Inter-annual variability and interaction of remote-sensed vegetation indexand atmospheric precipitation in the Aral Sea region
The remotely sensed Normalized Difference Vegetation Index(AVHRR NDVI) and precipitation data were analysed in the Aral Sea region in Central Asia during two recent decades. Both variables exhibited pronounced seasonal variation, with maximum precipitation in March and maximum NDVI in May–June. The regions of synchronous seasonal and interannual variability between the vegetation indexand precipitation were distinguished using the Empirical Orthogonal Functions (EOF) method and time-lagged correlations between EOF modes. At a seasonal scale, precipitation and the vegetation indexwere correlated with a time lag from 1 to 6 months in different regions with peak plant growth following precipitation maxima.