonic for two–three days overall the bay producing a large eddy and a small cyclonic eddy in front of Ensenada’s port, then the anticyclonic eddy evolves to produce the second spatial structure by splitting into two counter rotating eddies making the original anticyclonic one to be limited to the northern side of the bay and last three–four days and the small cyclonic eddy reverses its circulation. Such conditions are a consequence of the transport oscillations of the southward flow on the northwestern boundary and the mode with two eddies appears when the associated inflow is more intense. The transition between these two modes takes place in only one–two days. The time average circulation was also analyzed and the circulation with the two eddies dominates as it is of stronger currents and last longer.