THERMOHALINE TRAIL OF AN INTRATHERMOCLINE EDDY IN THE OCEAN

Abstract

A pronounced anticyclonic intrathermocline eddy (ITE) was found in the tropical Atlantic during the institute's Mezopoligon expedition in 1985. The data indicate that such eddies survive at intermediate depths for very long periods (at least 1 to 3 years), traveling within the thermocline, and gradually break down as a result of loss of heat and salt from the core. When searching for the trail of an intrathermocline eddy lens, focus should be on salinity anomalies below the depth interval in which the eddy core is located. The eddy and its core, i.e., a lens containing a compact potential vorticity anomaly, should move westward by virtue of the westward transport induced by the beta effect, and an amorphous thermohaline wake or trail, with no compact potential vorticity anomaly, should remain in the locations through which it passed or be carried laterally away from the path of the lens by background transport, similarly to smoke from the stacks of a ship on a westward course. This is the working hypothesis that was tested and is discussed in the paper.