Model simulations of the M₂ and the K₁ tide in the Nordic Seas and the Arctic Ocean

Abstract

The depth-integrated tidal equations have been solved numerically for a model basin covering the North Sea and the Norwegian-Greenland-Barents Seas and the Arctic Ocean. The model is implemented on a stereographic map projection with a grid size 50 × 50 km at 60° N. The semi-diurnal M2 component and the diurnal K₁ component have been simulated. Correlation coefficients between computed and measured M₂ and K₁, amplitudes for 116 tidal stations located all around the Nordic Seas were found to be 0.97 and 0.82, respectively. The standard deviation for the corresponding linear regression analysis is ±0.12 m and ±0.02 m, respectively. For the continental shelf along the western coast of Norway and the Barents Sea, the performance of the model is particularly good and the values for the correlation coefficients and standard deviations for this region are 0.97, 0.92, ±0.09 m and ±0.03 m.

The M² tide is mainly a co-oscillating tide driven by energy influx from the North Atlantic. The K¹ tide is strongly affected by the direct effect of the tide-generating force particularly in the North Sea region and along the coast of western Norway.

Different forms of boundary condition along the open boundary towards the North Atlantic have been implemented and tested by comparing the results of the simulation with measurements. Co-range and co-tidal charts are presented and the regional variation of the tidal currents is displayed by maps showing the principal axis of current ellipse and the sense of rotation of the current vector. Energy fluxes are computed for key sections within the model basin and a tidal energy budget for the main parts of the basins is given.