Improving global climate forecasts
3 November 2003
Scientists setting sail for Antarctica today will be researching how to more accurately predict the effects of global climate change.
Dr Sharman Stone, Parliamentary Secretary for the Environment and Heritage said a team of scientists will be studying the interaction between ocean water, temperatures and the underside of ice shelves to gain a better understanding of change processes.
"There has been an unprecedented level of ice-shelf collapse in some areas of the Antarctic in recent years," Dr Stone said.
"What is happening at the underside of the ice is sensitive to climate change as warmer ocean temperatures, or a shift in circulation patterns, could lead to the melting of Antarctic ice shelves.
"Once melted, ice shelves release a significant quantity of fresh water into the ocean effecting ocean circulation patterns."
Also, glaciologists suspect that ice shelves around the continent may act as barriers which reduce the flow of inland glacier systems into the surrounding ocean1, although the processes involved are not fully understood.
"As well, the barrier effect of ice shelves around the continent reduces the flow of fast inland fresh water streams and glacier systems into the surrounding ocean.
"Once the ice shelves break away or melt, the glacier and ice streams can discharge continental ice more rapidly, with potential ramifications for global sea levels," Dr Stone said.
Information collected during the field trip to the Amery Ice Shelf in eastern Antarctica is part of ongoing research by the Australian Government's Antarctic Division. Scientists and technical staff leave aboard the Antarctic resupply vessel Aurora Australis which sails from Hobart today.
For the first time, members of the Polar Research Institute of China will join Australians on site for this project, called the Amery Ice Shelf-Ocean Research (AMISOR). A NASA scientist from United States will also be part of the team.
"The team will use a recently-developed hot water drilling system to melt a hole around 100 kms inland, where the ice shelf tends to break up and produce icebergs (called the calving front).
"The hot water drill allows scientists to directly sample and measure water properties, and circulation under the ice shelf, as well as try to determine the rates of melting and freezing at the base," Dr Stone said.
"This 10-week project is the third in a series drilling boreholes 50 kilometres apart through the ice, up to half a kilometre thick.
"Measurements including sea water temperature, salinity and currents are taken of the ocean cavity accessed beneath the ice.
"This information helps to better understand the melting and freezing processes and their overall influence on sea water properties."
Dr Stone said NASA will deploy a video camera to record a unique view of the transition processes within the ice shelf itself. The hot water drill allows scientists to directly sample and measure water properties and circulation under the ice shelf, as well as try to determine the rates of melting and freezing at the base.
1. This has been reworded more circumspectly – the buttressing effect is not known for sure, and even the situation in the Peninsula may be a special case because of its atypical climate.