File:Ship-wave-shaped wave clouds induced by the Crozet Islands (morning overpass) (MODIS 2017-01-16).jpg

English: On January 11, 2017, the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite captured a true-color image of atmospheric waves fanning out behind the Crozet Islands.

The clouds take this shape because of the flow of the air in the atmosphere. Air flows without disruption over the open ocean and when clouds form over this smooth-flowing air, the clouds typically cover the sky in a uniform fashion. This can be seen in the marine clouds at the edges of the image.

When smooth-flowing air hits a high obstacle – in this case, the mountainous Crozet Islands – it splits, setting up turbulent motion in the atmosphere which, in turn, creates patterns in the clouds. In this case, air flowing from the southwest split rather evenly as it hit the islands, creating a wave pattern on the lee side. The classic V pattern is what is typically seen behind ships when they move through water. The cloud patterns were named after the classic V pattern, and are known as ship-wave-shaped wave clouds.

The Crozet Islands are in the southern Indian Ocean roughly halfway between Antarctica and Madagascar. They are part of France’s southern and Antarctic lands and are uninhabited except for a small research station.