Tacticians in this year's Sydney-Hobart yacht race will benefit from a technique developed by CSIRO marine scientists using satellites 1,300 kilometres away to identify conditions in the top two kilometres of the ocean.
Based on European and US/French environmental satellite observations of the ocean surface, Australian oceanographers have developed a weekly series of sea-level maps. These maps are equivalent to the now familiar pressure maps of the atmosphere and represent the 'weather' of the sea.
Sea-level undulation across hundreds of kilometres of ocean surface is caused by temperature and salinity variations. These variations create eddies and currents in the same way pressure variations cause winds in the atmosphere.
A technique has recently been developed which translates maps of sea-level into temperature and salinity maps, from the surface to a depth of about two kilometres.
Oceanographers are applying the technique to map ocean currents and eddies for professional fishermen, the shipping industry and maritime safety and environmental protection authorities.
Mr Ken Ridgway and a team of oceanographers from CSIRO's Division of Marine Research in Hobart have been testing the technique for the past 18 months by creating a three-dimensional profile of the Tasman Sea.
Mr Ridgway said the new development has been made possible by the accuracy of the latest satellite instruments which detect undulation in sea level and from which the speed and direction of currents and eddies can be verified and predicted. This information forms part of a navigators' race plan to Hobart.
He said the Australian research also coincides with the upgrading of Australia's submarine defence capability. The new advance in ocean mapping techniques will indicate altered ocean conditions such as varying densities which can significantly affect sonar and radar.
"Defence is only one area to benefit - our ability to simulate conditions in the ocean creates a significant tool for management of Australia's $16 billion a year marine industry."
Another application of this technique is in climate research where oceanographers are attempting to understand the links between sea surface temperature and fluctuations in Australian rainfall using computer models of ocean dynamics.
CSIRO's past observations have shown that currents and surface temperatures from the upper 1,000 metres of the Pacific and Indian Oceans significantly affect Australia's climate.
CSIRO oceanographers will again issue briefings to skippers and navigators on ocean conditions along the 630 nautical mile Sydney-Hobart course. Up-to-date images of sea surface temperatures during the race can be seen on a special World Wide Web site - http://www.dmr.csiro.au.
More information : Craig Macaulay 03-62325219