The Spirit of Mawson - Australasian Antarctic Expedition 2013 - 2014

Australasian Antarctic Expedition

Sea ice

Sea ice is frozen seawater that floats on the ocean surface. Blanketing millions of square kilometers, sea ice forms and melts with the polar seasons, affecting both human activity and biological habitat. Sea ice regulates the exchange of heat, moisture and saltiness in the polar oceans. There has been a marked increase in seasonal sea ice extent in this region over the last decade, and dramatically a complete change locally in and around Commonwealth Bay since the giant iceberg B09B, calved from the continent and collided spectacularly with the extended tongue of the Mertz Glacier in 2010.

The research program

  1. On the AAE 2013-2014 we wanted to monitor the recent regional marked changes in sea ice and compare with model predictions.
  2. On the AAE 2013-2014 we set out south to investigate the impact of giant iceberg B09B on ocean circulation and the local carbon cycle.
  3. On the AAE 2013-2014 we undertook ground observations to improve our interpretation of satellite observations.

Research Papers

Impacts of marine instability across the East Antarctic Ice Sheet on Southern Ocean dynamics

Phipps, S.J., Fogwill, C.J. and Turney, C.S.M.

Here we explore the effects of melting of the East Antarctic Ice Sheet on the Southern Ocean. Using a climate model, we find that melting changes the ocean circulation and causes warming of more than 1 °C at depth. We also discover the potential existence of a "domino effect", whereby the initial warming spreads westwards around the Antarctic continent. Melting of just one sector could therefore destabilise the wider Antarctic Ice Sheet, leading to substantial increases in global sea level.

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Impacts of a developing polynya off Commonwealth Bay, East Antarctica, triggered by grounding of iceberg B09B

Fogwill, C.J., van Sebille, E., Cougnon, E.A., Turney, C.S.M., Rintoul, S.R., Clark, G.F., Marzinelli, E.M., Rainsley, E.B. and Carter, L.

Here we report new data from in-situ oceanographic surveys and high-resolution ocean modelling experiments in the Commonwealth Bay region of East Antarctica, where in 2010 there was a major reconfiguration of the regional icescape due to the collision of the 97 km long iceberg B09B with the Mertz Glacier tongue. We compare post-calving observations with high-resolution ocean modelling which suggest that this reconfiguration has led to the development of a new polynya off Commonwealth Bay.

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