December 8, 2007 - Ship-Wave-Shaped Clouds, Bouvet Island, South Atlantic Ocean

Ship-Wave-Shaped Clouds, Bouvet Island, South Atlantic Ocean

The cloud patterns seen in this image, acquired by the MODIS on the Terra satellite on December 6, 2007, resemble ship waves or "Kelvin ship waves". These are the V-shaped wakes left by moving objects like 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 crested a wave, it cooled and clouds formed. Then, as the air sank into the trough, the air warmed, and clouds did not form. This pattern repeated 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 Bouvet Island, in the South Atlantic Ocean.

Image Facts
Satellite: Terra
Date Acquired: 12/06/2006
Resolutions: 1km ( B), 500m ( B), 250m ( B)
Bands Used: 1,4,3
Image Credit: Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC