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On the Tidal Currents Observed by Moorings in Prydz Bay, East Antarctica
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  • Chengyan Liu,
  • Zhaomin Wang,
  • Robin Robertson,
  • Chen Cheng,
  • Xi Liang,
  • Yang Wu,
  • Xiang Li,
  • Yu Liu,
  • Xiaojun Yuan
Chengyan Liu
Nanjing University of Information Science & Technology
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Zhaomin Wang
Hohai University

Corresponding Author:[email protected]

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Robin Robertson
Xiamen University
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Chen Cheng
Nanjing University of Information Science & Technology
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Xi Liang
National Marine Environmental Forecasting Center
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Yang Wu
Hohai University
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Xiang Li
Institute of Oceanology, Chinese Academy of Sciences
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Yu Liu
Marine Science and Technology College, Zhejiang Ocean University
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Xiaojun Yuan
Lamont-Doherty Earth Observatory of Columbia University
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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.