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African Vegetation: Comparing August 1984 and August 1994
For many years, scientists have believed that the southern expansion of the Sahara has been due to human activity. However, results from the AVHRR instrument and its measurements of vegetation suggest a different explanation: rainfall patterns. In drier years (1984 was one of the driest summers in recorded history in Northern Africa), the Sahara expands south, but in wetter years (such as 1994), vegetation moves back and there is no net expansion of the Sahara as had been previously suggested.

A fade between NDVI data of Northern Africa from August 1984 and August 1994, showing a recession of the Sahara    A fade between NDVI data of Northern Africa from August 1984 and August 1994, showing a recession of the Sahara
Duration: 6.0 seconds
Available formats:
  352x240 (29.97 fps) MPEG-1   942 KB
  320x242     JPEG         8 KB
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NDVI measures of African continent, August 1984    NDVI measures of African continent, August 1984

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  512 x 512         JPEG   207 KB


NDVI measures of African continent, August 1994    NDVI measures of African continent, August 1994

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NDVI measures of north Africa, August 1984    NDVI measures of north Africa, August 1984

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  640 x 486         TIFF (Without date) 591 KB
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  160 x 80           PNG       17 KB
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  640 x 486         TIFF (With date) 592 KB


NDVI measures of north Africa, August 1994    NDVI measures of north Africa, August 1994

Available formats:
  640 x 486         TIFF (Without date) 594 KB
  160 x 80           PNG       18 KB
  320 x 243         JPEG     70 KB
  640 x 486         TIFF (With date) 595 KB

Animation Number:590
Completed:1999-01-01
Animator:Jesse Allen (Raytheon) (Lead)
Scientists:Compton Tucker (NASA/GSFC)
 Sharon Nicholson (Florida State University)
Platforms/Sensors/Data Sets:NOAA-11/AVHRR (1994/08)
 NOAA-12/AVHRR (1994/08)
 NOAA-7/AVHRR (1984/08)
 NOAA-8/AVHRR (1984/08)
Video:SVS1999-0008 *
Keywords:
DLESE >> Climatology
DLESE >> Physical geography
SVS >> Sahara
GCMD >> Location >> Africa
More Information on this topic available at:
stories/NDVI/africa_august8494.html
 
 
Please give credit for this item to:
NASA/Goddard Space Flight Center
Scientific Visualization Studio


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