干旱区生态环境知识资源中心

Parameters describing the cyclic patterns of vegetation phenology can be derived from satellite image time series. The length of the annual vegetation period is a useful summary parameter, important for analyzing broad-scale ecological differences of vegetation and seasonal gains in biomass. Anomalies in season length can be linked to principal seasonal drivers of vegetation growth, namely temperature, precipitation and radiation. This study employs a record of satellite images for Mexico over 17 years. The 16-day composite of MODIS vegetation index at 250m spatial resolution was processed and season length was extracted. The long-term normal depicts longer seasons in southern Mexico and forested areas. Seasonal anomalies show spatial-temporal patterns with major variations in semi-arid northern Mexico, which were linked to climatic drivers.