Winter sea ice growth processes:

the impact of winter growth on sea ice thickness

The thickness and growth of coastal sea ice during winter is a key unknown when considering polar influences on climate. Much of the coastline of Antarctica is ice shelf. Melting and/or freezing at the base of an ice shelf influences the heat content and salinity of the water in contact with it. In turn this strongly controls near-surface oceanography.

The objective of this research is to assess the contribution that tiny crystals of ice, called frazil ice, make to the thickness of sea ice in coastal Antarctica. These crystals are nucleated in the ocean, and rise to the surface. They accumulate at the base of the sea ice and continue to freeze in place at the ice-water interface, where it is called platelet ice. Models suggest that this contribution is between 10 and 20% of sea ice thickness and that it extends northward to 60ºS. However there are currently no observations to guide modelling. Our overarching research question is therefore to assess the contribution of the ocean, conditioned by processes at the base of an Antarctic ice shelf, to the winter growth and thickness of the coastal sea ice.

During the southern winter of 2009 (February-October) there will be an extensive programme of sea ice and ocean measurements in McMurdo Sound, Antarctica. You can read the blog on the IPY site.

The team at Scott Base will also link to the IPY IGLO live event. There are two institutions that will be participating in the interactive portion of the event (Chicago Museum of Science and Industry and the National Museum of Mexico). Students at these locations will be able to ask questions about the work going on at Scott Base via the video conferencing system. Two other institutions (San Francisco Exploratorium and the Maryland Science Centre) will be tuning in via a webcast but will also be able to ask questions via email. More information can be found here.

Contractor University of Otago University of Otago Contact Dr Pat Langhorne

IPY Project Number: 141

NIWA media Release 17 Sept 08

Article on Antarctic sea ice and the climate system by Natalie Robinson (pdf)

Blog by the Winter-Over sea ice team

Physics of Antarctic Sea Ice - link to a 12 minute radio programme in the Our Changing World series, on the winter sea ice research