Tidal forcing and internal tide energetics around Svalbard: a numerical study
Master thesis
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Date
2020-06-27Metadata
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- Master theses [124]
Abstract
The hydrostatic and linear Regional Ocean Modeling System (ROMS) is used to examine the tidal forcing and the resulting baroclinic response and energetics of internal tides generated around Svalbard in the Arctic Ocean. In this region, the warm Atlantic water flows into the Arctic Ocean over variable bathymetric features, such as the Yermak Plateau and the continental slope and shelf break of Svalbard. Along its poleward path, vertical mixing processes contribute to removing heat from the Atlantic water. This research aims to quantify the tidal response in terms of, barotropic to baroclinic energy conversion and baroclinic energy dissipation using a realistic stratification distribution from autumn 2017, and forced separately by the dominant diurnal and semidiurnal tidal constituents. Tidal energetics are enhanced in distinct regions: the Yermak Plateau is dominated by the luni-solar and the principal lunar diurnal tides (K1 and O1), and the continental shelf and slope northeast of Svalbard by the principal lunar and solar semidiurnal tides (M2 and S2). The volume-integrated and time-averaged K1 energy conversion and dissipation of the tide in the Yermak Plateau region is 780MW (31% of the barotropic tidal energy input), whereas the M2 at the continental slope northeast of Svalbard is 70MW (2%). Over the sloping bathymetry, conversion mainly occurs in the 0.7 - 1.8km isobath range (upper and central slope), where radiation of internal waves is highly limited by rotational constraints. Generally, a substantial part of the converted energy dissipates locally in the 1.5 - 2.5km isobath range (central and lower slope), implying an important contribution to vertical mixing and the evolution of water mass properties in the region.