干旱区生态环境知识资源中心

Monitoring the impact of drought on vegetation conditions is a critical activity for assessing food security in semi-arid and arid countries in Africa. Remote sensing from space offers a unique opportunity to obtain consistent and timely information over large and inaccessible areas where field observations are scattered, inhomogeneous or frequently unavailable. In this study we outline a remote sensing method to estimate the probability of experiencing a biomass production deficit during the on-going season based on the statistical analysis of Earth Observation data. The method is based on the extraction of vegetation phenology from SPOT-VEGTATION time series of the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) and the subsequent computation of seasonally cumulated FAPAR as a proxy of vegetation gross primary production. Forecast of the overall seasonal performances, expressed in terms of probability of experiencing a critical deficit, are updated regularly whenever a new satellite observation is made available. Examples of application in the Sahel are discussed in this contribution.