Fig. 1: Monthly evolution of Niño-3.4 index for all El Niño (purple), fast decaying (FD; orange) El Niño, and slow decaying (SD; blue) El Niño.
From: Boosting effect of strong western pole of the Indian Ocean Dipole on the decay of El Niño events

a The thick curves and shading represent the average and spread of the indices, respectively. b The solid curves denote individual FD (orange) and SD (blue) events. “0” and “1” on the abscissa refer to the developing and decaying years of El Niño events, respectively.