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Floods in West Africa
| Title |
Floods in West Africa |
| Description |
Sandwiched between the vast Sahara Desert of northern Africa and the equatorial forest of central Africa is the semi-arid, but fertile Sahel grassland. One of Africa's most significant crop areas, the Sahel swings between frequent drought and frequent floods. In September 2007, floods dominated. Unusually heavy and persistent rains hammered much of the Sahel, swelling rivers from Senegal on the Atlantic coast to Kenya on the Indian Ocean coast. As many as 17 countries across the Sahel were flooded, affecting more than a million people, reported BBC News [ http://news.bbc.co.uk/2/hi/africa/6994995.stm#anchor ] on September 17. The Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) flying on NASA's Aqua [ http://aqua.nasa.gov/ ] satellite captured the top image of floods in Nigeria on September 14, 2007. The lower image, taken by Aqua MODIS on May 25, 2007, shows the region under normal conditions and is provided here for reference. On September 14, both the Niger River and its tributary, the Benue River, were running over their banks. Pools of water, dark blue to black in this false-color image, line the swollen rivers. The large image reveals that the floods extend along the full length of both rivers. Smaller tributaries are also notably flooded in the large image. The combination of infrared and visible light used in this image gives clouds a pale blue tint. Plant-covered land is bright green, and bare earth is tan. A photo-like, [ http://rapidfire.sci.gsfc.nasa.gov/subsets/?NAfrica_3_04/2007257/NAfrica_3_04.2007257.aqua ] true-color version of the image is available from the MODIS Rapid Response System, which provides daily images [ http://rapidfire.sci.gsfc.nasa.gov/subsets/?NAfrica_3_04/2007257 ] of Nigeria. The floods took a heavy toll on Nigeria. As of September 14, 41 people had died in floods in northern and central Nigeria, reported Agence France-Presse. [ http://www.reliefweb.int/rw/RWB.NSF/db900SID/TBRL-772N8M?OpenDocument&rc=1&emid=FL-2007-000123-NGA ] NASA images courtesy the MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC. |
|
Floods in West Africa
| Title |
Floods in West Africa |
| Description |
Sandwiched between the vast Sahara Desert of northern Africa and the equatorial forest of central Africa is the semi-arid, but fertile Sahel grassland. One of Africa's most significant crop areas, the Sahel swings between frequent drought and frequent floods. In September 2007, floods dominated. Unusually heavy and persistent rains hammered much of the Sahel, swelling rivers from Senegal on the Atlantic coast to Kenya on the Indian Ocean coast. As many as 17 countries across the Sahel were flooded, affecting more than a million people, reported BBC News [ http://news.bbc.co.uk/2/hi/africa/6994995.stm#anchor ] on September 17. The Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) flying on NASA's Aqua [ http://aqua.nasa.gov/ ] satellite captured the top image of floods in Nigeria on September 14, 2007. The lower image, taken by Aqua MODIS on May 25, 2007, shows the region under normal conditions and is provided here for reference. On September 14, both the Niger River and its tributary, the Benue River, were running over their banks. Pools of water, dark blue to black in this false-color image, line the swollen rivers. The large image reveals that the floods extend along the full length of both rivers. Smaller tributaries are also notably flooded in the large image. The combination of infrared and visible light used in this image gives clouds a pale blue tint. Plant-covered land is bright green, and bare earth is tan. A photo-like, [ http://rapidfire.sci.gsfc.nasa.gov/subsets/?NAfrica_3_04/2007257/NAfrica_3_04.2007257.aqua ] true-color version of the image is available from the MODIS Rapid Response System, which provides daily images [ http://rapidfire.sci.gsfc.nasa.gov/subsets/?NAfrica_3_04/2007257 ] of Nigeria. The floods took a heavy toll on Nigeria. As of September 14, 41 people had died in floods in northern and central Nigeria, reported Agence France-Presse. [ http://www.reliefweb.int/rw/RWB.NSF/db900SID/TBRL-772N8M?OpenDocument&rc=1&emid=FL-2007-000123-NGA ] NASA images courtesy the MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC. |
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Drought in East Africa
| Title |
Drought in East Africa |
| Description |
Drought has been looming over Kenya for several years, leaving many regions of the country parched and hungry. Now, as the 2004/2005 harvest draws to a close, the cereal deficit has grown to 300,000 metric tons, which means that up to 2.7 million people will need food aid this season?an unusually high number for Kenya. The second maize crop, scheduled to be harvested in March, is predicted to be 20 percent below average because of a lack of rain. The most recent shortages stem from a lack of rainfall during the short rainy season, which normally runs from November to January. Though some parts of Kenya received adequate rain, crop-growing regions in the Eastern, Central, and Coast Provinces received far-below-average rainfall. In Central Province alone, about 400,000 people are facing famine, according to government estimates. The impact of drought on the crops can be seen in this image, which shows the Normalized Difference Vegetation Index (NDVI) anomaly for Kenya as measured by the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) during the first two weeks of January. NDVI is a measure of vegetation density and health. The anomaly image compares current conditions to average conditions in 2001, 2002, 2003, and 2004 during the first two weeks of January. Between January 1 and January 16, 2005, brown clusters in the Coast and Eastern provinces show patterns of dryness where vegetation is less dense than it has been in the past. More pronounced drought areas surround Central Province. Grey pixels indicate regions where data were not available. An arch of green through the center of the country reveals where rainfall was plentiful and vegetation is thriving. NASA image created by Jesse Allen, Earth Observatory, using data provided by the joint Global Agricultural Monitoring Project between NASA, USDA?s Foreign Agricultural Service (FAS), and the University of Maryland. More data and information about this joint project is available at Satellite Information for Agricultural Monitoring [ http://tripwire.geog.umd.edu/usda/ ]. |
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Drought in East Africa
| Title |
Drought in East Africa |
| Description |
Six successive years of poor rain have left Eastern Africa in severe drought. Rain typically falls between February and June, and 2005 looked promising when rains started to fall in January. The promise dried up, however, when the rains stopped, leaving the latter half of March and the first half of April dry. The cumulative impact of poor rainfall on plants is visible in this vegetation anomaly image. The image was created using data collected by the Advanced Very High Resolution Radiometer between April 11, and April 20, 2005, compared to average conditions. Brown blankets regions where vegetation was less healthy and thick than normal, while green shows thicker vegetation than average. The band of brown that stretches west from Somalia reveals that the poor rainfall has withered vegetation across the region. Rainfall is essential for reviving pastoral lands and filling water catchments in this water-scarce region. Life in the pastoral societies impacted by this drought revolves around livestock. The poor rain and lack of vegetation have led to a decline in milk production and livestock deaths?a formula for famine. Millions throughout Sudan, Eritrea, Ethiopia, Somalia, and Kenya are in need of food aid. In Ethiopia, where 7.5 million require food aid, the most severely affected populations live in the south and the east. This correlates well with the image, which shows the most drought-affected vegetation in southeast Ethiopia. Heavy rains fell in Ethiopia and Somalia in late April, triggering deadly floods [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12846 ] in southeast Ethiopia. Though tragic, the rains may help alleviate the drought. NASA image created by Jesse Allen, Earth Observatory, using data obtained courtesy of Molly Brown, NASA GIMMS Group [ http://ltpwww.gsfc.nasa.gov/gimms/htdocs/ ] at Goddard Space Flight Center. |
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Drought in East Africa
| Title |
Drought in East Africa |
| Description |
Six successive years of poor rain have left Eastern Africa in severe drought. Rain typically falls between February and June, and 2005 looked promising when rains started to fall in January. The promise dried up, however, when the rains stopped, leaving the latter half of March and the first half of April dry. The cumulative impact of poor rainfall on plants is visible in this vegetation anomaly image. The image was created using data collected by the Advanced Very High Resolution Radiometer between April 11, and April 20, 2005, compared to average conditions. Brown blankets regions where vegetation was less healthy and thick than normal, while green shows thicker vegetation than average. The band of brown that stretches west from Somalia reveals that the poor rainfall has withered vegetation across the region. Rainfall is essential for reviving pastoral lands and filling water catchments in this water-scarce region. Life in the pastoral societies impacted by this drought revolves around livestock. The poor rain and lack of vegetation have led to a decline in milk production and livestock deaths?a formula for famine. Millions throughout Sudan, Eritrea, Ethiopia, Somalia, and Kenya are in need of food aid. In Ethiopia, where 7.5 million require food aid, the most severely affected populations live in the south and the east. This correlates well with the image, which shows the most drought-affected vegetation in southeast Ethiopia. Heavy rains fell in Ethiopia and Somalia in late April, triggering deadly floods [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=12846 ] in southeast Ethiopia. Though tragic, the rains may help alleviate the drought. NASA image created by Jesse Allen, Earth Observatory, using data obtained courtesy of Molly Brown, NASA GIMMS Group [ http://ltpwww.gsfc.nasa.gov/gimms/htdocs/ ] at Goddard Space Flight Center. |
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Drought in East Africa
| Title |
Drought in East Africa |
| Description |
The failure of the short-season rains left large sections of East Africa in severe drought in late 2005 and early 2006. In eastern Africa, most areas experience one of two rainfall patterns. Some places have a single "long rains" season that runs from March until November or December. Other areas have two rainy seasons: long rains between March/April and July/August, and "short rains" from October to December or January. The rains recharge lakes and reservoirs and nurture plants from crops and pasture lands to natural vegetation. For East Africa, 2005 was anything but a normal year. The long rainy season produced little rain, and the short rainy season failed altogether. As a result, rainfall totals for the year were only 20-60 percent of normal, depending on the region, reported the Famine Early Warning Network (FEWS NET). The drought's impact on vegetation can be seen in this vegetation index image, collected by the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) at the end of the short rainy season. The image shows how well plants were growing between December 19 and January 3 compared to average conditions between 2000 and 2004. The prevalence of deep reddish-brown across the image indicates that plants were growing poorly, if at all, in the dry conditions. The drought area shown in this image circles Lake Victoria in a north-south-oriented oval that stretches from southern Sudan and Ethiopia in the north to Tanzania in the south. Grey areas show where clouds covered the area throughout the composite period. The impact of the drought has been severe. "This drought has resulted in crop failures, pasture degradation, water shortages, and has raised serious food security concerns for the region," FEWS NET warned. By the end of January 2006, millions were in need of food aid, particularly pastoralists who depend on rain-fed pasture lands to maintain their livestock. Not all of East Africa has been affected. Kenya (center right) had a bumper harvest in 2005, but little of the crop made its way to the drought-hit pastoral districts of the country. NASA image created by Jesse Allen, Earth Observatory, using data provided by Inbal Reshef as part of the Global Agricultural Monitoring Project between NASA, USDA's Foreign Agricultural Service (FAS), and the University of Maryland. More data and information about this joint project is available at Satellite Information for Agricultural Monitoring. [ http://tripwire.geog.umd.edu/usda/ ] |
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East Africa Greens Up from H
…
| Title |
East Africa Greens Up from Heavy Rains |
| Description |
After devastating drought in 2005, eastern Africa experienced heavy rains and flooding during the 2006 "short rains" season that usually lasts from around October until December. Somalia, Ethiopia, Kenya, and Tanzania all experienced significant, sometimes deadly, flooding. [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=14026 ] What has been difficult for people and livestock, however, has been good for vegetation, including grazing areas and croplands. The resulting green-up is evident in this image, which compares satellite-observed vegetation in November 2006 to the average November conditions from 2000-2005. Places where vegetation was more luxuriant than normal are shown in green, while places where vegetation conditions were below normal are colored brown. Places near average are yellow. The data were collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) [ http://modis.gsfc.nasa.gov ] on NASA's Terra [ http://terra.nasa.gov ] satellite. Among the most changed areas is Kenya's Eastern province. Both the Marsabit National Reserve, which is next to the Ethiopia border, and the Merti Plateau to its south were dramatically more lush than they were near the end of 2005. [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=13329 ] Evidence of extensive flooding along the Shebele River in southeast Ethiopia (Shabelle in Somalia) is clear: unusually green vegetation traces out the path of the river and several of its tributaries. Although water levels in Lake Victoria have rebounded somewhat from the extremely low levels [ http://earthobservatory.nasa.gov/Study/Victoria/ ] measured in 2005, the vegetation in areas surrounding the lake appears to be slower to respond. NASA image created by Jesse Allen, Earth Observatory, using data provided courtesy of the USDA Foreign Agricultural Service and processed by Jen Small and Assaf Anyamba of the GIMMS Group [ http://ltpwww.gsfc.nasa.gov/gimms/htdocs/ ] at NASA GSFC. |
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Solar Eclipse over Africa
| Title |
Solar Eclipse over Africa |
| Description |
Eastern Africa was cloaked in darkness when the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Aqua [ http://aqua.nasa.gov/ ] satellite caught this image on October 3, 2005. The inky blackness that covers much of Ethiopia, Kenya, Uganda, and parts of Sudan and the Democratic Republic of the Congo in this image was caused when the Moon crossed in front of the Sun in an annular solar eclipse. During such an eclipse, the Sun is visible as a fiery circle around the black disk of the moon. In the dimness beneath the Moon's shadow, very little light remained for MODIS to capture this image. Under normal conditions [ http://rapidfire.sci.gsfc.nasa.gov/subsets/?NAfrica_3_07/2005276 ], the land in the lower half of the image is a lush green, with patches of tan where the land is bare. Here, the tan areas have a red tint in the low light, while the green is completely black. Red dots show where fires were burning in vegetated areas. In the top half of the image, the orange of the Sahara desert is shown in darker tones than normal [ http://rapidfire.sci.gsfc.nasa.gov/subsets/?NAfrica_2_07/2005276 ]. Only in the upper right corner of the image, where full daylight has returned, does the desert look normal. Gradations of darkness within the shadowed area can be seen in the clouds. Bright white clouds reflect light well, so they are easily visible, even in the shadow. Since some light reached the Earth, the clouds remain bright along the outer edges of the shadowed region. As the eclipse progressed, the moon's shadow traveled southeast across the globe. When this image was taken, the deepest shadow lay over Kenya in the lower right corner of the image. Here the clouds are darker, an indication that there was less light to reflect back to the satellite. If this had been a total solar eclipse, the shadow cast by the moon would have been complete. The difference between a total solar eclipse and an annular eclipse is caused by the Moon's orbit around the Earth. The Moon's orbit is not circular, it is elliptical, like a squashed circle with the Earth at its center. This means that the Moon is not always the same distance from the Earth. When it is close to the Earth, the Moon appears larger than when it is far away. During a total solar eclipse, the Moon is closer to the Earth and so is able to block out the Sun entirely. An annular eclipse occurs when the Moon is farther from the Earth, and so the Moon's disk is not large enough to cover the Sun. The large image provided above has a resolution of 500 meters per pixel. It is available in additional resolutions from the MODIS Rapid Response Team. Tiny blue flecks in the large image are defects in the data. NASA image courtesy the MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC. |
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Floods in Chad
| Title |
Floods in Chad |
| Description |
Ghana, [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=14528 ] Senegal, [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=14526 ] Mali, [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=14534 ] Uganda, [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=14536 ] and Sudan [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=14499 ] are available on the Earth Observatory. Daily images [ http://rapidfire.sci.gsfc.nasa.gov/subsets/ ] of Africa's Sahel region, where the floods were concentrated, are available from the MODIS Rapid Response System. NASA images courtesy the MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC., The Sahel grassland is a rain-dependent ecosystem. With no mountain snowpacks to provide water during the dry season or daily infusions of water from moist air masses, the fortunes of the great African grasslands depend entirely on seasonal rain. The contrast between the dry season and the rainy season is illustrated by this pair of images, both captured by the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Terra [ http://terra.nasa.gov/ ] satellite. MODIS took the top image on September 18, 2007, after several weeks of unusually heavy rain had fallen over the Sahel. At the time, as many as 17 countries were flooded, from Senegal, bordering on the Atlantic Ocean in the west, to Kenya on the continent's east coast. The lower image was taken on July 4, 4007, a short time before the rains started in earnest. The images show Lake Firtri and the Batha River in southern Chad, a short distance east of Lake Chad. In the combination of infrared and visible light used to create these images, water is typically black, though in this case, it is bright blue. Sediment in the water scatters light, creating the blue color. In July, the only visible water is in Lake Fitri. Traces of green vegetation in the wetlands around the lake and along the Batha River are the only indication that water might be present elsewhere in the scene. Beyond these green areas, the landscape around the lake is mostly the rosy tan of barren land. The cluster of waves in the land to the north of Lake Fitri is likely a dune field along the southernmost edge of the Sahara Desert. Clouds, turquoise blue in this false-color image, gather on the southern edge of the scene. By September 18, water had changed southern Chad completely. The region went from dry to flooded. Lake Fitri had nearly doubled in size as the wetlands filled with water. The Batha River ran high, its channel clearly defined by a bold blue line of water. The land is vibrant green, covered with the grasses that sprang up in response to the rains. The rains and resulting floods cut off or severely hampered access to refugee camps along Chad's southeastern border with the Darfur region of Sudan, making the delivery of supplies difficult, said the United Nations Office for the Coordination of Humanitarian Affairs in a report [ http://www.reliefweb.int/rw/rwb.nsf/db900sid/LRON-778HGZ?OpenDocument&rc=1&emid=FL-2007-000151-TCD ] issued on September 20. The rains were expected to continue through early October. Chad was just one of many African countries that were flooded in September 2007. As many as 17 countries and more than a million people were affected by flooding across Africa, reported BBC News on September 17. Images of flood areas in Nigeria, [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=14532 ] |
|
Floods in East Africa
| Title |
Floods in East Africa |
| Description |
As East Africa's short rainy season progressed into November, the downpour continued to stress rivers throughout Somalia, Ethiopia, and Kenya. The widespread flooding began with the rains in mid-October, and continued through the end of November when unusually heavy rain fell on drought-hardened earth, said the Famine Early Warning System Network [ http://www.reliefweb.int/rw/RWB.NSF/db900SID/HMYT-6VXLLM?OpenDocument&rc=1&emid=FL-2006-000169-SOM ] (FEWS NET). Between October 1 and November 10, 2006, most regions in southern Somalia received more than 300 percent of their normal rainfall, FEWS Net added. The rain had a dual effect on the land. In the long term, the rains will help the region recover from drought, but in some river basins, the rains triggered floods that destroyed crops. Among the river basins most severely affected by flooding is the Shabeelle River (Shabele River in Ethiopia). The top image, taken by the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Terra [ http://terra.nasa.gov/ ] satellite on November 17, 2006, shows just how much the Shabeelle River had swollen compared to 2005, when the region was in drought. Flooding along this section of the Shabeelle drove 50,000 from their homes in the town of Beletweyne, which was uninhabitable by November 17, said the United Nations. [ http://www.reliefweb.int/rw/RWB.NSF/db900SID/KKEE-6VLP43?OpenDocument&rc=1&emid=FL-2006-000169-SOM ] The floods are visible through scattered clouds, which are pale blue in this image. Water is black, plant-covered land is bright green, and sparsely vegetated land is tan-pink. NASA image courtesy Jeff Schmaltz, MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC |
|
Floods in East Africa
| Title |
Floods in East Africa |
| Description |
As East Africa's short rainy season progressed into November, the downpour continued to stress rivers throughout Somalia, Ethiopia, and Kenya. The widespread flooding began with the rains in mid-October, and continued through the end of November when unusually heavy rain fell on drought-hardened earth, said the Famine Early Warning System Network [ http://www.reliefweb.int/rw/RWB.NSF/db900SID/HMYT-6VXLLM?OpenDocument&rc=1&emid=FL-2006-000169-SOM ] (FEWS NET). Between October 1 and November 10, 2006, most regions in southern Somalia received more than 300 percent of their normal rainfall, FEWS Net added. The rain had a dual effect on the land. In the long term, the rains will help the region recover from drought, but in some river basins, the rains triggered floods that destroyed crops. Among the river basins most severely affected by flooding is the Shabeelle River (Shabele River in Ethiopia). The top image, taken by the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Terra [ http://terra.nasa.gov/ ] satellite on November 17, 2006, shows just how much the Shabeelle River had swollen compared to 2005, when the region was in drought. Flooding along this section of the Shabeelle drove 50,000 from their homes in the town of Beletweyne, which was uninhabitable by November 17, said the United Nations. [ http://www.reliefweb.int/rw/RWB.NSF/db900SID/KKEE-6VLP43?OpenDocument&rc=1&emid=FL-2006-000169-SOM ] The floods are visible through scattered clouds, which are pale blue in this image. Water is black, plant-covered land is bright green, and sparsely vegetated land is tan-pink. NASA image courtesy Jeff Schmaltz, MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC |
|
Floods in East Africa
| Title |
Floods in East Africa |
| Description |
December typically marks the end of the short rainy season in eastern Africa. By mid- to late December, the rains subside until March, when the long rainy season begins. Fluctuations in the amount of rain that falls during the short rainy season are normal, and in 2006, the rains were more intense than normal. The heavy rains triggered deadly floods from Somalia to Tanzania. In 2005, by contrast, the rains failed, and drought ensued. The difference between the two years is clearly illustrated by this pair of satellite images, collected by the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Aqua [ http://aqua.nasa.gov/ ] (top image) and Terra [ http://terra.nasa.gov/ ] (lower image) satellites. The images were made with both visible and infrared light to highlight the presence of water of the ground. In this type of image, water is typically black or dark blue, but sediment can give it a lighter color. Clouds are turquoise, plant-covered land is bright green, and bare or sparsely vegetated ground is tan-pink. The rain-induced floods of 2006 were visible in Tanzania on December 4, when MODIS captured the top image. In the image, Tanzania's Wembere River and surrounding waterways are swollen to such an extent that the shores of Lake Kitangiri are swallowed in the floods. According to the United Nations Integrated Regional Information Networks, [ http://allafrica.com/stories/200612050387.html ] floods in this region and the area to its immediate north submerged at least five villages, affecting about 177 people and killing one. A year earlier, on December 1, 2005, the rivers were barely visible, and both Lake Eyasi and Lake Kitangiri were much smaller. In the drought conditions that prevailed in 2005, the land was bare, with little vegetation growing, and skies were relatively clear. The heavy rains that produced floods in 2006 also brought green to the landscape and left large clouds overhead. NASA images created by Jesse Allen, Earth Observatory, using data provided courtesy of the MODIS Rapid Response [ http://rapidfire.sci.gsfc.nasa.gov/ ] team and the Level 1 and Atmospheric Archive Distribution System. [ http://ladsweb.nascom.nasa.gov/ ] |
|
Floods in East Africa
| Title |
Floods in East Africa |
| Description |
December typically marks the end of the short rainy season in eastern Africa. By mid- to late December, the rains subside until March, when the long rainy season begins. Fluctuations in the amount of rain that falls during the short rainy season are normal, and in 2006, the rains were more intense than normal. The heavy rains triggered deadly floods from Somalia to Tanzania. In 2005, by contrast, the rains failed, and drought ensued. The difference between the two years is clearly illustrated by this pair of satellite images, collected by the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Aqua [ http://aqua.nasa.gov/ ] (top image) and Terra [ http://terra.nasa.gov/ ] (lower image) satellites. The images were made with both visible and infrared light to highlight the presence of water of the ground. In this type of image, water is typically black or dark blue, but sediment can give it a lighter color. Clouds are turquoise, plant-covered land is bright green, and bare or sparsely vegetated ground is tan-pink. The rain-induced floods of 2006 were visible in Tanzania on December 4, when MODIS captured the top image. In the image, Tanzania's Wembere River and surrounding waterways are swollen to such an extent that the shores of Lake Kitangiri are swallowed in the floods. According to the United Nations Integrated Regional Information Networks, [ http://allafrica.com/stories/200612050387.html ] floods in this region and the area to its immediate north submerged at least five villages, affecting about 177 people and killing one. A year earlier, on December 1, 2005, the rivers were barely visible, and both Lake Eyasi and Lake Kitangiri were much smaller. In the drought conditions that prevailed in 2005, the land was bare, with little vegetation growing, and skies were relatively clear. The heavy rains that produced floods in 2006 also brought green to the landscape and left large clouds overhead. NASA images created by Jesse Allen, Earth Observatory, using data provided courtesy of the MODIS Rapid Response [ http://rapidfire.sci.gsfc.nasa.gov/ ] team and the Level 1 and Atmospheric Archive Distribution System. [ http://ladsweb.nascom.nasa.gov/ ] |
|
Night Trails of Africa
| Title |
Night Trails of Africa |
| Explanation |
Spanning southern to northern skies, stars trail [ http://www.astropix.com/HTML/I_ASTROP/BEGINNER.HTM ] across this panoramic view of the African night from equatorial Kenya [ http://www.cia.gov/cia/publications/factbook/geos/ke.html ]. The three hour long exposure [ http://www.astroleague.org/al/astrnote/astnot16.html ] was made on a clear, dark, mid November evening facing due west and covers just over 180 degrees along the horizon. So, the South Celestial Pole [ http://antwrp.gsfc.nasa.gov/apod/ap000715.html ] is at the center of the concentric arcs on the left and the North Celestial Pole [ http://antwrp.gsfc.nasa.gov/apod/ap980912.html ] is at the far right (scroll right). And, you guessed it(!), the stars setting along the Celestial Equator [ http://www.jpl.nasa.gov/basics/bsf2-2.html ] leave the straight trails near the middle of the picture. Well illustrated in this thoughtfully composed panorama [ http://www.photosymphony.com/ ], the star trails in the African night are, of course, not due to motions of the individual stars but simply reflect the daily rotation [ http://antwrp.gsfc.nasa.gov/apod/ap010110.html ] of planet Earth itself [ http://www.windows.ucar.edu/cgi-bin/tour_def/the_universe/ uts/earth2.html ]. |
|
Nalubaale Dam, Uganda: Image
…
nasa, nasaimageofthedaygalle
…
Dam KML file for use with ea
…
nalubaale_etm_2001331
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2001-11-27 |
| creator |
NASA -- NASA image by Robert Simmon, based on landsat.gsfc.nasa.gov/ Landsat-7 data provided by the UMD glcf.umiacs.umd.edu/index.shtml Global Land Cover Facility. |
| identifier |
nalubaale_etm_2001331 |
|
Floods in West Africa: Natur
…
nasa, nasanaturalhazards
* eoimages.gsfc.nasa.gov/ima
…
Nigeria_AMO_2007257
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2007-09-14 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
Nigeria_AMO_2007257 |
|
Floods in Chad: Image of the
…
nasa, nasaimageofthedaygalle
…
* eoimages.gsfc.nasa.gov/ima
…
Chad_TMO_2007261
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2007-09-18 |
| creator |
NASA -- NASA images courtesy the rapidfire.sci.gsfc.nasa.gov MODIS Rapid Response Team at NASA GSFC. |
| identifier |
Chad_TMO_2007261 |
|
Floods in East Africa: Natur
…
nasa, nasanaturalhazards
* eoimages.gsfc.nasa.gov/ima
…
Somalia_TMO_2006321
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2006-11-17 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
Somalia_TMO_2006321 |
|
El Nino and Rainfall: Image
…
nasa, nasaimageofthedaygalle
…
At the end of 2006, East Afr
…
precipanom_trmm_200611
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2006 |
| creator |
NASA -- NASA image created by Jesse Allen, Earth Observatory, using rainfall data provided courtesy of the precip.gsfc.nasa.gov/ Global Precipitation Climatology Product team at NASA Goddard Space Flight Center. |
| identifier |
precipanom_trmm_200611 |
|
Drought in East Africa: Natu
…
nasa, nasanaturalhazards
Six successive years of poor
…
eafrica_avhrr_11-20apr05
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2004-04-21 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
eafrica_avhrr_11-20apr05 |
|
Drought in East Africa: Natu
…
nasa, nasanaturalhazards
Six successive years of poor
…
eafrica_avhrr_11-20apr05
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2004-04-21 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
eafrica_avhrr_11-20apr05 |
|
Locusts in Kenya: Image of t
…
nasa, nasaimageofthedaygalle
…
'For the first time since 19
…
kenyandvia_spt_2007324
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2007-12-03 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
kenyandvia_spt_2007324 |
|
Solar Eclipse over Africa: I
…
nasa, nasaimageofthedaygalle
…
Eastern Africa was cloaked i
…
EastAfrica_AMO_2005276
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2005-10-03 |
| creator |
NASA -- NASA images courtesy the rapidfire.sci.gsfc.nasa.gov MODIS Rapid Response Team at NASA GSFC. |
| identifier |
EastAfrica_AMO_2005276 |
|
East Africa Greens Up from H
…
nasa, nasanaturalhazards
After devastating drought in
…
ge_17782
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2006-11-30 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
ge_17782 |
|
East Africa Greens Up from H
…
nasa, nasanaturalhazards
After devastating drought in
…
ge_17782
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2006-11-30 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
ge_17782 |
|
East Africa Greens Up from H
…
nasa, nasanaturalhazards
After devastating drought in
…
ge_17782
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2006-11-30 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
ge_17782 |
|
Floods Raise Water Levels on
…
nasa, nasaimageofthedaygalle
…
The 2006-2007 rainy season i
…
lakevic_ast_2006345
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2006-12-11 |
| creator |
NASA -- ASTER image by Jesse Allen using data provided by NASA, GSFC, METI, ERSDAC, JAROS, and U.S./Japan ASTER Science Team. Image and caption information from Jodie Smith, GIS Scientist, Early Warning and Environmental Monitoring, SAIC contractor to US Geological Survey Earth Resources Observation and Science, Sioux Falls, SD. JJason-1 data interpretation by Charon Birkett, University of Maryland, and Brian Beckley, SGT at NASA/GSFC. Lake level products courtesy of the USDA/FAS www.pecad.fas.usda.gov/cropexplorer/ CropExplorer Program. The USDA/NASA/SGT/UMD team acknowledges the AVISO data center at CNES and the NASA Physical Oceanography DAAC for the provision of the TOPEX/POSEIDON and Jason altimetric datasets. |
| identifier |
lakevic_ast_2006345 |
|
Drought in East Africa: Natu
…
nasa, nasanaturalhazards
The failure of the short-sea
…
eafrica_tmo_2005353_palette
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2005-12-19 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
eafrica_tmo_2005353_palette |
|
Drought in East Africa: Natu
…
nasa, nasanaturalhazards
The failure of the short-sea
…
eafrica_tmo_2005353_palette
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2005-12-19 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
eafrica_tmo_2005353_palette |
|
Flooding in Eastern Africa:
…
nasa, nasanaturalhazards
* eoimages.gsfc.nasa.gov/ima
…
ethopia_tmo_2006120
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2006-04-30 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
ethopia_tmo_2006120 |
|
Flooding in Eastern Africa:
…
nasa, nasanaturalhazards
* eoimages.gsfc.nasa.gov/ima
…
ethopia_tmo_2006120
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2006-04-30 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
ethopia_tmo_2006120 |
|
Africa in SRTM 3-D, Anaglyph
…
PIA04964
Sol (our sun)
C-Band Interferometric Radar
…
| Title |
Africa in SRTM 3-D, Anaglyph of Shaded Relief |
| Original Caption Released with Image |
This stereoscopic shaded relief image shows Africa's topography as measured by the Shuttle Radar Topography Mission (SRTM) in February 2000. Also shown are Madagascar, the Arabian Peninsula, and other adjacent regions. Previously, much of the topography here was not mapped in detail. Digital elevation data, such as provided by SRTM, are in high demand by scientists studying earthquakes, volcanism, and erosion patterns and for use in mapping and modeling hazards to human habitation. But the shape of Earth's surface affects nearly every natural process and human endeavor that occurs there, so elevation data are used in a wide range of applications. The image shown here is greatly reduced from the original data resolution, but still provides a good overview of the continent's landforms. It is best viewed while panning at full resolution while using image display software. The northern part of the continent consists of a system of basins and plateaus, with several volcanic uplands whose uplift has been matched by subsidence in the large surrounding basins. Many of these basins have been infilled with sand and gravel, creating the vast Saharan lands. The Atlas Mountains in the northwest were created by convergence of the African and Eurasian tectonic plates. The geography of the central latitudes of Africa is dominated by the Great Rift Valley, extending from Lake Nyasa to the Red Sea, and splitting into two arms to enclose an interior plateau and the nearly circular Lake Victoria, visible in the right center of the image. To the west lies the Congo Basin, a vast, shallow depression that rises to form an almost circular rim of highlands. Most of the southern part of the continent rests on a concave plateau comprising the Kalahari Basin and a mountainous fringe, skirted by a coastal plain that widens out in Mozambique in the southeast. Specific noteworthy features one may wish to explore in this scene include (1) the Richat Structure in Mauritania, a "bull's eye" geologic structure, (2) the Velingara Ring in Senegal, a possible meteorite impact crater, (3) the delta of the Niger River in Nigeria, (4) the Cameroon Line of volcanoes, crossing Cameroon and extending offshore, (5) long linear mountain ridges crossing the southern end of Africa, (6) Mount Kilimanjaro and neighboring volcanoes in Kenya and Tanzania, (7) the Afar Triangle in Ethiopia, Djibouti, and vicinity, where Earth's crust is being pulled in three directions by tectonic forces, (8) the Dead Sea fault line, between Israel and Jordan, (9) ancient shorelines, inland from the coast of Libya, and (10) vast seas of sand dunes, particularly across the Sahara Desert and much of the Arabian Peninsula. This anaglyph was created by deriving a shaded relief image from the SRTM data, draping it back over the SRTM elevation model, and then generating two differing perspectives, one for each eye. Illumination is from the north (top). When viewed through special glasses, the anaglyph is a, vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter. Elevation data used in this image were acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Geospatial-Intelligence Agency (NGA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C. Orientation: North toward the top, Mercator projection Image Data: Shaded SRTM elevation model Date Acquired: February 2000 |
|
Mt. Elgon, Africa, Shaded Re
…
PIA04958
Sol (our sun)
C-Band Interferometric Radar
…
| Title |
Mt. Elgon, Africa, Shaded Relief and Colored Height |
| Original Caption Released with Image |
Location: 1 degree north latitude, 35 degrees east longitude Orientation: North toward the top, Mercator projection Size: 223 by 223 kilometers (138 by 138 miles) Image Data: shaded and colored SRTM elevation model Date Acquired: February 2000, The striking contrast of geologic structures in Africa is shown in this shaded relief image of Mt. Elgon on the left and a section of the Great Rift Valley on the right. Mt. Elgon is a solitary extinct volcano straddling the border between Uganda and Kenya, and at 4,321 meters (14,178 feet) tall is the eighth highest mountain in Africa. It is positioned on the Pre-Cambriam bedrock of the Trans Nzoia Plateau, and is similar to other such volcanoes in East Africa in that it is associated with the formation of the Rift Valley. However one thing that sets Mt. Elgon apart is its age. Although there is no verifiable evidence of its earliest volcanic activity, Mt. Elgon is estimated to be at least 24 million years old, making it the oldest extinct volcano in East Africa. This presents a striking comparison to Mt. Kilimanjaro, the highest mountain in Africa at 5,895 meters (19,341 feet), which is just over one million years old. Judging by the diameter of its base, it is a common belief among geological experts that Mt. Elgon was once the highest mountains in Africa, however erosion has played a significant role in reducing the height to its present value. Juxtaposed with this impressive mountain is a section of the Great Rift Valley, a geological fault system that extends for about 4,830 kilometers (2,995 miles) from Syria to central Mozambique. Erosion has concealed some sections, but in some sections like that shown here, there are sheer cliffs several thousand feet high. The present configuration of the valley, which dates from the mid-Pleistocene epoch, results from a rifting process associated with thermal currents in the Earth's mantle. Two visualization methods were combined to produce the image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations. Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Geospatial-Intelligence Agency (NGA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C. |
|
TDRS satellite over African
…
| Title |
TDRS satellite over African Rift Valley, Kenya, Africa |
| Description |
This post deploy view of a TDRS satellite shows a segment of the African Rift Valley near Lake Baringo, Kenya, Africa (3.0S, 36.0E). The African Rift Valley system is a geologic fault having its origins in southern Turkey, through the near east forming the bed of the Jordan River, Gulf of Aqaba, the Red Sea and down through east Africa. The line of lakes and valleys of east Africa are the result of the faulting activity. |
| Date Taken |
1983-04-09 |
|
East African Rift Valley, Ke
…
| Title |
East African Rift Valley, Kenya |
| Description |
This rare, cloud free view of the East African Rift Valley, Kenya (1.5N, 35.5E) shows a clear view of the Turkwell River Valley, an offshoot of the African REift System. The East African Rift is part of a vast plate fracture which extends from southern Turkey, through the Red Sea, East Africa and into Mozambique. Dark green patches of forests are seen along the rift margin and tea plantations occupy the cooler higher ground. |
| Date Taken |
1990-01-20 |
|
Omo River Delta, Lake Turkan
…
| Title |
Omo River Delta, Lake Turkana, Ethiopia/Kenya border, Africa |
| Description |
As a result of land clearing operations in the local area, the Omo River Delta (4.5N, 36.0E) at the north end of Lake Turkana, on the Ethiopia/Kenya border has become enlarged through topsoil erosion. The delta measured 800 sq. km. in 1981 doubled to 1,600 sq. km. by 1988 and was up to 1,800 sq. km. in 1991. This is the same area where the Leaky Anthropological Team discovered the earliest remains of human ancestors. |
| Date Taken |
1991-09-18 |
|
STS-57 Earth observation of
…
| Title |
STS-57 Earth observation of Lake Victoria, Africa |
| Description |
STS-57 Earth observation taken aboard Endeavour, Orbiter Vehicle (OV) 105, is of Africa's Lake Victoria, which sits in the middle of the East African Rift Valley System.Lake Victoria is a major resource in eastern Africa, especially to the countries bordering the lake -- Uganda, Kenya and Tanzania. Typical summer indicators in equatorial Africa -- puffy clouds over land mass and clear skies over the lakes -- are in the view. Lake Albert in the western section of the Rift Valley and Lake Turkana in the eastern section can be seen to the west and east of Lake Victoria, respectively. Most of the other features on the right are obscured by clouds. NASA scientists studying the STS-57 Earth photography point out that the wide perspective of this scene gives a sense of the three-dimensional profile of the whole rift system. The scientists cite the way in which the component valleys of the rift system ramp up to Lake Victoria on either side. |
| Date Taken |
1993-07-01 |
|
STS-65 Earth observation of
…
| Title |
STS-65 Earth observation of Omo River Delta, Lake Turkana in Ethiopia / Kenya |
| Description |
STS-65 Earth observation taken aboard Columbia, Orbiter Vehicle (OV) 102, is of Omo River Delta and Lake Turkana in Ethiopia / Kenya. The Omo Delta at the north end of Lake Turkana (Rudolph) is one of the long-term environmental study sites of the Space Shuttle program. The environmental interest in this instance is the documentation of the delta's extension into the lake. This delta extension, or aggradation, is felt to be the result of large-scale soil erosion in the recently deforested areas of Ethiopia in the watershed of the Omo River. Using digitized, rectified, machine-classified, and mensurated NASA photography, it has been determined that the Omo Delta has increased in area by approximately 400% to about 1,800 square kilometers since it was first photographed during the Gemini program in 1965. This photograph documents the long-term and increasing turbidity of Lake Turkana and the continuing delta extension southward by both the northwest and northeast distributaries of the Om |
| Date Taken |
1994-07-23 |
|
|
