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TEN YEARS OF SPYING ON THE SEA'S SKIN IN NEW ATLAS25 July 2002 For 10 years, sophisticated instruments on satellites have been spying on the ocean's surface and beaming information about its temperature back from space to stations across Australia. The information has now been compiled into a CD-ROM atlas, released by the Australian Institute of Marine Science (AIMS) and CRC Reef Research Centre, that captures sea surface temperatures from the Great Barrier Reef between 1990 and 2000. "Scientists use temperatures of the sea's surface to track ocean currents, and to follow hot spots in the ocean so they can predict where coral bleaching will occur," said AIMS physical oceanographer, Craig Steinberg, one of the authors of the atlas. "Fish stocks often aggregate where warm and cold waters meet so the atlas will also help scientists to predict the location of some fish stocks." He said other maps showed the surface temperatures of the world's oceans but relied on a scale which was too coarse to be useful for coral reefs and coastal regions. The AIMS and CRC Reef atlas of reef water temperatures are around 10 times higher resolution than other temperature maps of the world's oceans. The atlas shows that 1998 was the hottest summer on record in the Great Barrier Reef (until this year's 2002 summer). Both events resulted in large-scale coral bleaching and preliminary surveys indicate that the bleaching is spatially correlated with the warmer regions seen in the Atlas. More recent data is being actively used by other researchers to help understand where and why the bleaching is occurring. Surface temperatures are measured by instruments called Advanced Very High Resolution Radiometers (AVHRR) which are attached to satellites that orbit about 850 kilometres above the Earth's surface and pass over Australia four or five times a day. These instruments are owned by the National Oceanic and Atmospheric Administration (NOAA) in the United States. Information from the AVHRR has been sent to a receiving station at AIMS and James Cook University near Townsville since the late 1980s. In Australia, similar receiving stations are located in Hobart, Darwin, Alice Springs and Perth. "The atlas compiles information from more than 4,000 images which are averaged to get a snapshot of the sea surface temperatures for each fortnight for the last 10 years. "The atlas is an enormous database of information. It is available on CD-ROM and can be viewed using a web browser. Anyone can use it, so the information is available cheaply to a wide audience." The next step for Craig Steinberg and his team will be to match the sea surface temperatures with ocean colour information so they can better link productivity hot spots with other oceanographic features such as currents and upwelling regions. Fish and other predators higher up the food chain are attracted to productivity hot spots. "Sea Surface Temperatures Atlas of the Great Barrier Reef. 1990-2000" by William Skirving, Mike Mahoney and Craig Steinberg is available on CD-ROM from the Australian Institute of Marine Science on 07 4753 4409 or by email on m.Mahoney@aims.gov.au. For more information: http://www.aims.gov.au/pages/facilities/remote-sensing/rs-sst-atlas.html For more information: Mr Craig Steinberg, AIMS on 07 4753 4345 or c.steinberg@aims.gov.au. |
