Trends in NDVI time series and their relation to rangeland and crop production in Senegal, 1987-1993

Growing archives of NDVI images derived from the NOAA-AVHRR provide opportunities for time-series analysis of changes in land-use and cover. In this study a time series (1987-1993) of 1.1 km spatial resolution NDVI images obtained from the NOAA-AVHRR sensor was used in combination with aboveground rangeland harvest measurements and agricultural yield statistics to assess trends in NDVI in Senegal, West Africa. Correlations between trends in maximum NDVI (TMN) and field measures of rangeland and crop production were positive and statistically significant. Spatial patterns of TMN corresponded well with current understanding of changing land-use and cover of Senegal from 1987-97. The results suggest that trend images derived from NDVI series may provide a useful way to identify land-cover change in Africa.