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African Vegetation: Comparing August 1984 and August 1994

by: NASA/Goddard Space Flight Center Scientific Visualization Studio

Publication date: 1/1/1999

Topics: Climatology, Physical geography, Sahara, Location, Africa, What -- NOAA 11, What -- NOAA 12, What -- NOAA 7, What -- NOAA 8, Where -- Florida

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. Note: A fade between NDVI data of Northern Africa from August 1984 and August 1994, showing a recession of the Sahara. Animator: Jesse Allen (Raytheon). Scientist: Compton Tucker (NASA/GSFC), Sharon Nicholson (Florida State University). Platforms/Sensors/Data Sets: NOAA-11/AVHRR, NOAA-12/AVHRR, NOAA-7/AVHRR, NOAA-8/AVHRR.