DETERMINATION OF VEGETATION PARAMETERS THROUGH MEASURED AND SIMULATEDAVHRR DATA OVER SALT-HAPEX-SAHEL SITE

Vegetation-related information is critical for modelling hydrological processes. Remotely sensed spectral data provide powerful means to cha racterize vegetation state. In this study, we investigate the opportun ities of such data when an automatic classification is applied to time -series of remotely sensed data. The analysis is then conducted by int erpreting the classification results in terms of surface physical para meters. The method consists in (1) selecting several control points in the HAPEX-Sahel square degree, during the rainy season of 1991 and 19 92, and (2) comparing the temporal evolution of the albedo-based norma lized difference vegetation index (NDVI) values and those deriving fro m the classification. The result shows that there is similarity betwee n the behaviour of the 1991 and 1992 temporal profiles estimated at al l control points.