African Vegetation: Comparing July 1984 and July 1994

  • Released Friday, January 1, 1999
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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

NDVI measures of African continent, July 1984

NDVI measures of African continent, July 1984

NDVI measures of African continent, July 1994

NDVI measures of African continent, July 1994

NDVI measures of north Africa, July 1984

NDVI measures of north Africa, July 1984

NDVI measures of north Africa, July 1994

NDVI measures of north Africa, July 1994

Video slate image reads, "Comparing July 1984 data and July 1994 data".

Video slate image reads, "Comparing July 1984 data and July 1994 data".

For More Information

See http://svs.gsfc.nasa.gov/stories/NDVI/africa_july8494.html

Credits

Please give credit for this item to:
NASA/Goddard Space Flight Center
Scientific Visualization Studio

This page was originally published on Friday, January 1, 1999.
This page was last updated on Wednesday, May 3, 2023 at 1:59 PM EDT.

Datasets used

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