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  Image: Geographic Location Direction Photo #: ISS030-E-193144 Date: Mar. 2012
Geographic Region: KERGUELEN ILES

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  Wave Clouds Near Ile aux Cochons, Southern Indian Ocean

This astronaut photograph from the International Space Station illustrates the formation of wave clouds in the wake--or downwind side--of Ile aux Cochons ("Isle of Pigs") located in the Southern Indian Ocean. The island is approximately located 3000 kilometers southeast of the southern tip of the African continent and 2300 kilometers northwest of Antarctica. The island itself, of which only a part of the eastern coastline is visible at image center, is volcanic in origin with a summit elevation of 775 meters above sea level. The Ile aux Cochons stratovolcano is thought to have erupted within the last 12,000 years, however no historical activity has been recorded.

The summit elevation is high enough for the land surface to interact with cloud layers and winds flowing past the island. Two major cloud layers are visible; a lower, more uniform layer consists of roughly parallel cloud "streets" that suggest a westerly flow pattern of air. When the air mass encounters the Ile aux Cochons, moisture-laden air rises and cools, causing more water vapor to condense into clouds.

As the air mass passes over the summit of Ile aux Cochons and descends, it may encounter alternating moist and dry air layers, enabling the formation of the discontinuous chevron-shaped wave clouds in the wake of the island. While their appearance suggests that the clouds are forming in the wake of the island and moving eastwards, in fact it is the air mass that is moving, with clouds forming in regions of moist air and dissipating in dry regions.

Ile aux Cochons is the westernmost of the islands that form the subantarctic Crozet Archipelago (part of the French Southern and Antarctic Lands). Accept for occasional research visits, the island is uninhabited. The island is an important breeding site for seabirds, including the world's largest King Penguin colony.
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Images: All Available Images Low-Resolution 160k
Mission: ISS030  
Roll - Frame: E - 193144
Geographical Name: KERGUELEN ILES  
Center Lat x Lon: 46.1S x 50.3E
Film Exposure:   N=Normal exposure, U=Under exposed, O=Over exposed, F=out of Focus
Percentage of Cloud Cover-CLDP: 100
Camera: N2
Camera Tilt: 37   LO=Low Oblique, HO=High Oblique, NV=Near Vertical
Camera Focal Length: 180  
Nadir to Photo Center Direction: S   The direction from the nadir to the center point, N=North, S=South, E=East, W=West
Stereo?:   Y=Yes there is an adjacent picture of the same area, N=No there isn't
Orbit Number:  
Date: 20120325   YYYYMMDD
Time: 114251   GMT HHMMSS
Nadir Lat: 43.6S  
Latitude of suborbital point of spacecraft
Nadir Lon: 51.0E  
Longitude of suborbital point of spacecraft
Sun Azimuth: 306   Clockwise angle in degrees from north to the sun measured at the nadir point
Space Craft Altitude: 208   nautical miles
Sun Elevation: 29   Angle in degrees between the horizon and the sun, measured at the nadir point
Land Views: ISLAND  
Water Views: OCEAN, SEA, WAVE  
Atmosphere Views:  
Man Made Views:  
City Views:  
Photo is not associated with any sequences

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