Earth from Space - Image Information

LOCATION Direction Photo #: ISS015-E-10704 Date: Jun. 2007
Geographic Region: CHILE

Grey Glacier, Chile:
The Southern Patagonian Icefield of Chile and Argentina hosts several spectacular glaciers--including Grey Glacier located in the Torres del Paine National Park in Chile. This glacier, which in 1996 had a measured total area of 270 square kilometers and a length of 28 kilometers (104 square miles in area, 17 miles long), begins in the Patagonian Andes Mountains to the west and terminates in three distinct lobes into Grey Lake. The image is a photograph taken by an astronaut aboard the International Space Station, and it captures a striking blue coloration of the glacier. The coloring is due to the ice's absorption of red wavelengths of light and scattering of blue wavelengths of light as it is transmitted through the ice.

Certain portions of the glacier visible in the image are indeed gray. Linear gray-brown moraines are accumulations of soil and rock debris that form along the edges of a glacier as it flows downhill across the landscape (much like a bulldozer blade). Glaciers flowing downslope through adjacent feeder valleys ultimately meet, and debris entrained along their sides becomes concentrated in the central portion of the resulting single, large glacier--much as smaller streams of water join to form a single large river. Three of these medial moraines are visible in the ice mass at image center left.

Gray-brown patches of debris from adjacent mountainsides color the surface of the easternmost lobe of the glacier (image top). Several crevasse fields are visible in the image. The crevasses, each a small canyon in the ice, form as a result of stress between slower- and faster-moving ice within the glacier. The crevasse patterns of Grey Glacier are complex, perhaps due to the three-lobed nature of its terminus, or end, into Grey Lake. The rugged surface of the glacier is also demonstrated by the jagged shadows it casts onto the surface of the lake.

All three lobes of Grey Glacier have retreated over the past 22 years, with the greatest loss of ice occurring along the westernmost lobe terminus. Grey Glacier, like others in southern Patagonia, loses ice from its terminus as it enters the water, a process known as calving. Calving produces large free-floating chunks of ice; some floating ice is visible near the central glacier lobe in the upper image. The observed retreat means that ice loss has been greater than ice replenishment. It is most likely due to a combination of increased regional temperatures and changes in precipitation amounts.

Images: All Available Images Low-Resolution 291k
Mission: ISS015  
Roll - Frame: E - 10704
Geographical Name: CHILE  
Center Lat x Lon: 50.9S x 73.2W
Film Exposure:   N=Normal exposure, U=Under exposed, O=Over exposed, F=out of Focus
Percentage of Cloud Cover-CLDP: 10
Camera:: E4
Camera Tilt: 38   LO=Low Oblique, HO=High Oblique, NV=Near Vertical
Camera Focal Length: 800  
Nadir to Photo Center Direction: W   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: 880  
Date: 20070604   YYYYMMDD
Time: 175744   GMT HHMMSS
Nadir Lat: 51.1S  
Latitude of suborbital point of spacecraft
Nadir Lon: 70.9W  
Longitude of suborbital point of spacecraft
Sun Azimuth: 342   Clockwise angle in degrees from north to the sun measured at the nadir point
Space Craft Altitude: 181   nautical miles
Sun Elevation: 15   Angle in degrees between the horizon and the sun, measured at the nadir point
Land Views: GLACIER  
Water Views: ICE, LAKE, RIVER  
Atmosphere Views:  
Man Made Views:  
City Views:  

Photo is not associated with any sequences

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