NORTH-POLE ICE THICKNESS AND ASSOCIATION WITH ICE MOTION HISTORY 1977-1992

Ice drafts measured by U.S. Navy submarine sonar near the North Pole f rom 1977 to 1992 were used together with Arctic Ocean drifting buoy da ta from 1979 to 1992 to investigate North Pole ice thickness changes d uring this 15-year period. A primary objective was to determine dynami cal forcing mechanisms and associated time scales relevant to ice thic kness variation. North Pole ice thickness showed much interannual vari ability, and no systematic decrease of ice thickness was observed. Cha nges in ice thickness were closely associated with long-term direction al deviation of ice motion from geostrophic wind-forcing, and with ice convergence and divergence at the North Pole during the 1-2 weeks pri or to submarine measurement. The geographic origin of ice within the A rctic Ocean was not associated with its eventual thickness at the Nort h Pole.