Green water off Oman in the Arabian Sea

This true-color Moderate Resolution Imaging Spectroradiometer (MODIS) image from October 4 was shows what is likely to be the impact of the southwest monsoon season on the biological productivity of the waters of the Arabian Sea. During the southwest, or summer, monsoon season, winds blow steadily from the southwest along the coast of Oman, setting up an ocean current that flows northeast. As the warm surface waters are pushed along by the winds, cold, nutrient-rich water from deep in the ocean wells up to the surface. This nutrient-laden water supports and abundance of marine plant life, and may be responsible for the colorful swirls seen in the ocean in this image. The monsoon reaches its peak in July, and tapers off toward the end of the year. Around December or January, the monsoon winds begin to blow from the northeast, but not as strongly as the southwest monsoon. Therefore, the surface waters of the ocean respond less strongly, and the weaker ocean currents that result are often not powerful enough to create upwelling. This difference in monsoon wind strength means that the waters of the Arabian Sea and northern Indian Ocean experience extremes of biological productivitywith half the year having abundant marine plant and animal life, while productivity in the other half of the year declines markedly. This region exhibits one of the sharpest seasonal contrasts in biological productivity in the world.
Source: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

Oman Dust Storm

This SeaWiFS images shows a dust storm blowing from Oman out over the Arabian Sea.
Source: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

Space radar image of Ubar optical/radar

This pair of images from space shows a portion of the southern Empty Quarter of the Arabian Peninsula in the country of Oman. On the left is a radar image of the region around the site of the fabled Lost City of Ubar, discovered in 1992 with the aid of remote sensing data. On the right is an enhanced optical image taken by the shuttle astronauts. Ubar existed from about 2800 BC to about 300 AD. and was a remote desert outpost where caravans were assembled for the transport of frankincense across the desert. The actual site of the fortress of the Lost City of Ubar, currently under excavation, is too small to show in either image. However, tracks leading to the site, and surrounding tracks, show as prominent, but diffuse, reddish streaks in the radar image. Although used in modern times, field investigations show many of these tracks were in use in ancient times as well. Mapping of these tracks on regional remote sensing images provided by the Landsat satellite was a key to recognizing the site as Ubar. The prominent magenta colored area is a region of large sand dunes. The green areas are limestone rocks, which form a rocky desert floor. A major wadi, or dry stream bed, runs across the scene and appears as a white line. The radar images, and ongoing field investigations, will help shed light on an early civilization about which little in known. The radar image was taken by the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR- C/X- SAR) and is centered at 18 degrees North latitude and 53 degrees East longitude. The image covers an area about 50 kilometers by 100 kilometers (31 miles by 62 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted, horizontally received; blue is C-band horizontally transmitted, horizontally received; green is L-band horizontally transmitted, vertically received. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASAs Mission to Planet Earth.
Source: NASA JPL

Space Radar Image of Central Plain, Oman

Bright, arc-shaped limestone hills and complex, branching drainage patterns dominate this three-frequency space radar image of a desert area in the north central plain of Oman. The hill along the left side of the image, called Jabal Fuhud, lies just south of the town of Fuhud, which appears as small bright rectangular features. The thin red lines that can be seen radiating out from this town are roads. The u-shaped hill in the right center of the image is called Jabal Natih. Layers in the limestone appear as stripes which parallel the crest of the hill. This region is an active area of petroleum production because these geological structures form natural traps for oil and gas. The branching patterns on the image are ancient drainage channels that formed when the climate in this area was much wetter. Two large dry river channels, called wadis, appear on the image. Wadi Umayri is the yellow stripe at the lower right corner of the image. A second orange-colored wadi runs from right to left below the two sets of hills. The bright yellow patterns between the wadis are areas of bedrock covered with a thin layer of sand. These rocks would not be visible in conventional satellite images or photgraphs. This image is centered at 22.25 degrees north latitude, 56.58 degrees east longitude. The area shown is approximately 42 kilometers by 78 kilometers (26 miles by 48 miles). 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 vertically 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 10, 1994, on board the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASAs Mission to Planet Earth program.
Source: NASA JPL

Space Radar Image of the Lost City of Ubar

This is a radar image of the region around the site of the lost city of Ubar in southern Oman, on the Arabian Peninsula. The ancient city was discovered in 1992 with the aid of remote sensing data. Archeologists believe Ubar existed from about 2800 B.C. to about 300 A.D. and was a remote desert outpost where caravans were assembled for the transport of frankincense across the desert. This image was acquired on orbit 65 of space shuttle Endeavour on April 13, 1994 by the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR). The SIR-C image shown is centered at 18.4 degrees north latitude and 53.6 degrees east longitude. The image covers an area about 50 by 100 kilometers (31 miles by 62 miles). The image is constructed from three of the available SIR-C channels and displays L- band, HH (horizontal transmit and receive) data as red, C- band HH as blue, and L-band HV (horizontal transmit,vertical receive) as green. The prominent magenta colored area is a region of large sand dunes, which are bright reflectors at both L- and C-band. The prominent green areas (L-HV) are rough limestone rocks, which form a rocky desert floor. A major wadi, or dry stream bed, runs across the middle of the image and is shown largely in white due to strong radar scattering in all channels displayed (L and C HH, L-HV). The actual site of the fortress of the lost city of Ubar, currently under excavation, is near the Wadi close to the center of the image. The fortress is too small to be detected in this image. However, tracks leading to the site, and surrounding tracks, appear as prominent, but diffuse, reddish streaks. These tracks have been used in modern times, but field investigations show many of these tracks were in use in ancient times as well. Mapping of these tracks on regional remote sensing images was a key to recognizing the site as Ubar in 1992. This image, and ongoing field investigations, will help shed light on a little known early civilization. Spaceborne Imaging Radar-C and X-Band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASAs Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASAs Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtange- legenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.v.(DLR), the major partner in science, operations, and data processing of X-SAR.
Source: NASA JPL

Anaglyph, Landsat overlay, Southernmost Coastal Oman

This 3-D view of a coastal area in southernmost Oman shows how topographic information can be used to enhance satellite images, deriving a better understanding of the proces ses that sculpt the landscape. The coastline in the upper half of the image appears to follow the same trend as a canyon in the lower half of the image. Both features are probably coincident with a single fault that cuts the limestone bedrock. Note how in this climate limestone erodes sharply along the stream courses resulting in deep and na rrow canyons. Generally the landscape is barren, but the darker areas have sparse vegetation that is supported by summer monsoon moisture. The Arabian Sea is on the right. This anaglyph was generated by first draping a Landsat Thematic Mapper image over a topographic map from the Shuttle Radar Topography Mission, then using the topographic dat a to create two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earths surface in its ful l three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter. Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30 meter (100 foot) spatial resolut ion of most Landsat images and will provide a valuable complement for studying the historic and growing Landsat data archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM project by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center, Sioux Falls, South Dakota. The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Ape rture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission was designed to collect three-dimensional measurements of the Earths surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) and the German (DLR) and Italian (ASI) space agencies. It is managed by NASAs Jet Propulsion Laboratory, Pasadena, CA, for NASAs Earth Science Enterprise, Washington, DC. Size: 20.5 by 18.3 kilometers (12.7 by 11.3 miles) Location: 16.9 deg. North lat., 53.7 deg. East lon. Orientation: North at top-left Date Acquired: February 15, 2000
Source: NASA/JPL/NIMA