Images
July 1, 2009 - Ship-wave-shape Clouds by the Aleutian Islands
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The cloud patterns seen in this image, acquired by the MODIS on the Terra
satellite on June 19, 2009, resemble ship waves, i.e., the V-shaped wakes left by moving objects, such as ships or even ducks. The pattern is not coincidental; wind behaves like a fluid, so when it encounters an obstacle, it must move around it, leaving behind a wake or a visible wave pattern. As the air crests a wave, it cools and clouds form. Then, as the air sinks into the trough, the air warms, and clouds don't form. This pattern repeats itself, with clouds appearing at the peak of every wave. In this case, the obstacle is an island. As the wind flows past the island, it is swept around and over it leaving a wake similar to that of a ship-- hence the name "ship-wave-shaped" clouds.
In this case, the wave clouds are being caused by the Aleutian Islands,
the outlines of which are visible on the image. The Aleutian Islands
extend westward from Alaska.
Image Facts
Satellite:
Terra
Date Acquired: 06/19/2009
Resolutions:
1km ( B), 500m ( B), 250m ( B)
Bands Used: 1,4,3
Image Credit:
Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC
The cloud patterns seen in this image, acquired by the MODIS on the Terra satellite on June 19, 2009, resemble ship waves, i.e., the V-shaped wakes left by moving objects, such as ships or even ducks. The pattern is not coincidental; wind behaves like a fluid, so when it encounters an obstacle, it must move around it, leaving behind a wake or a visible wave pattern. As the air crests a wave, it cools and clouds form. Then, as the air sinks into the trough, the air warms, and clouds don't form. This pattern repeats itself, with clouds appearing at the peak of every wave. In this case, the obstacle is an island. As the wind flows past the island, it is swept around and over it leaving a wake similar to that of a ship-- hence the name "ship-wave-shaped" clouds.
In this case, the wave clouds are being caused by the Aleutian Islands, the outlines of which are visible on the image. The Aleutian Islands extend westward from Alaska.
Image Facts
Satellite:
Terra
Date Acquired: 06/19/2009
Resolutions:
1km ( B), 500m ( B), 250m ( B)
Bands Used: 1,4,3
Image Credit:
Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC
