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Fires Across Alaska
| Title |
Fires Across Alaska |
| Description |
In the third week of August 2005, an area of high atmospheric pressure built up over Alaska. Large areas of high pressure often lead to calm weather, with light (or absent) surface winds. Unfortunately for Alaska residents, the high pressure system that parked over the state coincided with a period of significant fire activity, with more than a hundred forest fires churning out thick smoke. For several days the smoke piled up over the Interior leading to hazardous-air-quality warnings for many areas. This pair of images from the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite shows smoke measurements over Alaska and western Canada on August 15 (top) and August 21 (bottom). (The background for the image is NASA's Blue Marble. [ http://visibleearth.nasa.gov/view_rec.php?id=2429 ]) Increasing amounts of smoke are shown as an aerosol index with shades of blue (little or no smoke) to dull red (thick smoke). On August 15, a large mass of smoke had drifted westward over the Interior and spread out over the Bering Sea toward Russia. Less than a week later, the weather patterns shifted and the smoke blew to the east and north, over Yukon Territory in western Canada and over Victoria Island toward the Arctic Ocean. Smoke contains many substances, including carbon dioxide, carbon monoxide, water vapor, and particulate matter. OMI measures smoke by tracking black carbon particles, or soot, that absorb ultraviolet (UV) radiation, the wavelengths of sunlight that cause sunburns. By measuring how much UV radiation the soot absorbs, OMI provides estimates of the amount of black carbon aerosol in the smoke layer. This method of detecting aerosols based on their interaction with UV rather than visible (rainbow) light allows OMI to measure absorption by black carbon in smoke even if the smoke is mixed with or floating above clouds. Measurements of how much radiation aerosols absorb are important for scientists trying to calculate the net effect of aerosols on Earth's energy budget and climate. OMI was added to NASA's Aura satellite as part of a collaboration between the Netherlands Agency for Aerospace Programs and the Finnish Meteorological Institute. The sensor tracks global ozone change and monitors aerosols and pollution in the atmosphere. NASA image and caption information courtesy the OMI Science Team. |
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Fires Across Alaska
| Title |
Fires Across Alaska |
| Description |
In the third week of August 2005, an area of high atmospheric pressure built up over Alaska. Large areas of high pressure often lead to calm weather, with light (or absent) surface winds. Unfortunately for Alaska residents, the high pressure system that parked over the state coincided with a period of significant fire activity, with more than a hundred forest fires churning out thick smoke. For several days the smoke piled up over the Interior leading to hazardous-air-quality warnings for many areas. This pair of images from the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite shows smoke measurements over Alaska and western Canada on August 15 (top) and August 21 (bottom). (The background for the image is NASA's Blue Marble. [ http://visibleearth.nasa.gov/view_rec.php?id=2429 ]) Increasing amounts of smoke are shown as an aerosol index with shades of blue (little or no smoke) to dull red (thick smoke). On August 15, a large mass of smoke had drifted westward over the Interior and spread out over the Bering Sea toward Russia. Less than a week later, the weather patterns shifted and the smoke blew to the east and north, over Yukon Territory in western Canada and over Victoria Island toward the Arctic Ocean. Smoke contains many substances, including carbon dioxide, carbon monoxide, water vapor, and particulate matter. OMI measures smoke by tracking black carbon particles, or soot, that absorb ultraviolet (UV) radiation, the wavelengths of sunlight that cause sunburns. By measuring how much UV radiation the soot absorbs, OMI provides estimates of the amount of black carbon aerosol in the smoke layer. This method of detecting aerosols based on their interaction with UV rather than visible (rainbow) light allows OMI to measure absorption by black carbon in smoke even if the smoke is mixed with or floating above clouds. Measurements of how much radiation aerosols absorb are important for scientists trying to calculate the net effect of aerosols on Earth's energy budget and climate. OMI was added to NASA's Aura satellite as part of a collaboration between the Netherlands Agency for Aerospace Programs and the Finnish Meteorological Institute. The sensor tracks global ozone change and monitors aerosols and pollution in the atmosphere. NASA image and caption information courtesy the OMI Science Team. |
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Northwest Passage Open
| Title |
Northwest Passage Open |
| Description |
Although nearly open, the Northwest Passage was not necessarily easy to navigate in August 2007. Located 800 kilometers (500 miles) north of the Arctic Circle and less than 1,930 kilometers (1,200 miles) from the North Pole, this sea route poses significant challenges, and the severe depletion of sea ice means only one of these is reduced. Nevertheless, long-term opening of the passage would have global impacts on trade and natural resource use. You can download a 250-meter-resolution KMZ file of the Northwest Passage [ http://earthobservatory.nasa.gov/NaturalHazards/Archive/Aug2007/nwpassage_amo_2007241.kmz ] suitable for use with Google Earth. [ http://earth.google.com/ ] NASA image created by Jesse Allen, using data obtained from the Goddard Land Processes data archives (LAADS). [ http://laads.gsfc.nasa.gov/ ] Thanks to Walt Meier, NSIDC, U.S. National Ice Center, and John Falkingham, Environment Canada - Canadian Ice Service for image interpretation., For over 500 years, Arctic explorers have sought a passage between the North Atlantic and Pacific Oceans. Such a passage, often called the Northwest Passage, would connect Europe to Asia via shorter routes than the long voyage south around Africa. In 1497, English King Henry VII sent Italian explorer John Cabot to look for this hypothetical route and expeditions from some of the most famous explorers in the centuries that followed—Sir Francis Drake and Captain James Cook among them—met with failure. The combined efforts of a number of explorers eventually uncovered a winding path from the Atlantic to the Arctic and Pacific Oceans through the ice-bound islands of northern Canada. Even in modern times, navigating from the Atlantic to the Pacific through Canada's Arctic islands has been difficult. The summer of 2007, however, melted enough sea ice in Canada's far north to open up this long-sought passage. This image shows the islands north of mainland Canada adjacent to Greenland, as observed by the the Moderate Resolution Imaging Spectroradiometer (MODIS) [ http://modis.gsfc.nasa.gov/ ] flying on NASA's Aqua [ http://aqua.nasa.gov/ ] satellite on August 29, 2007. While the usual veil of clouds over the Arctic is visible through the scene, the sea ice pack that normally covers the water between the islands is absent. Areas often choked with ice at this time of year, but free of it in this MODIS scene, include the Parry and McClintock Channels and the McClure Strait. Larsen Sound and Victoria Strait are hidden beneath cloud cover, but they are also largely free of sea ice. [ http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17752 ] This provided a nearly ice-free connection between Baffin Bay (a long body of water between Canada's Baffin Island and Greenland that is regularly ice-free in summer) and the Arctic Ocean. An ice-free gap between the North American mainland and the Arctic sea, not shown here, extends all the way to the Bering Strait between Alaska and Russia, creating a connection almost free of all sea ice from the North Atlantic to the North Pacific. Multi-year ice (ice that survives more than one melt season) tends to be thicker and more resistant to melt than first-year ice (formed over just one winter). According to John Falkingham of the Canadian Ice Service, most of the multi-year ice melted from Victoria Strait and McClintock Channel in the summer of 2006, leaving these traditionally difficult areas more open. In mid-August 2007, only patchy areas of ice filled Victoria Strait and Larsen Sound. Falkingham described the Northwest Passage as "nearly open." Changes in the Northwest Passage were part of a larger pattern of melt in 2007 that also affected the East Siberian Sea. [ http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17743 ] |
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Ward Hunt Ice Shelf
| Title |
Ward Hunt Ice Shelf |
| Description |
The Arctic?s largest ice shelf is breaking up. The Ward Hunt Ice Shelf is a remnant of the compacted snow and ancient sea ice that extended along the northern shores of Ellesmere Island in Northern Canada until the early twentieth century. Rising temperatures have reduced the original shelf into a number of smaller shelves, the largest of which was the Ward Hunt Ice Shelf on the northwest fringe of the island. The Ward Hunt Ice Shelf encompasses Ward Hunt Island and covers the mouth of the Disraeli Fiord. Until recently, fresh melt water formed a 43-meter deep lake on top of almost 400 meters of seawater in the fiord. Called an epishelf lake, the relatively fresh water dammed by the 3000-year-old ice shelf became the basis of a rare ecosystem. Disraeli Fiord was the largest remaining epishelf lake in the Northern Hemisphere. Between 2000 and 2002, the Ward Hunt Ice Shelf began to crack and eventually broke in two, allowing the lake behind it to drain rapidly into the Arctic Ocean. Derek Mueller and Warwick Vincent, of the Centre d?études nordiques at Université Laval in Quebec, Canada and Martin Jeffries of the Geophysical Institute at the University of Alaska Fairbanks in Fairbanks, Alaska described the event in a paper published in Geophysical Research Letters [ http://dx.doi.org/10.1029/2003GL017931 ] on October 18, 2003. This Standard Beam Mode RADARSAT-1 image clearly shows a large crack dividing the ice shelf in half. The crack runs from the Arctic Sea to the right of Ward Hunt Island and the bright white ice grounded there and back to the rougher, mountainous region. The image, acquired September 27, 2003, has a resolution of 25 meters. Image courtesy RADARSAT International [ http://www.rsi.ca/home.htm ]. RADARSAT-1 data © Canadian Space Agency/Agence spatiale canadienne 2003. Received by the Canada Centre for Remote Sensing. Processed and distributed by RADARSAT International. |
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Ward Hunt Ice Shelf
| Title |
Ward Hunt Ice Shelf |
| Description |
The Arctic?s largest ice shelf is breaking up. The Ward Hunt Ice Shelf is a remnant of the compacted snow and ancient sea ice that extended along the northern shores of Ellesmere Island in Northern Canada until the early twentieth century. Rising temperatures have reduced the original shelf into a number of smaller shelves, the largest of which was the Ward Hunt Ice Shelf on the northwest fringe of the island. The Ward Hunt Ice Shelf encompasses Ward Hunt Island and covers the mouth of the Disraeli Fiord. Until recently, fresh melt water formed a 43-meter deep lake on top of almost 400 meters of seawater in the fiord. Called an epishelf lake, the relatively fresh water dammed by the 3000-year-old ice shelf became the basis of a rare ecosystem. Disraeli Fiord was the largest remaining epishelf lake in the Northern Hemisphere. Between 2000 and 2002, the Ward Hunt Ice Shelf began to crack and eventually broke in two, allowing the lake behind it to drain rapidly into the Arctic Ocean. Derek Mueller and Warwick Vincent, of the Centre d?études nordiques at Université Laval in Quebec, Canada and Martin Jeffries of the Geophysical Institute at the University of Alaska Fairbanks in Fairbanks, Alaska described the event in a paper published in Geophysical Research Letters [ http://dx.doi.org/10.1029/2003GL017931 ] on October 18, 2003. This Standard Beam Mode RADARSAT-1 image clearly shows a large crack dividing the ice shelf in half. The crack runs from the Arctic Sea to the right of Ward Hunt Island and the bright white ice grounded there and back to the rougher, mountainous region. The image, acquired September 27, 2003, has a resolution of 25 meters. Image courtesy RADARSAT International [ http://www.rsi.ca/home.htm ]. RADARSAT-1 data © Canadian Space Agency/Agence spatiale canadienne 2003. Received by the Canada Centre for Remote Sensing. Processed and distributed by RADARSAT International. |
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Ward Hunt Ice Shelf: Image o
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nasa, nasaimageofthedaygalle
…
* eoimages.gsfc.nasa.gov/ima
…
Ellesmere.A2002219.2035
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2002-08-07 |
| creator |
NASA -- Images courtesy Jacques Descloitres, rapidfire.sci.gsfc.nasa.gov MODIS Rapid Response Team at NASA GSFC. Image interpretation provided by Derek Mueller and Warwick Vincent, Centre d'Etudes nordiques, Universite Laval in Quebec, Canada and Martin Jeffries, Geophysical Institute, University of Alaska Fairbanks in Fairbanks, Alaska. |
| identifier |
Ellesmere.A2002219.2035 |
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Salt Domes on Melville Islan
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nasa, nasaimageofthedaygalle
…
They may look like meteor cr
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melville_l7_2002175
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2006 |
| creator |
NASA -- NASA image created by Jesse Allen, Earth Observatory, using data obtained from the University of Maryland's www.landcover.org/ Global Land Cover Facility. |
| identifier |
melville_l7_2002175 |
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Ellesmere Island National Pa
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nasa, nasaimageofthedaygalle
…
The northeastern corner of E
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aster_ellesmere_04aug03
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2003-08-04 |
| creator |
NASA -- Data made available by NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan asterweb.jpl.nasa.gov/ ASTER Science Team |
| identifier |
aster_ellesmere_04aug03 |
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Antarctic Sea Ice: Image of
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nasa, nasaimageofthedaygalle
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Of the 15 million square kil
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ge_08503
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2008-02-24 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
ge_08503 |
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Antarctic Sea Ice: Image of
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nasa, nasaimageofthedaygalle
…
Of the 15 million square kil
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ge_08503
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2008-02-24 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
ge_08503 |
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Black Carbon in Smoke over A
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nasa, nasaimageofthedaygalle
…
* eoimages.gsfc.nasa.gov/ima
…
alas.OMI20050815
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2005-08-15 |
| creator |
NASA -- NASA image and caption information courtesy the OMI Science Team. |
| identifier |
alas.OMI20050815 |
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Ward Hunt Ice Shelf: Natural
…
nasa, nasanaturalhazards
The Arctic's largest ice she
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wardhunt_radarsat_md
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2003-09-27 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
wardhunt_radarsat_md |
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Ward Hunt Ice Shelf: Natural
…
nasa, nasanaturalhazards
The Arctic's largest ice she
…
wardhunt_radarsat_md
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2003-09-27 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
wardhunt_radarsat_md |
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Northwest Passage Open: Natu
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nasa, nasanaturalhazards
For over 500 years, Arctic e
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nwpassage_amo_2007241
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2007-08-29 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
nwpassage_amo_2007241 |
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Mackenzie River Delta, Canad
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nasa, nasaimageofthedaygalle
…
Canada's Mackenzie River, th
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mack_delta_AST2005216
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2005-08-04 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
mack_delta_AST2005216 |
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Global View of the Arctic Oc
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PIA02970
Sol (our sun)
Imaging Radar
| Title |
Global View of the Arctic Ocean |
| Original Caption Released with Image |
NASA researchers have new insights into the mysteries of Arctic sea ice, thanks to the unique abilities of Canada's Radarsat satellite. The Arctic is the smallest of the world's four oceans, but it may play a large role in helping scientists monitor Earth's climate shifts. Using Radarsat's special sensors to take images at night and to peer through clouds, NASA researchers can now see the complete ice cover of the Arctic. This allows tracking of any shifts and changes, in unprecedented detail, over the course of an entire winter. The radar-generated, high-resolution images are up to 100 times better than those taken by previous satellites. Using this new information, scientists at NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., can generate comprehensive maps of Arctic sea ice thickness for the first time. "Before we knew only the extent of the ice cover," said Dr. Ronald Kwok, JPL principal investigator of a project called Sea Ice Thickness Derived From High Resolution Radar Imagery. "We also knew that the sea ice extent had decreased over the last 20 years, but we knew very little about ice thickness.""Since sea ice is very thin, about 3 meters (10 feet) or less,"Kwok explained, "it is very sensitive to climate change." Until now, observations of polar sea ice thickness have been available for specific areas, but not for the entire polar region. The new radar mapping technique has also given scientists a close look at how the sea ice cover grows and contorts over time. "Using this new data set, we have the first estimates of how much ice has been produced and where it formed during the winter. We have never been able to do this before, " said Kwok. "Through our radar maps of the Arctic Ocean, we can actually see ice breaking apart and thin ice growth in the new openings. " RADARSAT gives researchers a piece of the overall puzzle every three days by creating a complete image of the Arctic. NASA scientists then put those puzzle pieces together to create a time-lapsed view of this remote and inhospitable region. So far, they have processed one season's worth of images."We can see large cracks in the ice cover, where most ice grows, " said Kwok. "These cracks are much longer than previously thought, some as long as 2,000 kilometers (1,200 miles)," Kwok continued. "If the ice is thinning due to warming, we'll expect to see more of these long cracks over the Arctic Ocean. " Scientists believe this is one of the most significant breakthroughs in the last two decades of ice research. "We are now in a position to better understand the sea ice cover and the role of the Arctic Ocean in global climate change, " said Kwok. Radar can see through clouds and any kind of weather system, day or night, and as the Arctic regions are usually cloud-covered and subject to long, dark winters, radar is proving to be extremely useful. However, compiling these data into extremely detailed pictures of the Arctic is a challenging task."This is truly, a major innovation in terms of the quantities of data being processed and the novelty of the methods being used, " said Verne Kaupp, director of the Alaska SAR Facility at the University of Alaska, Fairbanks. The mission is a joint project between JPL, the Alaska SAR Facility, and the Canadian Space Agency. Launched by NASA in 1995, the Radarsat satellite is operated by the Canadian Space Agency. 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 changes affect our global environment. |
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Comparative Views of Arctic
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PIA02971
Sol (our sun)
Imaging Radar
| Title |
Comparative Views of Arctic Sea Ice Growth |
| Original Caption Released with Image |
NASA researchers have new insights into the mysteries of Arctic sea ice, thanks to the unique abilities of Canada's Radarsat satellite. The Arctic is the smallest of the world's four oceans, but it may play a large role in helping scientists monitor Earth's climate shifts. Using Radarsat's special sensors to take images at night and to peer through clouds, NASA researchers can now see the complete ice cover of the Arctic. This allows tracking of any shifts and changes, in unprecedented detail, over the course of an entire winter. The radar-generated, high-resolution images are up to 100 times better than those taken by previous satellites. The two images above are separated by nine days (earlier image on the left). Both images represent an area (approximately 96 by 128 kilometers, 60 by 80 miles)located in the Baufort Sea, north of the Alaskan coast. The brighter features are older thicker ice and the darker areas show young, recently formed ice. 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. Using this new information, scientists at NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., can generate comprehensive maps of Arctic sea ice thickness for the first time. "Before we knew only the extent of the ice cover," said Dr. Ronald Kwok, JPL principal investigator of a project called Sea Ice Thickness Derived From High Resolution Radar Imagery. "We also knew that the sea ice extent had decreased over the last 20 years, but we knew very little about ice thickness.""Since sea ice is very thin, about 3 meters (10 feet) or less,"Kwok explained, "it is very sensitive to climate change." Until now, observations of polar sea ice thickness have been available for specific areas, but not for the entire polar region. The new radar mapping technique has also given scientists a close look at how the sea ice cover grows and contorts over time. "Using this new data set, we have the first estimates of how much ice has been produced and where it formed during the winter. We have never been able to do this before," said Kwok. "Through our radar maps of the Arctic Ocean, we can actually see ice breaking apart and thin ice growth in the new openings." RADARSAT gives researchers a piece of the overall puzzle every three days by creating a complete image of the Arctic. NASA scientists then put those puzzle pieces together to create a time-lapsed view of this remote and inhospitable region. So far, they have processed one season's worth of images."We can see large cracks in the ice cover, where most ice grows," said Kwok. "These cracks are much longer than previously thought, some as long as 2,000 kilometers (1,200 miles)," Kwok continued. "If the ice is thinning due to warming, we'll expect to see more of these long cracks over the Arctic Ocean." Scientists believe this is one of the most, significant breakthroughs in the last two decades of ice research. "We are now in a position to better understand the sea ice cover and the role of the Arctic Ocean in global climate change," said Kwok. Radar can see through clouds and any kind of weather system, day or night, and as the Arctic regions are usually cloud-covered and subject to long, dark winters, radar is proving to be extremely useful. However, compiling these data into extremely detailed pictures of the Arctic is a challenging task."This is truly a major innovation in terms of the quantities of data being processed and the novelty of the methods being used," said Verne Kaupp, director of the Alaska SAR Facility at the University of Alaska, Fairbanks. The mission is a joint project between JPL, the Alaska SAR Facility, and the Canadian Space Agency. Launched by NASA in 1995, the Radarsat satellite is operated by the Canadian Space Agency. 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 changes affect our global environment. |
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