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Indonesia?s Ruang Volcano Er
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| Title |
Indonesia?s Ruang Volcano Erupts |
| Description |
*Full-resolution Images:* ÿÿÿTerra MODIS at 1:55 UTC (1.1 MB) ÿÿÿAqua MODIS at 4:50 UTC (748 KB) Mount Ruang, a stratovolcano in the Indonesian Sulawesi Islands, erupted on September 25, 2002, sending a large plume of ash (gray pixels) streaming westward toward Borneo and Sumatra. The eruption was preceded by earthquakes on the day before, followed by a thick, black column of volcanic ash ejected as high as 5,000 m into the sky on the 25th. While no fatalities were reported, more than 1,000 residents on Ruang Island were forced to evacuate to a nearby island. This comparison pair of true-color images was acquired by the Moderate Resolution Imaging Spectroradiometer, flying aboard NASA's Terra and Aqua satellites, on September 25. The top image was acquired by Terra MODIS at 1:55 UTC, while the bottom image was acquired by Aqua MODIS at 4:50 UTC. Notice how much the plume grew in that 3-hour span of time. (Note: the Aqua image appears noticeably different because the relative sun angle makes both the plume and the ocean surface appear much brighter.) Images courtesy Jacques Descloitres, MODIS Land Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov/ ] at NASA GSFC |
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Indonesia?s Ruang Volcano Er
…
| Title |
Indonesia?s Ruang Volcano Erupts |
| Description |
*Full-resolution Images:* ÿÿÿTerra MODIS at 1:55 UTC (1.1 MB) ÿÿÿAqua MODIS at 4:50 UTC (748 KB) Mount Ruang, a stratovolcano in the Indonesian Sulawesi Islands, erupted on September 25, 2002, sending a large plume of ash (gray pixels) streaming westward toward Borneo and Sumatra. The eruption was preceded by earthquakes on the day before, followed by a thick, black column of volcanic ash ejected as high as 5,000 m into the sky on the 25th. While no fatalities were reported, more than 1,000 residents on Ruang Island were forced to evacuate to a nearby island. This comparison pair of true-color images was acquired by the Moderate Resolution Imaging Spectroradiometer, flying aboard NASA's Terra and Aqua satellites, on September 25. The top image was acquired by Terra MODIS at 1:55 UTC, while the bottom image was acquired by Aqua MODIS at 4:50 UTC. Notice how much the plume grew in that 3-hour span of time. (Note: the Aqua image appears noticeably different because the relative sun angle makes both the plume and the ocean surface appear much brighter.) Images courtesy Jacques Descloitres, MODIS Land Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov/ ] at NASA GSFC |
|
Indonesia?s Ruang Volcano Er
…
| Title |
Indonesia?s Ruang Volcano Erupts |
| Description |
*Full-resolution Images:* ÿÿÿTerra MODIS at 1:55 UTC (1.1 MB) ÿÿÿAqua MODIS at 4:50 UTC (748 KB) Mount Ruang, a stratovolcano in the Indonesian Sulawesi Islands, erupted on September 25, 2002, sending a large plume of ash (gray pixels) streaming westward toward Borneo and Sumatra. The eruption was preceded by earthquakes on the day before, followed by a thick, black column of volcanic ash ejected as high as 5,000 m into the sky on the 25th. While no fatalities were reported, more than 1,000 residents on Ruang Island were forced to evacuate to a nearby island. This comparison pair of true-color images was acquired by the Moderate Resolution Imaging Spectroradiometer, flying aboard NASA's Terra and Aqua satellites, on September 25. The top image was acquired by Terra MODIS at 1:55 UTC, while the bottom image was acquired by Aqua MODIS at 4:50 UTC. Notice how much the plume grew in that 3-hour span of time. (Note: the Aqua image appears noticeably different because the relative sun angle makes both the plume and the ocean surface appear much brighter.) Images courtesy Jacques Descloitres, MODIS Land Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov/ ] at NASA GSFC |
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Deep Ocean Tsunami Waves off
…
nasa, nasaimageofthedaygalle
…
The initial tsunami waves re
…
PIA04373
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2004-12-26 |
| creator |
NASA -- Image courtesy NASA/GSFC/LaRC/JPL, MISR Team. Text by Clare Averill (Raytheon ITSS/JPL), Michael Garay and David J. Diner (JPL, California Institute of Technology), and Vasily Titov (NOAA/Pacific Marine Environmental Laboratory and University of Washington/Joint Institute for the Study of the Atmosphere and Oceans). |
| identifier |
PIA04373 |
|
Uplift and Subsidence Associ
…
PIA02435
Sol (our sun)
ASTER
| Title |
Uplift and Subsidence Associated with the Great Aceh-Andaman Earthquake of 2004 |
| Original Caption Released with Image |
The magnitude 9.2 Indian Ocean earthquake of December 26, 2004, produced broad regions of uplift and subsidence. In order to define the lateral extent and the downdip limit of rupture, scientists from Caltech, Pasadena, Calif., NASA's Jet Propulsion Laboratory, Pasadena, Calif., Scripps Institution of Oceanography, La Jolla, Calif., the U.S. Geological Survey, Pasadena, Calif., and the Research Center for Geotechnology, Indonesian Institute of Sciences, Bandung, Indonesia, first needed to define the pivot line separating those regions. Interpretation of satellite imagery and a tidal model were one of the key tools used to do this. These pre-Sumatra earthquake (a) and post-Sumatra earthquake (b) images of North Sentinel Island in the Indian Ocean, acquired from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft, show emergence of the coral reef surrounding the island following the earthquake. The tide was 30 plus or minus 14 centimeters lower in the pre-earthquake image (acquired November 21, 2000) than in the post-earthquake image (acquired February 20, 2005), requiring a minimum of 30 centimeters of uplift at this locality. Observations from an Indian Coast Guard helicopter on the northwest coast of the island suggest that the actual uplift is on the order of 1 to 2 meters at this site. In figures (c) and (d), pre-earthquake and post-earthquake ASTER images of a small island off the northwest coast of Rutland Island, 38 kilometers east of North Sentinel Island, show submergence of the coral reef surrounding the island. The tide was higher in the pre-earthquake image (acquired January 1, 2004) than in the post-earthquake image (acquired February 4, 2005), requiring subsidence at this locality. The pivot line must run between North Sentinel and Rutland islands. Note that the scale for the North Sentinel Island images differs from that for the Rutland Island images. The tidal model used for this study was based on data from JPL's Topex/Poseidon satellite. The model was used to determine the relative sea surface height at each location at the time each image was acquired, a critical component used to quantify the deformation. The scientists' method of using satellite imagery to recognize changes in elevation relative to sea surface height and of using a tidal model to place quantitative bounds on coseismic uplift or subsidence is a novel approach that can be adapted to other forms of remote sensing and can be applied to other subduction zones in tropical regions. ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with, critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, wetlands evaluation, thermal pollution monitoring, coral reef degradation, surface temperature mapping of soils and geology, and measuring surface heat balance. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate. |
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Breaking Tsunami Waves along
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PIA04372
Sol (our sun)
Multi-angle Imaging SpectroR
…
| Title |
Breaking Tsunami Waves along India's Eastern Coast |
| Original Caption Released with Image |
(3.8 MB) shows a region further south, at the northern end of India's Coromandel Coast, and covers an area of 43 kilometers x 58 kilometers. Cloud "motion" in these animations results from apparent displacements due to parallax associated with their height above the surface. The tsunami waves, on the other hand, are at sea level and show actual motion. When the waves arrive in the shallower water near the shore, they grow and, if they become large enough, they will break in a manner similar to typical oceanic waves, but on a much larger scale. The leading edge of the breaking waves is likely what is visible in the imagery. Additionally, if the tsunami waves impact the coast at an angle, they can produce what are known as "edge waves" which propagate parallel to the coast. There is clear evidence of edge wave generation in these images. Upon discovering the unique content of this imagery, MISR scientists contacted Dr. Vasily Titov at the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory in Seattle, WA. Dr. Titov is an expert in the propagation of tsunamis, and has generated a model animation of the tsunami's progression from its origin near Sumatra (see http://www.pmel.noaa.gov/tsunami/indo_1204.html [ http://www.pmel.noaa.gov/tsunami/indo_1204.html ]). The MISR imagery provides measurements of the location and timing of the breaking waves, their angle relative to the shoreline, and their speed of propagation, which is estimated from these data to be around 30 kilometers/hour. In conjunction with bathymetric measurements of ocean depth, this information can be used to refine and calibrate tsunami propagation models. According to Dr. Titov, improving these models has two primary benefits. First, a detailed understanding of wave interactions with coastal areas is necessary for developing damage mitigation approaches. Second, a better predictive capability of the models will make possible more accurate near-real-time forecasts of tsunami arrival times and effects. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82° north and 82° south latitude. These data products were generated from a portion of the imagery acquired during Terra orbit 26720 and utilize data from within blocks 77 and 78 within World Reference System-2 path 142. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology., At 00:58:53 UTC (Coordinated Universal Time) on 26 December 2004, a magnitude 9.0 earthquake occurred off the west coast of Sumatra, Indonesia. This was the fourth largest earthquake in the world since 1900 and the largest in over 40 years. It was caused by the release of stresses in the Earth that are built up as the Indian tectonic plate descends into the mantle beneath the Burma plate. It is estimated that the sea floor was displaced several meters due to the quake, resulting in large ocean waves, called "tsunamis" from the Japanese for "harbor waves." The tsunami moved rapidly across the deep ocean, with speeds estimated around 640 km/hr. When the waves reach shallow water near land, they slow considerably, but their size increases dramatically and they strike with catastrophic force. With human casualities exceeding 150,000, this event is one of the deadliest natural disasters in modern history, causing devastation along the shores of Indonesia, Sri Lanka, India, Thailand, and other countries. The initial tsunami waves reached the eastern Indian coast around 3:35 UTC, based on tide gauge measurements made at the port city of Vishakapatnam. The Multi-angle Imaging SpectroRadiometer (MISR) aboard NASA's Terra satellite passed over the eastern Indian coast between 5:10 to 5:20 UTC, when the tide gauge indicated the arrival of another series of waves. Because MISR's nine cameras imaged the coast over a time span of about 7 minutes, and because the the waves are unusually large, MISR was able to capture unique time-lapse imagery of the breaking waves. The still image shows four frames from the instrument's backward-viewing cameras spanning a period of about 2.5 minutes. This scene is located along the shores of Andhra Pradesh, near the mouth of the Godavari River, and covers an area of 42 kilometers x 37 kilometers. The arrows show the progression of the southwestern edges of the breakers. A series of frames spanning nearly 6 minutes has been made into a small animated GIF (below). An animated GIF (5.8 MB) covering a somewhat larger area of 86 kilometers x 49 kilometers is also available. A second animated GIF |
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Breaking Tsunami Waves along
…
PIA04372
Sol (our sun)
Multi-angle Imaging SpectroR
…
| Title |
Breaking Tsunami Waves along India's Eastern Coast |
| Original Caption Released with Image |
(3.8 MB) shows a region further south, at the northern end of India's Coromandel Coast, and covers an area of 43 kilometers x 58 kilometers. Cloud "motion" in these animations results from apparent displacements due to parallax associated with their height above the surface. The tsunami waves, on the other hand, are at sea level and show actual motion. When the waves arrive in the shallower water near the shore, they grow and, if they become large enough, they will break in a manner similar to typical oceanic waves, but on a much larger scale. The leading edge of the breaking waves is likely what is visible in the imagery. Additionally, if the tsunami waves impact the coast at an angle, they can produce what are known as "edge waves" which propagate parallel to the coast. There is clear evidence of edge wave generation in these images. Upon discovering the unique content of this imagery, MISR scientists contacted Dr. Vasily Titov at the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory in Seattle, WA. Dr. Titov is an expert in the propagation of tsunamis, and has generated a model animation of the tsunami's progression from its origin near Sumatra (see http://www.pmel.noaa.gov/tsunami/indo_1204.html [ http://www.pmel.noaa.gov/tsunami/indo_1204.html ]). The MISR imagery provides measurements of the location and timing of the breaking waves, their angle relative to the shoreline, and their speed of propagation, which is estimated from these data to be around 30 kilometers/hour. In conjunction with bathymetric measurements of ocean depth, this information can be used to refine and calibrate tsunami propagation models. According to Dr. Titov, improving these models has two primary benefits. First, a detailed understanding of wave interactions with coastal areas is necessary for developing damage mitigation approaches. Second, a better predictive capability of the models will make possible more accurate near-real-time forecasts of tsunami arrival times and effects. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82° north and 82° south latitude. These data products were generated from a portion of the imagery acquired during Terra orbit 26720 and utilize data from within blocks 77 and 78 within World Reference System-2 path 142. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology., At 00:58:53 UTC (Coordinated Universal Time) on 26 December 2004, a magnitude 9.0 earthquake occurred off the west coast of Sumatra, Indonesia. This was the fourth largest earthquake in the world since 1900 and the largest in over 40 years. It was caused by the release of stresses in the Earth that are built up as the Indian tectonic plate descends into the mantle beneath the Burma plate. It is estimated that the sea floor was displaced several meters due to the quake, resulting in large ocean waves, called "tsunamis" from the Japanese for "harbor waves." The tsunami moved rapidly across the deep ocean, with speeds estimated around 640 km/hr. When the waves reach shallow water near land, they slow considerably, but their size increases dramatically and they strike with catastrophic force. With human casualities exceeding 150,000, this event is one of the deadliest natural disasters in modern history, causing devastation along the shores of Indonesia, Sri Lanka, India, Thailand, and other countries. The initial tsunami waves reached the eastern Indian coast around 3:35 UTC, based on tide gauge measurements made at the port city of Vishakapatnam. The Multi-angle Imaging SpectroRadiometer (MISR) aboard NASA's Terra satellite passed over the eastern Indian coast between 5:10 to 5:20 UTC, when the tide gauge indicated the arrival of another series of waves. Because MISR's nine cameras imaged the coast over a time span of about 7 minutes, and because the the waves are unusually large, MISR was able to capture unique time-lapse imagery of the breaking waves. The still image shows four frames from the instrument's backward-viewing cameras spanning a period of about 2.5 minutes. This scene is located along the shores of Andhra Pradesh, near the mouth of the Godavari River, and covers an area of 42 kilometers x 37 kilometers. The arrows show the progression of the southwestern edges of the breakers. A series of frames spanning nearly 6 minutes has been made into a small animated GIF (below). An animated GIF (5.8 MB) covering a somewhat larger area of 86 kilometers x 49 kilometers is also available. A second animated GIF |
|
Breaking Tsunami Waves along
…
PIA04372
Sol (our sun)
Multi-angle Imaging SpectroR
…
| Title |
Breaking Tsunami Waves along India's Eastern Coast |
| Original Caption Released with Image |
(3.8 MB) shows a region further south, at the northern end of India's Coromandel Coast, and covers an area of 43 kilometers x 58 kilometers. Cloud "motion" in these animations results from apparent displacements due to parallax associated with their height above the surface. The tsunami waves, on the other hand, are at sea level and show actual motion. When the waves arrive in the shallower water near the shore, they grow and, if they become large enough, they will break in a manner similar to typical oceanic waves, but on a much larger scale. The leading edge of the breaking waves is likely what is visible in the imagery. Additionally, if the tsunami waves impact the coast at an angle, they can produce what are known as "edge waves" which propagate parallel to the coast. There is clear evidence of edge wave generation in these images. Upon discovering the unique content of this imagery, MISR scientists contacted Dr. Vasily Titov at the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory in Seattle, WA. Dr. Titov is an expert in the propagation of tsunamis, and has generated a model animation of the tsunami's progression from its origin near Sumatra (see http://www.pmel.noaa.gov/tsunami/indo_1204.html [ http://www.pmel.noaa.gov/tsunami/indo_1204.html ]). The MISR imagery provides measurements of the location and timing of the breaking waves, their angle relative to the shoreline, and their speed of propagation, which is estimated from these data to be around 30 kilometers/hour. In conjunction with bathymetric measurements of ocean depth, this information can be used to refine and calibrate tsunami propagation models. According to Dr. Titov, improving these models has two primary benefits. First, a detailed understanding of wave interactions with coastal areas is necessary for developing damage mitigation approaches. Second, a better predictive capability of the models will make possible more accurate near-real-time forecasts of tsunami arrival times and effects. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82° north and 82° south latitude. These data products were generated from a portion of the imagery acquired during Terra orbit 26720 and utilize data from within blocks 77 and 78 within World Reference System-2 path 142. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology., At 00:58:53 UTC (Coordinated Universal Time) on 26 December 2004, a magnitude 9.0 earthquake occurred off the west coast of Sumatra, Indonesia. This was the fourth largest earthquake in the world since 1900 and the largest in over 40 years. It was caused by the release of stresses in the Earth that are built up as the Indian tectonic plate descends into the mantle beneath the Burma plate. It is estimated that the sea floor was displaced several meters due to the quake, resulting in large ocean waves, called "tsunamis" from the Japanese for "harbor waves." The tsunami moved rapidly across the deep ocean, with speeds estimated around 640 km/hr. When the waves reach shallow water near land, they slow considerably, but their size increases dramatically and they strike with catastrophic force. With human casualities exceeding 150,000, this event is one of the deadliest natural disasters in modern history, causing devastation along the shores of Indonesia, Sri Lanka, India, Thailand, and other countries. The initial tsunami waves reached the eastern Indian coast around 3:35 UTC, based on tide gauge measurements made at the port city of Vishakapatnam. The Multi-angle Imaging SpectroRadiometer (MISR) aboard NASA's Terra satellite passed over the eastern Indian coast between 5:10 to 5:20 UTC, when the tide gauge indicated the arrival of another series of waves. Because MISR's nine cameras imaged the coast over a time span of about 7 minutes, and because the the waves are unusually large, MISR was able to capture unique time-lapse imagery of the breaking waves. The still image shows four frames from the instrument's backward-viewing cameras spanning a period of about 2.5 minutes. This scene is located along the shores of Andhra Pradesh, near the mouth of the Godavari River, and covers an area of 42 kilometers x 37 kilometers. The arrows show the progression of the southwestern edges of the breakers. A series of frames spanning nearly 6 minutes has been made into a small animated GIF (below). An animated GIF (5.8 MB) covering a somewhat larger area of 86 kilometers x 49 kilometers is also available. A second animated GIF |
|
Breaking Tsunami Waves along
…
PIA04372
Sol (our sun)
Multi-angle Imaging SpectroR
…
| Title |
Breaking Tsunami Waves along India's Eastern Coast |
| Original Caption Released with Image |
(3.8 MB) shows a region further south, at the northern end of India's Coromandel Coast, and covers an area of 43 kilometers x 58 kilometers. Cloud "motion" in these animations results from apparent displacements due to parallax associated with their height above the surface. The tsunami waves, on the other hand, are at sea level and show actual motion. When the waves arrive in the shallower water near the shore, they grow and, if they become large enough, they will break in a manner similar to typical oceanic waves, but on a much larger scale. The leading edge of the breaking waves is likely what is visible in the imagery. Additionally, if the tsunami waves impact the coast at an angle, they can produce what are known as "edge waves" which propagate parallel to the coast. There is clear evidence of edge wave generation in these images. Upon discovering the unique content of this imagery, MISR scientists contacted Dr. Vasily Titov at the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory in Seattle, WA. Dr. Titov is an expert in the propagation of tsunamis, and has generated a model animation of the tsunami's progression from its origin near Sumatra (see http://www.pmel.noaa.gov/tsunami/indo_1204.html [ http://www.pmel.noaa.gov/tsunami/indo_1204.html ]). The MISR imagery provides measurements of the location and timing of the breaking waves, their angle relative to the shoreline, and their speed of propagation, which is estimated from these data to be around 30 kilometers/hour. In conjunction with bathymetric measurements of ocean depth, this information can be used to refine and calibrate tsunami propagation models. According to Dr. Titov, improving these models has two primary benefits. First, a detailed understanding of wave interactions with coastal areas is necessary for developing damage mitigation approaches. Second, a better predictive capability of the models will make possible more accurate near-real-time forecasts of tsunami arrival times and effects. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82° north and 82° south latitude. These data products were generated from a portion of the imagery acquired during Terra orbit 26720 and utilize data from within blocks 77 and 78 within World Reference System-2 path 142. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology., At 00:58:53 UTC (Coordinated Universal Time) on 26 December 2004, a magnitude 9.0 earthquake occurred off the west coast of Sumatra, Indonesia. This was the fourth largest earthquake in the world since 1900 and the largest in over 40 years. It was caused by the release of stresses in the Earth that are built up as the Indian tectonic plate descends into the mantle beneath the Burma plate. It is estimated that the sea floor was displaced several meters due to the quake, resulting in large ocean waves, called "tsunamis" from the Japanese for "harbor waves." The tsunami moved rapidly across the deep ocean, with speeds estimated around 640 km/hr. When the waves reach shallow water near land, they slow considerably, but their size increases dramatically and they strike with catastrophic force. With human casualities exceeding 150,000, this event is one of the deadliest natural disasters in modern history, causing devastation along the shores of Indonesia, Sri Lanka, India, Thailand, and other countries. The initial tsunami waves reached the eastern Indian coast around 3:35 UTC, based on tide gauge measurements made at the port city of Vishakapatnam. The Multi-angle Imaging SpectroRadiometer (MISR) aboard NASA's Terra satellite passed over the eastern Indian coast between 5:10 to 5:20 UTC, when the tide gauge indicated the arrival of another series of waves. Because MISR's nine cameras imaged the coast over a time span of about 7 minutes, and because the the waves are unusually large, MISR was able to capture unique time-lapse imagery of the breaking waves. The still image shows four frames from the instrument's backward-viewing cameras spanning a period of about 2.5 minutes. This scene is located along the shores of Andhra Pradesh, near the mouth of the Godavari River, and covers an area of 42 kilometers x 37 kilometers. The arrows show the progression of the southwestern edges of the breakers. A series of frames spanning nearly 6 minutes has been made into a small animated GIF (below). An animated GIF (5.8 MB) covering a somewhat larger area of 86 kilometers x 49 kilometers is also available. A second animated GIF |
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Deep Ocean Tsunami Waves off
…
PIA04373
Sol (our sun)
Multi-angle Imaging SpectroR
…
| Title |
Deep Ocean Tsunami Waves off the Sri Lankan Coast |
| Original Caption Released with Image |
The initial tsunami waves resulting from the undersea earthquake that occurred at 00:58:53 UTC (Coordinated Universal Time) on 26 December 2004 off the island of Sumatra, Indonesia, took a little over 2 hours to reach the teardrop-shaped island of Sri Lanka. Additional waves continued to arrive for many hours afterward. At approximately 05:15 UTC, as NASA's Terra satellite passed overhead, the Multi-angle Imaging SpectroRadiometer (MISR) captured this image of deep ocean tsunami waves about 30-40 kilometers from Sri Lanka's southwestern coast. The waves are made visible due to the effects of changes in sea-surface slope on the reflected sunglint pattern, shown here in MISR's 46° forward-pointing camera. Sunglint occurs when sunlight reflects off a water surface in much the same way light reflects off a mirror, and the position of the Sun, angle of observation, and orientation of the sea surface determines how bright each part of the ocean appears in the image. These large wave features were invisible to MISR's nadir (vertical-viewing) camera. The image covers an area of 208 kilometers x 207 kilometers. Since the greatest impact of the tsunami was generally in an east-west direction, the havoc caused by the tsunami along the southwestern shores of Sri Lanka was not as severe as along the eastern coast, though there was still substantial damage in this region--as evidenced by the brownish debris in the water--because tsunami waves can diffract around land masses. The ripple-like wave pattern evident in this MISR image roughly correlates with the undersea boundary of the continental shelf. This surface manifestation is likely to be caused by interaction of deep waves with the ocean floor, rather than by the more usually-observed surface waves driven by winds. It is possible that this semi-concentric pattern represents wave reflection from the continental land mass, however, a combination of wave modeling and detailed bathymetric data is required to fully understand the dynamics. Examination of other MISR images of this area, taken under similar illumination conditions, has not uncovered any surface patterns resembling those seen here. This image is an example of how MISR's multiangular capability provides unique information for understanding how tsunamis propagate. Another application of MISR data enabled measuring the motion of breaking tsunami waves [ http://www-misr.jpl.nasa.gov/gallery/galhistory/2005_jan_12.html ], along the eastern shores of Andhra Pradesh, India. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82° north and 82° south latitude. These data products were generated from a portion of the imagery acquired during Terra orbit 26720 and utilize data from within blocks 85 to 86 within World Reference System-2 path 142. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology. |
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Smoke over Sumatra, Indonesi
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PIA03449
Sol (our sun)
Multi-angle Imaging SpectroR
…
| Title |
Smoke over Sumatra, Indonesia |
| Original Caption Released with Image |
At least once a year for a period lasting from a week to several months, northern Sumatra is obscured by smoke and haze produced by agricultural burning and forest fires. These data products from the Multi-angle Imaging SpectroRadiometer document the presence of airborne particulates on March 13, 2002, during Terra orbit 11880. On the left is an image acquired by MISR's 70-degree backward-viewing camera. On the right is a map of aerosol optical depth, a measure of the abundance of atmospheric particulates. This product utilized a test version of the MISR retrieval that incorporates an experimental set of aerosol mixtures. The haze has completely obscured northeastern Sumatra and part of the Strait of Malacca, which separates Sumatra and the Malaysian Peninsula. A northward gradient is apparent as the haze dissipates in the direction of the Malaysian landmass. Each panel covers an area of about 760 kilometers x 400 kilometers. Haze conditions had posed a health concern during late February (when schools in some parts of North Sumatra were closed), and worsened considerably in the first two weeks of March. By mid-March, local meteorology officials asked residents of North Sumatra's provincial capital, Medan, to minimize their outdoor activities and wear protective masks. Poor visibility at Medan airport forced a passenger plane to divert to Malaysia on March 14, and visibility reportedly ranged between 100 and 600 meters in some coastal towns southeast of Medan. The number and severity of this year's fires was exacerbated by dry weather conditions associated with the onset of a weak to moderate El Niño. The governments of Indonesia, Malaysia, and Brunei have agreed to ban open burning in plantation and forest areas. The enforcement of such fire bans, however, has proven to be an extremely challenging task. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology. |
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