The Jan Mayen Current of the Greenland Sea

Abstract

Oceanographic measurements acquired by the USNS Bartlett during September 1989 in and north of the area of the Jan Mayen Current (JMC) show that, in terms of upper layer baroclinic flow, about half of the JMC is a wide meander in the East Greenland Current (EGC) and about half continues eastward to close the Greenland Gyre (GG) on the south. This phenomenon has been charted in the past but has elicited no comment. Surface drifters and a numerical model corroborate this behavior. At deeper depths (>100 m) the meander dissipates with the flow becoming more easterly. A drifting float at 500 m depth confirms that the flow is relatively undeviated toward the east ultimately merging with the northward flowing Norwegian Atlantic Current. Near the GG the fresh water content of the water column is low in the upper layers but high in the middepths. Where there is a substantial content of EGC water (e.g., in the JMC), the converse is usually true. The FWC of the GG computed for the period 1953–1966 was smaller by a factor of 2 in both layers than in 1989, indicating that 1989 is in another period of low salinity comparable to that of 1968, the period of the Great Salinity Anomaly described by Dickson et al. (1988).