| Timing of plant life cycle events (phenology) and annual plant productivity represent key interactions between the atmosphere and the biosphere, with implications and feedbacks for climate and ecosystem functions. The El Niño-Southern Oscillation (ENSO) system is the dominant source of interannual climate variability in the western United States, with important effects on temperature, precipitation, and drought. In this study, the connection between ENSO and terrestrial vegetation dynamics is examined using remotely sensed vegetation indices, eddy covariance flux tower observations, ENSO indices, and spatially-resolved climate data. El Niño events are associated with an increase in primary production throughout the western U.S., and with an earlier growing season in much of the Pacific Northwest and parts of the Southwest. The correlation between total annual production and the Southern Oscillation Index is highest in mid- to late-winter prior to the growing season, suggesting some predictive power in advance of the growing season. |
