Diagnostic study of the Fram Strait marginal ice zone during summer from 1983 and 1984 Marginal Ice Zone Experiment Lagrangian observations

Abstract

From 1984 Marginal Ice Zone Experiment observations in Fram Strait, three main results concerning large scale, mesoscale, and summer marginal ice zone (MIZ) features are presented and discussed in this paper. Regarding the large scale, the main conclusion is that the East Greenland Current (EGC) is a narrow, stable current, in contradiction with past results presenting the EGC as a broad and unstable current. In the mesoscale, the West Spitsbergen Current (WSC) and the Norwegian Current are the main generators for eddies in Fram Strait. These eddies propagate northwestward, preferentially following topographic features like fracture zones, which are quite abundant in this region. In our opinion, these WSC eddies represent an important part of the Atlantic water recirculation in Fram Strait. When approaching the east Greenland continental slope, they interact with the EGC and they form well‐developed eddies. These ice edge eddies associated with ice edge tongues are quite recognizable with remote sensing techniques. The summer marginal ice zone in Fram Strait is clearly characterized by sea ice concentrations from 1/10 to 3/10 and floe sizes limited to 1 km or less. There is a well‐defined limit which separates the pack ice from the MIZ where no big ice floes are ever recorded. The breaking action of waves and swell propagating into the ice are likely to be the only mechanisms explaining such a drastic filtering effect. According to their amplitudes and directions, winds and eddies act in the MIZ in shrinking or stretching this zone.