Simulation of the interannual variability of the wind-driven Arctic sea-ice cover during 1958-1998

A thermodynamic-dynamic sea-ice model based on a granular material rheology developed by Tremblay and Mysak is used to study the interannual variabili ty of the Arctic sea-ice cover during the 41-year period 1958-98. Monthly w ind stress forcing derived from the National Centers for Environmental Pred iction (NCEP) Reanalysis data is used to produce the year-to-year variation s in the sea-ice circulation and thickness. We focus on analyzing the varia bility of the sea-ice volume in the Arctic Basin and the subsequent changes in sea-ice export into the Greenland Sea via Fram Strait. The relative con tributions of the Fram Strait sea-ice thickness and velocity anomalies to t he sea-ice export anomalies are first investigated, and the former is shown to be particularly important during several large export events. The sea-i ce export anomalies for these events are next linked to prior sea-ice volum e anomalies in the Arctic Basin. The origin and evolution of the sea-ice vo lume anomalies are then related to the sea-ice circulation and atmospheric forcing patterns in the Arctic. Large sea-ice export anomalies are generall y preceded by large volume anomalies formed along the East Siberian coast d ue to anomalous winds which occur when the Arctic High is centered closer t han usual to this coastal area. When the center of this High relocates over the Beaufort Sea and the Icelandic Low extends far into the Arctic Basin, the ice volume anomalies are transported to the Fram Strait region via the Transpolar Drift Stream. Finally, the link between the sea-ice export and t he North Atlantic Oscillation (NAO) index is briefly discussed. The overall results from this study show that the Arctic Basin and its ice volume anom alies must be considered in order to fully understand the export through Fr am Strait.