Trends and variations in the activity of global vegetation in response to climate variability between 1987 and 1997

Abstract

Eleven-year (1987-1997) time series data of remotely sensed vegetation index (NDVI) and meteorological observations (temperature, precipitation, cloud cover and relative humidity) provided a powerful tool to illuminate the response of global terrestrial vegetation to short-and long-term climate variability. NDVI being a sensitive estimator of the amount of photosynthetic active radiation intercepted by the canopy has been treated as a proxy for above ground net primary production (ANPP). Analyses of trends, multiple regression and correlation analyses were employed. The main result indicates a considerable increase (0.7~1.9%/year) of monthly vegetation production in all ecosystems over the investigated period, allied with an analogous increase (0.9~15%/year) in precipitation. Additionally, several direct relationships were also observed on the intra- and inter-annual time scales suggesting that the increase and variation of ANPP in most biomes could be mainly linked to the corresponding increase and variation in precipitation. Overall, the four climate variables play a considerable role in the inter-annual variability of ANPP of global vegetation.