5:15 PM - 7:15 PM
[ACG52-P02] Distinct behaviors of diurnal and semidiurnal internal waves on the southern slope of the Yermak Plateau
Keywords:Arctic Ocean, Yermak Plateau, Internal wave, Numerical simulation
The Yermak Plateau (YP) is located across the Arctic-Atlantic gateway in the northwest of the Svalbard archipelago. Internal waves are believed to cause intense turbulent mixing on the YP and hence influence the heat budget in the Arctic Ocean (AO). Understanding the internal waves here is therefore of great importance. Based on 3-D high-resolution numerical simulations with realistic tidal and subtidal forcing, diurnal and semidiurnal internal waves on the southern slope of the Yermak Plateau (YP) are investigated. The simulated results indicate that internal wave fields respond differently to the diurnal and semidiurnal forcing: Although both are located north of the critical latitude, there are significant differences in the propagation characteristics of diurnal and semidiurnal internal waves. The diurnal internal waves propagate clockwise along the continental slope in the form of topographic trapped waves, while the semidiurnal still exhibits as typical freely propagating internal waves. Diurnal internal waves induce large vertical displacements and hence large available potential energy which dominates the energy fields; while semidiurnal internal waves have intense baroclinic velocities, with the horizontal kinetic energy much larger than the available potential energy. Nonlinear interaction occurs when diurnal forcing is imposed, which gives rise to semidiurnal internal waves, especially in the shallow water. In contrast, nonlinear interaction is rather weak under the semidiurnal forcing. Both the diurnal and semidiurnal internal waves induce intense shears over the continental slope, leading to the enhancement of local energy dissipation. We believe that results of this study can provide insight on the dynamics of internal waves in the Arctic Ocean.