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Dust near Lake Chad
| Title |
Dust near Lake Chad |
| Description |
*Dust near Lake Chad* Dust clouds the air over Nigeria, Cameroon, and Chad in this Moderate Resolution Imaging Spectroradiometer [ http://modis.gsfc.nasa.gov ] (MODIS) image acquired on January 8, 2004, by the Aqua [ http://aqua.nasa.gov/ ] satellite. The streak of white in the top right corner is dust blowing out of the Bodele Depression. Dust storms in the Bodele depression are common. As recently as the 1960s, the area formed part of Lake Chad on the southern edges of the vast Sahara desert. Lack of rain and increased demand for irrigation water shrank the shorelines of the lake, leaving the Bodele depression dry. The low-lying area is now a major source of windblown dust in Europe, the Middle East, and the Western Hemisphere. The white and tan clouds in the center of the image are probably Saharan dust from previous storms. Hundreds of agricultural fires, shown as red dots, are also burning across the region. Burning is a common method of clearing farmland in central Africa. For more information, see Fires in West Africa [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=11876 ]. The high resolution image provided above is at MODIS? maximum resolution of 250 meters per pixel. Image courtesy Jesse Allen, based on data from the MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC |
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Dust Storm from the Bodele D
…
| Title |
Dust Storm from the Bodele Depression |
| Description |
On January 29, 2007, a characteristic dual-plume dust storm blew out of the Bodele Depression in northern Africa. The Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Aqua [ http://aqua.nasa.gov/ ] satellite took this picture the same day. This image shows two pale beige dust plumes blowing out of the Bodele Depression toward the southwest. The dust partially blurs the satellite's view of Lake Chad, which spans the borders of Niger, Nigeria, Cameroon, and Chad. NASA image courtesy the MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC. |
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Dust Storm in Central Africa
| Title |
Dust Storm in Central Africa |
| Description |
On March 23, 2005, winds were whipping across the sands of the southern Sahara Desert in northern Africa, spreading thick clouds of dust. The thickest plumes of dust are visible in Sudan, Chad and Niger, but dust also reaches southward into Nigeria (south of Niger) and Cameroon (east of Nigeria). On the Atlantic coast, scores of fires (marked in red) are burning in Senegal. Dust storms are frequent hazards to farmers and herders in the semi-arid lands at the southern margin of the Sahara. The winds can reach speeds up to 100 kilometers per hour, reducing visibility to zero, stripping the paint off cars, and causing sands dunes to move like waves across a sandy sea. South of the desert proper is a semi-arid region known as the Sahel, which is continually under threat of desertification, though not necessarily because of direct threats from the Sahara. Direct exposure to the Sahara threatens some farming regions in the West with encroachment of sand dunes, but in many other places, including Niger and the other countries around Lake Chad, cultivated land is buffered from direct exposure to the dunes of the Sahara by a green belt of bushes and trees. Here, the threat of desertification comes from the way people use, and overuse, the landscape. Too-frequent use of fire as an agricultural tool, cutting of trees, and overgrazing exacerbate naturally occurring droughts in this semi-arid landscape. Without vegetation to anchor the soil in place, wind erosion scours away the top soil. The loss of vegetation may even change the micro-climate of these green belts or pockets of vegetation through a reduction of humidity and rainfall. Areas that were once tenuously covered with vegetation become pockets of desert. For more about the processes of land degradation that lead to desertification, read a report on desertification [ http://pubs.usgs.gov/gip/deserts/desertification/ ] from the U.S. Geological Survey. The high-resolution image provided above has a spatial resolution of 1 kilometer per pixel. The MODIS Rapid Response System provides this image at additional resolutions. NASA image courtesy the MODIS Rapid Response Team, NASA-Goddard Space Flight Center |
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Dust Storm over Lake Chad
| Title |
Dust Storm over Lake Chad |
| Description |
Highly reflective dust was blowing from the northeast over Lake Chad (green splash at bottom of image) on April 9, 2003. Frequent dust storms are just one of the many factors slowly eating away at this prime source of freshwater for people, animals and plants in (counterclockwise from top left) Niger, Nigeria, Cameroon, and Chad. Increasing demand for irrigation is draining the lake, and blowing sand and desert dust are creating sand dunes that are encroaching on the vegetation along the perimeter of the lake (see high-resolution 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 |
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Dust Storms from Africa's Bo
…
| Title |
Dust Storms from Africa's Bodele Depression |
| Description |
Once serving as part of the floor for a much larger Lake Chad, the area now known as the Bodele Depression, located at the southern edge of the Sahara Desert in north central Africa, is slowly being transformed into a desert landscape. In the mid-1960s, Lake Chad was about the size of Lake Erie. But persistent drought conditions coupled with increased demand for freshwater for irrigation have reduced Lake Chad to about 5 percent of its former size. As the waters receded, the silts and sediments resting on the lakebed were left to dry in the scorching African sun. The small grains of the silty sand are easily swept up by the strong wind gusts that occasionally blow over the region. Once heaved aloft, the Bodele dust can be carried for hundreds or even thousands of kilometers. The remnants of Lake Chad appear as the olive-green feature set amid the tan and light brown hues of the surrounding landscape where the countries of Chad, Niger, Nigeria, and Cameroon all share borders. The Bodele Depression was the source of some very impressive dust storms that have swept over West Africa [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=11939 ] and the Cape Verde Islands [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=11935 ] in recent days. This true-color image was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS), flying aboard NASA?s Terra satellite, on February 7, 2004. A similar image was acquired later that same day by the MODIS instrument aboard NASA?s Aqua satellite. The high-resolution image available here is 500 meters per pixel, but both scenes are available at up to 250 meters per pixel?the sensor?s maximum resolution. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov/ ] at NASA GSFC |
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Dust Storms from Africa's Bo
…
| Title |
Dust Storms from Africa's Bodele Depression |
| Description |
Once serving as part of the floor for a much larger Lake Chad, the area now known as the Bodele Depression, located at the southern edge of the Sahara Desert in north central Africa, is slowly being transformed into a desert landscape. In the mid-1960s, Lake Chad was about the size of Lake Erie. But persistent drought conditions coupled with increased demand for freshwater for irrigation have reduced Lake Chad to about 5 percent of its former size. As the waters receded, the silts and sediments resting on the lakebed were left to dry in the scorching African sun. The small grains of the silty sand are easily swept up by the strong wind gusts that occasionally blow over the region. Once heaved aloft, the Bodele dust can be carried for hundreds or even thousands of kilometers. The remnants of Lake Chad appear as the olive-green feature set amid the tan and light brown hues of the surrounding landscape where the countries of Chad, Niger, Nigeria, and Cameroon all share borders. The Bodele Depression was the source of some very impressive dust storms that have swept over West Africa [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=11939 ] and the Cape Verde Islands [ http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.php3?img_id=11935 ] in recent days. This true-color image was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS), flying aboard NASA?s Terra satellite, on February 7, 2004. A similar image was acquired later that same day by the MODIS instrument aboard NASA?s Aqua satellite. The high-resolution image available here is 500 meters per pixel, but both scenes are available at up to 250 meters per pixel?the sensor?s maximum resolution. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov/ ] at NASA GSFC |
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Northern Africa Fire Season
| Title |
Northern Africa Fire Season |
| Description |
The agricultural fire season was underway in northern Africa in late November 2006. Each year around this time, farmers and people who raise livestock set fires across the region to clear dead vegetation and return its nutrients to the soil, preparing farmland for the next season's crops and preparing grazing lands for new growth of pasture grasses. This photo-like image from the Moderate Resolution Imaging Spectroradiometer (MODIS) [ http://modis.gsfc.nasa.gov ] on NASA's Aqua [ http://aqua.nasa.gov ] satellite on November 27 shows scores of active fires (marked in red) burning across several countries of north-central Africa: (clockwise from top left) Niger, Chad, Central African Republic, Cameroon, and Nigeria. Although these fires are not necessarily immediately hazardous, such large-scale burning can have a strong impact on weather, climate, human health, and natural resources. The image also illustrates the transition of vegetation from the Sahel—a semi-arid, sparse savanna landscape that extends roughly across the latitude belt of Lake Chad—to the much wetter, and more lush savannas and woodlands of the Guinea zone in the south. Only a faint tinge of green marks the Sahel in the top part of the image. Vegetation becomes a deeper green farther to the south where annual rainfall is much more abundant. The high-resolution image provided above has a spatial resolution of 500 meters per pixel. The MODIS Rapid Response System provides twice-daily images of northern Africa at additional resolutions [ http://rapidfire.sci.gsfc.nasa.gov/subsets/ ] via a clickable map. NASA image courtesy the MODIS Rapid Response Team, [ http://rapidfire.sci.gsfc.nasa.gov ] Goddard Space Flight Center |
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Northern Africa Fire Season
| Title |
Northern Africa Fire Season |
| Description |
In northern Africa south of the Sahara Desert, the agricultural fire season was clearly underway when the Moderate Resolution Imaging Spectroradiometer (MODIS) [ http://modis.gsfc.nasa.gov ] on NASA's Aqua [ http://aqua.nasa.gov ] satellite passed overhead on December 4, 2006, and captured this image. Places where MODIS detected actively burning fires are marked with red dots. Hundreds of fires are scattered across Nigeria, Cameroon, and the Central African Republic. People in Africa have been using fire to manage agricultural lands for hundreds, possibly thousands of years, and while the fires may not be immediately hazardous, such large-scale burning can have a strong impact on weather, climate, human health, and natural resources. The high-resolution image provided above has a spatial resolution of 500 meters per pixel. The MODIS Rapid Response System provides twice-daily images [ http://rapidfire.sci.gsfc.nasa.gov/subsets/ ] of sub-sections of northern Africa via a clickable map in a variety of resolutions and formats. NASA image courtesy the MODIS Rapid Response Team, [ http://rapidfire.sci.gsfc.nasa.gov ] Goddard Space Flight Center |
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Fires in Central Africa
| Title |
Fires in Central Africa |
| Description |
Fire season in Africa south of the Sahara Desert has roared to life in December 2003. This image from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite shows the location of more than 7,000 "hot pixels," which means that somewhere in each of those 1-square-kilometer pixels, MODIS detected a fire. In some cases these "hot spots" are isolated fires no larger than 1 square kilometer (and usually much smaller), and in other cases, they are a single large fire spread across several square kilometers. In this scene, these active fire detections have been marked in red. This scene spans three general biomes. In the top of the scene lies the almost-desert region known as the Sahel. Farther from the Sahara, toward the center of the scene, the Sahel becomes savanna. Along the bottom third of the image, tropical forests stretch in a deep green expanse that is punctuated by clearings and roads. Countries shown are (clockwise from top left) Nigeria, Cameroon, Chad, Central African Republic, Democratic Republic of Congo, and Congo. The high-resolution image provided above is 500 meters per pixel. The MODIS Rapid Response System provides this image at multiple spatial resolutions, including MODIS? maximum resolution of 250 meters. Image courtesy Jacques Descloitres, MODIS Rapid Response Team at NASA GSFC |
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Floods Across Africa's Sahel
| Title |
Floods Across Africa's Sahel |
| Description |
A tangle of rivers weaves across the uneven landscape of southwestern Chad, creating the wetlands that surround the Logone River. The backbone of the intersecting rivers in these images, the Logone flows northeast through Chad, forming part of the border with Cameroon, before joining the Chari River and emptying into Lake Chad. On September 26, 2006, when the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Terra [ http://terra.nasa.gov/ ] satellite captured the top image, the wetlands around the Logone were dark with water. Western Chad, like many other countries in Africa's Sahel region, experienced widespread flooding because of unusually heavy rains in August and September. According to the Dartmouth Flood Observatory, [ http://www.dartmouth.edu/%7efloods/Archives/2006sum.htm ] floods in Chad and Nigeria displaced tens of thousands of people and caused extensive agricultural and infrastructure losses. In the top image, floods, not evident two weeks earlier, form dark pools along the Logone River. These images are displayed in false color to highlight the presence of water. Here, water is black or dark blue, clouds are pale blue and white, plant-covered land is green, and lightly vegetated land is tan. Natural-color and false-color [ http://rapidfire.sci.gsfc.nasa.gov/subsets/?NAfrica_3_05/2006269 ] images of Chad are available from the MODIS Rapid Response Team twice daily. NASA images courtesy the MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC. |
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Floods Across Africa's Sahel
| Title |
Floods Across Africa's Sahel |
| Description |
A tangle of rivers weaves across the uneven landscape of southwestern Chad, creating the wetlands that surround the Logone River. The backbone of the intersecting rivers in these images, the Logone flows northeast through Chad, forming part of the border with Cameroon, before joining the Chari River and emptying into Lake Chad. On September 26, 2006, when the Moderate Resolution Imaging Spectroradiometer (MODIS [ http://modis.gsfc.nasa.gov ]) on NASA's Terra [ http://terra.nasa.gov/ ] satellite captured the top image, the wetlands around the Logone were dark with water. Western Chad, like many other countries in Africa's Sahel region, experienced widespread flooding because of unusually heavy rains in August and September. According to the Dartmouth Flood Observatory, [ http://www.dartmouth.edu/%7efloods/Archives/2006sum.htm ] floods in Chad and Nigeria displaced tens of thousands of people and caused extensive agricultural and infrastructure losses. In the top image, floods, not evident two weeks earlier, form dark pools along the Logone River. These images are displayed in false color to highlight the presence of water. Here, water is black or dark blue, clouds are pale blue and white, plant-covered land is green, and lightly vegetated land is tan. Natural-color and false-color [ http://rapidfire.sci.gsfc.nasa.gov/subsets/?NAfrica_3_05/2006269 ] images of Chad are available from the MODIS Rapid Response Team twice daily. NASA images courtesy the MODIS Rapid Response Team [ http://rapidfire.sci.gsfc.nasa.gov ] at NASA GSFC. |
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Widely Scattered Fires acros
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| Title |
Widely Scattered Fires across Central Africa |
| Description |
This pair of images from December 11, 2002, shows the diurnal (daily cycle) fire patterns in central Africa. The top image was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor on the Terra satellite in the morning, while the bottom image was captured by the MODIS on the Aqua satellite in the afternoon. From left to right, this image spans the countries of Nigeria, Cameroon, Chad, and the Central African Republic. At bottom right, a portion of Democratic Republic of Congo is visible. As the day progressed, fire activity (indicated by red dots) increased markedly. The increase is due to both human and environmental factors. Many, if not most, of these fires are set by humans for agricultural purposes: clearing farmland, returning nutrients to the soil, regenerating pasture. People become more active over the course of the day, and fire occurrence increases. Fire activity is also influenced by increasing temperatures and decreasing humidity as the morning progresses to afternoon. This increases the potential for planned fires to get out of control or to burn larger areas than intended. Another interesting difference between the morning and afternoon overpasses is how the relative position of the sun and the satellite during each overpass changes the appearance of the vegetation. Notice that in the Terra overpass, when the light from the sun would have been coming from the southeast, the vegetation at the right of the image appears dark, and the vegetation in the left half of the image appears bright. During the Aqua overpass, the reverse is true: the sun is coming from the southwest, and the vegetation appears bright in the east and dark in the west. This apparent change in surface observations due to change in the relative positions of the sun and the spacecraft is referred to as the bidirectional effect, and scientists must take the effect into consideration when using satellite data to study surface features on Earth. Image courtesy Jacques Descloitres, MODIS Rapid Response Team at NASA GSFC |
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Widely Scattered Fires acros
…
| Title |
Widely Scattered Fires across Central Africa |
| Description |
This pair of images from December 11, 2002, shows the diurnal (daily cycle) fire patterns in central Africa. The top image was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor on the Terra satellite in the morning, while the bottom image was captured by the MODIS on the Aqua satellite in the afternoon. From left to right, this image spans the countries of Nigeria, Cameroon, Chad, and the Central African Republic. At bottom right, a portion of Democratic Republic of Congo is visible. As the day progressed, fire activity (indicated by red dots) increased markedly. The increase is due to both human and environmental factors. Many, if not most, of these fires are set by humans for agricultural purposes: clearing farmland, returning nutrients to the soil, regenerating pasture. People become more active over the course of the day, and fire occurrence increases. Fire activity is also influenced by increasing temperatures and decreasing humidity as the morning progresses to afternoon. This increases the potential for planned fires to get out of control or to burn larger areas than intended. Another interesting difference between the morning and afternoon overpasses is how the relative position of the sun and the satellite during each overpass changes the appearance of the vegetation. Notice that in the Terra overpass, when the light from the sun would have been coming from the southeast, the vegetation at the right of the image appears dark, and the vegetation in the left half of the image appears bright. During the Aqua overpass, the reverse is true: the sun is coming from the southwest, and the vegetation appears bright in the east and dark in the west. This apparent change in surface observations due to change in the relative positions of the sun and the spacecraft is referred to as the bidirectional effect, and scientists must take the effect into consideration when using satellite data to study surface features on Earth. Image courtesy Jacques Descloitres, MODIS Rapid Response Team at NASA GSFC |
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Widely Scattered Fires acros
…
| Title |
Widely Scattered Fires across North Africa |
| Description |
On December 24, 2002, more than 5,000 fires (indicated with red dots) were burning across the north central African Sahel and savanna regions. This particular scene, acquired by the MODIS sensor aboard NASA?s Aqua satellite, shows the north central region of Africa spanning parts of the countries of Chad (top center), the Central African Republic (bottom center), and Cameroon (left). The resulting haze and smoke can be seen blowing westward and is particularly thick (gray pixels) toward the bottom left of this scene. Image courtesy Jacques Descloitres, MODIS Rapid Response Team, at NASA GSFC |
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Widely Scattered Fires acros
…
nasa, nasanaturalhazards
On December 24, 2002, more t
…
CAfrica_AMO2002358
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2002-12-24 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
CAfrica_AMO2002358 |
|
Dust Storms from Africa's Bo
…
nasa, nasanaturalhazards
Once serving as part of the
…
Bodele_TMO2004042
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2004-02-11 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
Bodele_TMO2004042 |
|
Dust Storm from the Bodele D
…
nasa, nasanaturalhazards
On January 29, 2007, a chara
…
bodele_amo_2007029
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2007-01-29 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
bodele_amo_2007029 |
|
Dust Storms from Africa's Bo
…
nasa, nasanaturalhazards
Once serving as part of the
…
Bodele_TMO2004038
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2004-02-07 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
Bodele_TMO2004038 |
|
Dust and Smoke near Lake Cha
…
nasa, nasaimageofthedaygalle
…
A combination of dust of smo
…
aqua_nigeria_08jan04
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2004-01-08 |
| creator |
NASA -- Image courtesy Jesse Allen, based on data from the rapidfire.sci.gsfc.nasa.gov MODIS Rapid Response Team at NASA GSFC |
| identifier |
aqua_nigeria_08jan04 |
|
Northern Africa Fire Season:
…
nasa, nasanaturalhazards
In northern Africa south of
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NAfrica_chad_AMO_2006338
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2006-12-04 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
NAfrica_chad_AMO_2006338 |
|
Northern Africa Fire Season:
…
nasa, nasanaturalhazards
The agricultural fire season
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NAfrica_chad_AMO_2006331
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2006-11-27 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
NAfrica_chad_AMO_2006331 |
|
Dust Storm and Fires in Cent
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nasa, nasaimageofthedaygalle
…
A science teacher or college
…
aqua_bodele_18nov04
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2004-11-18 |
| creator |
NASA -- NASA image created by Jesse Allen, Earth Observatory, using data obtained from the rapidfire.sci.gsfc.nasa.gov/ MODIS Rapid Response team. |
| identifier |
aqua_bodele_18nov04 |
|
Fires in Central Africa: Nat
…
nasa, nasanaturalhazards
Fire season in Africa south
…
CAfrica.A2003341
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2003-12-07 |
| creator |
NASA -- NASA Image Of The Day |
| identifier |
CAfrica.A2003341 |
|
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