On group velocity and spatial damping of diurnal continental shelf waves

Diurnal continental shelf waves (CSWs) are studied theoretically for an idealized topography. Wave attenuation is caused by the exchange of fluid on sloping with inner region through a permeable coastline. As example, we consider outside Lofoten-Vesterålen in north Norway. Here CSWs diurnal tidal frequencies possible small wave number range centered around zero group velocity. A previous investigation Robin condition (a weighted combination Dirichlet and Neumann conditions) at boundary has shown that spatial damping coefficient becomes infinitely large when velocity approaches zero. demonstrate this not result mathematical formulation, but reflects physical reality. We show modelling highly convoluted archipelagic as series densely packed vertical Hele Shaw cells. By comparing two ways describing coastal (Robin/Hele Shaw), may express parameter terms parameters (permeability, eddy viscosity) characterize flow porous shelf. The radiation stresses drive Lagrangian mean currents same cases. This means current distribution over unaltered compare case case.