[Level Up] [Doc Top] [Doc End] [Next Item] [Home Page]
Competitors in this year's Telstra MobileNet Sydney-Hobart yacht race will have access to the latest advances in ocean currents mapping being developed by the CSIRO for search and rescue authorities.
In recent years, ocean current information provided to competitors has been based purely on interpretation of satellite images of sea surface temperatures, which in turn highlight ocean currents and eddies.
However, information on ocean behaviour generated from a joint US/French satellite is being made available to CSIRO Oceanography. The satellite can record sea levels to within 10 cm accuracy, providing "isobar" maps indicating the speed and strength of ocean currents.
According to CSIRO Oceanography's Dr Peter Craig, the mapping initiative will add another refinement to marine forecasting capabilities for Australia's $16 billion a year marine industry.
"We see this as a very practical operational development from the science of oceanography that has broad industrial, environmental and recreational application.
"Importantly, for those people who go to sea, it introduces a dramatic new tool into the sea safety equation" he said.
Ocean mapping using the new sea level data is being developed in collaboration with the Bureau of Meteorology and the Australian Maritime Safety Authority. Charts equivalent to weather maps are now being produced and will be progressively improved over the next 12 months.
A sample of the maps was demonstrated today at the home of the Sydney-Hobart, the Cruising Yacht Club of Australia at Rushcutters Bay where another oceanographer, Dr George Creswell, has been briefing competitors on ocean current patterns for the past decade.
Dr Craig said that the maps highlight huge eddies as wide as 100 kilometres spinning off the East Australian Current, one of three major currents identified in the oceans off Australia.
The prediction of current and ocean movement includes details of the once unpredictable eddies, which can carry ocean drifters hundreds of kilometres at speeds of up to three knots, as well as impeding or boosting boat speed.
To prepare the charts, oceanographers use data from the TOPEX/Poseidon satellite together with deep ocean observations gathered over the past 30 years. From 1340 kilometres above the earth's surface the satellite measures sea surface heights. When the data reach the CSIRO, they are corrected and calibrated against long-term observations.
The work is the first initiative in developing an oceans analysis system to support research in the ecologically sustainable development of Australia's Exclusive Economic Zone (EEZ).
The EEZ extends 200 nautical miles from the coast and covers an area of 14 million square kilometres.
This year, the new data source will only be used as an interpretive tool for the Hobart race, with its central application in mapping currents off the continental shelf.
Scientists at CSIRO Oceanography are also preparing a computer model of the East Australian Current, and at the same time developing more sophisticated ways of combining the new data source with the old for a "nowcast" to put in the forecast models. As a result, they expect to see steady improvements in ocean current forecasting over the next few years. Data obtained from Sydney-Hobart yacht races will help in improving the forecasts.
To help validate the work, racing crews in this year's Sydney-Hobart will be asked to help oceanographers in a volunteer water temperature and salinity sampling program during the 630 nautical mile voyage to Hobart.,
Dr Craig said the information, invaluable for search and rescue, would also be useful in designing ocean outfalls, managing oil spills at sea, for fishermen and fisheries resource managers, defence and oil and gas platform design.
He said the development has been made possible by the accuracy of altimeters aboard the latest satellites but the basis for analysis has come from standard physical oceanographic practices of sampling salinity and temperature.
"The eddies are big and a satellite provides a snapshot of a feature we might take a day to cross in a research vessel.
"For the prediction of surface currents, remote sensing of sea surface temperatures gave us a tantalising approximate view, but now we can be much more accurate" he said.
For additional information please contact:
Dr Peter Craig[Level Up] [Doc Top] [Doc End] [Next Item] [Home Page]