Skip all navigation and jump to content Jump to site navigation Jump to section navigation.
NASA Logo - Goddard Space Flight Center + Visit NASA.gov
HOME PROJECTS RESOURCES SEARCH MAP

+ Advanced Search
Home
Home
View Most Recently Released Imagery
View Gallery of Imagery: A topical collection of SVS Imagery
Search Imagery by the keywords assigned to it
Search Imagery by the instruments that supplied data for a visualization product
Search Imagery by the series of visualizations that have been produced
Search Imagery by the scientist providing the data used in a visualization product
Search Imagery by the animator that created the product
Search Imagery by the identification number assigned to the visualization product
See other search options
Learn about the SVS Image Server
  + About the Server
  + Animation List
  + How to Use the Server


  + RSS Feeds
  + Podcasts


  + Opportunities
blank image
Previous Animation
Next Animation
African Vegetation: Comparing July 1984 and July 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 July 1984 and July 1994, showing a recession of the Sahara    A fade between NDVI data of Northern Africa from July 1984 and July 1994, showing a recession of the Sahara
Duration: 9.0 seconds
Available formats:
  352x240 (29.97 fps) MPEG-1   1 MB
  320x242     JPEG         7 KB
How to play our movies


NDVI measures of African continent, July 1984    NDVI measures of African continent, July 1984

Available formats:
  1152 x 1152     TIFF 2 MB
  512 x 512         JPEG   207 KB


NDVI measures of African continent, July 1994    NDVI measures of African continent, July 1994

Available formats:
  1024 x 1024     TIFF 1 MB
  512 x 512         JPEG   211 KB


NDVI measures of north Africa, July 1984    NDVI measures of north Africa, July 1984

Available formats:
  640 x 486         TIFF (Without date) 599 KB
  80 x 40             PNG         5 KB
  160 x 80           PNG       17 KB
  320 x 243         JPEG     66 KB
  640 x 486         TIFF (With date) 599 KB


NDVI measures of north Africa, July 1994    NDVI measures of north Africa, July 1994

Available formats:
  640 x 486         TIFF (Without date) 620 KB
  160 x 80           PNG       19 KB
  320 x 243         JPEG     69 KB
  640 x 486         TIFF (With date) 621 KB

Animation Number:589
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 (1994/07)
 NOAA-12/AVHRR (1994/07)
 NOAA-7/AVHRR (1984/07)
 NOAA-8/AVHRR (1984/07)
Video:SVS1999-0008 *
Keywords:
DLESE >> Climatology
DLESE >> Physical geography
SVS >> Sahara
GCMD >> Location >> Africa
More Information on this topic available at:
stories/NDVI/africa_july8494.html
 
 
Please give credit for this item to:
NASA/Goddard Space Flight Center
Scientific Visualization Studio


*Please note: the SVS does not fulfill requests for copies of the tapes in our library. On some of our animation pages, there is a direct link to a video distribution service from which tapes, handled by the Public Affairs Office (PAO)/Goddard TV, including some of our animations may be ordered. General information on this service can be found here.


Back to Top

USA.gov logo - the U.S. Government's official Web portal. + Privacy Policy and Important Notices
+ Reproduction Guidelines 		NASA NASA Official:
Content Contact:
Curator: