Extended Data Figure 2 : Evolution of ENSO and annual cycle along the Equator.

From: Evolution and forcing mechanisms of El Niño over the past 21,000 years

Extended Data Figure 2

Evolution of the amplitudes (standard deviation in 100-year window) of interannual (1.5–7 years) variability (a), the annual cycle of SST (b), total variability (<7 years) (c) and the ratio of the amplitudes of the interannual over the annual cycle (d) along the equatorial Pacific (5° S–5° N) in TRACE. The total variability is dominated by the annual cycle, except in the central-eastern Pacific, where ENSO becomes dominant. This occurs because ENSO variability shows a broad pattern from the central to the eastern Pacific, whereas the annual cycle is strong along the eastern boundary and decays rapidly towards the central Pacific.