Net Primary Production (NPP) is the annual net growth of vegetation (harvestable amount),
and is related to NDVI. In this study NPP was
calcualted as the accumulated increase in adjusted NDVI over an annual cycle
(36 dekad periods). Assuming one growing season and one harvest, NPP will
have the same value as maximum NDVI, but NPP will also accomodate intermediate
harvests (and discrete grazing periods).
The NPP over the Sahel was taken from NOAA-AVHRR NDVI.
THe data used here is in 8 km resolution and was pre-processed by
the GIMMS (Global Inventory Monitoring and Modeling System)
group at NASA's Goddard Space Flight Center.
To see NPP for individual years click on the time-table below the map.
