“Roaring Forties” winds, gyrating ocean currents pose Malaysia plane search nightmare


Satellite view shows stormy weather Thursday over region where debris from Malaysia Flight MH370 might have been found. (NASA, adapted by CWG)

The search for the remains of Malaysia Flight MH370 faces challenges from the elements that may prove insurmountable.

“The world’s largest hunt for a missing airliner has zeroed in on one of the most desolate corners of the planet, an area of ocean nearly two miles deep, swept by huge rolling swells and buffeted by strong winds known as the Roaring Forties,” begins a Post story on the extreme weather conditions in area some 1,500 miles southwest of Perth, Australia, where a satellite may have spotted debris.

The Roaring Forties refers to the belt of ripping westerly winds, aided by the Earth’s rotation, between roughly 40 and 50 degrees latitude in the southern hemisphere.  Winds rage in this region as it sits in the transition zone between the more tranquil, balmy subtropics and  frigid polar vortex zipping around the South Pole. Pressures and temperatures change rapidly here, driving the winds frequently over 30-40 mph, and give rise to storms.


Visualization of high altitude winds Thursday near the possible Malaysia Flight MH370 debris zone.  High winds are indicated by orange and red shades. A storm, or area of low pressure, was positioned just to the west. (earth.nullschool.net)

The winds in this area are uninhibited thanks to the absence of continents or mountains that might slow them down via friction, instead flowing over the relatively smooth Indian ocean surface.

The winds in the Roaring Forties belt are some of the fastest in the world, but topped at times by adjacent latitude zones to the south known as the Furious Fifties and Screaming Sixties.

In a sense, the winds in this part of the world reflect the planet’s effort to regulate temperatures and vent energy as the atmosphere redistributes hot air from the equator and cold air  from the South Pole. It accomplishes this transport of hot and cold air through what ABC Science describes as a “double figure 8 conveyor belt of air stretching from the Equator to the South Pole.”

Additional reading: The Roaring 40s (ABC Science Australia)

Shipping interests from the 16th to 19th century caught on to the Roaring Forties tail winds,  and the southern Indian ocean served as a popular navigation route from South Africa to Australia.

But this is not the best spot to track down possible plane debris.  Not only must search teams battle bouts of wind and rain, but a network of spiraling eddies on the ocean’s surface is also sure to toss plane fragments in random ways.


Visualization of surface eddies on March 17 in Malaysia Flight MH370 possible debris zone (earth.nullschool.net)

And what lies beneath the sea surface is even more chaotic, as the Post article explains:

Matthew England, of the Climate Change Centre at the University of New South Wales in Sydney, Australia, warned that this was a deep area of the Indian Ocean with rapid and complex currents, above an ocean floor marked by “plenty of ridges and canyons.”

“It’s an eddy-rich region,” he said. “Which means that superimposed on the long-term average current are these little eddies that spawn off the current and have a life of their own,” he said. “They pinch off a bit of water and might move counter to the main flow.”

As a storm system moved through the region Thursday, the weather turned turbulent with strong winds, high seas, and low visibility. Conditions eased today, but more challenging weather is poised to arrive late in the weekend. Notes the Post piece:

….Friday’s relatively benign weather in the area is unlikely to hold. The series of weather fronts expected to pass over the search area starting Sunday mean more low cloud cover, rain, winds reaching up to 30 to 40 knots, waves of up to 30 feet high and more whitecaps — all making it much harder to spot debris, according to Australian marine meteorologist Roger Badham.

“Really, when you look at things in the next seven days, this afternoon and tomorrow are by far the best conditions we will see until the following weekend,” he said.

Jason is currently the Washington Post’s weather editor. A native Washingtonian, Jason has been a weather enthusiast since age 10.
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Kevin Ambrose · March 21, 2014