The response of vegetation cover to precipitation and temperature in central/east Tibetan Plateau

The Tibetan Plateau is among the fewest extensive regions remote far from the influences of human activities. It provides an ideal site to study the response of vegetation cover to water/thermal (WT) conditions, esp. the response of natural vegetation cover. The paper aims to discuss the spatial variation and then the relations of WT climate elements with satellite derived NDVI. The discussion is taken with the supports of ground climatic observation data and AVHRR NDVI product (8 Km) from year 1982 to 2000, in central and east Tibetan Plateau where the gauge is basically dense enough to qualify related analyses. Based on the simulation of egetation spatial distribution trend surfaces, the transect comparison of different directions and the work of vegetation grouping, the relationships between NDVI and precipitation (N-P for short), between NDVI and temperature (N-T for short) are respectively investigated and analyzed, both spatially and biologically. The results presented by this study indicate that in central/east Plateau annual mean NDVI is less influenced by WT conditions if the covered vegetation is dense and evergreen or totally sparse; the N-T and N-P values of peripheral Plateau regions are low while the values of main plateau body are higher than 0.75; in addition, altitude tends to play an obvious negative role in the spatial distribution of thermal condition, and then in the distribution of vegetation cover.