Dls. Chong et al., RELATING THE GLOBAL VEGETATION INDEX TO NET PRIMARY PRODUCTIVITY AND ACTUAL EVAPOTRANSPIRATION OVER AFRICA, International journal of remote sensing, 14(8), 1993, pp. 1517-1546
Net Primary Productivity (NPP) and Actual Evapotranspiration (AET) are
key processes characterizing the vegetation activity. At a continenta
l scale, Annual Net Primary Productivity (ANPP) and annual AET are rel
ated to the integrated Normalized Difference Vegetation Index (NDVI).
When applied to the African continent, the ANPP/SIGMANDVI relation giv
es an estimation of the productivity with a precision comparable to th
ose given by climate models. The estimation of annual AET is possible
within climatic zones defined here by their Rain-Use Efficiencies (RUE
). On the other hand, on a monthly basis, the AET/SIGMANDVI relations
are less clear and are strongly dependent on the physiognomy of the ve
getation community considered. These results show the limits of using
SIGMANDVI for estimating the elementary processes of terrestrial veget
ation at a continental scale.