The tides of the southern Weddell Sea

Abstract

The tides of the Weddell Sea are described using all the available data. The primary data are a set of current meter and tide gauge records taken during the period of 1977 to 1979 in the southern Weddell Sea. These data show that the four major tidal constituents propagate from east to west along the coast of Queen Maud Land and around the Weddell Sea in a clockwise fashion. In the southern Weddell Sea the broad, deep continental shelf interacts with the tides and diurnal shelf waves are excited, mainly at the K 1 frequency. The preference of K 1 over O 1 might be due to the interaction of a variable shelf topography with a non-stationary mean current. The diurnal tidal currents are nearly barotropic while the semidiurnal tidal currents show distinct depth dependence. At 74°28'S the frequency of the M 2 tidal constituent equals the inertial frequency. Theory predicts that the M 2 velocity profile becomes strongly depth dependent at this latitude, and the observations support this prediction. The normalized variance associated with the cusps in the tidal spectra increases strongly towards the bottom for the semidiurnal constituents possibly due to the generation of internal waves at semidiurnal frequencies. The annual constituent, Sa, is quite large for tidal currents, probably due to environmental forcing.