Atmospheric circulation and variability of the vegetation in the Central Siberia (1982-2001)

Abstract

This paper analyses the spatial distribution of the inter-annual variability of vegetation activity in central Siberia and its relationship with atmospheric circulation variability. We used NOAA-AVHRR NDVI series from Pathfinder Land Data Set at 1 degree of spatial resolution, and we calculated the annual vegetation activity in each pixel (aNDVI) from 1982 to 2001. Principal Component Analysis was used to determine the general spatial patterns of interannual variability of vegetation activity. We identified three main modes, which explain more than 50 % of total variance, each corresponding to a large region. By means of surface pressure grids we analysed the main patterns of the seasonal atmospheric circulation in the study area. We investigated the effect of seasonal atmospheric circulation patterns on the inter-annual variation of vegetation activity. In general, the strongest relationships between the atmospheric circulation variability, climate and the aNDVI variability were found in areas where the climatic characteristics are more limiting for the vegetation development, such as the northern regions. This may be explained by the fact that in these areas the variability of atmospheric circulation modes determines summer temperatures, which have a direct impact on vegetation activity.