Tidal Motion Enhancement on Spitsbergen Bank, Barents Sea

• Published in: Journal of geophysical research. Oceans 2023-01, Vol.128 (1), p.n/a
• Main Authors: Kowalik, Z., Marchenko, A.
• Format: Article
• Language: English
• Subjects: Amplification; Bays; Buoys; Dipoles; Distribution; Diurnal; Diurnal tides; Diurnal variations; Geophysics; Ice; Ice drift; Ice floes; Ice formation; Islands; Mathematical models; Movement; Numerical models; Ocean currents; Oscillations; Pack ice; Peninsulas; Residual currents; Resolution; Sea level; Seamounts; Semidiurnal tides; Shelf waves; Shelving; Spatial discrimination; Spatial resolution; Tidal currents; Tidal mixing; Tidal motion; Tidal velocities; Tidal waves; Tides; Velocity; Waste disposal; Water currents; Wave dynamics; Wavelength
• ISSN: 2169-9275; 2169-9291
• DOI: 10.1029/2022JC018539

The higher resolution numerical model investigates the semidiurnal and diurnal tides over the shallow Spitsbergen Bank. The tidal wave is trapped around Bear Island, Hopen Island, and Central Hill at the Bank in the semidiurnal range of oscillations. Semidiurnal waves around Bear and Hopen Islands generate a trapped dipole in the sea level distribution revealed by sea level maximum and minimum traveling on the opposite sides of the island. The dipole induces significant sea‐level differences and amplified velocity around the island perimeter. The role of the tidal currents over the Bank is connected through the mixing and transport to the generation of frontal regions. Tidal mixing directly relates to the local ice formation on Spitsbergen Bank as these areas coincide with the regions of strong tidal currents. The trapping of the semidiurnal tides leads to residual (permanent) circulation of up to 15 cm s−1. As this motion interconnects different bathymetric regions of the Bank, it influences the exchange of properties between these regions. The strength of residual currents shows that the large‐scale slow thermohaline motion cannot be complete without residual tidal motion. The diurnal tides show a different distribution since higher spatial resolution reveals sea‐level variability in many locations. These short‐wavelength shelf waves occur at seamounts, submarine peninsulas, and bays. We investigate in detail the wave dynamics in proximity to Central Hill and Hopen Island. We use observations of the buoys deployed on the ice floes to compare the drift velocity to the computed tidal velocity. Plain Language Summary We researched tides at the Spitsbergen Bank in the Barents Sea to determine how the semidiurnal and diurnal tides are changed at the shallow Bank and in proximity to the islands. The semidiurnal tides (the strongest tide is M2) are trapped around the small islands. At the elongated Hopen Island, the speed intensifies toward both tips. At the near‐circular Bear Island, the amplifications are at the protruding capes. The tidal currents, which change at high and low water, often are unusually strong around these points and, together with the turbulent sea level and drifting ice, can be dangerous for ships. The strong tidal currents generate permanent clockwise circulation around the islands, called residual tidal motion. The clockwise tidal motion is essential for biological life, and waste disposal as whatever is disposed of near the islands will