ISS017-E-13789
| NASA Photo ID | ISS017-E-13789 |
| Focal Length | 400mm |
| Date taken | 2008.08.19 |
| Time taken | 14:36:09 GMT |
Resolutions offered for this image:
1000 x 1539 pixels 540 x 831 pixels 540 x 540 pixels 3072 x 2098 pixels 640 x 437 pixels
1000 x 1539 pixels 540 x 831 pixels 540 x 540 pixels 3072 x 2098 pixels 640 x 437 pixels
Cloud masks available for this image:
Spacecraft nadir point: 29.5° N, 17.0° E
Photo center point: 28.3° N, 16.2° E
Photo center point: 28.3° N, 16.2° E
Nadir to Photo Center: Southwest
Spacecraft Altitude: 191 nautical miles (354km)
Country or Geographic Name: | LIBYA |
Features: | DESERT, DENDRITIC DRAINAGE |
| Features Found Using Machine Learning: | |
Cloud Cover Percentage: | 10 (1-10)% |
Sun Elevation Angle: | 36° |
Sun Azimuth: | 264° |
Camera: | Nikon D2Xs Electronic Still Camera |
Focal Length: | 400mm |
Camera Tilt: | 24 degrees |
Format: | 4288E: 4288 x 2848 pixel CMOS sensor, RGBG imager color filter |
Film Exposure: | |
| Additional Information | |
| Width | Height | Annotated | Cropped | Purpose | Links |
|---|---|---|---|---|---|
| 1000 pixels | 1539 pixels | No | Yes | Earth From Space collection | Download Image |
| 540 pixels | 831 pixels | Yes | Yes | Earth From Space collection | Download Image |
| 540 pixels | 540 pixels | Yes | Yes | NASA's Earth Observatory web site | Download Image |
| 3072 pixels | 2098 pixels | No | No | Download Image | |
| 640 pixels | 437 pixels | No | No | Download Image |
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Image Caption: Desert Erosion, A Modern Libyan Landscape
This detailed astronaut photograph shows the classic patterns of an eroded desert landscape, about 300 kilometers (190 miles) south of Libya's Mediterranean coast. Widespread indented patterns are low escarpments and stream terraces generated by stream erosion--on those few occasions in any decade when enough rain falls for streams to flow. The only areas where sediment is being deposited are the streambeds, which appear in this image as sinuous zones with a distinct component of black minerals. These minerals give the streambeds a darker color than adjacent low escarpments (image top left and lower left). The sediment comes from a volcanic landscape immediately upstream to the west.
Other stream-generated features are several relict stream banks (indicated by ovals); one area even preserves both (parallel) banks of the original stream (far right oval). The ancient stream banks were cemented by minerals such as calcium carbonate and gypsum, introduced by the streams when they were active, probably during wetter climates in the past 2 million years. Relict stream courses show prior positions of streams, and help tell the region's paleoclimate story. They also provide Earth analogs for similar features on Mars.
The lack of vegetation is the first indication of the great aridity of the region, but sand dunes also appear as sinuous lines oriented perpendicular to the dominant northeasterly wind direction (transverse dunes). If the dominant wind direction remains the same, these transverse dunes would be expected to move further to the southwest over time (towards the top left). Some of the dunes cross the river courses, showing how seldom the rivers flow.
This detailed astronaut photograph shows the classic patterns of an eroded desert landscape, about 300 kilometers (190 miles) south of Libya's Mediterranean coast. Widespread indented patterns are low escarpments and stream terraces generated by stream erosion--on those few occasions in any decade when enough rain falls for streams to flow. The only areas where sediment is being deposited are the streambeds, which appear in this image as sinuous zones with a distinct component of black minerals. These minerals give the streambeds a darker color than adjacent low escarpments (image top left and lower left). The sediment comes from a volcanic landscape immediately upstream to the west.
Other stream-generated features are several relict stream banks (indicated by ovals); one area even preserves both (parallel) banks of the original stream (far right oval). The ancient stream banks were cemented by minerals such as calcium carbonate and gypsum, introduced by the streams when they were active, probably during wetter climates in the past 2 million years. Relict stream courses show prior positions of streams, and help tell the region's paleoclimate story. They also provide Earth analogs for similar features on Mars.
The lack of vegetation is the first indication of the great aridity of the region, but sand dunes also appear as sinuous lines oriented perpendicular to the dominant northeasterly wind direction (transverse dunes). If the dominant wind direction remains the same, these transverse dunes would be expected to move further to the southwest over time (towards the top left). Some of the dunes cross the river courses, showing how seldom the rivers flow.
