Tidal Wave-Elliptic Island Interaction above the Critical Latitude

Around Hopen Island, the satellite images and experiments with drifting buoys describe the movement of the drifting ice and depict tidally generated trapped motion. An analytical solution is applied to investigate the trapping phenomenon. A general solution is achieved by the superposition of the incident and reflected (scattered) waves for an el-liptically shaped island above the critical latitude. The incident wave simulates the tidal wave propagation toward the island and its prominent feature, an amphidromic point located to the southeast from Hopen Island. The analytical solution for the reflected wave is constructed in elliptic coordinates. Tide amplitudes and cophase lines are analyzed in the island's vi-cinity and compared to observations and numerical model results. A simulated drift of Lagrangian water particles con-structed with the help of analytical solutions reproduces well the observed clockwise trapped motion of the drifting buoy near Hopen Island. Since the resonance may amplify the semidiurnal incident tide, we have also investigated the natural modes of water oscillations near the island. While this paper focuses on the details of the model used at the specific site of Hopen Island, a similar trapping analysis can be applied to circular or elliptic islands that have a small scale relative to the barotropic Rossby deformation radius.

Automated summary

The movement of the drifting ice and tidally generated trapped motion around Hopen Island is described using satellite images and experiments with drifting buoys. An analytical solution is applied to investigate the trapping phenomenon, achieving a general solution through the superposition of incident and reflected waves. The simulated drift of Lagrangian water particles reproduces well the observed trapped motion near Hopen Island.