Horse widths
The horse latitudes ( English horse latitudes ) designate the areas between the trade areas and the west wind areas of the northern and southern hemispheres in the subtropical area of high pressure , occur in the winds from different directions and often calm prevails. They are approximately between 25 ° and 35 ° north and south latitude.
Cause of the calm
The reason for the frequent calm lies in the circulating air currents from the Hadley cell and Ferrel cell , which meet at high altitude on the horse latitudes, sink down and on the surface again into the trade winds directed south to the equator and northward to the polar front divide the directed air flow of the west wind zone.
At the intra-tropical convergence zone , a low pressure channel a few hundred kilometers wide near the equator, the trade winds meet, are heated by the strong solar radiation, rise, cool down again and lose moisture, which condenses and turns into precipitation. At a height of about 15 km, the air masses flow from the equator back to the northern and southern horse latitudes, where the air sinks to the surface of the earth, whereby it heats up and dries again. A high pressure area is created with little air movement inside and the occasional formation of subtropical anticyclones .
Consequences of the calm
The warm, dry air masses and the often cloudless sky of the horse latitudes lead to the formation of the large desert areas of the world such as the Sahara in Africa, the Arab and Syrian deserts in the Middle East, the Mojave and Sonoran deserts in the American Southwest and in northern Mexico, as well as the Atacama Desert , the Kalahari and the Australian Deserts in the southern hemisphere.
Origin of name
The etymology of the term is unknown.
One possible explanation lies in the term " dead horse ", which in English describes a job that has been paid for in advance. Accordingly, the advance that seafarers received before the voyage was often matched by the work done when the ships in the transatlantic trade reached the horse's breadth. This was sometimes celebrated by throwing a horse made of straw overboard.
Since the horse widths are characteristically a weak wind region, the sailing ships were often stuck in the calm for days or weeks. If the calm lasted too long, the thirsty horses (steeds) that the Spaniards brought with them on their way to their colonies had to be slaughtered or even thrown overboard. This could also have led to the naming of the horse widths.
Others
- In the novel Die Arbeiter des Meeres (1866), Victor Hugo mentions the practice of throwing horses overboard in the horse's breadth.
- A short, quirky song by the California band The Doors from 1967 is called Horse Latitudes .
Web links
See also
Individual evidence
- ^ Dtv-Lexikon, Volume 15, 1976, ISBN 3-423-03065-8 , p. 257.
- ↑ Kemp, Peter. The Oxford Companion to Ships and the Sea , London, Oxford University Press, 1976. Pages 233 and 399
- ↑ Helmut Meyer, Gudrun Meyer: Horses bridled differently: Forays through natural and art history . Schlütersche, Hannover 2002, ISBN 3-87706-695-X , p. 33 ( limited preview in Google Book search).
- ^ The Columbia Electronic Encyclopedia , Sixth Edition / Sixth Edition. New York: Columbia University Press, 2003