Middle Asia

Normalized Difference Vegetation Index (NDVI) is generally recognized as a good indicator of terrestial vegetation productivity. Understanding climatic influences, in particular precipitation and temperature, on NDVI enables prediction of productivity changes under different climatic conditions. We combined a NOAA/AVHRR NDVI dataset and a gridded climate dataset to analyse inter-annual and within-season relationship between NDVI and two ecoclimatic parameters (precipitation and temperature) in Kazakhstan and Middle Asia for the time-period 1981-1998. Evaluation of within-season relationship was based on monthly values of NDVI and climatic parameters during the growing season (April-October), while for evaluation of inter-annual relationship were taken either mean growing season values or mean values over the individual seasons (spring, summer, autumn). The results indicate that a strong correlation exists between NDVI and the two climatic parameters at inter-annual and within-seasonal scales. Temperature was the leading climatic factor controlling both inter-annual and within-season NDVI dynamics. The dynamic of vegetation activities over the period 1982-1998 was found to be strongly predicted by dynamic of annual precipitation and mean temperature over spring. For semi-desert and steppe vegetation, the inter-annual NDVI