Physical Oceanography (Oct 2023)
Variability of the Marginal Ice Zone and Eddy Generation in Fram Strait and near Svalbard in Summer Based on Satellite Radar Observations
Abstract
Purpose. The aim of the study is to investigate the spatial and temporal variability of drifting ice field edge and the features of eddy generation in the marginal ice zone (MIZ) in Fram Strait and near Svalbard during the warm period in 2007. Methods and Results. Satellite radar images of Envisat ASAR for June – September 2007 were used to fix the position of drifting ice field boundary and to reveal the surface manifestations of eddy generations in the MIZ. It is established that during the upper mentioned period, the ice – water boundary experienced unequal displacements along its entire length, and that a total range of the ice edge movements was 30–220 km. At different wind conditions, the ice edge motion was accompanied by the formation of ice filaments and eddies, the maximum number of which was recorded in June. The data analysis allowed us to identify more than 2000 pronounced MIZ eddies in which the structures with a cyclonic type of rotation were evidently predominant (78%). The larger eddies (10–20 km in diameter) were observed over the deep-water areas of Fram Strait and over the Greenland Sea shelf, whereas the smaller ones (~ 5 km in diameter) – in the coastal areas of Svalbard. The cases when the ice fragments were detached from the ice field and subsequently involved in the vortex motion were recorded. The ice drift and orbital motion velocities in the eddies were assessed. Conclusions. The ice edge displacements and the process of eddy generation in the MIZ are significantly affected by the wind conditions. When the wind direction changes abruptly, the ice field fragments can be detached. The identified MIZ eddies are mainly of cyclonic rotation direction.
