Tides and Tidal Currents in the Strait of Gibraltar Computed with the Hydrodynamical Numerical Model of Walter Hansen PDF Download

Author: T. Laevastu
Publisher:
ISBN:
Category :
Languages : en
Pages : 28

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Book Description
The Hydrodynamical Numerical (HN) model of Walter Hansen has been used to compute tides and currents in the Strait of Gibraltar. The model has two open boundaries at which the tides were prescribed at each time step, using four tidal constituents. The grid size was two nautical miles, and the time step (from Courant criterion) was 24 seconds. Equilibrium was established after 20 hours of real-time computation. The main results from these model runs were: (1) At mean tides, the inflowing currents are stronger and last somewhat longer than the outflowing currents. (2) There is net inflow into the Mediterranean Sea caused by tidal currents alone (excluding wind and sea level difference). (3) The tides computed with the HN model were in good agreement with those obtained from the harmonic method at points where harmonic constants were available. There was also a good agreement between computed currents and the few available current measurements. (4) The HN model gave a net transport of 1-48 cukm per hour into the Mediterranean in the upper 100 m. This value is somewhat higher than previous estimates; however, heat budget considerations require a higher water exchange through the Strait of Gibraltar than do previous estimates. (Author).