Beyond the spring barrier?

摘要

The El Nino cycle is the most powerful multiannual climate oscillation on Earth. Because of its influence on global patterns of temperature and precipitation', El Nino directly affects the livelihoods of millions of people worldwide, as well as the state of terrestrial and marine ecosystems. Predicting the onset of an El Nino or La Nina phase as far in advance as possible has therefore long been a goal of climate science. Yet the advance warning achieved by El Nino forecasts has been limited by an apparent predictability barrier: forecasts issued before the preceding Northern Hemisphere spring, about two months before the onset and nine months before the full manifestation of an El Nino event, typically show very limited skill'. Writing in Nature Geoscience, Izumo and colleagues3 suggest that a better understanding of the role the Indian Ocean Dipole may allow El Nino and La Nina to be predicted more than a year in advance, thus leaping over this springtime predictability barrier.