Shelf waves with diurnal tidal frequency at the Greenland shelf edge

Tidal analysis was carried out on current measurements at a “cross-shelf” transect off Greenland at 71°N. The diurnal tides manifest themselves mainly as a barotropic continental shelf wave, travelling southward along the shelf slope. This follows from the amplitude distribution of the diurnal tidal components and from the rotation sense of the tidal ellipses at different cross-slope locations, as calculated with simple two-dimensional models. The well organized cross-slope pattern of the velocity amplitudes is absent in observations further north near 75°N. These observations suggest that the local vanishing of the group velocity, which is caused by topography, is of importance for the existence and local amplification of these continental shelf waves with diurnal tidal frequency.