Transpolar Sea Ice Drift in the Vicinity of the Yermak Plateau as Observed byARCTEMIZ 86 Buoys

摘要

Strong diurnal tidal currents, in a region dominated by semidiurnal tidal surfacedisplacements, were observed in the record of ARCTEMIZ 1986 buoys as they drifted over the Yermak Plateau, a submarine feature northwest of Svalbard. Similar diurnal currents in this area were first observed from observations taken during the FRAM III and FRAM IV ice station drift experiments. Selective enhancement of topographic vorticity waves by resonant forcing from the K sub 1 diurnal tide over the steeply sloping northern, northwestern and western flanks of the plateau is forwarded as an explanation for these anomalously strong diurnal currents. Diurnal were observed in the trajectories of two buoys while they were over the northern flank of the Yermak Plateau. These loops were similar to those observed during MIZEX 84. The loops occurred during diurnal clockwise velocity peaks which have the same periodicity as the fortnightly (spring-neap) beat of surface height inequality caused by the superposition of the two principal semidiurnal tides. Sea ice forced by the added convergent grinding motion arising from these enhanced diurnal clockwise currents should have a surface morphology observably different from ice which did not flow through this area, i.e., that which passes through Fram Strait to the west of the Yermak Plateau. Keywords: Ocean tides; Diurnal variations; Arctic Ocean; Ocean bottom topography; Theses. Resonance/vortices. (EDC)