VC predicts the motion of the ocean

Nov 05, 2013
VC predicts the motion of the ocean
Credit: Photo by sub_lime79 via Flickr.

Australian National University Vice-Chancellor, Professor Ian Young AO, has just published research that will help you every morning with the surf report.

Research led by the Vice-Chancellor will allow oceanographers and meteorologists to better predict the rate at which ocean swells decay, or deteriorate, as they travel across the globe.

"Ocean cargo shipping, offshore oil and gas production, and even recreational activities such as surfing, are all dependent on wave action," says Professor Young.

"It is therefore critical that we are able to predict swell."

It is estimated that 75 per cent of across the world are not actually generated by local winds. Instead, they are driven by distant storms which propagate as swell.

"Imagine you drop a rock in a pond. Waves radiate out from the rock. You don't need anything to push the waves. Once generated, they propagate by themselves.

"So, for most of the Indian, Pacific and South Atlantic oceans, it is actually the weather in the Southern Ocean thousands of kilometres away that dominates the wave conditions," explains Professor Young.

"The Southern Ocean is dominated by big low pressure systems that move across it year round. These systems generate waves that then grow and can travel tens of thousands of kilometres from where they were actually formed, to crash on a beach in Australia."

Professor Young, who is affiliated with the Research School of Earth Sciences, used orbiting satellites to track swell generated in the Southern Ocean and measure the rate of decay as it travelled north towards Australia.

The results showed that the decay of the swell depends on how steep the wave actually is.

"Steep waves decay very quickly. However, typical swell is not very steep and can travel across oceanic basins with only a relatively small loss of energy."

Over 200 individual cases were tracked, making this study the first to provide such comprehensive data of this decay.

"What we were able to do is track the swell from the satellite as it moved from the south to the north, some 1400 kilometres. We only chose cases where there was no wind so that we could be confident that all we were measuring was the swell decay.

"We can take these results and put them into a mathematical formula that can be put straight into computer models used by national weather bureaus.

"This will increase our ability to better predict wave action. As 70 per cent of the world's oceans are dominated by swell, it's extremely important to be able to predict them accurately."

Explore further: Lava from Hawaii volcano picks up speed

More information: (Phys.org) —Professor Young's research is published today in The Journal of Physical Oceanography: journals.ametsoc.org/doi/abs/1… .1175/JPO-D-13-083.1

Related Stories

Tropical cyclone waves detected with infrasound sensor array

Jan 15, 2013

The strong winds of a tropical cyclone whip up the sea surface, driving ocean waves a dozen meters (about 40 feet) high. When one such ocean wave runs into another wave that has an equal period but is traveling in the opposite ...

Understanding freak waves

Sep 27, 2011

(PhysOrg.com) -- Rogue waves, once considered nothing more than a sailor’s myth, are more predictable than ever thanks to new research from the oceanography team at Swinburne University of Technology.

Huge waves from 1 storm slam coasts some 6000 km apart

May 30, 2007

Huge waves that struck Reunion Island and coastlines across Indonesia earlier this month all originated from the same storm that occurred south of Cape Town, South Africa, and were tracked across the entire Indian Ocean for ...

Wind and waves growing across globe: study

Mar 25, 2011

(PhysOrg.com) -- Oceanic wind speeds and wave heights have increased significantly over the last quarter of a century according to a major new study undertaken by ANU Vice-Chancellor Professor Ian Young. ...

Recommended for you

Icelandic volcano sits on massive magma hot spot

Oct 24, 2014

Spectacular eruptions at Bárðarbunga volcano in central Iceland have been spewing lava continuously since Aug. 31. Massive amounts of erupting lava are connected to the destruction of supercontinents and ...

NASA sees Tropical Storm Ana still vigorous

Oct 24, 2014

NASA's TRMM satellite saw that Tropical Storm Ana was still generating moderate rainfall is it pulled away from Hawaii. The next day, NASA's Aqua satellite saw that wind shear was having an effect on the ...

User comments : 0