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Altamaha River Delta, Georgi
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PIA03157
Sol (our sun)
AirSAR
| Title |
Altamaha River Delta, Georgia Sea Islands |
| Original Caption Released with Image |
The history of sea islands in the Altamaha River delta on the coast of Georgia is revealed in this image produced from data acquired by the Airborne Synthetic Aperture Radar (AIRSAR), developed and operated by NASA's Jet Propulsion Laboratory, Pasadena, Calif. The outlines of long-lost plantation rice fields, canals, dikes and other inlets are clearly defined. Salt marshes are shown in red, while dense cypress and live oak tree canopies are seen in yellow-greens. Agricultural development of the Altamaha delta began soon after the founding of the Georgia Colony in 1733. About 25 plantations were located on the low-lying islands and shores by the 19th century, taking advantage of the rich alluvial flow and annual inundation of water required by some crops. The first major crop was indigo, when demand for that faded, rice and cotton took its place. A major storm in 1824 destroyed much of the town of Darien (upper right) and put many of the islands under 20 feet of water. The Civil War ended the plantation system, and many of the island plantations disappeared under heavy brush and new growth pine forests. Some were used as tree farms for paper and pulp industries, while the Butler Island (center left) plantation became a wildlife conservation site growing wild sea rice for migrating ducks and other waterfowl. Margaret Mitchell is reputed to have used the former owner of the Butler Plantation as a basis for the Rhett Butler character in her novel "Gone With The Wind," taking the first name from Rhett's Island (lower right). These data were obtained during a 1994-95 campaign along the Georgia coast. AIRSAR's ability to detect vegetation canopy density, hydrological features and other topographic characteristics is a useful tool in landscape archaeology. AIRSAR flies aboard a NASA DC-8 based at NASA's Dryden Flight Research Center, Edwards, Calif. The analysis on the data shown was accomplished by Dr. Gary Mckay, Department of Archaeology and Geography, and Ian Morrison, Department of Archaeology, both of the University of Edinburgh (Scotland). AIRSAR is part of NASA's Earth Enterprise program. JPL is managed by the California Institute of Technology, Pasadena. |
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Fraser, Colorado
PIA04266
Sol (our sun)
AirSAR
| Title |
Fraser, Colorado |
| Original Caption Released with Image |
This sequence of three images in northern Colorado was taken by NASA's Airborne Synthetic Aperture Radar (AirSar) for the joint NASA-National Oceanic and Atmospheric Administration Cold Land Processes Experiment. The images were produced from data acquired on February 19, 21 and 23, 2002 (top to bottom), and demonstrate the effects of snow on the radar backscatter at different frequencies. The images are centered at 40 degrees north latitude and 106 degrees west longitude, 12 kilometers (7.5 miles) west of the town of Fraser. The colors red, green and blue indicate the relative total power of the radar backscatter at P-, L-, and C-bands, respectively. The top image was acquired before snowfall, the middle image was acquired the morning after the snow. When the snow melted, the most prominent changes were visible and can be seen in the bottom image. In this image, melting snow allows less of the radar signal to backscatter and some features appear darker. The Cold Land Processes Experiment is a multi-year experiment to study how snow processes work and how snow-covered areas affect weather and climate. Fraser, Colo., is one of three study areas in northern Colorado and southern Wyoming providing ideal natural laboratories for snow research. AirSar flies aboard a NASA DC-8 based at NASA's Dryden Flight Research Center, Edwards, Calif. Built, operated and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., AirSar is part of NASA's Earth Science Enterprise program. JPL is a division of the California Institute of Technology in Pasadena. |
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Radar Image with Color as He
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PIA03866
Sol (our sun)
AirSAR
| Title |
Radar Image with Color as Height, Sman Teng, Temple, Cambodia |
| Original Caption Released with Image |
This image of Cambodia's Angkor region, taken by NASA's Airborne Synthetic Aperture Radar (AIRSAR), reveals a temple (upper-right) not depicted on early 19th Century French archeological survey maps and American topographic maps. The temple, known as "Sman Teng," was known to the local Khmer people, but had remained unknown to historians due to the remoteness of its location. The temple is thought to date to the 11th Century: the heyday of Angkor. It is an important indicator of the strategic and natural resource contributions of the area northwest of the capitol, to the urban center of Angkor. Sman Teng, the name designating one of the many types of rice enjoyed by the Khmer, was "discovered" by a scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif., working in collaboration with an archaeological expert on the Angkor region. Analysis of this remote area was a true collaboration of archaeology and technology. Locating the temple of Sman Teng required the skills of scientists trained to spot the types of topographic anomalies that only radar can reveal. This image, with a pixel spacing of 5 meters (16.4 feet), depicts an area of approximately 5 by 4.7 kilometers (3.1 by 2.9 miles). North is at top. Image brightness is from the P-band (68 centimeters, or 26.8 inches) wavelength radar backscatter, a measure of how much energy the surface reflects back toward the radar. Color is used to represent elevation contours. One cycle of color represents 25 meters (82 feet) of elevation change, so going from blue to red to yellow to green and back to blue again corresponds to 25 meters (82 feet) of elevation change. AIRSAR flies aboard a NASA DC-8 based at NASA's Dryden Flight Research Center, Edwards, Calif. In the TOPSAR mode, AIRSAR collects radar interferometry data from two spatially separated antennas (2.6 meters, or 8.5 feet). Information from the two antennas is used to form radar backscatter imagery and to generate highly accurate elevation data. Built, operated and managed by JPL, AIRSAR is part of NASA's Earth Science Enterprise program. JPL is a division of the California Institute of Technology in Pasadena. |
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Upolu Island, Western Samoa
PIA02854
Sol (our sun)
AirSAR
| Title |
Upolu Island, Western Samoa |
| Original Caption Released with Image |
Island nations in the South Pacific Ocean experience natural disasters associated with typhoons, and with their proximity to the Pacific Ocean's "Ring of Fire." This radar image shows most of the northern coast of the island of Upolu in the nation of Western Samoa. Disaster managers use digital elevation models (DEMs) generated from radar data to assist in research toward disaster mitigation and management. Geologists also use DEM data of volcanic features, such as the line of circular craters in this image, to study eruption rates and volumes, and volcanic landform evolution. The capital of Western Samoa, Apia, is in the lower left of the image. Angular black areas in the image are areas where steep topography causes holes in the data, these holes can be filled in by collecting data at other look directions. Color represents topography and intensity represents across-section of the radar backscatter. Since rough areas return more of the incident signal, they appear brighter on the image than relatively smooth areas, such as the ocean surface , along the left side of the image. This image was acquired by the AIRborne Synthetic Aperture (AIRSAR) radar instrument aboard a DC-8 aircraft operated out of NASA's Dryden Flight Research Center. AIRSAR collects fully polarimetric data at three wavelengths, C-band(0.057 meter), L-band (0.25 meter) and P-band (0.68 meter). AIRSAR also collects cross-track and along track interferometric data that results in topographic measurements and motion detection, respectively. This image was collected during the Pacific Rim mission, a three-month mission from July to October 2000 that collected data at over 200 sites in eighteen countries and territories around the Pacific Rim. AIRSAR is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise,Washington, D.C. Size: 10 km (6.2 miles) x 63 km (37.3 miles) Location: 14.16 deg. North lat., 171.75 deg. West Orientation: North towards the left side of image Date Acquired: August 10, 2000 |
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Upolu Island, Western Samoa
PIA02853
Sol (our sun)
AirSAR
| Title |
Upolu Island, Western Samoa |
| Original Caption Released with Image |
Island nations in the South Pacific Ocean experience natural disasters associated with typhoons, and with their proximity to the Pacific Ocean's "Ring of Fire." This radar image shows the western end of the island of Upolu in the nation of Western Samoa. Disaster managers use digital elevation models (DEMs) generated from radar data to assist in research toward disaster mitigation and management. Geologists also use DEM data of volcanic features, such as the circular craters in this image, to study eruption rates and volumes, and volcanic landform evolution. Black areas near the top of the image are areas where steep topography causes holes in the data, these holes can be filled in by collecting data at other look directions. Color represents topography and intensity represents across-section of the radar backscatter. Since rough areas return more of the incident signal, they appear brighter on the image than relatively smooth areas, such as the ocean surface at the top of the image. This image was acquired by the AIRborne Synthetic Aperture (AIRSAR) radar instrument aboard a DC-8 aircraft operated out of NASA's Dryden Flight Research Center. AIRSAR collects fully polarimetric data at three wavelengths, C-band(0.057 meter), L-band (0.25 meter) and P-band (0.68 meter). AIRSAR also collects cross-track and along track interferometric data that results in topographic measurements and motion detection, respectively. This image was collected during the Pacific Rim mission, a three-month mission from July to October 2000 that collected data at over 200 sites in eighteen countries and territories around the Pacific Rim. AIRSAR is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise,Washington, D.C. Size: 10 km (6.2 miles) x 10 km (6.2 miles) Location: 14.02 deg. North lat., 171.52 deg. West Orientation: North at top Date Acquired: August 10, 2000 |
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Mt. Pinatubo, Phillipines -
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PIA03513
Sol (our sun)
AirSAR
| Title |
Mt. Pinatubo, Phillipines - Comparison of November, 1996 and September, 2000 |
| Original Caption Released with Image |
Built, operated and managed by the Jet Propulsion Laboratory, Pasadena, Calif., AIRSAR is part of NASA's Earth Science Enterprise program. JPL is a division of the California Institute of Technology in Pasadena., The effects of the June 15, 1991, eruption of Mt. Pinatubo continue to affect the lives of people living near the volcano on the island of Luzon in the Philippines. The eruption produced a large amount of volcanic debris that was deposited on the flanks of the volcano as part of pyroclastic flows. This debris consists of unconsolidated ash and boulders, and following heavy rains, it mixes with the rain run-off to form volcanic mudflows called lahars. Lahars are moving rivers of concrete slurry that are highly erosive. They can sweep down existing river valleys, carving deep canyons where the slopes are steep, or depositing a mixture of fine ash and larger rocks on the gentler slopes. The deposits left from a lahar soon solidify into a material similar to concrete, but while they are moving, lahars are dynamic features, and in a single river valley, the active channel may change locations within a few minutes or hours. These changes represent a significant natural hazard to local communities. These images from the NASA's airborne imaging radar AIRSAR instrument show two snapshots in the evolution of the lahars in the lower Pasig-Potrero River, just north of the town of Bacalor, east of the summit of the volcano. These images were collected on November 29, 1996 and September 25, 2000. The radar is particularly good at picking out spatial variations in the average particle size of the lahar deposits, which show up as a variety of different colored units at lower right. The active river channel is dark in both images, and is particularly well-defined in the September 2000 image. In the November 1996 image, the area of the flooded channel is much wider, so that the radar images are quite effective at showing where the drier surface materials are located. Also visible as a series of linear features in both images is a series of concrete dikes that have been constructed to protect the adjacent agricultural land from the lahar deposits. Some of this land has recently been developed as fish ponds, which are visible in the lower left of the 2000 image as a series of small, dark blue rectangles. Scientists have been using airborne radar data collected by NASA's AIRSAR instrument in their studies of the aftereffects of the Mt. Pinatubo eruption. AIRSAR collected imaging radar data over the volcano during a mission to the Pacific Rim region in late 1996 and on a follow-up mission to the area in late 2000. These data sets, along with remote sensing data collected from satellites, provide valuable information about the dynamic landscape and its hazards. AIRSAR collects radar interferometry used to produce digital elevation models. By comparing topographic data collected in 1996 and again in 2000, volcanologists can study how the shape and size of the volcano is changing. The detailed topography is also used to determine the highest risk areas for lahars to flow. AIRSAR flies aboard a NASA DC-8 based at NASA's Dryden Flight Research Center, Edwards, Calif. |
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Mt. Pinatubo, Phillippines -
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PIA03512
Sol (our sun)
AirSAR
| Title |
Mt. Pinatubo, Phillippines - Perspective View |
| Original Caption Released with Image |
The effects of the June 15, 1991, eruption of Mt. Pinatubo continue to affect the lives of people living near the volcano on the island of Luzon in the Philippines. The eruption produced a large amount of volcanic debris that was deposited on the flanks of the volcano as part of pyroclastic flows. This perspective view looking toward the east shows the western flank of the volcano where most of these pyroclastic flows were deposited. This debris consists of ash and boulders that mix with water after heavy rains to form volcanic mudflows called lahars. Lahars are moving rivers of concrete slurry that are highly erosive. They can sweep down existing river valleys, carving deep canyons where the slopes are steep, or depositing a mixture of fine ash and larger rocks on the gentler slopes. The deposits left from a lahar soon solidify into a material similar to concrete, but while they are moving, lahars are dynamic features, and in a single river valley the active channel may change locations within a few minutes or hours. These changes represent a significant natural hazard to local communities. The topographic data were collected by NASA's airborne imaging radar AIRSAR instrument on November 29, 1996. Colors are from the French SPOT satellite imaging data in both visible and infrared wavelengths collected in February 1996. Areas of vegetation appear red and areas without vegetation appear light blue. River valleys radiate out from the summit of the volcano (upper center). Since the eruption, lahars have stripped these valleys of any vegetation. The Pasig-Potrero River flows to the northeast off the summit in the upper right of the image. Scientists have been using airborne radar data collected by the AIRSAR instrument in their studies of the aftereffects of the Mt. Pinatubo eruption. AIRSAR collected imaging radar data over the volcano during a mission to the Pacific Rim region in late 1996 and on a follow-up mission to the area in late 2000. These data sets along with remote sensing data collected from satellites provide valuable information on the dynamic landscape and the hazards that it poses. AIRSAR flies aboard a NASA DC-8 based at NASA's Dryden Flight Research Center, Edwards, Calif. Built, operated and managed by the Jet Propulsion Laboratory, Pasadena, Calif., AIRSAR is part of NASA's Earth Science Enterprise program. JPL is a division of the California Institute of Technology in Pasadena. |
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