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| CSIRO | SOLVE | Issue 8 | Aug 06 | |
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COVER STORY
WEALTH FROM OCEANS:
Currents of Change By Brad Collis
Seven-day forecasts of ocean ‘weather’ – temperature, salinity and currents – will benefit seafarers, fishermen and even touristsA powerful new suite of ocean models that can predict the influence of ocean currents on marine activity – from sonar operations to weather forecasting – has been developed in a milestone collaboration between the Royal Australian Navy, the Bureau of Meteorology (BoM) and CSIRO through the Wealth from Oceans Flagship. The $15 million ‘BLUElink – Ocean Forecasting Australia’ project will become operational in January 2007 after three years of intensive research and development. It puts Australia at the leading edge of ocean forecasting and provides significant new capabilities for naval and other marine operations, as well as for weather and climate research. The BLUElink model will be able to predict ocean ‘weather’ – temperature, salinity and currents – in a three-dimensional presentation up to seven days in advance. The sophisticated modelling uses data gathered from satellites and a global network of ‘Argo’ floats that provide detailed information about what is happening deep within the ocean. As a major scientific collaboration, the BLUElink project drew on the specialist expertise of the three partners to achieve what one of the Navy’s most senior officers, Navy Systems Commander Commodore Geoff Geraghty, describes as a technological triumph. “This is a massive R&D project that has been brought to fruition,” Commodore Geraghty says. “For the Navy it is a powerful tactical decision aid. The ocean is the environment we work in and this development allows us to work much closer to our full capabilities.” However, Commodore Geraghty says the project also contributes to ‘public good’ research intended to benefit everyone: “It brings enormous benefits to all marine operations, such as fishing, tourism, offshore engineering and mining, and coastal management, as well as research into big issues such as climate change.” Commodore Geraghty says the scale of the project – which has created one of only a handful of global-to-coastal ocean forecasting systems in the world, and the first for the southern hemisphere – needed a level and breadth of scientific expertise that was only possible through intensive collaboration. The BLUElink forecasting system focuses on four regions of Australia’s territory:
Operational oceanographers and meteorologists from the Navy worked with leading CSIRO marine, computer modelling and BoM scientists using advanced supercomputers.
The BoM will release ocean forecasts twice weekly. They will include the latest changes in ocean currents and temperatures, and will help build up the knowledge and predictability of severe weather events near Australia’s coasts, particularly tropical cyclones. Commodore Geraghty says the ‘engine’ that powers the model is the network of remote sensing satellites and robotic Argo floats that have been deployed around the world in recent years to measure and transmit ocean conditions. In recognition of the important data that Argo floats provide, the Navy will buy another 20 floats to expand the network in Australian waters and further lift the BLUElink model’s effectiveness. The Argo floats have revolutionised ocean observation by measuring ocean conditions at varying depths. The floats are designed to drift with the ocean currents, sinking as deep as 2000 metres to collect temperature and salinity data and then surfacing to transmit the data to satellites. By 2007, about 3000 Argo floats will have been released as part of an international collaboration in all major oceans. Dr Andreas Schiller, from CSIRO Marine and Atmospheric Research in Hobart, who leads the Wealth from Oceans Flagship’s involvement, says the project brought together the Navy’s long history of data collection, the CSIRO’s research capabilities and the Bureau’s operational expertise: “The end result is absolutely cutting-edge technology. The project pushed everyone to the edge of their technical and resources capabilities.” Dr Schiller says that while the model is based on physical oceanography, the information it provides will be of considerable value to other areas of marine research such as fisheries. “To test the model we used ‘hindcasting’, in which we input historic data and assessed how the model performed against the known outcomes,” he explains. In this way, researchers have used the model to replicate conditions in the oceans around Australia since 1992. “One practical spin-off already is that we have been able to give our fisheries research colleagues maps of how the ocean has changed over the past 10 years,” Dr Schiller says. “This allows them to draw informed conclusions about long-term trends in the way changes in the ocean are affecting fish populations.” He says the Australian project is one of about five global ocean forecasting systems under development around the world, linking to an international pilot program that will combine ocean-borne and satellite data from a range of sources with high-resolution ocean circulation models. The BLUElink model’s resolution will be 10 kilometres, but Dr Schiller says the Navy plans to ‘nest’ an even more finely focused 2 km model inside the larger model. In explaining the principal motives behind the model’s development, the Navy’s director of oceanography and meteorology, Commander Andrew McCrindell, says the main rationale for the model was that while atmospheric conditions can be forecast up to seven days in advance, ocean conditions have only been available as near-real-time measurements. Also, while several northern hemisphere countries have ocean forecasting models, Australia needed to develop its own because of the unique circumstances created by the Leeuwin Current running down the west Australian coast, and the East Australian Current. These carry warm tropical water south and have a strong influence over water temperature and density (salinity) at varying depths in Australia’s 200 nautical mile Exclusive Economic Zone. “For the Navy, these factors have particular relevance for sonar operations because they determine where and how far sound travels in the ocean,” Commander McCrindell says. “Predicting the passage of sound improves the capability of our warships and provides tactical advantage for our Collins Class submarines. Different water density can diffract sound waves upwards or downwards, creating misleading signals and gaps in sonar coverage.” Commander McCrindell says that knowing sonar conditions several days in advance will mean that a taskforce sailing to a particular area will arrive fully prepared for the environmental conditions in which it will operate. He says that aside from its use by the Navy, BLUElink will provide:
Dr Neville Smith, chief scientist at the BoM and one of the instigators of the project, says BLUElink will provide an unprecedented view of the ocean state, particularly in those regions of strong environmental and economic interest to Australia. Flagship director Craig Roy says BLUElink exemplifies the mission of the Wealth from Oceans Flagship: “BLUElink is addressing a major national challenge through the three partners pooling their resources and capabilities. “By bringing together Australia’s best scientists in this domain, BLUElink is delivering a critical capability to Australia that would otherwise not be possible without this partnership.” APPLICATION BLUElink, a powerful system of ocean models, will be able to predict ocean ‘weather’ – temperature, salinity and currents – in a three-dimensional presentation up to seven days in advance BENEFIT Places Australia at the leading edge of ocean forecasting and provides significant new capabilities for naval operations and fisheries, as well as for weather and climate research For further information contact: |
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