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Sun of Goddard Space Flight Center (GSFC) and Washington from 2005
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Iapetus Thermal Radiation Im
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| Description |
Iapetus Thermal Radiation Image |
| Full Description |
This image of the infrared heat radiation from Saturn's moon Iapetus was obtained by the Cassini composite infrared spectrometer instrument 16 hours before Cassini's closest approach to this mysterious moon, on December 31, 2004. The thermal radiation is shown as both a grayscale image, equivalent to what we would see if our eyes were sensitive to infrared wavelengths near 15 microns, and as a color-coded temperature map. A previously-released mosaic obtained by Cassini's imaging camera shortly before the composite infrared spectrometer observation, with similar scale and orientation, is also shown for comparison. Temperatures reach nearly 130 Kelvin (-226 Fahrenheit) at noon on the equator on the dark material that covers most of this side of Iapetus, making high noon on Iapetus's dark side probably the warmest places in the Saturn system. This is much warmer than temperatures on another Saturnian moon, Phoebe, measured by composite infrared spectrometer in June 2004. Those Phoebe temperature measurements peaked near 112 Kelvin (-258 Fahrenheit), because though Phoebe is almost as dark as Iapetus's dark material and absorbs nearly as much sunlight, Phoebe rotates much more quickly (once every 9 hours, compared to 79 days for Iapetus). That means the surface has less time to heat up during the day. Temperatures on Iapetus's bright material are much colder, peaking near 100 Kelvin (-280 Fahrenheit), both because the bright material absorbs less sunlight and because it is further from the equator on this side of Iapetus. Temperatures in the large crater near the center of the disc are slightly different from those in surrounding areas, because sloping surfaces within the crater are warmer where they are tilted towards the Sun and cooler when tilted away from the Sun. 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 and its two onboard cameras were designed, developed and assembled at JPL. The composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md. For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the instrument team's home page, http://cirs.gsfc.nasa.gov/. *Credit*: NASA/JPL/GSFC |
| Date |
January 10, 2005 |
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Iapetus Temperature Variatio
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| Description |
Iapetus Temperature Variation Map |
| Full Description |
This plot shows how daytime temperatures at low latitudes on the dark material on Saturn's moon Iapetus vary with time of day, from about 130 Kelvin (-226 Fahrenheit) at noon to about 70 Kelvin (-334 Fahrenheit) at sunset. The observations are compared to a "forecast" model (green line) which predicts temperatures based on an assumed value of a parameter called the "thermal inertia. This measures how well the surface can retain heat as conditions change. Rock or solid ice has a high thermal inertia, roughly 2,000,000 as measured in the obscure units used for thermal inertia, meaning that it is good at storing heat and cools down or heats up relatively slowly. On Iapetus, in contrast, temperatures drop precipitously in the afternoon as the Sun sinks towards the horizon, and a very small value of the thermal inertia (30,000 units) is needed in the model to match the data. This means that Iapetus's surface is extremely bad at storing heat, and is thus extremely fluffy, probably due to the pulverizing effect of billions of years of meteorite impacts, though the mysterious process that has darkened this side of Iapetus may also have played a role. 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 and its two onboard cameras were designed, developed and assembled at JPL. The composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md. For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the instrument team's home page, http://cirs.gsfc.nasa.gov/. *Credit*: NASA/JPL/GSFC |
| Date |
January 10, 2005 |
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Enceladus Temperature Map
| Description |
Enceladus Temperature Map |
| Full Description |
This image shows the surprise that startled Cassini scientists on the composite infrared spectrometer team when they got their first look at the infrared (heat) radiation from the south pole of Saturn's moon Enceladus. There is a dramatic warm spot centered on the pole that is probably a sign of internal heat leaking out of the icy moon. The data were taken during the spacecraft's third flyby of this intriguing moon on July 14, 2005. Based on data from previous flybys, which did not show the south pole well, team members expected that the south pole would be very cold, as shown in the left panel. Enceladus is one of the coldest places in the Saturn system because its extremely bright surface reflects 80 percent of the sunlight that hits it, so only 20 percent is available to heat the surface. As on Earth, the poles should be even colder than the equator because the sun shines at such an oblique angle there. The right hand panel shows a global temperature image made from measurements of Enceladus' heat radiation at wavelengths between 9 and 16.5 microns. Cassini made the observation from a distance of 84,000 kilometers (52,000 miles) on the approach to Enceladus, and the image shows details as small as 25 kilometers (16 miles). Equatorial temperatures are much as expected, topping out at about 80 degrees Kelvin (-315 degrees Fahrenheit), but the south pole is occupied by a well-defined warm region reaching 85 Kelvin (-305 degrees Fahrenheit). That is 15 degrees Kelvin (27 degrees Fahrenheit) warmer than expected. The composite infrared spectrometer data further suggest that small areas of the pole are at even higher temperatures, well over 110 degrees Kelvin (-261 degrees Fahrenheit). Evaporation of this relatively warm ice probably generates the cloud of water vapor detected above Enceladus' south pole by several other Cassini instruments. The south polar temperatures are very difficult to explain if sunlight is the only energy source heating the surface, though exotic sunlight-trapping mechanisms have not yet been completely ruled out. It therefore seems likely that portions of the polar region are warmed by heat escaping from the interior of the moon. This would make Enceladus only the third solid body in the solar system, after Earth and Jupiter's volcanic moon Io, where hot spots powered by internal heat have been detected. 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 composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The composite infrared spectrometer team homepage is, http://cirs.gsfc.nasa.gov/ . Credit: NASA/JPL/GSFC |
| Date |
July 29, 2005 |
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Slower Spinning Rings #1
| Description |
Slower Spinning Rings #1 |
| Full Description |
The Cassini composite infrared spectrometer obtained temperature maps of Saturn's main rings (A, B and C) that showed ring temperatures decreasing with increasing solar phase angle (the change of the sun-spacecraft-ring angle) on both the lit and unlit sides of the rings. Temperature changes throughout Saturn's main rings, as measured by the instrument, indicate that Saturn ring particles spin slowly compared to their orbital periods of 6 to 14 hours. They may spin several times per orbit to less than one time per orbit. Scans are shown for the lit and unlit rings, at relatively low (less than 60-degree) and high (more than 130-degree) phase angles. Each scan was painted on the rings at the correct ring orientation, creating a false color image. Warmer temperatures about minus 262 degrees Fahrenheit (110 Kelvin) are shown in red and cooler temperatures about minus 343 degrees (65 K) are shown in blue. Other colors indicate temperatures between minus 343 degrees and minus 262 degrees (65 K and 110 K). The scans of the lit rings are shown in the two panels on the left and scans of the unlit rings are shown in the two panels on the right. The thermal characteristics of each main ring vary noticeably with phase angle. Radial scans of the A, B and C rings show a decrease in temperature with increasing phase angle for both the lit and unlit sides of the rings. The C ring and Cassini Division exhibit the largest change in temperature. The temperature of the lit C ring decreases by about 22 degrees (12 Kelvin) between low and high phase angles. A similar contrast is present for the unlit side of the C ring. The C ring and Cassini Division are darker than the A and B rings so they can absorb more heat from the Sun. The lit B ring shows a temperature contrast of approximately 18 degrees (10 K) while the unlit B ring shows very little thermal contrast. Very little sunlight may make it through the thick B ring to its unlit side. The lit A ring is particularly interesting because the magnitude of the thermal contrast decreases with increasing radial distance from Saturn. The outer A ring shows only a small temperature change with phase angle, possibly because it contains smaller, or more rapidly rotating ring particles, which would have more uniform temperatures with phase angle. 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 composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md. For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the instrument team's home page, http://cirs.gsfc.nasa.gov/. Credit: NASA/JPL/GSFC |
| Date |
September 5, 2005 |
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Slower Spinning Rings #2
| Description |
Slower Spinning Rings #2 |
| Full Description |
Temperature changes mapped with Cassini's composite and infrared spectrometer throughout Saturn's main rings show the ring temperatures decreasing with the increase of the Sun-spacecraft-ring angle (called phase angle) on both the lit and unlit sides of the rings. These temperature changes indicate that the ring particles spin slowly compared to their orbital periods of 6 to 14 hours. They may spin several times per orbit to less than one time per orbit. Four scans are shown for the lit and unlit rings, at relatively low (less than 60 degrees) and high (more than 130 degrees) phase angles. Warmer temperatures about minus 262 degrees Fahrenheit (110 Kelvin) are shown in red and cooler temperatures about minus 343 degrees (65 K) are shown in blue. Other colors indicate temperatures between minus 343 degrees and minus 262 degrees (65 K and 110 K). The top two scans are for the lit rings and the bottom two scans are for the unlit rings. The change in ring temperature between each scan can be seen clearly. The thermal characteristics of each main ring vary noticeably with phase angle. Radial scans of the A, B and C rings show a decrease in temperature with increasing phase angle for both the lit and unlit sides of the rings. The C ring and Cassini Division exhibit the largest change in temperature. The temperature of the lit C ring decreases by about 22 degrees (12 Kelvin) between low and high phase angles. A similar contrast is present for the unlit side of the C ring. The C ring and Cassini Division are darker than the A and B rings so they can absorb more heat from the Sun. The lit B ring shows a temperature contrast of approximately 18 degrees (10 K) while the unlit B ring shows very little thermal contrast. Very little sunlight may make it through the thick B ring to its unlit side. The lit A ring is particularly interesting because the magnitude of the thermal contrast decreases with increasing radial distance from Saturn. The outer A ring shows only a small temperature change with phase angle, possibly because it contains smaller, or more rapidly rotating ring particles, which would have more uniform temperatures with phase angle. 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 composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md. For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the instrument team's home page, http://cirs.gsfc.nasa.gov/. |
| Date |
September 5, 2005 |
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Iapetus Temperature Map
| Description |
Iapetus Temperature Map |
| Full Description |
This temperature map of Saturn's moon Iapetus is constructed from observations of Iapetus's infrared heat radiation taken with the Cassini composite infrared spectrometer instrument during the Dec. 31, 2004 flyby. The orange asterisk marks the point on Iapetus where the Sun is directly overhead. Temperatures reach nearly 130 Kelvin (-226 Fahrenheit) at noon on the equator on the dark material that covers most of this side of Iapetus, making high noon on Iapetus's dark side probably the warmest places in the Saturn system. This is much warmer than temperatures on the moon Phoebe measured by the composite infrared spectrometer in June 2004, which peaked near 112 Kelvin (-258 Fahrenheit). That's because, although Phoebe is almost as dark as Iapetus's dark material and absorbs nearly as much sunlight, Phoebe rotates much more quickly (once every 9 hours, compared to 79 days for Iapetus). That means the surface has less time to heat up during the day. Temperatures on Iapetus' bright material are much colder, peaking near 100 Kelvin (-280 Fahrenheit), both because the bright material absorbs less sunlight and because it is further from the equator on this side of Iapetus. 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 and its two onboard cameras were designed, developed and assembled at JPL. The composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md. For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the instrument team's home page, http://cirs.gsfc.nasa.gov/. *Credit*: NASA/JPL/GSFC |
| Date |
January 10, 2005 |
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Hubble Finds Mysterious Disk
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Hubble Finds Mysterious Disk of Blue Stars Around Black Hole |
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Rice Cultivation in Northwes
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| Title |
Rice Cultivation in Northwest Italy |
| Description |
The lowlands of Lombardy and Piedmont in northwest Italy are some of the most highly developed irrigation areas in the world. Irrigated lands cover at least 160,000 acres in this part of Italy, where rice is the most important crop. These views of the region were acquired on May 8, 2005, by NASA's Multi-angle Imaging SpectroRadiometer (MISR). The multiple viewing angles provided by MISR's nine cameras make it possible to tell wet surfaces, including flooded lands, from other surfaces, and they also make cities easy to locate. The left-hand image is a natural-color view acquired by MISR's downward-looking (nadir) camera, and the right-hand image is a combination of red band data from MISR's 60-degree-backward-, nadir, and 60-degree-forward-viewing cameras. (Red band is what scientists call the "channel" on the sensor that detects red light.) Color changes indicate surface texture, which is influenced by terrain, vegetation structure, soil type, and surface wetness. Wet surfaces or areas with standing water appear in blue or purple-blue hues. The purple-blue areas that dominate the center-left part of the image are part of the extensive irrigation network that exists throughout the plains and meadows of the region. Cities with tall buildings appear in red-orange hues. In this type of image, the city of Milan is the most obvious. The small orange area in the center of the purple inundated area indicates the location of Vercelli, and the larger city of Milan is the orange area to the northeast, on the other side of the Ticino River. To a lesser extent, the cities of Novara, Pavia, Galliate, Mortara, and Vigevano are also identifiable by their orange hues. MISR can tell various surface features like cities or irrigated areas apart because of the way surfaces reflect light. A smooth water surface tends to reflect sunlight away from the Sun. This effect is most apparent when a satellite views the surface with the Sun in front of the camera. Similarly, rough surfaces tend to reflect light back towards the Sun, and this "backward scattering" is most obvious when a satellites views a surface with the Sun behind the camera. Clouds present over the high country to the west of the Lago Maggiore (upper left corner) and along the coast of the Golfo di Genova (bottom) appear in a different spot for each view angle, creating a rainbow-like appearance. Mountains also have a "wavy" look in the multi-angle combination because, like clouds, their height above the surface makes them appear in a different spot in each camera's view angle. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously, viewing the entire globe between 82 degrees North and 82 degrees South latitude every nine days. This image covers an area of about 131 kilometers by 191 kilometers. These data products were generated from a portion of the imagery acquired during Terra orbit 28660 and utilize data from block 54 within World Reference System-2 path 193. MISR was, built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is managed for NASA by the California Institute of Technology. Image courtesy NASA/GSFC/LaRC/JPL, MISR Team. [ http://www-misr.jpl.nasa.gov/ ] Text by Clare Averill (Raytheon ITSS/JPL) |
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Rice Cultivation in Northwes
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nasa, nasaimageofthedaygalle
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The lowlands of Lombardy and
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PIA04380
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2005-05-08 |
| creator |
NASA -- Image courtesy NASA/GSFC/LaRC/JPL, www-misr.jpl.nasa.gov/ MISR Team. Text by Clare Averill (Raytheon ITSS/JPL) |
| identifier |
PIA04380 |
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Seasonal Changes in Earth's
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nasa, nasaimageofthedaygalle
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Triggered by seasonal change
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misr_albedo_2004
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2005 |
| creator |
NASA -- Image courtesy NASA/GSFC/LaRC/JPL, www-misr.jpl.nasa.gov/ MISR Team. Text by John Martonchik (JPL) and Clare Averill (Raytheon ITSS/JPL). |
| identifier |
misr_albedo_2004 |
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Saharan Dust Cloud Sails Tow
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PIA03539
Sol (our sun)
Multi-angle Imaging SpectroR
…
| Title |
Saharan Dust Cloud Sails Toward U.S. |
| Original Caption Released with Image |
A huge dust cloud blown westward from the Algerian desert is now wafting over the southeastern United States. The cloud, about the size of the entire continent, was expected to produce dramatic sunsets and possibly a light coating of red-brown dust on vehicles from Florida to Texas. This image, captured by JPL's Multi-angle Imaging SpectroRadiometer (MISR) aboard the NASA Earth Observing System's Terra Satellite on July 20, 2005, shows the dust cloud just off the west coast of Africa near Mauritania and Senegal. The image covers about 1,800 kilometers (1,200 miles) north-south, and 400 kilometers (260 miles) east-west. MISR, which views Earth at nine different angles in four wavelengths, can derive the amount, size and shape of airborne particles. This means it can distinguish desert dust, by far the most common non-spherical atmospheric aerosol, from pollution and forest fire particles, which are typically spherical. This image was taken by MISR's 26 degree forward-viewing camera on Terra Orbit 29724, Path 208, Blocks 69-81. The Multi-angle Imaging SpectroRadiometer [ http://www-misr.jpl.nasa.gov/ ] observes the daylit Earth continuously from pole to pole, and the entire globe about once per week. 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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Tracking Hurricane Wilma Acr
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PIA04386
Sol (our sun)
Multi-angle Imaging SpectroR
…
| Title |
Tracking Hurricane Wilma Across the Caribbean |
| Original Caption Released with Image |
Information on cloud top heights at different stages in the life cycle of the rapidly intensifying Hurricane Wilma may prove useful for evaluating the ability of numerical weather models to predict the intensity changes of hurricanes. NASA's Multi-angle Imaging SpectroRadiometer (MISR) acquired this sequence of images and cloud-top height observations for Hurricane Wilma as it progressed across the Caribbean in October 2005. Each pair in the sequence has a photo-like view of the storm on the left and a matching color-coded image of cloud-top height on the right. Cloud-top heights range from 0 (purple) to 18 (red) kilometers altitude. Areas where cloud heights could not be determined are shown in dark gray. The pair on the left show Wilma on Tuesday, October 18, when Hurricane watches were posted for Cuba and Mexico. The central pair shows the eye of Hurricane Wilma just hours before the storm began to cross the Yucatan Peninsula on Friday, October 21. At that time, Wilma was a powerful Category 4 Hurricane on the Saffir-Simpson scale, and had a minimum recorded central pressure of 930 millibars. Hurricane Wilma surged from tropical storm to Category 5 hurricane status in record time, but the storm slowed and weakened considerably after battering Mexico's Yucatan Peninsula and the Caribbean. The right-hand image pair displays the eastern edges of a weakened Wilma, when Wilma had been reduced to Category 2 status and was just starting to reach southern Florida on the morning of Sunday, October 23. Wilma gathered speed and strengthened on Sunday night, crossing Florida as a Category 3 storm on Monday, October 24. On the 18th, Wilma looked a bit ragged. Its eye is located at the center of the left edge, and its outer bands of clouds appear to be dominated by a rather loose collection of thunderstorms. In the photo-like images, these look like areas of "boiling clouds," and in the cloud-height image, these appear as orange blobs, sometimes topped with pinkish-red. On October 21 (center), when Wilma was a Category 4 storm, cloud-top height on the eastern side of the storm near the eye reached 18 kilometers in altitude, with lower heights on the western side. The image from the 23rd shows the eastern edge of Wilma as it approached Florida (upper right) and Cuba (center right). MISR has nine different cameras which view the Earth from a variety of angles. Shifts in the clouds' apparent position from one camera's perspective to another's allows MISR to measure the height of the cloud-tops. MISR scientists have programmed computers to compare the different views, identify features that appear to shift from view to view, and use that information to calculate cloud height automatically. The height fields pictured have not been corrected for the effects of cloud motion. Wind-corrected heights (which have higher accuracy but sparser spatial coverage) are within about 1 kilometer of the heights shown here. The Multi-angle Imaging SpectroRadiometer, observes the daylit Earth continuously, viewing the entire globe between 82° north and 82° south latitude every nine days. Each image covers an area of about 380 kilometers by 1830 kilometers. The data products were generated from a portion of the imagery acquired during Terra orbits 31037, 31081 and 31110, and utilize data from within blocks 68-83 within World Reference System-2 paths 13, 16 and 18, respectively. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is managed for NASA by the California Institute of Technology. |
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St. Louis, Missouri
PIA09362
Sol (our sun)
Multi-angle Imaging SpectroR
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| Title |
St. Louis, Missouri |
| Original Caption Released with Image |
St. Louis is tucked in a bend of the Mississippi River, just south of the point at which the Illinois River joins the larger Mississippi, and where the Missouri River flows in from the west. Drainage patterns to the east, on the Illinois side, are highlighted with green vegetation. Meandering rivers in the verdant Ozark Plateau appear to the south and west. This true-color view from NASA's Multi-angle Imaging SpectroRadiometer (MISR) was taken with the instrument's downward looking (nadir) camera on October 15, 2005. The urban areas of greater St. Louis show up as grey-white, including nearby Kirkwood, Webster Groves, Clayton, University City, Ferguson, St. Ann, St. Charles, and East St. Louis. The region is home to nearly three million people. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Science Mission Directorate, 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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Cloud Spirals and Outflow in
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PIA04384
Sol (our sun)
Multi-angle Imaging SpectroR
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| Title |
Cloud Spirals and Outflow in Tropical Storm Katrina |
| Original Caption Released with Image |
On Tuesday, August 30, 2005, NASA's Multi-angle Imaging SpectroRadiometer retrieved cloud-top heights and cloud-tracked wind velocities for Tropical Storm Katrina, as the center of the storm was situated over the Tennessee valley. At this time Katrina was weakening and no longer classified as a hurricane, and would soon become an extratropical depression. Measurements such as these can help atmospheric scientists compare results of computer-generated hurricane simulations with observed conditions, ultimately allowing them to better represent and understand physical processes occurring in hurricanes. Because air currents are influenced by the Coriolis force (caused by the rotation of the Earth), Northern Hemisphere hurricanes are characterized by an inward counterclockwise (cyclonic) rotation towards the center. It is less widely known that, at high altitudes, outward-spreading bands of cloud rotate in a clockwise (anticyclonic) direction. The image on the left shows the retrieved cloud-tracked winds as red arrows superimposed across the natural color view from MISR's nadir (vertical-viewing) camera. Both the counter-clockwise motion for the lower-level storm clouds and the clockwise motion for the upper clouds are apparent in these images. The speeds for the clockwise upper level winds have typical values between 40 and 45 m/s (144-162 km/hr). The low level counterclockwise winds have typical values between 7 and 24 m/s (25-86 km/hr), weakening with distance from the storm center. The image on the right displays the cloud-top height retrievals. Areas where cloud heights could not be retrieved are shown in dark gray. Both the wind velocity vectors and the cloud-top height field were produced by automated computer recognition of displacements in spatial features within successive MISR images acquired at different view angles and at slightly different times. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously, viewing the entire globe between 82° north and 82° south latitude every nine days. This image covers an area of about 380 kilometers by 1970 kilometers. These data products were generated from a portion of the imagery acquired during Terra orbit 30324 and utilize data from blocks 55-68 within World Reference System-2 path 22. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is managed for NASA by the California Institute of Technology. |
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Flooding in the Aftermath of
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PIA04385
Sol (our sun)
Multi-angle Imaging SpectroR
…
| Title |
Flooding in the Aftermath of Hurricane Katrina |
| Original Caption Released with Image |
These views of the Louisiana and Mississippi regions were acquired before and one day after Katrina made landfall along the Gulf of Mexico coast, and highlight many of the changes to the rivers and vegetation that occurred between the two views. The images were acquired by NASA's Multi-angle Imaging SpectroRadiometer (MISR) on August 14 and August 30, 2005. These multiangular, multispectral false-color composites were created using red band data from MISR's 46° backward and forward-viewing cameras, and near-infrared data from MISR's nadir camera. Such a display causes water bodies and inundated soil to appear in blue and purple hues, and highly vegetated areas to appear bright green. The scene differentiation is a result of both spectral effects (living vegetation is highly reflective at near-infrared wavelengths whereas water is absorbing) and of angular effects (wet surfaces preferentially forward scatter sunlight). The two images were processed identically and extend from the regions of Greenville, Mississippi (upper left) to Mobile Bay, Alabama (lower right). There are numerous rivers along the Mississippi coast that were not apparent in the pre-Katrina image, the most dramatic of these is a new inlet in the Pascagoula River that was not apparent before Katrina. The post-Katrina flooding along the edges of Lake Pontchartrain and the city of New Orleans is also apparent. In addition, the agricultural lands along the Mississippi floodplain in the upper left exhibit stronger near-infrared brightness before Katrina. After Katrina, many of these agricultural areas exhibit a stronger signal to MISR's oblique cameras, indicating the presence of inundated soil throughout the floodplain. Note that clouds appear in a different spot for each view angle due to a parallax effect resulting from their height above the surface. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously, viewing the entire globe between 82° north and 82° south latitude every nine days. Each image covers an area of about 380 kilometers by 410 kilometers. The data products were generated from a portion of the imagery acquired during Terra orbits 30091 and 30324 and utilize data from blocks 64-67 within World Reference System-2 path 22. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is managed for NASA by the California Institute of Technology. |
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The Size of Dust and Smoke
PIA04382
Sol (our sun)
Multi-angle Imaging SpectroR
…
| Title |
The Size of Dust and Smoke |
| Original Caption Released with Image |
Desert dust particles tend to be larger in size than aerosols that originate from the processes of combustion. How precisely do the size of the aerosol particles comprising the dust that obscured the Red Sea on July 26, 2005, contrast with the size of the haze particles that obscured the United States eastern seaboard on the same day? NASA's Multi-angle Imaging SpectroRadiometer (MISR), which views Earth at nine different angles in four wavelengths, provides information about the amount, size, and shape of airborne particles. Here, MISR aerosol amount and size is presented for these two events. These MISR results distinguish desert dust, the most common non-spherical aerosol type, from pollution and forest fire particles. Determining aerosol characteristics is a key to understanding how aerosol particles influence the size, abundance, and rate of production of cloud droplets, and to a better understanding of how aerosols influence clouds and climate. The left panel of each of these two image sets (Red Sea, left, U.S. coastline, right) is a natural-color view from MISR's 70-degree forward viewing camera. The color-coded maps in the central panels show aerosol optical depth, the right panels provide a measure of aerosol size, expressed as the "Angstrom exponent." For the optical depth maps, yellow pixels indicate the most optically-thick aerosols, whereas the red, green and blue pixels represent progressively decreasing aerosol amounts. For this dramatic dust storm over the Red Sea, the aerosol is quite thick, and in some places, the dust over water is too optically thick for MISR to retrieve the aerosol amount. For the eastern seaboard haze, the thickest aerosols have accumulated over the Atlantic Ocean off the coasts of South Carolina and Georgia. Cases where no successful retrieval occurred, either due to extremely high aerosol optical thickness or to clouds, appear as dark gray pixels. For the Angstrom exponent maps, the blue and green pixels (smaller values) correspond with more large particles, whilst the yellow and red pixels, representing higher Angstrom exponents, correspond with more small particles. Angstrom exponent is related to the way the aerosol optical depth (AOD) changes with wavelength -- a more steeply decreasing AOD with wavelength indicates smaller particles. The greater the magnitude of the Angstrom exponent, the greater the contribution of smaller particles to the overall particle distribution. For optically thick desert dust storms, as in this case, the Angstrom exponent is expected to be relatively low -- likely below 1. For the eastern seaboard haze, the Angstrom exponent is significantly higher, indicating the relative abundance of small pollution particles, especially over the Atlantic where the aerosol optical depth is also very high. With a nearly simultaneous data acquisition time, the MODIS instrument also collected data for these events, and image features for both the dust storm and the haze are available., The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously, viewing the entire globe between 82° north and 82° south latitude every nine days. This image covers an area of about 1,265 kilometers by 400 kilometers. These data products were generated from a portion of the imagery acquired during Terra orbits 29809 and 29814 and utilize data from blocks 60 to 67 and 71 to 78 within World Reference System-2 paths 17 and 170, respectively. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is managed for NASA by the California Institute of Technology. |
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Super Typhoon Haitang
PIA07968
Sol (our sun)
SeaWinds Scatterometer
| Title |
Super Typhoon Haitang |
| Original Caption Released with Image |
Typhoon Haitang is shown here churning steadily towards Taiwan and China. This image shows the storm's swirling wind patterns as observed by NASA's QuikScat satellite on July 14, 2005, at 19:19 UTC (14:19 Eastern Daylight Time). At this time, the typhoon was located hundreds of kilometers from the nearest major land masses. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, shown in purple, surround the center of the storm. Measurements of the wind strength of Typhoon Haitang show sustained winds of around 85 knots and gusts up to 105 knots at the time of the QuickScat observations. The images, however, reveal lower wind speeds. This is because the power of the storm makes accurate measurements difficult. The scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. Tropical cyclones (the generic term for hurricanes and typhoons), however, are difficult to measure. To relate the radar energy return to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 kilometers per hour or 58 miles per hour). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. "QuikScat Background" NASA's Quick Scatterometer (QuikScat) spacecraft was launched from Vandenberg Air Force Base, California on June 19, 1999. QuikScat carries the SeaWinds scatterometer, a specialized microwave radar that measures near-surface wind speed and direction under all weather and cloud conditions over the Earth's oceans. More information about the QuikScat mission and observations is available at http://winds.jpl.nasa.gov [ http://photojournal.jpl.nasa.gov/catalog/PIA07968 http://winds.jpl.nasa.gov ]. QuikScat is managed for NASA's Science Mission Directorate, Washington, DC, by NASA's Jet Propulsion Laboratory, Pasadena, CA. JPL also built the SeaWinds radar instrument and is providing ground science processing systems. NASA's Goddard Space Flight Center, Greenbelt, MD, managed development of the satellite, designed and built by Ball Aerospace & Technologies Corp., Boulder, CO. The National Oceanic and Atmospheric Administration has contributed support to ground systems processing and related activities. |
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Hurricane Emily
PIA07969
Sol (our sun)
SeaWinds Scatterometer
| Title |
Hurricane Emily |
| Original Caption Released with Image |
When NASA's Quick Scatterometer (QuikScat) captured this image on July 13, 2005, Emily was just a few hours away from becoming a hurricane. The tropical storm was approaching Trinidad with winds of 95 kilometers per hour (60 miles per hour or 50 knots) when this image was taken at 5:05 p.m. Eastern Daylight Savings Time (21:05 UTC). The image reveals the structure of the storm, with wind speed shown in color and direction indicated by barbs. The white barbs indicate regions of heavy rain. Both the heaviest downpours and the strongest winds, shown in purple, are just east of the center of the storm. Compared to an image taken in the morning of July 13, this powerful section of the storm has expanded and moved closer to the center as Emily developed through the day. Emily is the fifth tropical storm of the 2005 Atlantic hurricane season, and the second storm to reach hurricane status. By July 15, Emily reached Category 3 status on the Saffir-Simpson scale with winds of 205 km/hr (125 mph). "QuikScat Background" NASA's Quick Scatterometer (QuikScat) spacecraft was launched from Vandenberg Air Force Base, California on June 19, 1999. QuikScat carries the SeaWinds scatterometer, a specialized microwave radar that measures near-surface wind speed and direction under all weather and cloud conditions over the Earth's oceans. More information about the QuikScat mission and observations is available at http://winds.jpl.nasa.gov [ http://photojournal.jpl.nasa.gov/catalog/PIA07969 http://winds.jpl.nasa.gov ]. QuikScat is managed for NASA's Science Mission Directorate, Washington, DC, by NASA's Jet Propulsion Laboratory, Pasadena, CA. JPL also built the SeaWinds radar instrument and is providing ground science processing systems. NASA's Goddard Space Flight Center, Greenbelt, MD, managed development of the satellite, designed and built by Ball Aerospace & Technologies Corp., Boulder, CO. The National Oceanic and Atmospheric Administration has contributed support to ground systems processing and related activities. |
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Drought in the Black Hills
PIA04379
Sol (our sun)
Multi-angle Imaging SpectroR
…
| Title |
Drought in the Black Hills |
| Original Caption Released with Image |
Annotated Color-Coded Map Despite good rainfall and record-setting snowstorms in the spring of 2005, most of northeastern Wyoming, the Black Hills, and western South Dakota remain in the midst of a severe drought. This set of images and maps from NASA's Multi-angle Imaging SpectroRadiometer (MISR) contrast the appearance of the Black Hills region of northwestern South Dakota on July 12, 2000 (left column), with views acquired four years later, on July 14, 2004 (right column). The natural-color images along the top are from MISR's nadir (downward-looking) camera. The browning that appears in 2004 compared with 2000 indicates that the vigor of green vegetation was significantly diminished in 2004. The color-coded maps (along the bottom) provide a quantitative measurement of the sunlight reflected from these surfaces, and the loss of sunlight-absorbing vegetation between the 2000 and 2004 dates. As the vegetation faded with the drought, the albedo at the surface increased. Albedo measures the fraction of incident sunlight that is reflected by a surface, and can vary between zero (if all the incident sunlight is absorbed and none is reflected) and one (if all sunlight is reflected and none is absorbed). Dense forest has a low albedo, bright desert, snow and clouds, have a high albedo. Here, albedo is provided for the wavelengths of sunlight that plants use for photosynthesis (400 - 700 nanometers). This measurement is known as the albedo for Photosynthetically Active Radiation (PAR). Surfaces with greater absorption of PAR appear here in blue hues, whereas surfaces with lower absorption appear as green, yellow, orange or red. Black pixels indicate areas where albedo could not be derived, usually due to the presence of clouds. In July 2004, low albedo areas (blue pixels) are notably reduced in extent, and higher albedo areas (yellow, orange and red pixels) have increased. Because incoming sunlight is scattered by tiny particles in the atmosphere, satellite measurements of albedo and other surface properties must correct for the effects of the intervening atmosphere. These albedo retrievals make use of MISR's simultaneously derived aerosol properties to make these corrections. The multiangular nature of MISR data is also used to account for the fact that most surfaces reflect sunlight into all upward directions, with intensities that vary with angle of view. 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. This image area covers about 243 kilometers by 259 kilometers. These data products were generated from a portion of the imagery acquired during Terra orbits 3020 and 24325 and utilize data from within blocks 54 to 56 within World Reference System-2 paths 33 and 34. 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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Drought in the Black Hills
PIA04379
Sol (our sun)
Multi-angle Imaging SpectroR
…
| Title |
Drought in the Black Hills |
| Original Caption Released with Image |
Annotated Color-Coded Map Despite good rainfall and record-setting snowstorms in the spring of 2005, most of northeastern Wyoming, the Black Hills, and western South Dakota remain in the midst of a severe drought. This set of images and maps from NASA's Multi-angle Imaging SpectroRadiometer (MISR) contrast the appearance of the Black Hills region of northwestern South Dakota on July 12, 2000 (left column), with views acquired four years later, on July 14, 2004 (right column). The natural-color images along the top are from MISR's nadir (downward-looking) camera. The browning that appears in 2004 compared with 2000 indicates that the vigor of green vegetation was significantly diminished in 2004. The color-coded maps (along the bottom) provide a quantitative measurement of the sunlight reflected from these surfaces, and the loss of sunlight-absorbing vegetation between the 2000 and 2004 dates. As the vegetation faded with the drought, the albedo at the surface increased. Albedo measures the fraction of incident sunlight that is reflected by a surface, and can vary between zero (if all the incident sunlight is absorbed and none is reflected) and one (if all sunlight is reflected and none is absorbed). Dense forest has a low albedo, bright desert, snow and clouds, have a high albedo. Here, albedo is provided for the wavelengths of sunlight that plants use for photosynthesis (400 - 700 nanometers). This measurement is known as the albedo for Photosynthetically Active Radiation (PAR). Surfaces with greater absorption of PAR appear here in blue hues, whereas surfaces with lower absorption appear as green, yellow, orange or red. Black pixels indicate areas where albedo could not be derived, usually due to the presence of clouds. In July 2004, low albedo areas (blue pixels) are notably reduced in extent, and higher albedo areas (yellow, orange and red pixels) have increased. Because incoming sunlight is scattered by tiny particles in the atmosphere, satellite measurements of albedo and other surface properties must correct for the effects of the intervening atmosphere. These albedo retrievals make use of MISR's simultaneously derived aerosol properties to make these corrections. The multiangular nature of MISR data is also used to account for the fact that most surfaces reflect sunlight into all upward directions, with intensities that vary with angle of view. 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. This image area covers about 243 kilometers by 259 kilometers. These data products were generated from a portion of the imagery acquired during Terra orbits 3020 and 24325 and utilize data from within blocks 54 to 56 within World Reference System-2 paths 33 and 34. 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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Enceladus Temperature Map
PIA06432
Saturn
Composite Infrared Spectrome
…
| Title |
Enceladus Temperature Map |
| Original Caption Released with Image |
. The composite infrared spectrometer team homepage is http://cirs.gsfc.nasa.gov/ [ http://cirs.gsfc.nasa.gov/ ]., This image shows the surprise that startled Cassini scientists on the composite infrared spectrometer team when they got their first look at the infrared (heat) radiation from the south pole of Saturn's moon Enceladus. There is a dramatic warm spot centered on the pole that is probably a sign of internal heat leaking out of the icy moon. The data were taken during the spacecraft's third flyby of this intriguing moon on July 14, 2005. Based on data from previous flybys, which did not show the south pole well, team members expected that the south pole would be very cold, as shown in the left panel. Enceladus is one of the coldest places in the Saturn system because its extremely bright surface reflects 80 percent of the sunlight that hits it, so only 20 percent is available to heat the surface. As on Earth, the poles should be even colder than the equator because the sun shines at such an oblique angle there. The right hand panel shows a global temperature image made from measurements of Enceladus' heat radiation at wavelengths between 9 and 16.5 microns. Cassini made the observation from a distance of 84,000 kilometers (52,000 miles) on the approach to Enceladus, and the image shows details as small as 25 kilometers (16 miles). Equatorial temperatures are much as expected, topping out at about 80 degrees Kelvin (-315 degrees Fahrenheit), but the south pole is occupied by a well-defined warm region reaching 85 Kelvin (-305 degrees Fahrenheit). That is 15 degrees Kelvin (27 degrees Fahrenheit) warmer than expected. The composite infrared spectrometer data further suggest that small areas of the pole are at even higher temperatures, well over 110 degrees Kelvin (-261 degrees Fahrenheit). Evaporation of this relatively warm ice probably generates the cloud of water vapor detected above Enceladus' south pole by several other Cassini instruments. The south polar temperatures are very difficult to explain if sunlight is the only energy source heating the surface, though exotic sunlight-trapping mechanisms have not yet been completely ruled out. It therefore seems likely that portions of the polar region are warmed by heat escaping from the interior of the moon. This would make Enceladus only the third solid body in the solar system, after Earth and Jupiter's volcanic moon Io, where hot spots powered by internal heat have been detected. 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 composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov [ http://saturn.jpl.nasa.gov ] |
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Cyclones in the Pacific
PIA07415
Sol (our sun)
SeaWinds Scatterometer
| Title |
Cyclones in the Pacific |
| Original Caption Released with Image |
The SeaWinds scatterometer aboard NASA's QuikScat satellite collected the data used to create this colorful image of Cyclone Olaf churning in the South Pacific on February 16, 2005. The colored background shows the near-surface wind speeds at 2.5-kilometer resolution. The strongest winds, shown in purple, are at the center of the storm, with gradually weakening winds forming rings around the center. The black barbs indicate wind speed and direction at QuikScat's nominal, 25-kilometer resolution, white barbs indicate areas of heavy rain. "QuikScat Background" NASA's Quick Scatterometer (QuikScat) spacecraft was launched from Vandenberg Air Force Base, California on June 19, 1999. QuikScat carries the SeaWinds scatterometer, a specialized microwave radar that measures near-surface wind speed and direction under all weather and cloud conditions over the Earth's oceans. More information about the QuikScat mission and observations is available at http://winds.jpl.nasa.gov [ http://photojournal.jpl.nasa.gov/catalog/PIA07415 http://winds.jpl.nasa.gov ]. QuikScat is managed for NASA's Science Mission Directorate, Washington, DC, by NASA's Jet Propulsion Laboratory, Pasadena, CA. JPL also built the SeaWinds radar instrument and is providing ground science processing systems. NASA's Goddard Space Flight Center, Greenbelt, MD, managed development of the satellite, designed and built by Ball Aerospace & Technologies Corp., Boulder, CO. The National Oceanic and Atmospheric Administration has contributed support to ground systems processing and related activities. |
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Tropical Storm Katrina
PIA07432
Sol (our sun)
SeaWinds Scatterometer
| Title |
Tropical Storm Katrina |
| Original Caption Released with Image |
. QuikScat is managed for NASA's Science Mission Directorate, Washington, DC, by NASA's Jet Propulsion Laboratory, Pasadena, CA. JPL also built the SeaWinds radar instrument and is providing ground science processing systems. NASA's Goddard Space Flight Center, Greenbelt, MD, managed development of the satellite, designed and built by Ball Aerospace & Technologies Corp., Boulder, CO. The National Oceanic and Atmospheric Administration has contributed support to ground systems processing and related activities., Tropical Storm Katrina is shown here as observed by NASA's QuikScat satellite on August 25, 2005, at 08:37 UTC (4:37 a.m. in Florida). At this time, the storm had 80 kilometers per hour (50 miles per hour, 43 knots) sustained winds. The storm does not appear to yet have reached hurricane strength. The greater danger may be not with her winds, but with Katrina's rains. The storm is moving slowly, just 13 km/hr (8 mph), and is expected to slow as it moves over land. This means that Katrina 's heavy rains will linger longer over one area, dumping 15-25 centimeters (6-10 inches) of rain over Florida and the Bahamas and possibly up to 38 cm (15 inches) in some regions, the National Hurricane Center warns. The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, shown in purple, surround the center of the storm. Measurements of the wind strength of Tropical Storm Katrina show sustained winds similar to those shown by these QuikScat observations, though not identical. This is because the power of the storm makes accurate measurements difficult. The scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface, and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction, giving scientists a way to monitor wind around the world. Tropical cyclones (the generic term for hurricanes and typhoons) and to a lesser extent, weaker storm systems like Katrina, are difficult to measure. To relate the radar energy return to actual wind speed, scientists compare measurements taken from buoys and other ground stations to data the satellite acquired at the same time and place. Because the high wind speeds generated by cyclones are rare, scientists do not have corresponding ground information to know how to translate data from the satellite for wind speeds above 50 knots (about 93 km/hr or 58 mph). Also, the unusually heavy rain found in a cyclone distorts the microwave pulses in a number of ways, making a conversion to accurate wind speed difficult. Instead, the scatterometer provides a nice picture of the relative wind speeds within the storm and shows wind direction. For more information about the storm, please visit the National Hurricane Center [ http://www.nhc.noaa.gov/ ]. "QuikScat Background" NASA's Quick Scatterometer (QuikScat) spacecraft was launched from Vandenberg Air Force Base, California on June 19, 1999. QuikScat carries the SeaWinds scatterometer, a specialized microwave radar that measures near-surface wind speed and direction under all weather and cloud conditions over the Earth's oceans. More information about the QuikScat mission and observations is available at http://winds.jpl.nasa.gov [ http://photojournal.jpl.nasa.gov/catalog/PIA07432 http://winds.jpl.nasa.gov ] |
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