Abstract
Mooring observations of tidal currents in Prydz Bay, East Antarctica are
presented here. They were found to be mixed diurnal-semidiurnal over the
continental shelf, with significant seasonality. Barotropic tides
dominated the tidal currents at the calving front of the inner
continental shelf of the Amery Ice Shelf (AIS), except at the western
corner of the AIS where the seabed is abruptly deeper. The spatial and
temporal averaged magnitude of tidal currents for all the current meter
records was only 2.58 cm s-1, much weaker than in the Ross or Weddell
seas. However, the observed maximum tidal current was about 13.12 cm s-1
at the AIS calving front. In addition, the ratio of the tidal heat flux
standard deviation to the residual heat flux standard deviation could be
up to 41% at the AIS front, implying the tides have the potential to
modulate the heat content of the AIS cavity. To identify the footprints
of the tidal influences on the AIS basal mass balance, we further
assessed the temperature and salinity records from six boreholes drilled
through the AIS. Interestingly, tide-like pulsing was identified in the
ocean layer adjacent to the AIS basal surface, highlighting the
potential tidal influences on the heat exchanges at the ice-ocean
interface. Our assessment of the tidal currents in Prydz Bay underlines
that the critical role of tides should be highlighted in investigations
of interactions between the ocean and the AIS, and other ice shelves.