Rows of giant clouds of the sky like a besieged city of Birmingham in Alabama last Friday (Dec, 16). Tsunami wave-shaped cloud of swirling it makes the local weather stations swamped with questions people who come bring pictures that strange cloud, "Is this a tsunami in the sky?"
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Tsunami Clouds along the horizon in Birmingham, Ala., on Friday (Dec. 16). (Picture from: http://www.inquisitr.com/)
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Experts say the cloud is an example of "Kelvin-Helmholtz waves". Whether in the sky or in oceans, this type of turbulence is always formed when a liquid layer or rapidly moving meiuncur above a thick layer that moves more slowly, thus dragging the surface.
Waves of water for example, is formed when a layer of fluid on it (air) moves faster than the fluid layer beneath it (water). When the difference between wind and water speed increased to a certain point. Waves broke? forms such as crescent bend forward. Form that is referred to as Kelvin-Helmholtz wave form.
According to Chris Walcek, meteorologist at the Atmospheric Sciences Research Center at the State University of New York at Albany, the wind moving fast across the sky can drag the top of the slow-moving clouds underneath in the same way.
"In the pictures sky Birmingham, there may be a layer of cold air near the surface wind speed is low," said Walcek. "That is why there are clouds or fog in that layer. On the top layer of slow-moving cold cloud was likely there is a layer of warm air to move faster."
Generally, the difference in wind speed and temperature of both layers of the atmosphere is so small, or just too big. Kelvin-Helmholtz waves are formed when wind speed and temperature differences in the two layers touching the appropriate point. "This photo shows the air between two layers of the atmosphere is nearing the threshold of turbulence, and mix to combine these two layers into one," he said. *** [LIVESCIENCE | KORAN TEMPO 3742]
