Skip to Content | Contact

Platelet ice attachment to instrument strings beneath the Amery Ice Shelf

Platelet ice attachment to instrument strings beneath the Amery Ice Shelf
Mike Craven

Authors

M. Craven
Australian Antarctic Division, Channel Highway, Kingston, Tasmania, 7050, Australia
and Antarctic Climate & Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7001, Australia

R. C. Warner
Australian Antarctic Division, Channel Highway, Kingston, Tasmania, 7050, Australia
and Antarctic Climate & Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7001, Australia

B. K. Galton-Fenzi
Australian Antarctic Division, Channel Highway, Kingston, Tasmania, 7050, Australia
and Antarctic Climate & Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7001, Australia

L. Herraiz-Borreguerro
Antarctic Climate & Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7001, Australia

S. W. Vogel
Australian Antarctic Division, Channel Highway, Kingston, Tasmania, 7050, Australia
and Antarctic Climate & Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7001, Australia

I. Allison
Antarctic Climate & Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7001, Australia

Abstract

Instruments suspended beneath the Amery Ice Shelf through hot water drilled boreholes record sporadic decreases in pressure of 10-20 decibars at sites where active growth of a marine ice layer occurs at the base of the shelf. These events are attributed to the buoyancy gained from accretion of platelet ice crystals to the moorings. Some events are transient, which we interpret as temporary achievement of buoyancy by the moorings before returning to pre-event pressures, probably due to mechanical dislodgement of loosely attached crystals. Driven by these pressure level changes temperatures recorded at the shallowest instruments (within 20 m of the shelf base) track in situ freezing point temperatures during these events. These results provide indirect evidence for the presence of frazil in the sub-ice shelf mixed layer and the active accretion of marine ice at the base of the Amery Ice Shelf. They also provide insight into the annual cycle of sub-ice ocean circulation confirming previous modelling results. The attachment of platelet ice to and vertical displacement of moorings has important ramifications for future project design and instrument deployment, as well as implications for the interpretation of oceanographic data from the sub-ice shelf environment.

Latest news

  • Conference prize winners
    27 Jun 2013

    The Strategic Science in Antarctica conference concluded yesterday and two days of workshops have commenced. Congratulations to those who were awarded prizes for their contributions to the conference.

  • Watch the welcome message from Australia's Environment Minister
    24 Jun 2013

    In a welcome message via video from Canberra, Australia’s Environment Minister, Tony Burke, reflected on the foresight of earlier decision-makers who agreed to set aside an entire continent for scientific research.

  • Last minute information for attendees
    20 Jun 2013

    There's not too long to wait until the start of the Strategic Science in Antarctica conference, and we hope you’re as excited as we are! Read on for more information about the final program, registration, Twitter, presenters, posters and social functions.

More news…

Key dates

  • 11th June 2013
    Registrations close
  • 21st June 2013
    Registrations at the AAD open for staff
  • 24th June 2013
    Registrations at the venue open
  • 24th June 2013
    Conference commences
  • 26th June 2013
    Conference concludes

More key dates…

This page was last modified on 23 September 2013.