| Summary: | Strong diurnal tidal currents, in a region dominated by semidiurnal tidal surface displacements, 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. The selective enhancement of topographic vorticity waves by resonant forcing from the K 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 loops 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 fort nightly (spring-neap) beat of surface height inequality caused by the superposition of the two principal semidiurnal tides. Sea ice for ced by the added convergent grinding motion arising from these enhanced diurnal clockwise currents should have a surface morphology different from the ice which did not flow through this area i.e., that which passes through Fram Strait to the west of the Yermak Plateau. Approved for public release; distribution is unlimited. Lieutenant, United States Navy http://archive.org/details/transpolarseiced1094537542
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