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How does the Southern Ocean regulate global climate?

Major research project to examine carbon cycling, circulation dynamics

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A new research project will help explain how the Southern Ocean helps regulate the global climate. bberwyn photo.

Staff Report

FRISCO — Even though it’s eparated from the rest of the world’s oceans by a strong circulation of currents and a distinct temperature gradient, the Southern Ocean is known to be a key driver of global climate and carbon cycles.

Climate researchers and oceanographers may soon know a lot more about the enigmatic ocean as they deploy hundreds of robotic floats deployed around Antarctica in a six-year, $21 million research project aimed at understanding ocean dynamics, chemistry and carbon cycling. The new instruments will increase the flow of Southern Ocean data 30-fold. Continue reading

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Climate: Does the Southern Ocean hold the ice age key?

Abysmal waters play huge role in global carbon cycles

The water in the Antarctic Sound can be smooth as glass, and sometimes look thick and oily, probably because it's so cold. Click on the photo to learn about some of the environmental issues in Antarctica.

The water in the Antarctic Sound can be smooth as glass. bberwyn photo.

By Summit Voice

FRISCO — The remote Southern Ocean, encircling Antarctica, may be a key driver of the carbon cycle, inhaling and exhaling enough carbon to help shift the global climate in and out of ice ages.

For decades, scientists have been trying to figure out what exactly, along with the known wobbles in Earth’s journey around the sun, may cause the huge shifts that lead to vast ice sheets covering many of the planet’s land masses. Continue reading

Scientist find source of mysterious Southern Ocean sound

New data could help minke whale conservation efforts

A group of Antarctic minke whales. Photo courtesy Ari S. Friedlaender, Oregon State University

A group of Antarctic minke whales, which have been identified as the source of a mysterious sound in the Southern Ocean. Photo courtesy Ari S. Friedlaender, Oregon State University.

Staff Report

FRISCO — If you’ve ever heard mysterious sounds that you can’t identify, you’re not alone. For decades, researchers have tried to trace the source of a unique rhythmic sound in the remote Southern Ocean that’s often been recorded, but never definitively pinpointed — until now.

This week, scientists with NOAA’s Northeast Fisheries Science Center said the sound is generated by the Antarctic Minke whale, the smallest of the “great whales” or rorquals, a group that includes the blue whale, Bryde’s whale, and humpback, fin, and sei whales. Rorqual whales are relatively streamlined in appearance, have pointed heads and, with the exception of humpback whales, small pointed fins. Continue reading

Climate: Freshwater cap around Antarctica inhibiting natural upwelling of warmer water

Findings may help explain recent expansion of Antarctic sea ice

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Study shows impacts of increased precipitation over Southern Ocean. bberwyn photo.

Staff Report

FRISCO — Enhanced rainfall over the Southern Ocean may be blocking the release of relatively warm waters from the depths, researchers said this week in a study published in Nature Climate Change.

The research shows that salinity at the surface of the Southern Ocean has steadily decreased since the 1950s. This lid of fresh water on top of the ocean prevents mixing with the warm waters underneath. As a result, the deep ocean heat has been unable to get out and melt back the wintertime Antarctic ice pack. Continue reading

Unraveling the secrets of ocean waves

Satellite tracking helps researcher develop a formula to predict swell decay

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Surfers catch an evening wave at Half Moon Bay, Cailifornia, bberwyn photo.

By Summit Voice

FRISCO — Surfers have long tracked swells across thousands of miles of open ocean to try and predict when the best waves might hit their local beach, and new research by an Australian National University professor may help fine-tune those forecasts.

“Ocean cargo shipping, offshore oil and gas production, and even recreational activities such as surfing, are all dependent on wave action,” said Ian Young, vice-chancellor of ANU. “It is therefore critical that we are able to predict swell.”

Young, who is affiliated with the Research School of Earth Sciences, was interested in determining the rate at which ocean swells decay as they travel across the ocean, so he tracked them with orbiting satellites. 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,” he said.

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 1,400 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,” he said.

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

“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 … 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’s research is published in the Journal of Physical Oceanography.

Scientists track ocean ‘black holes’

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An illustration for Edgar Allen Poe‘s “Descent into the Maelstrom.”

Little-known giant eddies may affect climate and pollution transport

By Summit Voice

FRISCO — As long ago as the 1800s, Edgar Allen Poe described ocean maelstroms as cohereent “water islands” that maintain their structure within the greater swirl of ocean currents. But just in the last few years, researchers have used fluid dynamics models to map those eddies and start explaining how they factor into global climate and the the spread of pollution.

In a press release issued this week, the Swiss Federal Institute of Technology described how scientists are tracing huge eddies, more than 150 kilometres in diameter, that rotate and drift across the ocean.

The research suggests that the number of such eddies is growing in the Southern Ocean, increasing the northward transport of warm and salty water. Intriguingly, the scientists said, this could moderate the negative impact of melting sea ice in a warming climate. Continue reading

Climate: Winds driving Antarctic sea ice growth

Global warming likely to reverse trend in coming decades

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Antarctic sea ice extent has been growing the past few decades, bberwyn photo.

By Summit Voice

FRISCO — Climate scientists have long suspected that increasing winds around Antarctica have been the main cause of growing sea ice extent in the southern hemisphere, and new research from the University of Washington shows how and why that might be happening — even as overall global temperatures warm.

Global warming deniers have tried to use the growth of Antarctic sea as a weapon in their battle against science, but climate researchers point out that the loss of Arctic sea ice far outweighs the small increase in the southern hemisphere. And the new research suggests that, as global temperatures continue to increase, Antarctic sea ice is all but certain to start shrinking.

Overall, Antarctic sea ice has been increasing by about 1 percent annually, which has led to record sea ice extent in the region the past few years. As of September 16, Antarctic sea ice extent reached about 7.51 million square miles, a record for the date and about 3.9 percent above the 30 year average. By contrast, this year’s Arctic summer minimum ice extent is approximately 30 percent below the 30-year average. Continue reading

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