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This three-frequency space radar image of west central Egypt shows detailed patterns of eroded sedimentary rock formations emerging through a vast sea of sand dunes. The broad black bands that dominate the image are thick ridges of sand known as longitudinal dunes. In this region of the Sahara, a single ridge may be as long as several hundred kilometers. Thin red lines within the black bands are bright reflections from the steep crests of the sand ridges. Between the dunes are colorful patterns of rock outcrops that are either exposed at the surface or covered with very thin layers of sand that the radar "sees" through. Some of the rock areas are fringed in red, indicating that only the long wavelength L-band signal is penetrating the sand to image the rock surface. Most of the other color variations are due to different roughness textures of the rock surface, which are caused by different types of rocks, such as limestone, shale and sandstone. Scientists are using the penetrating capabilities of radar imaging in desert areas to study structural geology, mineral exploration, ancient climates, water resources and archaeology. This image is 55 kilometers by 31.7 kilometers (34.1 miles by 19.6 miles) and is centered at 26.2 degrees north latitude, 26.9 degrees east longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations as follows: red is L-band, horizontally transmitted and received; green is C-band, horizontally transmitted and received; and blue is X-band, vertically transmitted and received. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on April 17, 1994 onboard the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth. #####
Description
This three-frequency space radar image of west central Egypt shows detailed patterns of eroded sedimentary rock formations emerging through a vast sea of sand dunes. The broad black bands that dominate the image are thick ridges of sand known as longitudinal dunes. In this region of the Sahara, a single ridge may be as long as several hundred kilometers. Thin red lines within the black bands are bright reflections from the steep crests of the sand ridges. Between the dunes are colorful patterns of rock outcrops that are either exposed at the surface or covered with very thin layers of sand that the radar "sees" through. Some of the rock areas are fringed in red, indicating that only the long wavelength L-band signal is penetrating the sand to image the rock surface. Most of the other color variations are due to different roughness textures of the rock surface, which are caused by different types of rocks, such as limestone, shale and sandstone. Scientists are using the penetrating capabilities of radar imaging in desert areas to study structural geology, mineral exploration, ancient climates, water resources and archaeology. This image is 55 kilometers by 31.7 kilometers (34.1 miles by 19.6 miles) and is centered at 26.2 degrees north latitude, 26.9 degrees east longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations as follows: red is L-band, horizontally transmitted and received; green is C-band, horizontally transmitted and received; and blue is X-band, vertically transmitted and received. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on April 17, 1994 onboard the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth. #####
Description
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