Models of cross shelf transport introduced by the Lofoten Maelstrom

The drift of particles released in the tidal current (Moskstraumen) near Lofotodden, located at 67°50′N, 12°50′E, has been studied. The periodical tidal current combined with a background current is found to introduce a transport between Vestfjorden inside Lofotodden and the shelf outside. This particular transport may be important for the drift of cod eggs, larvae and other important biological and chemical tracers. A fine-resolution numerical model provided the Eulerian tidal current field based on which the particle trajectories are calculated using a Lagrangian particle tracking technique. The tracking algorithm was extended by a random-walk method to simulate small scale turbulence. An idealized current model of the area is also developed for use as a simplification tool to reveal the basic mechanisms of the drift and to demonstrate the sensibility of time stepping in numerical integration.