ISS Astronaut Photograph Captures Wave Clouds Near Pig Island in Southern Indian Ocean

Posted on April 25, 2012

The photograph taken by an astronaut about the International Space Station (ISS) shows wave clouds on the downwind side of Ile aux Cochons, an uninhabited island in the southern Indian Ocean. It is also known as Pig Island.

You can see a much larger photo here. Pig Island is volcanic in origin and has a summit elevation of 775 meters (2,543 feet) above sea level.

NASA's Earth Observatory says the summit is high enough to interact with the cloud layers. Clouds form when air masses run into the summit as moisture-laden air rises and cools. The Earth Observatory says that once the air masses have passed over the summit, "they descend and may encounter alternating moist and dry air layers, enabling the formation of these discontinuous, chevron-shaped wave clouds."



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