Trends and ENSO/AAO Driven Variability in NDVI Derived Productivity and Phenology alongside the Andes Mountains

摘要: Increasing water use and droughts, along with climate variability land change, have seriously altered vegetation growth patterns ecosystem response in several regions alongside the Andes Mountains. Thirty years of new generation biweekly normalized difference index (NDVI3g) time series data show significant cover specific trends annual productivity surface phenological response. Productivity is represented by growing season mean NDVI values (July to June). Arid semi-arid sub humid types (Atacama desert, Chaco Patagonia) across Argentina, northern Chile, northwest Uruguay southeast Bolivia negative productivity, while some temperate forest agricultural areas Chile Brazil, Peru positive productivity. The start (SOS) length (LOS) results large regional hot spots where later SOS often coincides reduced A longer generally found for locations south (sub-antarctic forest) Argentina (Patagonia steppe), central (Pampa-mixed grasslands agriculture) has a shorter LOS. Some shifts LOS one months. seasonal Multivariate ENSO Indicator (MEI) Antarctic Oscillation (AAO) impact on phenology southeastern northeastern Pampa), southern (mixed shrubland, sub-antarctic forest), Paraguay (Chaco).