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Images of Alaska and Jet Propulsion Laboratory (JPL)
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Lambert Glacier and Amery Ic
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The Lambert Glacier, seen in
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2/20/01
| Date |
2/20/01 |
| Description |
The Lambert Glacier, seen in the center of this image, is one of the largest and longest of Antarctica's glaciers. It drains about 900,000 square kilometers (560,000 square miles) of East Antarctica. On the southern half of the image, several smaller ice streams, channeled by numerous exposed mountains including the Mawson Escarpment to the east, merge into the Lambert, which broadens as it eventually flows into the ocean and forms the Amery Ice Shelf. The Lambert has clearly visible surface flowlines, which extend hundreds of kilometers into the interior. In the center section, isolated features on the ice shelf that appear bright in the radar image are likely due to past occurrences of surface meltwater accumulating into small lakes and troughs. This mosaic was derived from RADARSAT imagery obtained during the 1997 Antarctic Mapping Mission and shows an area approximately 900 kilometers by 675 kilometers (560 by 415 miles). The Lambert Glacier is centered at approximately 72 degrees south latitude and 67.5 degrees east longitude. The Antarctic Mapping Mission is a joint project between NASA and the Canadian Space Agency. The project is led by Ohio State University in Columbus in partnership with the Alaska Synthetic Aperture Radar (SAR) Facility at the University of Alaska Fairbanks, NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the Vexcel Corporation, Boulder, Colo. The Canadian Space Agency's RADARSAT-1 satellite carries a synthetic aperture radar, an imaging radar sensor that operates at C-band (5.3 GHz frequency) with horizontal transmit-horizontal receive polarization from an orbital altitude of about 800 kilometers (500 miles). The 1997 Antarctic Mapping Mission took place between Sept. 19 and Oct. 14 and mapped the entire Antarctic continent. The 2000 Antarctic Mapping Mission lasted from Sept. 3 to Nov. 4 and obtained complete coverage of Antarctica north of 82 degrees south latitude. Photo Credit: Canadian Space Agency/NASA/Ohio State University, Jet Propulsion Laboratory, Alaska SAR facility # # # # # |
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Weddell Sea/ScanSAR
Two radar images are shown i
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10/26/95
| Date |
10/26/95 |
| Description |
Two radar images are shown in this composite to compare the size of a standard spaceborne radar image (small inset) to the image that is created when the radar instrument is used in the ScanSAR mode (large image). The predominant image shows two large ocean circulation features, called eddies, at the northernmost edge of the sea ice pack in the Weddell Sea, off Antarctica. The eddy processes in this region play an important role in the circulation of the global ocean and the transportation of heat toward the pole. The large image is the first wide-swath, multi- frequency, multi-polarization radar image ever processed. To date, no other spaceborne radar sensors have obtained swaths exceeding 100 kilometers (62 miles) in width. This developmental image was produced at NASA's Jet Propulsion Laboratory by the Alaska SAR Facility's ScanSAR processor system, using radar data obtained on October 5, 1994, during the second flight of the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR- C/X-SAR) onboard the space shuttle Endeavour. The image is oriented approximately east-west, with a center location of around 56.6 degrees south latitude and 6.5 degrees west longitude. Image dimensions are 240 km by 350 km (149 miles by 218 miles). The smaller image inset (upper right edge) was obtained by SIR-C/X-SAR on October 6, 1994, and covers a portion of the same ice features that are shown in the large image. The inset image dimensions are 18 km by 50 km (11 miles by 31 miles). The ocean eddies have a clockwise (or cyclonic) rotation and are roughly 40 km to 60 km (25 miles to 37 miles) in diameter. The dark areas are new ice and the lighter green areas are small sea- ice floes that are swept along by surface currents, both of these areas are shown within the eddies and to the south of the eddies. First year seasonal ice, typically 0.5 meter to 0.8 meter (1.5 feet to 2.5 feet) thick, is shown in the darker green area in the lower right corner. The open ocean to the north is uniformly bright and appears blue, due to high winds making the surface rough. The colors in both images were obtained using the following radar channels: red is C-band vertically transmitted and vertically received, green is L-band horizontally transmitted and vertically received, and blue is L-band vertically transmitted and vertically received. The ScanSAR processor is being designed for implementation in 1996 at NASA's Alaska SAR Facility, located at the University of Alaska, Fairbanks, and will produce digital images from the forthcoming Canadian RADARSAT satellite, since its C-band horizontally transmitted, horizontally received polarization radar routinely obtains data over a considerable range of swath-widths and resolutions, including the important wide-swath (300 km to 500 km/186 miles to 310 miles) mode. ##### |
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Amery Ice Shelf
This view of the Amery Ice S
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2/20/01
| Date |
2/20/01 |
| Description |
This view of the Amery Ice Shelf is a mosaic of radar images from the 2000 Antarctic Mapping Mission. The blue line represents the coastline seen during the 1997 Antarctic Mapping Mission. The yellow coastline dates from the mid-1970s. Over the past 25 years, the Amery has been in a period of general advancement, moving seaward about 25 kilometers (15.5 miles). From 1997-2000, the ice shelf edge extended seaward about 5 kilometers (3 miles). Note that the coastal areas adjacent to the Amery Ice Shelf on both sides show little change. The two Antarctic mapping missions provide highly accurate coastal baselines needed for future comparisons. This image is centered at approximately 69 degrees south and 72.5 degrees east, covering an area about 115 by 165 kilometers (70 by 100 miles). The Antarctic Mapping Mission is a joint project between NASA and the Canadian Space Agency. The project is led by Ohio State University in Columbus in partnership with the Alaska Synthetic Aperture Radar (SAR) Facility at the University of Alaska Fairbanks, NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the Vexcel Corporation, Boulder, Colo. The Canadian Space Agency's RADARSAT-1 satellite carries a synthetic aperture radar, an imaging radar sensor that operates at C-band (5.3 GHz frequency) with horizontal transmit-horizontal receive polarization from an orbital altitude of about 800 kilometers (500 miles). The 1997 Antarctic Mapping Mission took place between Sept. 19 and Oct. 14 and mapped the entire Antarctic continent. The 2000 Antarctic Mapping Mission lasted from Sept. 3 to Nov. 4 and obtained complete coverage of Antarctica north of 82 degrees south latitude. Photo Credit: Canadian Space Agency/NASA/Ohio State University, Jet Propulsion Laboratory, Alaska SAR facility # # # # # |
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Antarctic Peninsula
The Antarctica Peninsula is
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2/20/01
| Date |
2/20/01 |
| Description |
The Antarctica Peninsula is the furthest north extension of the Antarctic continent and is exposed to slightly warmer climate conditions than the greater continent. This mosaic from the 2000 Antarctic Mapping Mission shows most of the peninsula. The blue line is the coastline seen in the 1997 Antarctic Mapping Mission. The broad Larsen Ice Shelf lies to the east, extending into the Weddell Sea, and smaller ice shelves including the Wordie and George VI are in the southwest corner. The northern Larsen Shelf has been retreating since the 1960s, with major collapses in the 1990s. Warming in both the air and ocean underlying the ice shelves leads to increased fracturing and eventually calving of the ice shelf fronts into icebergs. The 1995 Larsen calving events were due to anomalously warm summer temperatures in the early 1990s. The warming noted in the Antarctica Peninsula, as measured from several research stations located there, is not sufficient to affect the thicker and more extensive West Antarctic ice shelves to the south on the main continent. The two RADARSAT mosaics from 1997 and 2000 Antarctic imaging campaigns provide highly accurate snapshots of this rapidly changing region of the greater Antarctic continent. The Antarctic Mapping Mission is a joint project between NASA and the Canadian Space Agency. The project is led by Ohio State University in Columbus in partnership with the Alaska Synthetic Aperture Radar (SAR) Facility at the University of Alaska Fairbanks, NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the Vexcel Corporation, Boulder, Colo. The Canadian Space Agency's RADARSAT-1 satellite carries a synthetic aperture radar, an imaging radar sensor that operates at C-band (5.3 GHz frequency) with horizontal transmit-horizontal receive polarization from an orbital altitude of about 800 kilometers (500 miles. The 1997 Antarctic Mapping Mission took place between Sept. 19 and Oct. 14 and mapped the entire Antarctic continent. The 2000 Antarctic Mapping Mission lasted from Sept. 3 to Nov. 4 and obtained complete coverage of Antarctica north of 82 degrees south latitude. Photo Credit: Canadian Space Agency/NASA/Ohio State University, Jet Propulsion Laboratory, Alaska SAR Facility # # # # # |
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Larsen Ice Shelf
This sub-image of the Antarc
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2/20/01
| Date |
2/20/01 |
| Description |
This sub-image of the Antarctic Peninsula from the 2000 Antarctic Mapping Mission focuses on the northern end of the Larsen Ice Shelf. The blue line shows the coastline in 1997, the red line in 1992, based on synthetic aperture radar imagery from the European Space Agency, and the yellow line in the mid-1970s. The northern Larsen has been retreating since the 1960s, with major collapses in the 1990s. The southern Larsen was advancing until a major collapse in 1995. Small areas, however, also show advancement since 1997, including a section near the Sobral Peninsula in the center of the image. These advancements may indicate early rebuilding of the overall extent of the Larsen Shelf. The two RADARSAT mosaics from 1997 and 2000 Antarctic imaging campaigns provide highly accurate snapshots of this rapidly changing region of the greater Antarctic continent. The Antarctic Mapping Mission is a joint project between NASA and the Canadian Space Agency. The project is led by Ohio State University in Columbus in partnership with the Alaska Synthetic Aperture Radar (SAR) Facility at the University of Alaska Fairbanks, NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the Vexcel Corporation, Boulder, Colo. The Canadian Space Agency's RADARSAT-1 satellite carries a synthetic aperture radar, an imaging radar sensor that operates at C-band (5.3 GHz frequency) with horizontal transmit-horizontal receive polarization from an orbital altitude of about 800 kilometers (500 miles). The 1997 Antarctic Mapping Mission took place between Sept. 19 and Oct. 14 and mapped the entire Antarctic continent. The 2000 Antarctic Mapping Mission lasted from Sept. 3 to Nov. 4 and obtained complete coverage of Antarctica north of 82 degrees south latitude. Photo Credit: Canadian Space Agency/NASA/Ohio State University, Jet Propulsion Laboratory, Alaska SAR Facility # # # # # |
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Global View of the Arctic Oc
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The Arctic Ocean has been ma
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8/21/00
| Date |
8/21/00 |
| Description |
The Arctic Ocean has been mapped in an unprecedented manner by scientists at NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif. Using advanced radar that sees through all weather conditions, researchers will now be able to determine how the Earth's warming may be changing the sea ice cover. Sea ice in the polar region is a large barometer of global climate conditions. The mission is a joint project between JPL and the Alaska Synthetic Aperture Radar Facility, University of Alaska, Fairbanks. JPL manages the Sea Ice Thickness Derived from High Resolution Radar Imagery project for NASA's Earth Science Enterprise, Washington, DC. The Earth Science Enterprise is dedicated to studying how natural and human-induced change affects our global environment. This image is posted on the World Wide Web at http://www.jpl.nasa.gov/pictures/seaice . |
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Comparative Views of Arctic
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Scientists at NASA's Jet Pro
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8/21/00
| Date |
8/21/00 |
| Description |
Scientists at NASA's Jet Propulsion Laboratory (JPL) have used high resolution radar to see, for the first time ever, the development of the Arctic sea ice cover. The images show a comparison of ice growth during the Arctic winter. The two images are separated by nine days. Both images represent an area located in the Baufort Sea, north of the Alaskan coast. This radar view covers an area of 96 by 128 kilometers (60 by 80 miles). The brighter features are older thicker ice and the darker areas show young, recently formed ice. The earlier image is shown on the left. Within the nine-day span, large and extensive cracks in the ice cover have formed due to ice movement. These cracks expose the open ocean to the cold, frigid atmosphere where sea ice grows rapidly and thickens. Formation of sea ice in the Arctic Ocean affects the heat balance in the global atmosphere and ocean. The mission is a joint project between JPL and the Alaska Synthetic Aperture Radar Facility, University of Alaska, Fairbanks. JPL manages the Sea Ice Thickness Derived from High Resolution Radar Imagery project for NASA's Earth Science Enterprise, Washington, DC. The Earth Science Enterprise is dedicated to studying how natural and human-induced change affects our global environment. This image is available at http://www.jpl.nasa.gov/pictures/seaice . ##### |
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L-Band West Texas
This radar image of the Midl
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6/22/95
| Date |
6/22/95 |
| Description |
This radar image of the Midland/Odessa region of West Texas, demonstrates an experimental technique, called ScanSAR, that allows scientists to rapidly image large areas of the Earth's surface. The large image covers an area 245 kilometers by 225 kilometers (152 miles by 139 miles). It was obtained by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR- C/X-SAR) flying aboard the space shuttle Endeavour on October 5, 1994. The smaller inset image is a standard SIR-C image showing a portion of the same area, 100 kilometers by 57 kilometers (62 miles by 35 miles) and was taken during the first flight of SIR-C on April 14, 1994. The bright spots on the right side of the image are the cities of Odessa (left) and Midland (right), Texas. The Pecos River runs from the top center to the bottom center of the image. Along the left side of the image are, from top to bottom, parts of the Guadalupe, Davis and Santiago Mountains. North is toward the upper right. Unlike conventional radar imaging, in which a radar continuously illuminates a single ground swath as the space shuttle passes over the terrain, a Scansar radar illuminates several adjacent ground swaths almost simultaneously, by "scanning" the radar beam across a large area in a rapid sequence. The adjacent swaths, typically about 50 km (31 miles) wide, are then merged during ground processing to produce a single large scene. Illumination for this L-band scene is from the top of the image. The beams were scanned from the top of the scene to the bottom, as the shuttle flew from left to right. This scene was acquired in about 30 seconds. A normal SIR- C image is acquired in about 13 seconds. The ScanSAR mode will likely be used on future radar sensors to construct regional and possibly global radar images and topographic maps. The ScanSAR processor is being designed for 1996 implementation at NASA's Alaska SAR Facility, located at the University of Alaska Fairbanks, and will produce digital images from the forthcoming Canadian RADARSAT satellite. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's 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 NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (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. ##### |
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Shirase Glacier
This detailed image of the S
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2/20/01
| Date |
2/20/01 |
| Description |
This detailed image of the Shirase Glacier from the 2000 Antarctic Mapping Mission shows how the glacier has been retreating. The 1997 coastline appears in blue, the 1962 coastline in green and the mid-1970s coastline in yellow. The Shirase was at its furthest extent in 1962, then it retreated about 60 kilometers (38 miles) in the mid-1970s to a position that nearly matches the 2000 position. In fact, previous in-situ measurements indicate that the Shirase was at one time one of the fastest advancing glaciers in Antarctica. In comparison, adjacent areas to the northwest show current positions similar to both 1962 and 1997 coastlines, with significant retreat periods in the mid-1970s. The Antarctic Mapping Mission is a joint project between NASA and the Canadian Space Agency. The project is led by Ohio State University in Columbus in partnership with the Alaska Synthetic Aperture Radar (SAR) Facility at the University of Alaska Fairbanks, NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the Vexcel Corporation, Boulder, Colo. The Canadian Space Agency's RADARSAT-1 satellite carries a synthetic aperture radar, an imaging radar sensor that operates at C-band (5.3 GHz frequency) with horizontal transmit-horizontal receive polarization from an orbital altitude of about 800 kilometers (500 miles). The 1997 Antarctic Mapping Mission took place between Sept. 19 and Oct. 14 and mapped the entire Antarctic continent. The 2000 Antarctic Mapping Mission lasted from Sept. 3 to Nov. 4 and obtained complete coverage of Antarctica north of 82 degrees south latitude. Photo Credit: Canadian Space Agency/NASA/Ohio State University, Jet Propulsion Laboratory, Alaska SAR facility # # # # # |
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Shirase Glacier Region
The Shirase Glacier retreate
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2/20/01
| Date |
2/20/01 |
| Description |
The Shirase Glacier retreated significantly between the 1997 and 2000 Antarctic Mapping Missions. Located in the Indian Ocean sector of Antarctica called Enderby Land, the Shirase drains a basin of about 165,000 square kilometers (about 64 square miles), which extends some 500 kilometers (310 miles) inland from the coast. The glacier appears in the lower central portion of this image at the head of the embayment. As the blue coastline from the 1997 Antarctic Mapping Mission indicates, the floating tongue of the Shirase extended about 12 kilometers (7.5 miles) further northward from the current 2000 position. However, earlier coastline maps show that the extent of the Shirase is extremely variable. This image covers an area of about 375 kilometers (240 miles) by 240 kilometers (150 miles). Most of the image area offshore of the blue 1997 coastline is a mixture of bright-appearing icebergs and darker-appearing sea ice. The Antarctic Mapping Mission is a joint project between NASA and the Canadian Space Agency. The project is led by Ohio State University in Columbus in partnership with the Alaska Synthetic Aperture Radar (SAR) Facility at the University of Alaska Fairbanks, NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the Vexcel Corporation, Boulder, Colo. The Canadian Space Agency's RADARSAT-1 satellite carries a synthetic aperture radar, an imaging radar sensor that operates at C-band (5.3 GHz frequency) with horizontal transmit-horizontal receive polarization from an orbital altitude of about 800 kilometers (500 miles. The 1997 Antarctic Mapping Mission took place between Sept. 19 and Oct. 14 and mapped the entire Antarctic continent. The 2000 Antarctic Mapping Mission lasted from Sept. 3 to Nov. 4 and obtained complete coverage of Antarctica north of 82 degrees south latitude. Photo Credit: Canadian Space Agency/NASA/Ohio State University, Jet Propulsion Laboratory, Alaska SAR facility # # # # # |
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Lambert Glacier Velocity Map
This image shows the movemen
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2/20/01
| Date |
2/20/01 |
| Description |
This image shows the movement of the Lambert Glacier. The ice velocity vectors were obtained by using RADARSAT SAR imagery from the 2000 Antarctic Mapping Mission. Yellow represents the areas of no motion, which are either exposed land or stationary ice. The smaller confluent glaciers have generally low velocities, shown in green, of 100-300 meters (330-980 feet) per year, which gradually increase as they flow down the rapidly changing continental slope into the upper reaches of the faster flowing Lambert Glacier. Most of the Lambert Glacier itself has velocities between 400-800 meters (1,310-2,620 feet) per year, with a slight slowing in the middle section. As the glacier extends across Amery Ice Shelf, velocities increase to 1000-1200 meters (3,280-3,937 feet) per year as the ice sheet spreads out and thins. Only a handful of in-situ velocity measurements have been previously reported of this huge glacier system. While the in-situ and radar-derived measurements appear to be qualitatively similar, the extent and accuracy of the new measurements are unprecedented and provide quantitative baselines for future comparisons. The ice velocities are obtained from pairs of images obtained 24 days apart, using a technique called radar interferometry. This technique enables a highly precise alignment of image pairs that provides accurate measurements of topography as well as surfaces that have changed or moved over the short time interval, including glaciers. The Antarctic Mapping Mission is a joint project between NASA and the Canadian Space Agency. The project is led by Ohio State University in Columbus in partnership with the Alaska Synthetic Aperture Radar (SAR) Facility at the University of Alaska Fairbanks, NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the Vexcel Corporation, Boulder, Colo. The Canadian Space Agency's RADARSAT-1 satellite carries a synthetic aperture radar, an imaging radar sensor that operates at C-band (5.3 GHz frequency) with horizontal transmit-horizontal receive polarization from an orbital altitude of about 800 kilometers (500 miles). The 1997 Antarctic Mapping Mission took place between Sept. 19 and Oct. 14 and mapped the entire Antarctic continent. The 2000 Antarctic Mapping Mission lasted from Sept. 3 to Nov. 4 and obtained complete coverage of Antarctica north of 82 degrees south latitude. Photo Credit: Canadian Space Agency/NASA/Ohio State University, Jet Propulsion Laboratory, Alaska SAR facility # # # # # |
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Wordie Ice Shelf
The Wordie Ice Shelf, shown
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2/20/01
| Date |
2/20/01 |
| Description |
The Wordie Ice Shelf, shown in this sub-image of the Antarctic Peninsula from the 2000 Antarctic Mapping Mission, has been disintegrating since the 1960s with significant retreat during the 1990s through 2000. The yellow line represents the coastline in the mid-1970s and the blue line shows where the coast was in 1997. The Antarctic Mapping Mission is a joint project between NASA and the Canadian Space Agency. The project is led by Ohio State University in Columbus in partnership with the Alaska Synthetic Aperture Radar (SAR) Facility at the University of Alaska Fairbanks, NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the Vexcel Corporation, Boulder, Colo. The Canadian Space Agency's RADARSAT-1 satellite carries a synthetic aperture radar, an imaging radar sensor that operates at C-band (5.3 GHz frequency) with horizontal transmit-horizontal receive polarization from an orbital altitude of about 800 kilometers (500 miles). The 1997 Antarctic Mapping Mission took place between Sept. 19 and Oct. 14 and mapped the entire Antarctic continent. The 2000 Antarctic Mapping Mission lasted from Sept. 3 to Nov. 4 and obtained complete coverage of Antarctica north of 82 degrees south latitude. Photo Credit: Canadian Space Agency/NASA/Ohio State University, Jet Propulsion Laboratory, Alaska SAR facility # # # # # |
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Titan: Larger and Larger Lak
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| Description |
Titan: Larger and Larger Lakes |
| Full Description |
This radar image, obtained by Cassini's radar instrument during a near-polar flyby on Feb. 22, 2007, shows a big island smack in the middle of one of the larger lakes imaged on Saturn's moon Titan. This image offers further evidence that the largest lakes are at the highest latitudes. The island is about 90 kilometers (62 miles) by 150 kilometers (93 miles) across, about the size of Kodiak Island in Alaska or the Big Island of Hawaii. The island may actually be a peninsula connected by a bridge to a larger stretch of land. As you go farther down the image, several very small lakes begin to appear, which may be controlled by local topography. This image was taken in synthetic aperture mode at 700 meter (2,300 feet) resolution. North is toward the left. The image is centered at about 79 north degrees north and 310 degrees west. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov/home/index.cfm. Credit: NASA/JPL |
| Date |
February 27, 2007 |
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Alaskan Glacier Quakes
| title |
Alaskan Glacier Quakes |
| date |
08.02.2003 |
| description |
NASA and United States Geological Survey (USGS) scientists found that retreating glaciers in southern Alaska may be opening the way for future earthquakes. The study examined the likelihood of increased earthquake activity in southern Alaska as a result of rapidly melting glaciers. As glaciers melt they lighten the load on the Earth's crust. Tectonic plates, that are mobile pieces of the Earth's crust, can then move more freely, which increases the probability of earthquakes occurring in this region. |
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Chicxulub Crater
| title |
Chicxulub Crater |
| date |
01.24.1992 |
| description |
This is a computer-generated gravity map image of the Chicxulub Crater found on Mexico's Yucatan Peninsula. The buried impact structure has been implicated in the mass extinction of life 65 million years ago and may be much larger than scientists first suspected. New analyses of gravity measurements in the region have turned up evidence that the feature is a multiring basin with a fourth, outer ring about 300 kilometers in diameter. At this diameter, the Chixulub Basin represents one of the largest collisions in the inner solar system since the so-called "heavy bombardment" ended almost four billion years ago. (The period of heavy bombardment was caused by the impact of debris from the early formation of the solar system raining in on the newly formed planets.) The only comparable post-bombardment basin is the 280-kilometer-diameter Mead Basin on Venus. *Image Credit*: Virgil L. Sharpton, University of Alaska, Fairbanks |
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Icy Comet NEAT
| title |
Icy Comet NEAT |
| date |
05.07.2004 |
| description |
This image of Comet C/2001 Q4 (NEAT) was taken at the WIYN 0.9-meter telescope at Kitt Peak National Observatory near Tucson, AZ, on May 7, 2004. The image was taken with the Mosaic I camera, which has a one-square degree field of view, or about five times the size of the Moon. Even with this large field, only the comet's coma and the inner portion of its tail are visible. This color image was assembled by combining images taken through blue, green and red filters. A small star cluster (C0736-105, or Melotte 72) is visible in the lower right of the image, between the head of the comet and the bright red star in the lower-right corner. Comet C/2001 Q4 (NEAT) was discovered on August 24, 2001, by the Near Earth Asteroid Tracking (NEAT) system operated by NASA's Jet Propulsion Laboratory, Pasadena, CA. *Image Credit*: T. Rector (University of Alaska Anchorage), Z. Levay and L.Frattare (Space Telescope Science Institute) and National Optical Astronomy Observatory/Association of Universities for Research in Astronomy/National Science Foundation |
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Mapping the Amazon: Mosaic t
…
| Title |
Mapping the Amazon: Mosaic tiles animation |
| Abstract |
A satellite can cover the Amazon in just two months. The mapping team chose a Japanese satellite outfitted with synthetic aperture radar, or SAR for short. SAR is a natural fit for the Amazon. It can penetrate the clouds that pour rain for half of the year and the smoke from trees burned by farmers to clear land. SAR even works at night. As you might imagine, the satellite collects a pile of data. In raw form, these observations are gibberish. Focusing them requires a supercomputer to crunch fifteen hundred trillion calculations. The output is rich images of the Amazon. Scientists listed worked as a team on Mosaicking Software and Mosaic Production. |
| Completed |
2000-12-19 |
|
Mapping the Amazon: Mosaic t
…
| Title |
Mapping the Amazon: Mosaic tiles animation |
| Abstract |
A satellite can cover the Amazon in just two months. The mapping team chose a Japanese satellite outfitted with synthetic aperture radar, or SAR for short. SAR is a natural fit for the Amazon. It can penetrate the clouds that pour rain for half of the year and the smoke from trees burned by farmers to clear land. SAR even works at night. As you might imagine, the satellite collects a pile of data. In raw form, these observations are gibberish. Focusing them requires a supercomputer to crunch fifteen hundred trillion calculations. The output is rich images of the Amazon. Scientists listed worked as a team on Mosaicking Software and Mosaic Production. |
| Completed |
2000-12-19 |
|
Mapping the Amazon: Mosaic t
…
| Title |
Mapping the Amazon: Mosaic tiles animation |
| Abstract |
A satellite can cover the Amazon in just two months. The mapping team chose a Japanese satellite outfitted with synthetic aperture radar, or SAR for short. SAR is a natural fit for the Amazon. It can penetrate the clouds that pour rain for half of the year and the smoke from trees burned by farmers to clear land. SAR even works at night. As you might imagine, the satellite collects a pile of data. In raw form, these observations are gibberish. Focusing them requires a supercomputer to crunch fifteen hundred trillion calculations. The output is rich images of the Amazon. Scientists listed worked as a team on Mosaicking Software and Mosaic Production. |
| Completed |
2000-12-19 |
|
Mapping the Amazon: Deforest
…
| Title |
Mapping the Amazon: Deforestation |
| Abstract |
One feature that appears in this mosaic of images showing the Amazon River is tree-clearing that happened between two seasons. Scientists listed worked as a team on Mosaicking Software and Mosaic Production. |
| Completed |
2000-12-19 |
|
Mapping the Amazon: Deforest
…
| Title |
Mapping the Amazon: Deforestation |
| Abstract |
One feature that appears in this mosaic of images showing the Amazon River is tree-clearing that happened between two seasons. Scientists listed worked as a team on Mosaicking Software and Mosaic Production. |
| Completed |
2000-12-19 |
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Mapping the Amazon: Deforest
…
| Title |
Mapping the Amazon: Deforestation |
| Abstract |
One feature that appears in this mosaic of images showing the Amazon River is tree-clearing that happened between two seasons. Scientists listed worked as a team on Mosaicking Software and Mosaic Production. |
| Completed |
2000-12-19 |
|
Mapping the Amazon: Mosaic p
…
| Title |
Mapping the Amazon: Mosaic pan |
| Abstract |
Pan across Amazon rainforest mosaic showing low water season (blue) and high water season (yellow). Together, these snapshots reveal conditions on the ground. Scientists listed worked as a team on Mosaicking Software and Mosaic Production. |
| Completed |
2000-12-19 |
|
Mapping the Amazon: Mosaic p
…
| Title |
Mapping the Amazon: Mosaic pan |
| Abstract |
Pan across Amazon rainforest mosaic showing low water season (blue) and high water season (yellow). Together, these snapshots reveal conditions on the ground. Scientists listed worked as a team on Mosaicking Software and Mosaic Production. |
| Completed |
2000-12-19 |
|
Mapping the Amazon: Mosaic p
…
| Title |
Mapping the Amazon: Mosaic pan |
| Abstract |
Pan across Amazon rainforest mosaic showing low water season (blue) and high water season (yellow). Together, these snapshots reveal conditions on the ground. Scientists listed worked as a team on Mosaicking Software and Mosaic Production. |
| Completed |
2000-12-19 |
|
Mapping the Amazon: Mosaic p
…
| Title |
Mapping the Amazon: Mosaic pan |
| Abstract |
Pan across Amazon rainforest mosaic showing low water season (blue) and high water season (yellow). Together, these snapshots reveal conditions on the ground. Scientists listed worked as a team on Mosaicking Software and Mosaic Production. |
| Completed |
2000-12-19 |
|
Mapping the Amazon: Mosaic p
…
| Title |
Mapping the Amazon: Mosaic pan |
| Abstract |
Pan across Amazon rainforest mosaic showing low water season (blue) and high water season (yellow). Together, these snapshots reveal conditions on the ground. Scientists listed worked as a team on Mosaicking Software and Mosaic Production. |
| Completed |
2000-12-19 |
|
Mapping the Amazon: Mosaic p
…
| Title |
Mapping the Amazon: Mosaic pan |
| Abstract |
Pan across Amazon rainforest mosaic showing low water season (blue) and high water season (yellow). Together, these snapshots reveal conditions on the ground. Scientists listed worked as a team on Mosaicking Software and Mosaic Production. |
| Completed |
2000-12-19 |
|
Mapping the Amazon: The Mout
…
| Title |
Mapping the Amazon: The Mouth of the Amazon |
| Abstract |
The Amazon rain forest is the largest tropical forest in the world. It stretches across South America from nearly ocean to ocean. No seasonal view of this territory existed until a NASA-university collaboration began mapping the Amazon - from space. Scientists listed worked as a team on Mosaicking Software and Mosaic Production. |
| Completed |
2000-12-19 |
|
Mapping the Amazon: The Mout
…
| Title |
Mapping the Amazon: The Mouth of the Amazon |
| Abstract |
The Amazon rain forest is the largest tropical forest in the world. It stretches across South America from nearly ocean to ocean. No seasonal view of this territory existed until a NASA-university collaboration began mapping the Amazon - from space. Scientists listed worked as a team on Mosaicking Software and Mosaic Production. |
| Completed |
2000-12-19 |
|
Mapping the Amazon: The Mout
…
| Title |
Mapping the Amazon: The Mouth of the Amazon |
| Abstract |
The Amazon rain forest is the largest tropical forest in the world. It stretches across South America from nearly ocean to ocean. No seasonal view of this territory existed until a NASA-university collaboration began mapping the Amazon - from space. Scientists listed worked as a team on Mosaicking Software and Mosaic Production. |
| Completed |
2000-12-19 |
|
| Photo Description |
NASA JPL scientists Yunling Lou and Dr. Eric Rignot work on line selection while flying AirSAR missions over the Antarctic Peninsula. AirSAR 2004 is a three-week expedition in Central and South America by an international team of scientists that is using an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world are combining ground research with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. These photos are from the DC-8 aircraft while flying an AirSAR mission over Antarctica. The Antarctic Peninsula is more similar to Alaska and Patagonia than to the rest of the Antarctic continent. It is drained by fast glaciers, receives abundant precipitation, and melts significantly in the summer months. In recent decades, the Peninsula has experienced significant atmospheric warming (about 2 degrees C since 1950), which has triggered a vast and spectacular retreat of its floating ice shelves, glacier reduction, a decrease in permanent snow cover and a lengthening of the melt season. As a result, the contribution to sea level from this region could be rapid and substantial. With an area of 120,000 km, or ten times the Patagonia ice fields, the Peninsula could contribute as much as 0.4mm/yr sea level rise, which would be the largest single contribution to sea level from anywhere in the world. This region is being studied by NASA using a DC-8 equipped with the Airborne Synthetic Aperture Radar developed by scientists from NASA?s Jet Propulsion Laboratory. AirSAR will provide a baseline model and unprecedented mapping of the region. This data will make it possible to determine whether the warming trend is slowing, continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level. |
| Project Description |
AirSAR collects multi-frequency and multi-polarization radar data for a variety of science applications. It also acquires data in interferometric modes, providing topographic information (cross-track mode) or ocean current information (along-track interferometry). This March 2004 deployment was planned to: * Study the extent and distribution of archeological Mayan civilization (using foliage-penetrating radar) * Study the glaciers of Patagonia and the Antarctic peninsula * Investigate new techniques for the measurement of the forest structure of dense tropical forests * Fill in the largest "void" in the SRTM-derived map of South American topography * Collect additional data for various research initiatives During the deployment data is collected over Central and South America and Antarctica. During the approximately 100 flight hours, AirSAR is acquiring polarimetric and/or interferometric data along a 20,000 km track, or about 200,000 sq. km of data over 40 sites for 30 scientists. AirSAR will collect data related to the following NASA Code YS science programs: * Cryospheric Science * Land Cover/Land Use Change * Natural Hazards * Physical Oceanography * Terrestrial Ecology * Hydrology NASA used a DC-8 aircraft as a flying science laboratory. The platform aircraft, was based at NASA's Dryden Flight Research Center, Edwards, Calif., collected data for many experiments in support of scientific projects serving the world scientific community. Included in this community were NASA, federal, state, academic and foreign investigators. Data gathered by the DC-8 at flight altitude and by remote sensing has been used for scientific studies in archeology, ecology, geography, hydrology, meteorology, oceanography, volcanology, atmospheric chemistry, soil science and biology. |
| Photo Date |
March 16, 2004 |
|
Deadly Earthquake, Xianjing
…
| Title |
Deadly Earthquake, Xianjing Province, China |
| Description |
A destructive earthquake of magnitude 6.4 rattled China?s Xinjiang province at 10:04 AM (local time) on February 24, 2003. Over 250 people were killed. This remote, flat, and mostly featureless area of western China (called the Tarim Basin by geologists) is different from most other regions with frequent earthquakes. Typical seismically active areas are mountainous, like Alaska and coastal California, and lie along the boundaries of tectonic plates. In contrast, the Tarim Basin (which lies on the Eurasian Plate) remains flat while it is being squeezed by the motion of the Indian Plate?which is 1000 km (620 miles) away. Instead of deforming into belts of mountain ranges, the Tarim Basin is transmitting force applied by the Indian Plate to the interior of Asia, where the Tian Shan mountains are rising. The Tian Shan can be seen at the top edge of the large image. The approximate epicenter of the earthquake is represented by a white dot in this image, acquired on August 29, 2001, (before the earthquake) by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). ASTER is an instrument aboard NASA's Terra [ http://terra.nasa.gov/ ] satellite. The false-color image combines near-infrared, red, and green wavelengths. Crops, almost certainly irrigated, appear red in this scene, while barren landscape appears brown. Image courtesy NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://asterweb.jpl.nasa.gov/ ] |
|
Ice Surge in Barrow, Alaska
| Title |
Ice Surge in Barrow, Alaska |
| Description |
Like a frozen tsunami, large blocks of sea ice crashed ashore in the town of Barrow, Alaska, on January 23 and 24, 2006, according to a report from the Associated Press. Driven by fierce Arctic winds and strong eastward currents, the ice surged ashore in "car-sized blocks." This pair of radar images of northern Alaska on January 1 and 24, 2006, shows the movement of the sea ice southward and onto the shore at Point Barrow. The observations were collected by a radar on NASA's QuikSCAT [ http://winds.jpl.nasa.gov/missions/quikscat/index.cfm ] satellite. On January 1, a thin strip of open water (dark area) separates the sea ice (across the top of the images) from the Alaska coast. By January 24, the sea ice had moved south and east, closing the small gap and climbing onto shore. The animations are based on daily images from January 1-30, 2006. Images provided by Dr. David Long, Brigham Young University Center for Remote Sensing. |
|
Ice Surge in Barrow, Alaska
| Title |
Ice Surge in Barrow, Alaska |
| Description |
Like a frozen tsunami, large blocks of sea ice crashed ashore in the town of Barrow, Alaska, on January 23 and 24, 2006, according to a report from the Associated Press. Driven by fierce Arctic winds and strong eastward currents, the ice surged ashore in "car-sized blocks." This pair of radar images of northern Alaska on January 1 and 24, 2006, shows the movement of the sea ice southward and onto the shore at Point Barrow. The observations were collected by a radar on NASA's QuikSCAT [ http://winds.jpl.nasa.gov/missions/quikscat/index.cfm ] satellite. On January 1, a thin strip of open water (dark area) separates the sea ice (across the top of the images) from the Alaska coast. By January 24, the sea ice had moved south and east, closing the small gap and climbing onto shore. The animations are based on daily images from January 1-30, 2006. Images provided by Dr. David Long, Brigham Young University Center for Remote Sensing. |
|
Ice Surge in Barrow, Alaska
| Title |
Ice Surge in Barrow, Alaska |
| Description |
Like a frozen tsunami, large blocks of sea ice crashed ashore in the town of Barrow, Alaska, on January 23 and 24, 2006, according to a report from the Associated Press. Driven by fierce Arctic winds and strong eastward currents, the ice surged ashore in "car-sized blocks." This pair of radar images of northern Alaska on January 1 and 24, 2006, shows the movement of the sea ice southward and onto the shore at Point Barrow. The observations were collected by a radar on NASA's QuikSCAT [ http://winds.jpl.nasa.gov/missions/quikscat/index.cfm ] satellite. On January 1, a thin strip of open water (dark area) separates the sea ice (across the top of the images) from the Alaska coast. By January 24, the sea ice had moved south and east, closing the small gap and climbing onto shore. The animations are based on daily images from January 1-30, 2006. Images provided by Dr. David Long, Brigham Young University Center for Remote Sensing. |
|
Ice Types in the Beaufort Se
…
| Title |
Ice Types in the Beaufort Sea, Alaska |
| Description |
browse image, of orbit 6663 (420 KB JPEG) Determining the amount and type of sea ice in the polar oceans is crucial to improving our knowledge and understanding of polar weather and long term climate fluctuations. These views from two satellite remote sensing instruments, the synthetic aperture radar (SAR) on board the RADARSAT satellite and the Multi-angle Imaging SpectroRadiometer (MISR), illustrate different methods that may be used to assess sea ice type. Sea ice in the Beaufort Sea off the north coast of Alaska was classified and mapped in these concurrent images acquired March 19, 2001 and mapped to the same geographic area. To identify sea ice types, the National Oceanic and Atmospheric Administration (NOAA) National Ice Center constructs ice charts using several data sources including RADARSAT SAR images such as the one shown at left. SAR classifies sea ice types primarily by how the surface and subsurface roughness influence radar backscatter. In the SAR image, white lines delineate different sea ice zones as identified by the National Ice Center. Regions of mostly multiyear ice (A) are separated from regions with large amounts of first year and younger ice (B-D), and the dashed white line at bottom marks the coastline. In general, sea ice types that exhibit increased radar backscatter appear bright in SAR and are identified as rougher, older ice types. Younger, smoother ice types appear dark to SAR. Near the top of the SAR image, however, red arrows point to bright areas in which large, crystalline "frost flowers" have formed on young, thin ice, causing this young ice type to exhibit an increased radar backscatter. Frost flowers are strongly backscattering at radar wavelengths (cm) due to both surface roughness and the high salinity of frost flowers, which causes them to be highly reflective to radar energy. Surface roughness is also registered by MISR, although the roughness observed is at a different spatial scale. Older, rougher ice areas are predominantly backward scattering to the MISR cameras, whereas younger, smoother ice types are predominantly forward scattering. The MISR map at right was generated using a statistical classification routine (called ISODATA) and analyzed using ice charts from the National Ice Center. Five classes of sea ice were found based upon the classification of MISR angular data. These are described, based on interpretation of the SAR image, by the image key. Very smooth ice areas that are predominantly forward scattering are colored red. Frost flowers are largely smooth to the MISR visible band sensor and are mapped as forward scattering. Areas mapped as blue are predominantly backward scattering, and the other three classes have statistically distinct angular signatures and fall within the middle of the forward/backward scattering continuum. Some areas that may be first year or younger ice between the multi year ice floes are not discernible to SAR, illustrating how MISR potentially can make a unique contribution, to sea ice mapping. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. The MISR Browse Image Viewer [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://eosweb.larc.nasa.gov/MISRBR/ ] provides access to low-resolution true-color versions of these images. This data product was generated from a portion of the imagery acquired during Terra orbit 6663. The MISR image has been cropped to include an area that is 200 kilometers wide, and utilizes data from blocks 30 to 33 within World Reference System-2 path 71. Image courtesy NASA/GSFC/LaRC/JPL, MISR Team. [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://www-misr.jpl.nasa.gov/ ] RADARSAT image courtesy NOAA Satellite Active Archive. Figure reprinted courtesy of IEEE. |
|
Ice Types in the Beaufort Se
…
| Title |
Ice Types in the Beaufort Sea, Alaska |
| Description |
browse image, of orbit 6663 (420 KB JPEG) Determining the amount and type of sea ice in the polar oceans is crucial to improving our knowledge and understanding of polar weather and long term climate fluctuations. These views from two satellite remote sensing instruments, the synthetic aperture radar (SAR) on board the RADARSAT satellite and the Multi-angle Imaging SpectroRadiometer (MISR), illustrate different methods that may be used to assess sea ice type. Sea ice in the Beaufort Sea off the north coast of Alaska was classified and mapped in these concurrent images acquired March 19, 2001 and mapped to the same geographic area. To identify sea ice types, the National Oceanic and Atmospheric Administration (NOAA) National Ice Center constructs ice charts using several data sources including RADARSAT SAR images such as the one shown at left. SAR classifies sea ice types primarily by how the surface and subsurface roughness influence radar backscatter. In the SAR image, white lines delineate different sea ice zones as identified by the National Ice Center. Regions of mostly multiyear ice (A) are separated from regions with large amounts of first year and younger ice (B-D), and the dashed white line at bottom marks the coastline. In general, sea ice types that exhibit increased radar backscatter appear bright in SAR and are identified as rougher, older ice types. Younger, smoother ice types appear dark to SAR. Near the top of the SAR image, however, red arrows point to bright areas in which large, crystalline "frost flowers" have formed on young, thin ice, causing this young ice type to exhibit an increased radar backscatter. Frost flowers are strongly backscattering at radar wavelengths (cm) due to both surface roughness and the high salinity of frost flowers, which causes them to be highly reflective to radar energy. Surface roughness is also registered by MISR, although the roughness observed is at a different spatial scale. Older, rougher ice areas are predominantly backward scattering to the MISR cameras, whereas younger, smoother ice types are predominantly forward scattering. The MISR map at right was generated using a statistical classification routine (called ISODATA) and analyzed using ice charts from the National Ice Center. Five classes of sea ice were found based upon the classification of MISR angular data. These are described, based on interpretation of the SAR image, by the image key. Very smooth ice areas that are predominantly forward scattering are colored red. Frost flowers are largely smooth to the MISR visible band sensor and are mapped as forward scattering. Areas mapped as blue are predominantly backward scattering, and the other three classes have statistically distinct angular signatures and fall within the middle of the forward/backward scattering continuum. Some areas that may be first year or younger ice between the multi year ice floes are not discernible to SAR, illustrating how MISR potentially can make a unique contribution, to sea ice mapping. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. The MISR Browse Image Viewer [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://eosweb.larc.nasa.gov/MISRBR/ ] provides access to low-resolution true-color versions of these images. This data product was generated from a portion of the imagery acquired during Terra orbit 6663. The MISR image has been cropped to include an area that is 200 kilometers wide, and utilizes data from blocks 30 to 33 within World Reference System-2 path 71. Image courtesy NASA/GSFC/LaRC/JPL, MISR Team. [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://www-misr.jpl.nasa.gov/ ] RADARSAT image courtesy NOAA Satellite Active Archive. Figure reprinted courtesy of IEEE. |
|
Islands of the Four Mountain
…
| Title |
Islands of the Four Mountains |
| Description |
In the northern Pacific Ocean off the southwest coast of Alaska, the planet is building new land. Arcing southwestward from Alaska like the tail of a kite, the Aleutian Islands are a string of active and dormant volcanoes fed by magma created by the collision of the Pacific Plate with the North American Plate. [ http://geology.er.usgs.gov/eastern/plates.html ] In the northeast part of the range, a cluster of summits known as the Islands of the Four Mountains is home to Cleveland Volcano, one of the Aleutians' most frequently active volcanoes. This image of the central part of the Islands of the Four Mountains group was captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) [ http://asterweb.jpl.nasa.gov ] on NASA's Terra [ http://terra.nasa.gov ] satellite on July 27, 2007. In the center of the image, Cleveland Volcano is connected to Chuginadak Volcano by a thin strip of land that appears to be barely above sea level in places. Together these mountains make up Chuginadak Island. Vegetation on the lower slopes of the mountains is bright green, while bare rock is charcoal-colored. Even so late in the summer, snow streaks the summits. Although no ash clouds or fresh lava flows are visible, more subtle signs of recent activity at Cleveland Volcano do exist. A close-up view of the summit (lower image) shows a cloud that aerial photography confirmed was a steam plume. The other obvious sign of recent activity is the near absence of snow on the mountain. Cleveland's slopes are almost completely bare, while neighboring summitsall of which are lower in elevationare capped with snow. Heat from the volcano frequently melts the snow pack on Cleveland. Scientists at the Alaska Volcano Observatory [ http://www.avo.alaska.edu/ ] keep track of activity in the Aleutian Islands for scientific and practical purposes: ash eruptions can create hazards for airplanes, which frequently pass through the area on their way from North America to Asia and Europe. The scientists use a combination of seismic data, Webcams, field visits, aerial photography, and satellite observations to do their jobs. At the time it captured this image, ASTER also collected thermal infrared data (not pictured) that documented that the crater was still warm (41 degrees Celsius, or 106 Fahrenheit) when Terra passed overhead. You can download a 15-meter-resolution KMZ file of the Islands of the Four Mountains [ http://earthobservatory.nasa.gov/Newsroom/NewImages/Images/aleutians_ast_2007178.kmz ] suitable for use with Google Earth. [ http://earth.google.com/ ] NASA image created by Jesse Allen, using data provided courtesy of NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. [ http://asterweb.jpl.nasa.gov/ ] |
|
Eruption on Augustine Island
…
| Title |
Eruption on Augustine Island, Alaska |
| Description |
Hot pyroclastic flows (avalanches of hot ash, pumice, rock and volcanic gas) poured down the side of the Augustine Volcano in the early hours of February 1, 2006, when the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) [ http://asterweb.jpl.nasa.gov/ ] took this image. This nighttime view of the volcano shows the eruption in terms of heat from the thermal infrared part of the electromagnetic spectrum. The hot flows glow white in contrast to the cold, snow-covered land surrounding them. Ash and steam rise from the volcano, the ash tinting the plume grey-blue. Around Augustine Island, the ocean is warmer than the land surface and so appears white, while clouds are a dingy white and grey. Sitting in Cook Inlet of southern Alaska, the Augustine volcano is the most active volcano in the Eastern Aleutian arc. According to the Global Volcanism Program [ http://www.volcano.si.edu ], explosive activity at the volcano began on January 11, 2006. Hourly updates on the eruption are available from the Alaska Volcano Observatory [ http://www.avo.alaska.edu/activity/Augustine.php ]. NASA image created by Jesse Allen, Earth Observatory, using data obtained courtesy of the NASA/GSFC/METI/ERSDAC/JAROS and U.S./Japan ASTER Science Team |
|
Eruption on Augustine Island
…
| Title |
Eruption on Augustine Island, Alaska |
| Description |
Alaska's Augustine Volcano started 2006 with a bang, producing explosive eruptions in mid-January. The volcano had quieted by March 2006, although the Alaska Volcano Observatory (AVO) [ http://www.avo.alaska.edu/activity/Augustine.php ] warned that explosive eruptions could still occur at any time. The volcano continued a fairly similar behavior pattern in April. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) [ http://asterweb.jpl.nasa.gov ] on NASA 's Terra [ http://terra.nasa.gov ] satellite captured this image on April 18, 2006. According to the AVO, Augustine's seismic activity jumped that day. The volcano continued its customary steam plume, and light winds allowed the plume to rise directly above the summit about 300 to 600 meters (1,000 to 2,000 feet). This image shows the steam plume flowing from the summit in the south. The cloudy form to the north could be cloud, or a steam plume from the volcano's pyroclastic flow depositshot rock fragments and ash. Augustine Volcano is considered the most active volcano in the eastern Aleutian arc. Its biggest historical eruption occurred in 1883 when the volcano's dome collapsed. The volcano erupted again in 1986, producing an avalanche of ash, rock fragments, and gas. Augustine's activity spans a longer time span than historical records cover, and its oldest dated volcanic rocks are more than 40,000 years old. NASA image created by Jesse Allen, Earth Observatory, using data obtained courtesy of the NASA/GSFC/METI/ERSDAC/JAROS and U.S./Japan ASTER Science Team. |
|
October Skylights
| Title |
October Skylights |
| Explanation |
With brilliant Venus [ http://nssdc.gsfc.nasa.gov/planetary/factsheet/ venusfact.html ] above the western horizon at sunset and Jupiter [ http://galileo.jpl.nasa.gov/ ] and Saturn [ http://www.jpl.nasa.gov/cassini/ ] high in the east by early evening, November's night sky is filled with bright planets. October's sky featured bright planets as well and, triggered by the active Sun, some lovely auroral displays [ http://www.exploratorium.edu/learning_studio/ auroras/ ]. This colorful aurora was recorded by astrophotographer Wade Clark in skies above Hamilton, Washington, USA on the night of October 4th. Through the shimmering northern lights [ http://climate.gi.alaska.edu/Curtis/aurora/ aurora.html ] Jupiter and Saturn are easy to spot [ http://antwrp.gsfc.nasa.gov/apod/ap000929.html ] flanking the V-shaped head of Taurus [ http://server.remc12.k12.mi.us/csplanet/myth/ taurus.html ] the Bull. Of course, just above lies the lovely Pleiades star cluster. Solar activity [ http://spaceweather.com/ ] will also produce auroral shows in November, particularly at high northern and southern latitudes. Plus, November skygazers can certainly anticipate a celestial performance on the evening of the 17th/18th -- the moonlit Leonid meteor shower [ http://spacescience.com/headlines/y2000/ast10oct_1.htm ]. |
|
Comet and Aurora Over Alaska
| Title |
Comet and Aurora Over Alaska |
| Explanation |
Can you spot the comet? Flowing across the frozen Alaskan [ http://www.state.ak.us/ ] landscape is an easily visible, colorful aurora. Just to the lower left, however, well in the background, is something harder to spot: Comet Ikeya-Zhang [ http://cometography.com/lcomets/2002c1.html ], the brightest comet of recent years. Although the aurora [ http://www.geo.mtu.edu/weather/aurora/ ] faded in minutes, the comet [ http://cfa-www.harvard.edu/cfa/ps/icq/CometMags.html#2002C1 ] is just now beginning to fade [ http://cfa-www.harvard.edu/iau/Ephemerides/Comets/2002C1.html ]. It remains just barely visible [ http://encke.jpl.nasa.gov/ ] without aid, however, before sunrise in the East. The comet is actually a giant dirt-covered snowball [ http://antwrp.gsfc.nasa.gov/apod/ap010926.html ] that spends most of its time in the outer Solar System [ http://antwrp.gsfc.nasa.gov/apod/ap020214.html ] -- to where it is now returns. The above photograph [ http://science.nasa.gov/spaceweather/comets/gallery_iz_pg7.html ] was taken on March 20 when Comet Ikeya-Zhang [ http://antwrp.gsfc.nasa.gov/apod/ap020318.html ] was near its brightest. Careful inspection of the photo will uncover several other sky delights, including the giant galaxy M31 [ http://antwrp.gsfc.nasa.gov/apod/ap991114.html ]. |
|
A Dust Devil on Mars
| Title |
A Dust Devil on Mars |
| Explanation |
Does the surface of Mars [ http://www.nineplanets.org/mars.html ] change? When inspecting yearly images of the Martian surface [ http://antwrp.gsfc.nasa.gov/apod/ap020827.html ] taken by the robot spacecraft Mars Global Surveyor [ http://mars.jpl.nasa.gov/mgs/overvu/overview.html ] currently orbiting Mars [ http://antwrp.gsfc.nasa.gov/apod/mars.html ], sometimes new dark trails [ http://antwrp.gsfc.nasa.gov/apod/ap000317.html ] are visible. Although originally a mystery, the culprit is now usually known to be a dust devil [ http://mars.jpl.nasa.gov/gallery/duststorms/ ], a huge swirling gas-cloud with similarities to a terrestrial tornado. Pictured above [ http://www.msss.com/mars_images/moc/8_2002_releases/dustdevil/ ], a recent image has not only captured a new dark trail but the actual dust devil [ http://www.gi.alaska.edu/ScienceForum/ASF2/227.html ] itself climbing a crater wall [ http://antwrp.gsfc.nasa.gov/apod/ap000626.html ]. Dust devils [ http://www.aspsky.org/mercury/mercury/0002/carr1.html ] are created when Martian air [ http://www.pbs.org/saf/1109/features/mars.htm ] is heated by a warm surface and begins to spin as it rises. Dust devils [ http://nssdc.gsfc.nasa.gov/planetary/marspath/dustdevil.html ] can stretch 8 kilometers high but usually last only a few minutes. |
|
Mercury And The Moon
| Title |
Mercury And The Moon |
| Explanation |
Mercury is [ http://nssdc.gsfc.nasa.gov/planetary/factsheet/mercuryfact.html ] the closest planet to the Sun and never moves far from our parent star in Earth's sky [ http://space.jpl.nasa.gov/ ]. Racing around its tight orbit, this well-done world is a little over 1/3 the diameter of Earth and is often lost to our view [ http://www.seds.org/nineplanets/nineplanets/see.html ] in the solar glare. But, just one day before the August 11 total solar eclipse [ http://www.exploratorium.edu/eclipse/personal_accounts.html ], astronomer Tunc Tezel captured this fleeting view of a close conjunction of Mercury and the soon to be silhouetted Moon [ http://antwrp.gsfc.nasa.gov/apod/ap990818.html ] as seen from Turkey. Mercury at [ http://antwrp.gsfc.nasa.gov/apod/ap980906.html ] the lower right shines brightly in reflected sunlight while only a thin crescent of the almost new Moon is [ http://www.inconstantmoon.com/index.htm ] directly illuminated. The rest of the lunar nearside is faintly visible though, illuminated by light [ http://www.gi.alaska.edu/ScienceForum/ASF11/1191.html ] from an almost full Earth [ http://space.jpl.nasa.gov/cgi-bin/wspace?tbody=3&vbody=103&month=8&day=10¢ury=19&decade=9&year=9&hour=00&minute=0&rfov=30&fovmul=-1&bfov=30 ]. On Monday, November 15th, Mercury will [ http://sunearth.gsfc.nasa.gov/eclipse/OH/transit99.html ] actually be seen to transit or pass across the disk of the Sun for well placed observers in the pacific hemisphere. |
|
Southern Hemisphere Polygona
…
| title |
Southern Hemisphere Polygonal Patterned Ground |
| Description |
On Earth, "periglacial" is a term that refers to regions and processes where cold climate contributes to the evolution of landforms and landscapes. Common in periglacial environments on Earth, such as the arctic of northern Canada, Siberia, and Alaska, is a phenomenon called "patterned ground". The "patterns" in "patterned ground" often take the form of large polygons, each bounded by either troughs or ridges made up of rock particles different in size from those seen in the interior of the polygon. On Earth, many polygons in periglacial environments are directly linked to water: they typically form from stresses induced by repeated freezing and thawing of water, contraction from stress induced by changing temperatures, and sorting of rocks brought to the surface along polygon boundaries by the freeze-thaw processes. Although not exclusively formed by freezing and thawing of water, that is often the dominant mechanism on Earth. Polygons similar to those found in Earth's arctic and antarctic regions are also found in the polar regions of Mars. Typically, they occur on crater floors, or on intercrater plains, between about 60° and 80° latitude. The polygons are best seen when bright frost or dark sand has been trapped in the troughs that form the polygon boundaries. Three examples of martian polygons seen by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) are shown here. Each is located in the southern hemisphere: (a) Polygon troughs highlighted by frost as the south polar cap retreats during spring. The circular features are the locations of buried craters that were originally formed by meteor impact. This image, E09-00029, is located at 75.1°S, 331.3°W, and was acquired on 1 October 2001. (b) Summertime view of polygons, highlighted by dark, windblown sand, on the floor of a crater at 71.2°S, 282.6°W. The image, E12-02319, was obtained on 21 January 2002. (c) Polygon troughs highlighted by the retreating south polar frost cap during southern summer near 80.7°S, 70.4°W. This picture, M11-01795, was taken by MOC on 13 January 2000. Some Mars researchers assume that polygons on the Red Planet are key indictors that ground ice is present or was present in the recent past. However, whether these polygons actually required water ice to form is, in fact, unknown, since dry processes are also known on Earth for form similar polygons. Photo Credit: NASA/JPL/Malin Space Science Systems |
|
NASA Radar Gives Fresh Look
…
nasa, nasaimageofthedaygalle
…
A NASA mission to study Alas
…
airsar_alaska_0918
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2001 |
| creator |
NASA -- Images courtesy AirSAR, the Alaska Synthetic Aperture Radar Facility, and JPL |
| identifier |
airsar_alaska_0918 |
|
Still Waiting for El Nino: I
…
nasa, nasaimageofthedaygalle
…
The Pacific Ocean doesn't sh
…
topex_20020614
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2002-06-14 |
| creator |
NASA -- Image courtesy NASA/JPL sealevel.jpl.nasa.gov/ Topex and Jason Team |
| identifier |
topex_20020614 |
|
Strong, Long-Lasting La Nina
…
nasa, nasaimageofthedaygalle
…
After dominating the tropica
…
topex_june_la_nina
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2000-06-09 |
| creator |
NASA -- Image courtesy NASA Jet Propulsion Lab |
| identifier |
topex_june_la_nina |
|
La Nina and Pacific Decadal
…
nasa, nasaimageofthedaygalle
…
A cool-water anomaly known a
…
sst_anomaly_AMSRE_2008105
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2008 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
sst_anomaly_AMSRE_2008105 |
|
|
