Roaring Forties

General Weather Discussions and Analysis

Roaring Forties

Postby Ptarmigan » Mon Jan 12, 2015 12:18 am

The lack of land mass in the Southern Hemisphere allows westerlies to be stronger. The landmass of Asia, Europe, and North America weaken those westerlies. Those westerlies form from rising warm air of the equator, which is usually wet and goes towards the pole due to cooler air. Air sinks at 30 degrees latitude, which is why we have deserts for the most part like Sonoran, Sahara, Gobi, or Kalahari Desert. The air heads towards the polar regions, which is cold and feeds into the polar vortex. The winds is from Earth's rotation and air traveling from equator to poles.

The lack of land mass in the Southern Hemisphere allows strong westerlies, which means the oceans are rough. It is very rough in the South Indian and South Pacific Ocean. The waves are very high in those areas, especially in South Indian Ocean. It was thought that Malaysian Airlines Flight 370 may have crashed south of 40 degrees. Interestingly, the most remote spot away from any landmass is in the Roaring Forties in South Pacific, which is Point Nemo.

Those strong westerlies is also why there are less tropical cyclone development south of the Equator. Tropical cyclones that cross Tropic of Capricorn become extratropical. It also plays a role in the climate of Southern South America, New Zealand, and Tasmania. Many islands in the Roaring Forties and southward are very windy and stormy like Kerguelen and Macquarie Island.

Of course if you go further south, the oceans get rougher and stormier. South of 50 degrees is Furious Fifties, while south of 60 degrees is Shrieking or Screaming Sixties. It holds true when you are closer to Antarctica. It is no wonder why few ships go through the Roaring Forties as the oceans is very rough. Sailing competitions usually go through that area.

http://en.wikipedia.org/wiki/Roaring_Forties
http://www.abc.net.au/science/articles/ ... 038604.htm
http://www.antarctica.gov.au/living-and ... uly-2013/2
http://foreignpolicy.com/2014/03/27/mh3 ... ian-ocean/
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Ptarmigan
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