Sea Ice, Climate and Fram Strait 
Kenneth Hunkins 
Lamont-Doherty Geological Observatory, Palisades, NY 10964 
When sea ice is formed the albedo of the ocean surface increases from its open water 
value of about 0.1 to a value as high as 0.8. This albedo change affects the radiation balance 
and thus has the potential to alter climate. Sea ice also partially seals off the ocean from the 
atmosphere, reducing the exchange of gases such as carbon dioxide. This is another possible 
mechanism by which climate might be affected. 
The central Arctic Ocean is covered throughout the year with polar pack ice about 3 m in 
thickness. However, the shelf areas and the surrounding seas such as the Barents and Bering 
are covered only seasonally with ice about 1 m in thickness (Fig. 1). In the absence of land 
masses and ocean currents sea ice might be expected to have a zonally uniform distribution. But 
the actual distribution is highly irregular in southward extent. The most striking deviation 
occurs east of Greenland where a tongue of sea ice extends 2,000 km southward of Fram Strait, 
the passage between Greenland and Spitsbergen, in winter and half that distance in summer. The 
seas just east of this tongue from Fram Strait southward are free of ice throughout the year. 
Sea ice is exported from the Arctic Ocean into the Greenland Sea and North Atlantic (Fig. 2). 
This Strait and the surrounding region have been studied by two recent research programs. The 
FRAM Expeditions from 1979-82 investigated the oceanographic conditions north of the Strait with 
the aid of manned drifting stations and helicopters. The Marginal Ice Zone Experiment (MIZEX 
83-84) is an international, multidisciplinary study of processes controlling the edge of the ice 
pack in that area including the interactions between sea, air and ice. 
Ci USUALLY ICE COVERED 
USUALLY BECOMES ICE FREE 
FOR SEVERAL MONTHS 
Fig. 1. Maximum and minimum extent of sea ice in the Northern Hemisphere. 
