Forskel mellem versioner af "Bruger:Brol/sandkasse"

4.953 bytes tilføjet ,  for 2 måneder siden
ingen ændringskommentar
*{{cite speech|last=Leigh|first=Andrew|author-link=Andrew Leigh|title=Canberra is the Best City in Australia|url=|accessdate=13 September 2013|date=3 October 2010|event=Festival of Dangerous Ideas|location=Sydney Opera House|archiveurl=|archivedate=13 September 2013}}
[[File:Turbid Waters Surround New Zealand.jpg|thumb|The Roaring Forties in the [[Cook Strait]] of [[New Zealand]] produce high waves, and they erode the shore as shown in this image.]]
De '''brølende fyrrere''' (en: Roaring Forties) er kraftige vestenvinde på den sydlige halvkugle, som overvejende er mellem 40 og 50 grader syd.<ref name=ABCScience>{{cite web |url= |title=Roaring forties |last=Catchpole |first=Heather |date=20. september 2007 |accessdate=7. april 2011 |publisher=ABC Science |work=In Depth}}</ref> De kraftige vinde skyldes en kombination af flere ting: Luft fra [[Ækvator]] presses mod [[Sydpolen]], jordens rotation og kun få landmasser til at bryde vinden.
De brølende fyrrere var en stor hjælp til sejlskibe, som fulgte [[Brouwers rute]] fra [[Europa]] til [[Ostindien]] eller [[Australien]] during the [[Age of Sail]], and in modern usage are favoured by yachtsmen on round-the-world voyages and competitions. The boundaries of the Roaring Forties are not consistent, and shift north or south depending on the season. Similar but stronger conditions occurring in more southerly latitudes are referred to as the '''Furious Fifties''' and the '''Shrieking''' or '''Screaming Sixties'''.
{{See also|Atmospheric circulation}}
Hot air rises at the [[Equator]] and is pushed towards the poles by cooler air travelling towards the Equator (an atmospheric circulation feature known as the [[Hadley Cell]]).<ref name=ABCScience/> At about 30 degrees from the equator, the outward-travelling air sinks to lower altitudes, and continues toward the poles closer to the ground (the [[Ferrel Cell]]), then rises up again from about 60 degrees as the air joins the [[Polar vortex]].<ref name=ABCScience/> This travel in the 30 to 60 degree zone combines with the rotation of the earth to move the air currents from west to east, creating westerly winds.<ref name=ABCScience/>
Unlike in the northern hemisphere, the large tracts of open ocean south of the [[40th parallel south]] (interrupted only by [[Tasmania]], [[New Zealand]], and [[southern Cone|the southern part]] of [[South America]]) allow higher windspeeds to develop.<ref name=ABCScience/> Similar but stronger wind conditions prevalent closer to the [[South Pole]] are referred to as the "Furious Fifties" ([[50th parallel south|50]] to [[60th parallel south|60 degrees south]]), and the "Shrieking" or "Screaming Sixties" (below 60 degrees south).<ref name=EcoPhoto>{{cite web |url= |title=Exploring the Southern Ocean |date=21 December 2009 |accessdate=7 April 2011 |publisher=Eco-Photo Explorers}}</ref> The latitude ranges for the Roaring Forties and similar winds are not consistent, shifting towards the South Pole in the southern summer, and towards the Equator in the southern winter.<ref name=ABCScience/>
==Use for sailing==
[[File:ClipperRoute.png|thumb|right|350px|The [[Clipper Route]], taken by ships sailing from Europe to Australia in order to take advantage of the Roaring Forties]]
During the [[Age of Sail]], ships travelling from Europe to the [[East Indies]] or [[Australasia]] would sail down the west coast of Africa and round the [[Cape of Good Hope]] to use the Roaring Forties to speed their passage across the Indian Ocean,<ref name="OxfordCompanion">{{cite encyclopedia |editor=Dear, I. C. B. |editor2=Kemp, Peter |encyclopedia=The Oxford Companion to Ships and the Sea |title=Roaring Forties |url= |accessdate=14 April 2011 |year=2007 |publisher=Oxford Reference Online, Oxford University Press |isbn=0-19-860616-8 |oclc=60793921}}</ref> then on the return leg, continue eastwards across the Pacific Ocean and south of [[Cape Horn]] before sailing up the east coast of the [[Americas]] to home. It was first used by Dutch explorer [[Hendrik Brouwer]] in his [[Brouwer Route]], discovered in 1611, which effectively halved the duration of the trip from Europe to [[Java]].{{citation needed|date=July 2015}} "To run the easting down" was the phrase used to describe the fast passages achieved in the Roaring Forties.<ref name="OxfordCompanion" />
Round-the-world sailors also take advantage of the Roaring Forties to speed travel times, in particular those involved in [[Around the world sailing record|record attempts or races]].<ref name="OxfordCompanion" />
==See also==
* [[xClipper route]]
* [[xSubtropical ridge]]
* [[xWinds in the Age of Sail]]
* [[xAntarctic Circumpolar Current]]
* [[xSoutherly buster]]
==External links==
* [ Clipper Ships in Heavy Weather]
[[Category:xMaritime history of Australia]]
[[Category:xAge of Sail]]
[[Category:xLines of latitude]]