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Hurricane Dennis
Title Hurricane Dennis
Abstract The formation of Hurricane Dennis on July 5 made that the earliest date on record that four named storms formed in the Atlantic basin. Dennis proved to be a powerful and destructive storm in the Caribbean Sea and the Gulf of Mexico. It crossed over Cuba on July 8 and 9, leaving at least 10 dead, and caused additional deaths in Haiti. After re-emerging over open water, Dennis re-strengthened into a dangerous Category 4 hurricane with top wind speeds of 233 kilometers per hour (145 mph). The storm passed within 90 kilometers (55 miles) of Pensacola, Florida, and hit land about 80 kilometers (50 miles) east of where Hurricane Ivan struck in September, 2004. A large storm surge of more than 10 feet was created in certain areas, and many homes and businesses in low-lying areas were flooded.
Completed 2005-07-11
Aerosols from Earth Probe TO …
Title Aerosols from Earth Probe TOMS: Venezuela from 3/11/98 to 4/4/98 (3 times @ 1.5 days/sec)
Completed 1998-12-07
Progression of Hurricane Den …
Title Progression of Hurricane Dennis, 2005 (WMS)
Abstract The formation of Hurricane Dennis on July 5 made that the earliest date on record that four named storms formed in the Atlantic basin. Dennis proved to be a powerful and destructive storm in the Caribbean Sea and the Gulf of Mexico. It crossed over Cuba on July 8 and 9, leaving at least 10 dead, and caused additional deaths in Haiti. After re-emerging over open water, Dennis re-strengthened into a dangerous Category 4 hurricane with top wind speeds of 233 kilometers per hour (145 mph). The storm passed within 90 kilometers (55 miles) of Pensacola, Florida, and hit land about 80 kilometers (50 miles) east of where Hurricane Ivan struck in September, 2004. A large storm surge of more than 10 feet was created in certain areas, and many homes and businesses in low-lying areas were flooded.
Completed 2005-07-18
Duckweed on Lake Maracaibo
Title Duckweed on Lake Maracaibo
Description Traces of duckweed still form green swirls atop Lake Maracaibo in northern Venezuela. The weed, more formally called "Lemna obscura", began to grow on the lake sometime between January and March 2004. With an outlet to the Caribbean Sea, Lake Maracaibo is usually too salty to support duckweed and other similar aquatic plants. The lake's fresh water sits on top of a dense layer of salty water. The lower, salty layer traps nutrients at the bottom of the lake, depriving any potential surface plants of the nutrients they need to survive. This year, however, unusually heavy rain brought additional fresh water to the lake, which stirred the layers and allowed nutrients to float to the surface. It is also likely that the heavy rains brought the duckweed to the center of Lake Maracaibo. Since the plant doesn't normally grow on the lake, there was some question as to how it got there. The current hypothesis, according to Federico Troncone, the Head of the Water Quality Division of the Institution for the Conservation of Lake Maracaibo (a government research group charged with the study of Lake Maracaibo under the Ministry of Environment and Natural Resources) is that the plants were carried from ponds on the edges of the lake, where they do grow, to the main body of Lake Maracaibo on stronger-than-normal currents. Normally, the plants that get washed into Lake Maracaibo die or their growth is limited by the lack of nutrients. This year, when the rains dislodged the plants and carried them to the center of the lake, the plants ended up in fertile waters. For a brief time, while nutrients were plentiful, the plants doubled in area every day. Then, as the lake began to settle back into its normal layers with nutrient-rich waters on the bottom instead of the top, the duckweed's growth slowed and eventually stopped. The trend is clear in the image pair shown above. In the right image, taken on June 26 by the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Aqua [ http://aqua.nasa.gov/ ] satellite, the swirls of duckweed appear more solid and cover a broader area. In the more recent image, acquired by MODIS on NASA's Aqua [ http://aqua.nasa.gov/ ], satellite on September 1, the swirls are thinner. By the end of June, when the first image was taken, the duckweed already covered less of the lake than it did at its height. In mid-May, the plant covered 14.5 percent of Lake Maracaibo, according to Eduardo Klein, the Director of the Institute of Marine Sciences and Technologies at Simon Bolivar University in Caracas, Venezuela. He and colleague Carlos Castillo based their analysis in part on MODIS images, such as the above, provided through collaboration with University of South Florida. By the end of August, the weed only covered 5.36 percent of the lake. While the duckweed appears to be dying down, scientists at ICLAM fear that heavy rains during the next few weeks could recreate the conditions that allowed the duckweed to grow in the first place. If that happens, the duckweed could begin to grow again. For more information, see Duckweed Invasion in Lake Maracaibo [ http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=16605 ]. NASA images courtesy the MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC
Duckweed on Lake Maracaibo
Title Duckweed on Lake Maracaibo
Description Traces of duckweed still form green swirls atop Lake Maracaibo in northern Venezuela. The weed, more formally called "Lemna obscura", began to grow on the lake sometime between January and March 2004. With an outlet to the Caribbean Sea, Lake Maracaibo is usually too salty to support duckweed and other similar aquatic plants. The lake's fresh water sits on top of a dense layer of salty water. The lower, salty layer traps nutrients at the bottom of the lake, depriving any potential surface plants of the nutrients they need to survive. This year, however, unusually heavy rain brought additional fresh water to the lake, which stirred the layers and allowed nutrients to float to the surface. It is also likely that the heavy rains brought the duckweed to the center of Lake Maracaibo. Since the plant doesn't normally grow on the lake, there was some question as to how it got there. The current hypothesis, according to Federico Troncone, the Head of the Water Quality Division of the Institution for the Conservation of Lake Maracaibo (a government research group charged with the study of Lake Maracaibo under the Ministry of Environment and Natural Resources) is that the plants were carried from ponds on the edges of the lake, where they do grow, to the main body of Lake Maracaibo on stronger-than-normal currents. Normally, the plants that get washed into Lake Maracaibo die or their growth is limited by the lack of nutrients. This year, when the rains dislodged the plants and carried them to the center of the lake, the plants ended up in fertile waters. For a brief time, while nutrients were plentiful, the plants doubled in area every day. Then, as the lake began to settle back into its normal layers with nutrient-rich waters on the bottom instead of the top, the duckweed's growth slowed and eventually stopped. The trend is clear in the image pair shown above. In the right image, taken on June 26 by the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Aqua [ http://aqua.nasa.gov/ ] satellite, the swirls of duckweed appear more solid and cover a broader area. In the more recent image, acquired by MODIS on NASA's Aqua [ http://aqua.nasa.gov/ ], satellite on September 1, the swirls are thinner. By the end of June, when the first image was taken, the duckweed already covered less of the lake than it did at its height. In mid-May, the plant covered 14.5 percent of Lake Maracaibo, according to Eduardo Klein, the Director of the Institute of Marine Sciences and Technologies at Simon Bolivar University in Caracas, Venezuela. He and colleague Carlos Castillo based their analysis in part on MODIS images, such as the above, provided through collaboration with University of South Florida. By the end of August, the weed only covered 5.36 percent of the lake. While the duckweed appears to be dying down, scientists at ICLAM fear that heavy rains during the next few weeks could recreate the conditions that allowed the duckweed to grow in the first place. If that happens, the duckweed could begin to grow again. For more information, see Duckweed Invasion in Lake Maracaibo [ http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=16605 ]. NASA images courtesy the MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC
Hurricane Dennis
Title Hurricane Dennis
Description The swirling clouds of Tropical Storm Dennis span from the northern tip of Venezuela to the southern half of the island of Hispaniola in this Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) image. NASA's Terra [ http://terra.nasa.gov/ ] satellite captured this image on July 6, 2005, at 10:05 a.m. local time (15:05 UTC) when Dennis was building to winds of 110 kilometers per hour (70 mph). The storm was moving northwest across the Caribbean and should pass between the eastern arm of Haiti and Jamaica, hammering both with four to eight inches of rain. The National Hurricane Center [ http://www.nhc.noaa.gov/ ] predicts that Dennis may become a major hurricane—Category 3 or higher—by July 8. This image is available in additional resolutions from the MODIS Rapid Response System. NASA image courtesy Jeff Schmaltz, MODIS Land Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC
Hurricane Emily
Title Hurricane Emily
Description Hurricane Emily is shown here in the Carribbean north of Venezuela on July 14, 2005. The image was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite at 17:20 UTC (13:20 Eastern Daylight Time). At this time, it was a well developed and powerful hurricane with winds over 150 kilometers an hour (85 knots). It passed through the chain of islands known as the Windward Islands, causing one death in the city of St. George?s on Grenada. It is building up towards a Category 4 hurricane, the second strongest storm on the Saffir-Simpson intensity scale. Projections take it glancing off Jamaica, striking the Yucatan Peninsula in Mexico, and continuing across into the Gulf of Mexico to make landfall again somewhere near Brownsville, Texas on the border with Mexico and the United States. Predicting hurricane strength and intensity is challenging, and Emily might be either stronger or weaker than expected, and it may not stay on its predicted course. The hurricane has already become somewhat stronger than first anticipated. NASA image created by Jesse Allen, Earth Observatory, using data obtained from the MODIS Rapid Response team.
Fires Across Northern South …
Title Fires Across Northern South America
Description In eastern Columbia (left) and northern Venezuela (right), a vast stretch of plains called the Llanos rests at the eastern foothills of the Andes Mountains. The Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite detected numerous fires (red dots) scattered across the region, even in wetland areas between two of the Llanos? majors rivers: the Apure (running from center toward the right of the image) and the Meta (flowing northeast from bottom left). Where the Meta leaves the Columbia-Venezuela border, it is joined by the Atabapo River and becomes the Orinoco, which flows out to meet the Atlantic. In the high-resolution imagery, dark purplish-brown burn scars are apparent against the green vegetation of the prairies. At bottom right, the grasses of the llanos give way to the upper reaches of the Amazon Rainforest. This image was captured December 12, 2002. Image courtesy Jeff Schmaltz, MODIS Rapid Response Team, NASA GSFC
Fires Across Northern South …
Title Fires Across Northern South America
Description Widespread biomass burning in northern South America that began in late 2002 has continued into the new year. This true-color Moderate Resolution Imaging Spectroradiometer (MODIS) image from the Terra satellite on January 4, 2003, shows active fire detections (red dots) in Columbia (left) and Venezuela (right). Image courtesy Jeff Schmaltz, MODIS Rapid Response Team, NASA GSFC
Fires Across Northern South …
Title Fires Across Northern South America
Description Fires were still burning across the Llanos on January 13, 2003. This Moderate Resolution Imaging Spectroradiometer (MODIS) image shows Columbia (left) and Venezuela (right) and numerous fires (red dots) scattered across the region. Image courtesy Jeff Schmaltz, MODIS Rapid Response Team, NASA GSFC
Fires Across Northern South …
Title Fires Across Northern South America
Description Widespread fires are producing smoky skies over Columbia (left) and Venezuela (right) on March 4, 2003. This image from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite shows fire detections marked with red dots. The high-resolution image provided above is 500 meters per pixel. The MODIS Rapid Response System provides this image at MODIS' maximum spatial resolution of 250 meters. Image courtesy Jeff Schmaltz, MODIS Rapid Response Team, NASA GSFC
Fires Across Northern South …
Title Fires Across Northern South America
Description In northern South America, fires (red dots) continue to cover a wide area of Columbia (far left) and Venezuela (center and right). This image from the Moderate Resolution Imaging Spectroradiometer (MODIS) on March 20, 2003, shows fires concentrated heavily east of keyhole-shaped Lake Maracaibo. A thick cloud of smoke hangs over the country. The high-resolution image provided above is 500 meters per pixel. The MODIS Rapid Response System provides this image at MODIS' maximum spatial resolution of 250 meters. Image courtesy Jeff Schmaltz, MODIS Rapid Response Team, NASA GSFC
Fires Across Northern South …
Title Fires Across Northern South America
Description Biomass burning in Columbia (left) and Venezuela (right) appears to be intensifying as of March 22, 2003. This image from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite shows hundreds of fires marked in red, and thick smoke hanging over the southern part of the image. The high-resolution image provided above is 500 meters per pixel. The MODIS Rapid Response System provides this image at MODIS' maximum spatial resolution of 250 meters. Image courtesy Jeff Schmaltz, MODIS Rapid Response Team, NASA GSFC
Oil Slicks on Lake Maracaibo …
Title Oil Slicks on Lake Maracaibo, Venezuela
Description browse image of orbit 16081 (310 KB JPEG) Several oil slicks occurred on Lake Maracaibo in northwestern Venezuela between December 2002 and January 2003, and were observed by various satellite instruments. These images from the Multi-angle Imaging SpectroRadiometer (MISR) provide new information relating to one such event near the center of Lake Maracaibo on December 26, 2002. In unpolluted areas, the water surface is "ruffled" by wind and the resulting wave facets divert reflected rays into many directions. An oil film dampens the presence of small wind-driven "capillary" waves, resulting a smoother, more mirror-like surface. Also, oil is more strongly absorbing than the surrounding water. Therefore, at most viewing angles, a surface slick will appear darker than the surrounding unpolluted areas, whereas near the specular angle (the angle at which a perfect mirror reflects light) it will appear brighter. Simultaneous observation at multiple view angles therefore enhances the reliability of oil-slick detection using optical imaging. An example of how the optical contrast of an oil film on a water surface changes as a function of viewing angle is illustrated by these false-color MISR images, comprised of near-infrared, red and blue spectral data at three different angles, using the vertical-viewing camera (left), the 26ø-forward-viewing camera (center) and the 46ø-forward-viewing camera (right). A swirly area in the middle of the lake appears darker than the surrounding waters at both the nadir and 46° views, but brighter than the surrounding waters at the 26° view. Of the three images, only the 26° camera observes close to specular reflection angle. Lake Maracaibo is the largest lake in South America. The lake is somewhat saline, since it is connected to the Gulf of Venezuela by a narrow strait in the north. Venezuela is the largest oil producing nation in the Western Hemisphere, and the Lake Maracaibo basin includes the largest oil fields and almost a quarter of this nation's population. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously from pole to pole, and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. The MISR Browse Image Viewer [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://eosweb.larc.nasa.gov/MISRBR/ ] provides access to low-resolution true-color versions of these images. These data products were generated from a portion of the imagery acquired during Terra orbit 16081. The panels cover an area of 72 kilometers x 225 kilometers. Image courtesy NASA/GSFC/LaRC/JPL, MISR Team. [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://www-misr.jpl.nasa.gov/ ] Text by Clare Averill (Acro Service Corporation/JPL)
Oil Slicks on Lake Maracaibo …
Title Oil Slicks on Lake Maracaibo, Venezuela
Description browse image of orbit 16081 (310 KB JPEG) Several oil slicks occurred on Lake Maracaibo in northwestern Venezuela between December 2002 and January 2003, and were observed by various satellite instruments. These images from the Multi-angle Imaging SpectroRadiometer (MISR) provide new information relating to one such event near the center of Lake Maracaibo on December 26, 2002. In unpolluted areas, the water surface is "ruffled" by wind and the resulting wave facets divert reflected rays into many directions. An oil film dampens the presence of small wind-driven "capillary" waves, resulting a smoother, more mirror-like surface. Also, oil is more strongly absorbing than the surrounding water. Therefore, at most viewing angles, a surface slick will appear darker than the surrounding unpolluted areas, whereas near the specular angle (the angle at which a perfect mirror reflects light) it will appear brighter. Simultaneous observation at multiple view angles therefore enhances the reliability of oil-slick detection using optical imaging. An example of how the optical contrast of an oil film on a water surface changes as a function of viewing angle is illustrated by these false-color MISR images, comprised of near-infrared, red and blue spectral data at three different angles, using the vertical-viewing camera (left), the 26ø-forward-viewing camera (center) and the 46ø-forward-viewing camera (right). A swirly area in the middle of the lake appears darker than the surrounding waters at both the nadir and 46° views, but brighter than the surrounding waters at the 26° view. Of the three images, only the 26° camera observes close to specular reflection angle. Lake Maracaibo is the largest lake in South America. The lake is somewhat saline, since it is connected to the Gulf of Venezuela by a narrow strait in the north. Venezuela is the largest oil producing nation in the Western Hemisphere, and the Lake Maracaibo basin includes the largest oil fields and almost a quarter of this nation's population. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously from pole to pole, and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. The MISR Browse Image Viewer [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://eosweb.larc.nasa.gov/MISRBR/ ] provides access to low-resolution true-color versions of these images. These data products were generated from a portion of the imagery acquired during Terra orbit 16081. The panels cover an area of 72 kilometers x 225 kilometers. Image courtesy NASA/GSFC/LaRC/JPL, MISR Team. [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://www-misr.jpl.nasa.gov/ ] Text by Clare Averill (Acro Service Corporation/JPL)
Fires in Northern South Amer …
Title Fires in Northern South America
Description Across the grassy plains, known as the "Llanos," that stretch across Venezuela and Columbia in northern South America, numerous fires (yellow) were detected by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite on February 1, 2004. The area supports ranching and other agriculture, and many of these fires are probably intentional fires set by people for land management purposes. Though not necessarily hazardous, such large-scale burning can have a strong impact on weather, climate, human health, and natural resources. At bottom left, a pall of smoke hangs over the area, and a few scattered fires in the heart of the forests (deep green areas at right) could be related to deforestation. Image courtesy Jesse Allen, based on data from the MODIS Rapid Response Team at NASA GSFC
Fires in Venezuela
Title Fires in Venezuela
Description As can be seen in this true-color scene acquired on April 9, 2002, many fires dotted the landscape across Venezuela. This image was acquired by the Moderate-resolution Imaging Spectroradiometer [ http://modarch.gsfc.nasa.gov/ ] (MODIS), flying aboard NASA?s Terra [ http://terra.nasa.gov/ ] satellite. Please note that the high-resolution scene provided here is 500 meters per pixel. For a copy of this scene at the sensor?s fullest resolution, visit the MODIS Rapidfire [ http://rapidfire.sci.gsfc.nasa.gov/gallery/?2002092-0402 ] site. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov/ ] at NASA GSFC
Flooding in Columbia and Ven …
Title Flooding in Columbia and Venezeula
Description February is typically the dry season in northern Venezuela, but not in 2005. Torrential rains brought deadly floods to the country's coastal provinces, including the capital, Caracas. In this Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) image, blue smudges along the coast show flooding in the Falcon Province. In these false-color images, clear water is black, while muddy water is blue. Clouds are white and pale blue, and vegetation is green. When this image was acquired by NASA's Terra [ http://terra.nasa.gov/ ] satellite on February 14, up to 25,000 people had been affected by floods throughout the country. NASA image credited by Jesse Allen, Earth Observatory, using data obtained from the MODIS Rapid Response team.
Flooding in Columbia and Ven …
Title Flooding in Columbia and Venezeula
Description February is typically the dry season in northern Venezuela, but not in 2005. Torrential rains brought deadly floods to the country's coastal provinces, including the capital, Caracas. In this Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) image, blue smudges along the coast show flooding in the Falcon Province. In these false-color images, clear water is black, while muddy water is blue. Clouds are white and pale blue, and vegetation is green. When this image was acquired by NASA's Terra [ http://terra.nasa.gov/ ] satellite on February 14, up to 25,000 people had been affected by floods throughout the country. NASA image credited by Jesse Allen, Earth Observatory, using data obtained from the MODIS Rapid Response team.
Flooding in Columbia and Ven …
Title Flooding in Columbia and Venezeula
Description February is typically the dry season in northern Venezuela, but not in 2005. Torrential rains brought deadly floods to the country's coastal provinces, including the capital, Caracas. In this Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) image, blue smudges along the coast show flooding in the Falcon Province. In these false-color images, clear water is black, while muddy water is blue. Clouds are white and pale blue, and vegetation is green. When this image was acquired by NASA's Terra [ http://terra.nasa.gov/ ] satellite on February 14, up to 25,000 people had been affected by floods throughout the country. NASA image credited by Jesse Allen, Earth Observatory, using data obtained from the MODIS Rapid Response team.
Flooding in Columbia and Ven …
Title Flooding in Columbia and Venezeula
Description Unseasonable torrential rains drenched northern South America in February 2005. By February 17, at least 55 had died in floods and mudslides in the mountains of northeastern Colombia, and dozens more had been killed across the border in Venezuela. On February 11, the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Aqua [ http://aqua.nasa.gov/ ] satellite detected high water levels on rivers southwest of Lake Maracaibo. The swollen, sediment-laden rivers form a wide blue smudge across the bright green vegetation in the top false-color image. By contrast, more clearly defined river channels were filled with clear, darker water on January 27. In both images, clouds are white and pale blue, while bare earth is pink. NASA image created by Jesse Allen, Earth Observatory, using data obtained from the MODIS Rapid Response team.
Flooding in Columbia and Ven …
Title Flooding in Columbia and Venezeula
Description Unseasonable torrential rains drenched northern South America in February 2005. By February 17, at least 55 had died in floods and mudslides in the mountains of northeastern Colombia, and dozens more had been killed across the border in Venezuela. On February 11, the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Aqua [ http://aqua.nasa.gov/ ] satellite detected high water levels on rivers southwest of Lake Maracaibo. The swollen, sediment-laden rivers form a wide blue smudge across the bright green vegetation in the top false-color image. By contrast, more clearly defined river channels were filled with clear, darker water on January 27. In both images, clouds are white and pale blue, while bare earth is pink. NASA image created by Jesse Allen, Earth Observatory, using data obtained from the MODIS Rapid Response team.
Flooding in Columbia and Ven …
Title Flooding in Columbia and Venezeula
Description Though water levels have subsided since mid-February, the Escalante River of southwestern Venezuela and northeastern Colombia was still flooded on February 26, 2005. The floods along this river and others were triggered by days of heavy rain early in February, and resulted in nearly 100 deaths and left thousands homeless throughout both countries. In this image, taken by the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Terra [ http://terra.nasa.gov/ ] satellite, the muddy flood water is light blue. The river covers a broader area than it did on January 27, 2005. In both images, clouds are white and turquoise, plant-covered land is bright green, and deep, clear water is black. Further evidence of flooding can be seen in Lake Maracaibo in the center of the image. Flood water carries dirt into the rivers that empty into the lake. The sediment entering the lake reflects light, which makes the water appear a lighter shade of blue in satellite imagery. While sediment is present in the southwest corner of the lake on January 27, the sediment plume is much brighter and larger on February 26. On both dates, green swirls of duck weed [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12404 ] float on the surface of the lake. NASA image created by Jesse Allen, Earth Observatory, using data obtained from the MODIS Rapid Response team and the Goddard Land Processes DAAC.
Flooding in Columbia and Ven …
Title Flooding in Columbia and Venezeula
Description Though water levels have subsided since mid-February, the Escalante River of southwestern Venezuela and northeastern Colombia was still flooded on February 26, 2005. The floods along this river and others were triggered by days of heavy rain early in February, and resulted in nearly 100 deaths and left thousands homeless throughout both countries. In this image, taken by the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Terra [ http://terra.nasa.gov/ ] satellite, the muddy flood water is light blue. The river covers a broader area than it did on January 27, 2005. In both images, clouds are white and turquoise, plant-covered land is bright green, and deep, clear water is black. Further evidence of flooding can be seen in Lake Maracaibo in the center of the image. Flood water carries dirt into the rivers that empty into the lake. The sediment entering the lake reflects light, which makes the water appear a lighter shade of blue in satellite imagery. While sediment is present in the southwest corner of the lake on January 27, the sediment plume is much brighter and larger on February 26. On both dates, green swirls of duck weed [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12404 ] float on the surface of the lake. NASA image created by Jesse Allen, Earth Observatory, using data obtained from the MODIS Rapid Response team and the Goddard Land Processes DAAC.
Tropical Storm Isidore
Title Tropical Storm Isidore
Description This image captures the formation of Hurricane Isidore, the first major storm of the 2002 Atlantic hurricane season. Isidore first developed from a tropical disturbance north of Venezuela on September 14. The image shows the vertical structure of precipitation within Isidore?s clouds, taken through the center of the storm at 7 a.m. local time on September 21, 2002. In this scene, the rain cross section is oriented from southwest to northeast and is labeled ?AB.? The larger cloud and rainband structure is shown in white, while rainfall intensity is indicated by the different colors. Blue represents light rain and red shows the heaviest rain. At the time this image was acquired, Isidore was passing through the narrow Yucatan Strait and was beginning to grow in intensity. Winds were 85 knots and the central pressure was 969 millibars. TRMM captured these data at a point when a slender eye was beginning to develop and intense thunderstorms were erupting in the storm?s core. Maximum cloud top heights of 10 km are shown adjacent to the eye. Isidore later became a major Category 3 hurricane before making landfall over the Yucatan Peninsula. As of the evening of Sept. 24, Isidore was being watched for possible landfall along the U.S. Gulf Coast. Image courtesy Hal Pierce, NASA GSFC Mesoscale Atmospheric Processes Branch (Code 912). For more information and other examples of TRMM data, visit the TRMM [ http://earthobservatory.nasa.gov/cgi-bin/redirect?http://trmm.gsfc.nasa.gov/ ] Web site.
Solar Eclipse in View
Title Solar Eclipse in View
Explanation Friday's solar eclipse [ http://sunearth.gsfc.nasa.gov/eclipse/SEmono/HSE2005/ HSE2005.html ] will be a rare hybrid - briefly appearing as [ http://skyandtelescope.com/observing/objects/eclipses/ article_1445_1.asp ] either an annular eclipse or a total eclipse when viewed from along the narrow track of the Moon's shadow [ http://antwrp.gsfc.nasa.gov/apod/ap040926.html ]. Unfortunately that track, never more than about 30 kilometers wide, lies [ http://sunearth.gsfc.nasa.gov/eclipse/SEmono/HSE2005/ HSE2005fig/HSE2005map1b.GIF ] mostly across the Pacific Ocean, beginning south of New Zealand and just ending in Venezuela. Skywatchers along the beginning and end of the shadow track will see an annular eclipse of the Sun, with the Moon's silhouette briefly surrounded by a bright ring of fire [ http://antwrp.gsfc.nasa.gov/apod/ap030605.html ], while observers along the middle of the track will witness a total eclipse [ http://antwrp.gsfc.nasa.gov/apod/ap031122.html ] phase. But the good news is that over a much broader region of the globe, including New Zealand and much of South and North America, a partial eclipse can be seen as the Moon appears to take a bite [ http://antwrp.gsfc.nasa.gov/apod/ap001221.html ] out of the Sun. If you want to view the eclipse [ http://skyandtelescope.com/observing/highlights/ article_1492_1.asp ], take care to do it safely [ http://www.mreclipse.com/Totality/TotalityCh11.html ], and check the times [ http://sunearth.gsfc.nasa.gov/eclipse/SEmono/HSE2005/ PSE2005.html ] for your specific location [ http://sunearth.gsfc.nasa.gov/eclipse/OH/LC/ LC2005-2.html#2005Apr08H ]. So, what location is this solar eclipse view from? The picture above [ http://antwrp.gsfc.nasa.gov/apod/ap031208.html ] was recorded in November of 2003 from within the track of the Moon's shadow across Antarctica, of course.
Fires Across Northern South …
nasa, nasanaturalhazards
Widespread biomass burning i …
Venezuela.TMOA2003004
mediatype IMAGE
mediatype image
date 2003-01-04
creator NASA -- NASA Image Of The Day
identifier Venezuela.TMOA2003004
Fires Across Northern South …
nasa, nasanaturalhazards
Widespread fires are produci …
Colombia.AMOA2003063
mediatype IMAGE
mediatype image
date 2003-03-04
creator NASA -- NASA Image Of The Day
identifier Colombia.AMOA2003063
Fires Across Northern South …
nasa, nasanaturalhazards
In eastern Columbia (left) a …
NSAmerica.TMOA2002346
mediatype IMAGE
mediatype image
date 2002-12-12
creator NASA -- NASA Image Of The Day
identifier NSAmerica.TMOA2002346
Duckweed on Lake Maracaibo: …
nasa, nasanaturalhazards
* eoimages.gsfc.nasa.gov/ima …
Maracaibo_AMO_2004245
mediatype IMAGE
mediatype image
date 2004-09-01
creator NASA -- NASA Image Of The Day
identifier Maracaibo_AMO_2004245
Fires in Northern South Amer …
nasa, nasanaturalhazards
Across the grassy plains, kn …
terra_venezuela_01feb04
mediatype IMAGE
mediatype image
date 2004-02-01
creator NASA -- NASA Image Of The Day
identifier terra_venezuela_01feb04
Fires Across Northern South …
nasa, nasanaturalhazards
In northern South America, f …
Venezuela.AMOA2003079
mediatype IMAGE
mediatype image
date 2003-03-20
creator NASA -- NASA Image Of The Day
identifier Venezuela.AMOA2003079
Fires Across Northern South …
nasa, nasanaturalhazards
Fires were still burning acr …
Venezuela.TMOA2003013
mediatype IMAGE
mediatype image
date 2003-01-13
creator NASA -- NASA Image Of The Day
identifier Venezuela.TMOA2003013
Hurricane Dennis: Natural Ha …
nasa, nasanaturalhazards
The swirling clouds of Tropi …
Dennis_TMO_2005187
mediatype IMAGE
mediatype image
date July 6, 2005
creator NASA -- NASA Image Of The Day
identifier Dennis_TMO_2005187
Fires Across Northern South …
nasa, nasanaturalhazards
Biomass burning in Columbia …
Venezuela.AMOA2003081
mediatype IMAGE
mediatype image
date 2003-03-22
creator NASA -- NASA Image Of The Day
identifier Venezuela.AMOA2003081
Oil Slicks on Lake Maracaibo …
PIA04331
Sol (our sun)
Multi-angle Imaging SpectroR …
Title Oil Slicks on Lake Maracaibo, Venezuela
Original Caption Released with Image Several oil slicks occurred on Lake Maracaibo in northwestern Venezuela between December 2002 and January 2003, and were observed by various satellite instruments. These images from the Multi-angle Imaging SpectroRadiometer (MISR) provide new information relating to one such event near the center of Lake Maracaibo on December 26, 2002. In unpolluted areas, the water surface is "ruffled" by wind and the resulting wave facets divert reflected rays into many directions. An oil film dampens the presence of small wind-driven "capillary" waves, resulting a smoother, more mirror-like surface. Also, oil is more strongly absorbing than the surrounding water. Therefore, at most viewing angles, a surface slick will appear darker than the surrounding unpolluted areas, whereas near the specular angle (the angle at which a perfect mirror reflects light) it will appear brighter. Simultaneous observation at multiple view angles therefore enhances the reliability of oil-slick detection using optical imaging. An example of how the optical contrast of an oil film on a water surface changes as a function of viewing angle is illustrated by these false-color MISR images, comprised of near-infrared, red and blue spectral data at three different angles, using the vertical-viewing camera (left), the 26°-forward-viewing camera (center) and the 46°-forward-viewing camera (right). A swirly area in the middle of the lake appears darker than the surrounding waters at both the nadir and 46° views, but brighter than the surrounding waters at the 26° view. Of the three images, only the 26° camera observes close to specular reflection angle. Lake Maracaibo is the largest lake in South America. The lake is somewhat saline, since it is connected to the Gulf of Venezuela by a narrow strait in the north. Venezuela is the largest oil producing nation in the Western Hemisphere, and the Lake Maracaibo basin includes the largest oil fields and almost a quarter of this nation's population. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously from pole to pole, and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. These data products were generated from a portion of the imagery acquired during Terra orbit 16081. The panels cover an area of 72 kilometers x 225 kilometers, and utilize data from blocks 81 to 83 within World Reference System-2 path 8. 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.
Flooding Resulting From Hurr …
PIA00365
Sol (our sun)
Atmospheric Infrared Sounder …
Title Flooding Resulting From Hurricane Isidore, Comparing Data from September 12 and 28, 2002
Original Caption Released with Image Extent of Flooding due to Hurricane Isidore revealed in images from the Atmospheric Infrared Sounding System (AIRS) on Aqua Tropical Storm Isidore was born in mid-September north of Venezuela. It subsequently hit Mexico's Yucatan Peninsula as a Category 3 hurricane and came ashore near New Orleans on September 26th packing winds just below hurricane strength. Around the time of September 27, the storm was downgraded to a tropical depression as the system moved into Tennessee. At the time the Aqua spacecraft first passed over Isidore, it was classified as a Category 3 (possibly 4) hurricane, with minimum pressure of 934 mbar, maximum sustained wind speeds of 110 knots (gusting to 135) and an eye diameter of 20 nautical miles. Isidore was later downgraded to a Tropical Storm and then a Tropical Depression as it lost energy. Figures 1 and 2, two images from the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellites show no significant weather systems over the southeastern United States on September 12 and September 28 (16 days apart). However, the microwave component of the Atmospheric Infrared Sounder Experiment on NASA's Aqua spacecraft shows a striking difference. The difference in the two microwave images (figures 3 and 4) from the AIRS Advanced Microwave Sounding Unit is primarily due to flooding after Tropical Storm Isidore. Water has a very low surface emissivity at this frequency, and that causes surface water to appear very cold (even though it is not). Land appears relatively warm (well above freezing - 273 K, even at night as seen is these images), but if there is standing water, the apparent temperature drops precipitously. Figure 4, taken just about a day after the remnants of Isidore passed over the southeast, shows heavy flooding along the Mississippi, especially in the states of Mississippi and Tennessee, but other states are also affected. The spatial resolution of the AMSU-A instrument is relatively large (each measurement spot is about 25 miles in diameter at the center of the swath), but the enormous thermal contrast in the microwave between land and water makes even small flooded areas stand out., Figure 5: Difference image, 9/12 and 9/28) The Aqua spacecraft has an exact 16-day repeat cycle, that is why the pre-Isidore image is 16 days prior to the post-Isidore image. They have exactly the same coverage, which makes it possible to obtain a difference image (figure 5). The difference image is the difference between the September 28 and September 12 images shown. In the difference image, white indicates no difference at all, green is very little difference, blue/purple indicates primarily heavy flooding. Red indicates warming likely due to warmer weather. (The straight lines on the right and left edges of the difference image are caused by slight differences between the two repeat passes of Aqua). The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.
Flooding Resulting From Hurr …
PIA00365
Sol (our sun)
Atmospheric Infrared Sounder …
Title Flooding Resulting From Hurricane Isidore, Comparing Data from September 12 and 28, 2002
Original Caption Released with Image Extent of Flooding due to Hurricane Isidore revealed in images from the Atmospheric Infrared Sounding System (AIRS) on Aqua Tropical Storm Isidore was born in mid-September north of Venezuela. It subsequently hit Mexico's Yucatan Peninsula as a Category 3 hurricane and came ashore near New Orleans on September 26th packing winds just below hurricane strength. Around the time of September 27, the storm was downgraded to a tropical depression as the system moved into Tennessee. At the time the Aqua spacecraft first passed over Isidore, it was classified as a Category 3 (possibly 4) hurricane, with minimum pressure of 934 mbar, maximum sustained wind speeds of 110 knots (gusting to 135) and an eye diameter of 20 nautical miles. Isidore was later downgraded to a Tropical Storm and then a Tropical Depression as it lost energy. Figures 1 and 2, two images from the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellites show no significant weather systems over the southeastern United States on September 12 and September 28 (16 days apart). However, the microwave component of the Atmospheric Infrared Sounder Experiment on NASA's Aqua spacecraft shows a striking difference. The difference in the two microwave images (figures 3 and 4) from the AIRS Advanced Microwave Sounding Unit is primarily due to flooding after Tropical Storm Isidore. Water has a very low surface emissivity at this frequency, and that causes surface water to appear very cold (even though it is not). Land appears relatively warm (well above freezing - 273 K, even at night as seen is these images), but if there is standing water, the apparent temperature drops precipitously. Figure 4, taken just about a day after the remnants of Isidore passed over the southeast, shows heavy flooding along the Mississippi, especially in the states of Mississippi and Tennessee, but other states are also affected. The spatial resolution of the AMSU-A instrument is relatively large (each measurement spot is about 25 miles in diameter at the center of the swath), but the enormous thermal contrast in the microwave between land and water makes even small flooded areas stand out., Figure 5: Difference image, 9/12 and 9/28) The Aqua spacecraft has an exact 16-day repeat cycle, that is why the pre-Isidore image is 16 days prior to the post-Isidore image. They have exactly the same coverage, which makes it possible to obtain a difference image (figure 5). The difference image is the difference between the September 28 and September 12 images shown. In the difference image, white indicates no difference at all, green is very little difference, blue/purple indicates primarily heavy flooding. Red indicates warming likely due to warmer weather. (The straight lines on the right and left edges of the difference image are caused by slight differences between the two repeat passes of Aqua). The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.
Flooding Resulting From Hurr …
PIA00365
Sol (our sun)
Atmospheric Infrared Sounder …
Title Flooding Resulting From Hurricane Isidore, Comparing Data from September 12 and 28, 2002
Original Caption Released with Image Extent of Flooding due to Hurricane Isidore revealed in images from the Atmospheric Infrared Sounding System (AIRS) on Aqua Tropical Storm Isidore was born in mid-September north of Venezuela. It subsequently hit Mexico's Yucatan Peninsula as a Category 3 hurricane and came ashore near New Orleans on September 26th packing winds just below hurricane strength. Around the time of September 27, the storm was downgraded to a tropical depression as the system moved into Tennessee. At the time the Aqua spacecraft first passed over Isidore, it was classified as a Category 3 (possibly 4) hurricane, with minimum pressure of 934 mbar, maximum sustained wind speeds of 110 knots (gusting to 135) and an eye diameter of 20 nautical miles. Isidore was later downgraded to a Tropical Storm and then a Tropical Depression as it lost energy. Figures 1 and 2, two images from the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellites show no significant weather systems over the southeastern United States on September 12 and September 28 (16 days apart). However, the microwave component of the Atmospheric Infrared Sounder Experiment on NASA's Aqua spacecraft shows a striking difference. The difference in the two microwave images (figures 3 and 4) from the AIRS Advanced Microwave Sounding Unit is primarily due to flooding after Tropical Storm Isidore. Water has a very low surface emissivity at this frequency, and that causes surface water to appear very cold (even though it is not). Land appears relatively warm (well above freezing - 273 K, even at night as seen is these images), but if there is standing water, the apparent temperature drops precipitously. Figure 4, taken just about a day after the remnants of Isidore passed over the southeast, shows heavy flooding along the Mississippi, especially in the states of Mississippi and Tennessee, but other states are also affected. The spatial resolution of the AMSU-A instrument is relatively large (each measurement spot is about 25 miles in diameter at the center of the swath), but the enormous thermal contrast in the microwave between land and water makes even small flooded areas stand out., Figure 5: Difference image, 9/12 and 9/28) The Aqua spacecraft has an exact 16-day repeat cycle, that is why the pre-Isidore image is 16 days prior to the post-Isidore image. They have exactly the same coverage, which makes it possible to obtain a difference image (figure 5). The difference image is the difference between the September 28 and September 12 images shown. In the difference image, white indicates no difference at all, green is very little difference, blue/purple indicates primarily heavy flooding. Red indicates warming likely due to warmer weather. (The straight lines on the right and left edges of the difference image are caused by slight differences between the two repeat passes of Aqua). The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.
Flooding Resulting From Hurr …
PIA00365
Sol (our sun)
Atmospheric Infrared Sounder …
Title Flooding Resulting From Hurricane Isidore, Comparing Data from September 12 and 28, 2002
Original Caption Released with Image Extent of Flooding due to Hurricane Isidore revealed in images from the Atmospheric Infrared Sounding System (AIRS) on Aqua Tropical Storm Isidore was born in mid-September north of Venezuela. It subsequently hit Mexico's Yucatan Peninsula as a Category 3 hurricane and came ashore near New Orleans on September 26th packing winds just below hurricane strength. Around the time of September 27, the storm was downgraded to a tropical depression as the system moved into Tennessee. At the time the Aqua spacecraft first passed over Isidore, it was classified as a Category 3 (possibly 4) hurricane, with minimum pressure of 934 mbar, maximum sustained wind speeds of 110 knots (gusting to 135) and an eye diameter of 20 nautical miles. Isidore was later downgraded to a Tropical Storm and then a Tropical Depression as it lost energy. Figures 1 and 2, two images from the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellites show no significant weather systems over the southeastern United States on September 12 and September 28 (16 days apart). However, the microwave component of the Atmospheric Infrared Sounder Experiment on NASA's Aqua spacecraft shows a striking difference. The difference in the two microwave images (figures 3 and 4) from the AIRS Advanced Microwave Sounding Unit is primarily due to flooding after Tropical Storm Isidore. Water has a very low surface emissivity at this frequency, and that causes surface water to appear very cold (even though it is not). Land appears relatively warm (well above freezing - 273 K, even at night as seen is these images), but if there is standing water, the apparent temperature drops precipitously. Figure 4, taken just about a day after the remnants of Isidore passed over the southeast, shows heavy flooding along the Mississippi, especially in the states of Mississippi and Tennessee, but other states are also affected. The spatial resolution of the AMSU-A instrument is relatively large (each measurement spot is about 25 miles in diameter at the center of the swath), but the enormous thermal contrast in the microwave between land and water makes even small flooded areas stand out., Figure 5: Difference image, 9/12 and 9/28) The Aqua spacecraft has an exact 16-day repeat cycle, that is why the pre-Isidore image is 16 days prior to the post-Isidore image. They have exactly the same coverage, which makes it possible to obtain a difference image (figure 5). The difference image is the difference between the September 28 and September 12 images shown. In the difference image, white indicates no difference at all, green is very little difference, blue/purple indicates primarily heavy flooding. Red indicates warming likely due to warmer weather. (The straight lines on the right and left edges of the difference image are caused by slight differences between the two repeat passes of Aqua). The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.
Flooding Resulting From Hurr …
PIA00365
Sol (our sun)
Atmospheric Infrared Sounder …
Title Flooding Resulting From Hurricane Isidore, Comparing Data from September 12 and 28, 2002
Original Caption Released with Image Extent of Flooding due to Hurricane Isidore revealed in images from the Atmospheric Infrared Sounding System (AIRS) on Aqua Tropical Storm Isidore was born in mid-September north of Venezuela. It subsequently hit Mexico's Yucatan Peninsula as a Category 3 hurricane and came ashore near New Orleans on September 26th packing winds just below hurricane strength. Around the time of September 27, the storm was downgraded to a tropical depression as the system moved into Tennessee. At the time the Aqua spacecraft first passed over Isidore, it was classified as a Category 3 (possibly 4) hurricane, with minimum pressure of 934 mbar, maximum sustained wind speeds of 110 knots (gusting to 135) and an eye diameter of 20 nautical miles. Isidore was later downgraded to a Tropical Storm and then a Tropical Depression as it lost energy. Figures 1 and 2, two images from the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellites show no significant weather systems over the southeastern United States on September 12 and September 28 (16 days apart). However, the microwave component of the Atmospheric Infrared Sounder Experiment on NASA's Aqua spacecraft shows a striking difference. The difference in the two microwave images (figures 3 and 4) from the AIRS Advanced Microwave Sounding Unit is primarily due to flooding after Tropical Storm Isidore. Water has a very low surface emissivity at this frequency, and that causes surface water to appear very cold (even though it is not). Land appears relatively warm (well above freezing - 273 K, even at night as seen is these images), but if there is standing water, the apparent temperature drops precipitously. Figure 4, taken just about a day after the remnants of Isidore passed over the southeast, shows heavy flooding along the Mississippi, especially in the states of Mississippi and Tennessee, but other states are also affected. The spatial resolution of the AMSU-A instrument is relatively large (each measurement spot is about 25 miles in diameter at the center of the swath), but the enormous thermal contrast in the microwave between land and water makes even small flooded areas stand out., Figure 5: Difference image, 9/12 and 9/28) The Aqua spacecraft has an exact 16-day repeat cycle, that is why the pre-Isidore image is 16 days prior to the post-Isidore image. They have exactly the same coverage, which makes it possible to obtain a difference image (figure 5). The difference image is the difference between the September 28 and September 12 images shown. In the difference image, white indicates no difference at all, green is very little difference, blue/purple indicates primarily heavy flooding. Red indicates warming likely due to warmer weather. (The straight lines on the right and left edges of the difference image are caused by slight differences between the two repeat passes of Aqua). The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.
Flooding Resulting From Hurr …
PIA00365
Sol (our sun)
Atmospheric Infrared Sounder …
Title Flooding Resulting From Hurricane Isidore, Comparing Data from September 12 and 28, 2002
Original Caption Released with Image Extent of Flooding due to Hurricane Isidore revealed in images from the Atmospheric Infrared Sounding System (AIRS) on Aqua Tropical Storm Isidore was born in mid-September north of Venezuela. It subsequently hit Mexico's Yucatan Peninsula as a Category 3 hurricane and came ashore near New Orleans on September 26th packing winds just below hurricane strength. Around the time of September 27, the storm was downgraded to a tropical depression as the system moved into Tennessee. At the time the Aqua spacecraft first passed over Isidore, it was classified as a Category 3 (possibly 4) hurricane, with minimum pressure of 934 mbar, maximum sustained wind speeds of 110 knots (gusting to 135) and an eye diameter of 20 nautical miles. Isidore was later downgraded to a Tropical Storm and then a Tropical Depression as it lost energy. Figures 1 and 2, two images from the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellites show no significant weather systems over the southeastern United States on September 12 and September 28 (16 days apart). However, the microwave component of the Atmospheric Infrared Sounder Experiment on NASA's Aqua spacecraft shows a striking difference. The difference in the two microwave images (figures 3 and 4) from the AIRS Advanced Microwave Sounding Unit is primarily due to flooding after Tropical Storm Isidore. Water has a very low surface emissivity at this frequency, and that causes surface water to appear very cold (even though it is not). Land appears relatively warm (well above freezing - 273 K, even at night as seen is these images), but if there is standing water, the apparent temperature drops precipitously. Figure 4, taken just about a day after the remnants of Isidore passed over the southeast, shows heavy flooding along the Mississippi, especially in the states of Mississippi and Tennessee, but other states are also affected. The spatial resolution of the AMSU-A instrument is relatively large (each measurement spot is about 25 miles in diameter at the center of the swath), but the enormous thermal contrast in the microwave between land and water makes even small flooded areas stand out., Figure 5: Difference image, 9/12 and 9/28) The Aqua spacecraft has an exact 16-day repeat cycle, that is why the pre-Isidore image is 16 days prior to the post-Isidore image. They have exactly the same coverage, which makes it possible to obtain a difference image (figure 5). The difference image is the difference between the September 28 and September 12 images shown. In the difference image, white indicates no difference at all, green is very little difference, blue/purple indicates primarily heavy flooding. Red indicates warming likely due to warmer weather. (The straight lines on the right and left edges of the difference image are caused by slight differences between the two repeat passes of Aqua). The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.
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