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Mass Concentration in Antarc …
Title Mass Concentration in Antarctica
Description Compared to electricity or magnetism, gravity is a weak force, yet it affects objects as large as oceans, stars, and galaxies. Earth's gravity is not uniform all over the planet. The planet's valleys, ocean trenches, plains, and mountain peaks cause variations in the density of the Earth's surface and, consequently, its gravity field. Launched on March 17, 2002, NASA's Gravity Recovery and Climate Experiment (GRACE) [ http://www.csr.utexas.edu/grace/ ] takes detailed measurements of Earth's gravity field from space. GRACE consists of two satellites that assess differences in Earth's gravity field by tracking tiny changes in their distance from each other. Areas on Earth with greater gravity—known as mass concentrations—pull the leading GRACE satellite away from the trailing satellite. In June 2006, researchers at Ohio State University announced that GRACE had found a mass concentration under the ice in East Antarctica. This image shows GRACE's measurements of gravity, indicated in galileos [ http://en.wikipedia.org/wiki/Gal_(unit) ] per meter. Areas with more intense gravity appear in red, and areas with less intense gravity appear in blue. Yellow and green show levels in between these extremes. Not far from the coast is a 320-kilometer-wide mass concentration, outlined in white. This spot attracted the researchers's attention. The mass concentration GRACE detected indicates an area containing unusually dense material. Such mass concentrations can result from more than one cause. One possible explanation is an upwelling of volcanic rock from deep within Earth's crust. Ralph von Frese, a geology professor at Ohio State University, proposed that the mass concentration may have resulted from an asteroid impact. Approximately 251 million years ago, our planet experienced the worst extinction in its history. Called the Permo-Triassic extinction, this event was far more destructive than the extinction event 65 million years ago that ended the Age of the Dinosaurs. An asteroid impact is widely believed to have caused the dinosaur extinction, and a crater that dates to that time is located on the Yucatan Peninsula. Although multiple explanations have been proposed for the earlier, Permo-Triassic extinction, Von Frese supports the view that an asteroid impact caused it, too. According to Von Frese, the mass concentration GRACE detected in Antarctica could be the crater from an asteroid that triggered the Permo-Triassic extinction. GRACE's discovery is just the first step in understanding this mass concentration. More clues can come from a visit to the site, as well as chemical analyses that provide a geologic age for the rocks in that area. If the rocks date to the same time as the Permo-Triassic extinction, GRACE may have made an important discovery about the history of life (and death) on Earth. Images courtesy Pam Frost Gorder, Ohio State University
Earth's Shrinking Antarctic …
Title Earth's Shrinking Antarctic Ice Sheet
Explanation Is the continent at the end of the Earth slowly melting? For millions of years, Antarctica [ http://antwrp.gsfc.nasa.gov/apod/ap991116.html ], the frozen continent at the southern end of planet Earth, has been encased in a gigantic sheet [ http://www.pbs.org/wgbh/nova/ice/chill.html ] of ice. Recently, the orbiting robotic GRACE satellite [ http://www.csr.utexas.edu/grace/ ] has been taking sensitive measurements of the gravity [ http://antwrp.gsfc.nasa.gov/apod/ap030723.html ] for the entire Earth, including Antarctica [ http://en.wikipedia.org/wiki/Antarctica ]. Recent analysis [ http://www.jpl.nasa.gov/news/news.cfm?release=2006-028 ] of Gravity Recovery and Climate Experiment [ http://en.wikipedia.org/wiki/Gravity_Recovery_and_Climate_Experiment ] (GRACE) data indicate that the Antarctic ice sheet [ http://en.wikipedia.org/wiki/Antarctic_Ice_Sheet ] might have lost enough mass to cause the worlds' oceans to rise about 1.2 millimeters, on the average, from between 2002 and 2005. Although this may not seem like much, the equivalent amount of water is about 150 trillion liter [ http://en.wikipedia.org/wiki/Liter ]s, equivalent to the amount of water used by US residents [ http://asuwlink.uwyo.edu/~mthomas/ ] in three months. Uncertainties in the measurement make the mass loss uncertain by about 80 trillion liters. Pictured above [ http://www.jpl.nasa.gov/news/news.cfm?release=2006-028 ] is an iceberg [ http://express.howstuffworks.com/wq-iceberg.htm ] that is a small part of the Antarctic ice sheet [ http://antwrp.gsfc.nasa.gov/apod/ap050223.html ]. The picture was taken on the Riiser-Larsen ice shelf in December 1995. Future research will likely focus on trying to better understand the data, take more data, predict future trends, and understand possible effects [ http://www.epa.gov/globalwarming/kids/gw.html ] of these trends on the future climate [ http://www.giss.nasa.gov/edu/gwdebate/ ] of our entire home planet [ http://antwrp.gsfc.nasa.gov/apod/ap050102.html ].
Artist's concept of Gravity …
Title Artist's concept of Gravity Recovery and Climate Experiment
Description Artist's concept of Grace
Date 12.21.2002
Artist's concept of Gravity …
Title Artist's concept of Gravity Recovery and Climate Experiment
Description Artist's concept of Grace
Date 12.21.2002
Antarctic Tides: Image of th …
nasa, nasaimageofthedaygalle …
To know whether Antarctic ic …
antarctica_gra_2004
mediatype IMAGE
mediatype image
date 2004
creator NASA -- Images courtesy Ohio State University
identifier antarctica_gra_2004
Antarctic Tides: Image of th …
nasa, nasaimageofthedaygalle …
To know whether Antarctic ic …
antarctica_gra_2004
mediatype IMAGE
mediatype image
date 2004
creator NASA -- Images courtesy Ohio State University
identifier antarctica_gra_2004
Studying Earth's Gravity Fie …
nasa, nasaimageofthedaygalle …
The first image released fro …
global_gra_2002340
mediatype IMAGE
mediatype image
date 2002
creator NASA -- Image courtesy www.csr.utexas.edu/grace/ GRACE Science Team NASA, German Aerospace Center, University of Texas Center for Space Research, and GeoForschungsZentrum Potsdam.
identifier global_gra_2002340
Mass Concentration in Antarc …
nasa, nasaimageofthedaygalle …
Compared to electricity or m …
antarctica_gra_2006
mediatype IMAGE
mediatype image
date 2002-03-17
creator NASA -- Images courtesy Pam Frost Gorder, Ohio State University
identifier antarctica_gra_2006
Earth's Gravity Field: Image …
nasa, nasaimageofthedaygalle …
The joint NASA-German Aerosp …
PIA04652
mediatype IMAGE
mediatype image
date 2003
creator NASA -- Image courtesy NASA Jet Propulsion Laboratory, University of Texas www.csr.utexas.edu/ Center for Space Research, and op.gfz-potsdam.de/ GeoForschungsZentrum Potsdam
identifier PIA04652
Greenland Ice Sheet Losing M …
nasa, nasaimageofthedaygalle …
, in the online edition of t …
grace_greenland_mass_trend
mediatype MISC
mediatype texts
date 2006-10-19
creator NASA -- NASA image courtesy Scott Luthcke
identifier grace_greenland_mass_trend
Greenland Ice Sheet Losing M …
nasa, nasaimageofthedaygalle …
, in the online edition of t …
grace_greenland_mass_trend
mediatype IMAGE
mediatype texts
date 2006-10-19
creator NASA -- NASA image courtesy Scott Luthcke
identifier grace_greenland_mass_trend
The Rising Sea Level: Image …
nasa, nasaimageofthedaygalle …
Rising or falling sea level …
sealevel_jason_200606
mediatype IMAGE
mediatype texts
date 2005
creator NASA -- Graph adapted by Robert Simmon from Leuliette, E., Nerem, R., and Mitchum, G. (2004). Calibration of TOPEX/Poseidon and Jason altimeter data to construct a continuous record of mean sea level change. Marine Geodesy, 27(1-2), 79-94.
identifier sealevel_jason_200606
The Rising Sea Level: Image …
nasa, nasaimageofthedaygalle …
Rising or falling sea level …
sealevel_jason_200606
mediatype MISC
mediatype texts
date 2005
creator NASA -- Graph adapted by Robert Simmon from Leuliette, E., Nerem, R., and Mitchum, G. (2004). Calibration of TOPEX/Poseidon and Jason altimeter data to construct a continuous record of mean sea level change. Marine Geodesy, 27(1-2), 79-94.
identifier sealevel_jason_200606
NASA and German Space Agency …
nasa, nasahighlightsimagegal …
NASA Deputy Administrator Lo …
463519main_4
mediatype IMAGE
mediatype image
date 2010-06-17
creator NASA
identifier 463519main_4
Water Flow in the Amazon: Im …
nasa, nasaimageofthedaygalle …
The Amazon River basin carri …
geoid_gra_2003
mediatype IMAGE
mediatype image
date 2003
creator NASA -- Images courtesy Paul Thompson www.csr.utexas.edu/grace/ GRACE Science Team
identifier geoid_gra_2003
Retreating Ice and Snow in G …
nasa, nasaimageofthedaygalle …
In October 2006, a study usi …
segreenland_tmo_2006242
mediatype IMAGE
mediatype image
date 2006-08-30
creator NASA -- NASA image by Jesse Allen, Earth Observatory. Image interpretation provided by Ian Joughin, University of Washington, and Ted Scambos, National Snow and Ice Data Center.
identifier segreenland_tmo_2006242
Water Storage Anomalies in M …
nasa, nasaimageofthedaygalle …
Seasonal variations in preci …
Missanomaly_GRA_2005
mediatype IMAGE
mediatype image
date 2005
creator NASA -- Images created by Ben Zaitchik and Matt Rodell, Hydrological Sciences Branch, NASA Goddard Space Flight Center.
identifier Missanomaly_GRA_2005
Earthquake Signal Visible in …
PIA03625
Sol (our sun)
K-Band Ranging System
Title Earthquake Signal Visible in GRACE Data
Original Caption Released with Image Figure1 This figure shows the effect of the December 2004 great Sumatra earthquake on the Earth?s gravity field as observed by GRACE. The signal is expressed in terms of the relative acceleration of the two GRACE satellites, in this case a few nanometers per second squared, or about 1 billionth of the acceleration we experience everyday at the Earth?s surface.GRACE observations show comparable signals in the region of the earthquake. Other natural variations are also apparent in the expected places, whereas no other significant change would be expected in the region of the earthquake GRACE, twin satellites launched in March 2002, are making detailed measurements of Earth's gravity field which will lead to discoveries about gravity and Earth's natural systems. These discoveries could have far-reaching benefits to society and the world's population.
Earthquake Signal Visible in …
PIA03625
Sol (our sun)
K-Band Ranging System
Title Earthquake Signal Visible in GRACE Data
Original Caption Released with Image Figure1 This figure shows the effect of the December 2004 great Sumatra earthquake on the Earth?s gravity field as observed by GRACE. The signal is expressed in terms of the relative acceleration of the two GRACE satellites, in this case a few nanometers per second squared, or about 1 billionth of the acceleration we experience everyday at the Earth?s surface.GRACE observations show comparable signals in the region of the earthquake. Other natural variations are also apparent in the expected places, whereas no other significant change would be expected in the region of the earthquake GRACE, twin satellites launched in March 2002, are making detailed measurements of Earth's gravity field which will lead to discoveries about gravity and Earth's natural systems. These discoveries could have far-reaching benefits to society and the world's population.
Artist's concept of Gravity …
PIA04236
Title Artist's concept of Gravity Recovery and Climate Experiment
Original Caption Released with Image Artist's concept of Grace
Artist's concept of Gravity …
PIA04235
Title Artist's concept of Gravity Recovery and Climate Experiment
Original Caption Released with Image Artist's concept of Grace
New Views of Earth's Gravity …
PIA04652
Sol (our sun)
K-Band Ranging System
Title New Views of Earth's Gravity Field from GRACE
Original Caption Released with Image Gravity and the Earth's Shape Gravity is the force that is responsible for the weight of an object and is determined by how the material that makes up the Earth is distributed throughout the Earth. Because gravity changes over the surface of the Earth, the weight of an object changes along with it. One can define standard gravity as the value of gravity for an perfectly smooth 'idealized' Earth, and the gravity 'anomaly' is a measure of how actual gravity deviates from this standard. Gravity reflects the Earth's surface topography to a high degree and is associated with features that most people are familiar with such as large mountains and deep ocean trenches. Progress in Measuring the Earth's Gravity Field Through GRACE Prior to GRACE, the Earth's gravity field was determined using measurements of varying quality from different satellites and of incomplete coverage. Consequently the accuracy and resolution of the gravity field were limited. As is shown in Figure 1, the long wavelength components of the gravity field determined from satellite tracking were limited to a resolution of approximately 700 km. At shorter wavelengths, the errors were too large to be useful. Only broad geophysical features of the Earth's structure could be detected (see map 1). In contrast, GRACE, by itself, has provided accurate gravity information with a resolution of 200 km. Now, much more detail is clearly evident in the Earth's geophysical features (see map 2). High resolution features detected by GRACE that are representative of geophysical phenomena include the Tonga/Kermadec region (a zone where one tectonic plate slides under another), the Himalayan/Tibetan Plateau region (an area of uplift due to colliding plates), and the mid-Atlantic ridge (an active spreading center in the middle of the Atlantic ocean where new crust is being created). Future GRACE gravity models are expected to increase the resolution further. The second figure confirms that the Grace data is global, homogeneous and highly accurate. These are all properties that have been sought for gravity model development., Ocean Circulation Measurements from Grace The arrows in the three data sets in Figure 3 depict ocean currents off the East Coast of the United States, 1,000 meters (approximately 3,280 feet) beneath the surface. The top panel is obtained from the GRACE geoid, satellite altimetry and ship measurements of temperature and salt. The bottom panel is computed in the same manner as the top one, except that the best geoid prior to GRACE is used instead of the GRACE geoid. The middle panel shows direct measurement of those currents by floats deployed from ships. Notice that the current arrows in the Gulf Stream extension, East and slightly South of Washington DC, point eastward, toward Europe, in the two upper panels, but in the opposite direction in the lower panel. Colors indicate the strength of the ocean current, with red being strongest and blue-green weakest. Areas in white have no available data. The Gulf Stream region of the North Atlantic is among the best studied in the world's oceans, with a significant quantity of high-quality data available on it as a result of shipborne instrument measurements. In less well studied regions, the new information provided by GRACE, together with satellite altimetry, will increase our knowledge of ocean circulation.
New Views of Earth's Gravity …
PIA04652
Sol (our sun)
K-Band Ranging System
Title New Views of Earth's Gravity Field from GRACE
Original Caption Released with Image Gravity and the Earth's Shape Gravity is the force that is responsible for the weight of an object and is determined by how the material that makes up the Earth is distributed throughout the Earth. Because gravity changes over the surface of the Earth, the weight of an object changes along with it. One can define standard gravity as the value of gravity for an perfectly smooth 'idealized' Earth, and the gravity 'anomaly' is a measure of how actual gravity deviates from this standard. Gravity reflects the Earth's surface topography to a high degree and is associated with features that most people are familiar with such as large mountains and deep ocean trenches. Progress in Measuring the Earth's Gravity Field Through GRACE Prior to GRACE, the Earth's gravity field was determined using measurements of varying quality from different satellites and of incomplete coverage. Consequently the accuracy and resolution of the gravity field were limited. As is shown in Figure 1, the long wavelength components of the gravity field determined from satellite tracking were limited to a resolution of approximately 700 km. At shorter wavelengths, the errors were too large to be useful. Only broad geophysical features of the Earth's structure could be detected (see map 1). In contrast, GRACE, by itself, has provided accurate gravity information with a resolution of 200 km. Now, much more detail is clearly evident in the Earth's geophysical features (see map 2). High resolution features detected by GRACE that are representative of geophysical phenomena include the Tonga/Kermadec region (a zone where one tectonic plate slides under another), the Himalayan/Tibetan Plateau region (an area of uplift due to colliding plates), and the mid-Atlantic ridge (an active spreading center in the middle of the Atlantic ocean where new crust is being created). Future GRACE gravity models are expected to increase the resolution further. The second figure confirms that the Grace data is global, homogeneous and highly accurate. These are all properties that have been sought for gravity model development., Ocean Circulation Measurements from Grace The arrows in the three data sets in Figure 3 depict ocean currents off the East Coast of the United States, 1,000 meters (approximately 3,280 feet) beneath the surface. The top panel is obtained from the GRACE geoid, satellite altimetry and ship measurements of temperature and salt. The bottom panel is computed in the same manner as the top one, except that the best geoid prior to GRACE is used instead of the GRACE geoid. The middle panel shows direct measurement of those currents by floats deployed from ships. Notice that the current arrows in the Gulf Stream extension, East and slightly South of Washington DC, point eastward, toward Europe, in the two upper panels, but in the opposite direction in the lower panel. Colors indicate the strength of the ocean current, with red being strongest and blue-green weakest. Areas in white have no available data. The Gulf Stream region of the North Atlantic is among the best studied in the world's oceans, with a significant quantity of high-quality data available on it as a result of shipborne instrument measurements. In less well studied regions, the new information provided by GRACE, together with satellite altimetry, will increase our knowledge of ocean circulation.
New Views of Earth's Gravity …
PIA04652
Sol (our sun)
K-Band Ranging System
Title New Views of Earth's Gravity Field from GRACE
Original Caption Released with Image Gravity and the Earth's Shape Gravity is the force that is responsible for the weight of an object and is determined by how the material that makes up the Earth is distributed throughout the Earth. Because gravity changes over the surface of the Earth, the weight of an object changes along with it. One can define standard gravity as the value of gravity for an perfectly smooth 'idealized' Earth, and the gravity 'anomaly' is a measure of how actual gravity deviates from this standard. Gravity reflects the Earth's surface topography to a high degree and is associated with features that most people are familiar with such as large mountains and deep ocean trenches. Progress in Measuring the Earth's Gravity Field Through GRACE Prior to GRACE, the Earth's gravity field was determined using measurements of varying quality from different satellites and of incomplete coverage. Consequently the accuracy and resolution of the gravity field were limited. As is shown in Figure 1, the long wavelength components of the gravity field determined from satellite tracking were limited to a resolution of approximately 700 km. At shorter wavelengths, the errors were too large to be useful. Only broad geophysical features of the Earth's structure could be detected (see map 1). In contrast, GRACE, by itself, has provided accurate gravity information with a resolution of 200 km. Now, much more detail is clearly evident in the Earth's geophysical features (see map 2). High resolution features detected by GRACE that are representative of geophysical phenomena include the Tonga/Kermadec region (a zone where one tectonic plate slides under another), the Himalayan/Tibetan Plateau region (an area of uplift due to colliding plates), and the mid-Atlantic ridge (an active spreading center in the middle of the Atlantic ocean where new crust is being created). Future GRACE gravity models are expected to increase the resolution further. The second figure confirms that the Grace data is global, homogeneous and highly accurate. These are all properties that have been sought for gravity model development., Ocean Circulation Measurements from Grace The arrows in the three data sets in Figure 3 depict ocean currents off the East Coast of the United States, 1,000 meters (approximately 3,280 feet) beneath the surface. The top panel is obtained from the GRACE geoid, satellite altimetry and ship measurements of temperature and salt. The bottom panel is computed in the same manner as the top one, except that the best geoid prior to GRACE is used instead of the GRACE geoid. The middle panel shows direct measurement of those currents by floats deployed from ships. Notice that the current arrows in the Gulf Stream extension, East and slightly South of Washington DC, point eastward, toward Europe, in the two upper panels, but in the opposite direction in the lower panel. Colors indicate the strength of the ocean current, with red being strongest and blue-green weakest. Areas in white have no available data. The Gulf Stream region of the North Atlantic is among the best studied in the world's oceans, with a significant quantity of high-quality data available on it as a result of shipborne instrument measurements. In less well studied regions, the new information provided by GRACE, together with satellite altimetry, will increase our knowledge of ocean circulation.
New Views of Earth's Gravity …
PIA04652
Sol (our sun)
K-Band Ranging System
Title New Views of Earth's Gravity Field from GRACE
Original Caption Released with Image Gravity and the Earth's Shape Gravity is the force that is responsible for the weight of an object and is determined by how the material that makes up the Earth is distributed throughout the Earth. Because gravity changes over the surface of the Earth, the weight of an object changes along with it. One can define standard gravity as the value of gravity for an perfectly smooth 'idealized' Earth, and the gravity 'anomaly' is a measure of how actual gravity deviates from this standard. Gravity reflects the Earth's surface topography to a high degree and is associated with features that most people are familiar with such as large mountains and deep ocean trenches. Progress in Measuring the Earth's Gravity Field Through GRACE Prior to GRACE, the Earth's gravity field was determined using measurements of varying quality from different satellites and of incomplete coverage. Consequently the accuracy and resolution of the gravity field were limited. As is shown in Figure 1, the long wavelength components of the gravity field determined from satellite tracking were limited to a resolution of approximately 700 km. At shorter wavelengths, the errors were too large to be useful. Only broad geophysical features of the Earth's structure could be detected (see map 1). In contrast, GRACE, by itself, has provided accurate gravity information with a resolution of 200 km. Now, much more detail is clearly evident in the Earth's geophysical features (see map 2). High resolution features detected by GRACE that are representative of geophysical phenomena include the Tonga/Kermadec region (a zone where one tectonic plate slides under another), the Himalayan/Tibetan Plateau region (an area of uplift due to colliding plates), and the mid-Atlantic ridge (an active spreading center in the middle of the Atlantic ocean where new crust is being created). Future GRACE gravity models are expected to increase the resolution further. The second figure confirms that the Grace data is global, homogeneous and highly accurate. These are all properties that have been sought for gravity model development., Ocean Circulation Measurements from Grace The arrows in the three data sets in Figure 3 depict ocean currents off the East Coast of the United States, 1,000 meters (approximately 3,280 feet) beneath the surface. The top panel is obtained from the GRACE geoid, satellite altimetry and ship measurements of temperature and salt. The bottom panel is computed in the same manner as the top one, except that the best geoid prior to GRACE is used instead of the GRACE geoid. The middle panel shows direct measurement of those currents by floats deployed from ships. Notice that the current arrows in the Gulf Stream extension, East and slightly South of Washington DC, point eastward, toward Europe, in the two upper panels, but in the opposite direction in the lower panel. Colors indicate the strength of the ocean current, with red being strongest and blue-green weakest. Areas in white have no available data. The Gulf Stream region of the North Atlantic is among the best studied in the world's oceans, with a significant quantity of high-quality data available on it as a result of shipborne instrument measurements. In less well studied regions, the new information provided by GRACE, together with satellite altimetry, will increase our knowledge of ocean circulation.
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