Extended Data Fig. 1: Observed multi-year La Niña events.
From: Increased occurrences of consecutive La Niña events under global warming
a, Time series of Niño3.4 SST anomaly in 1900–2021 averaged from several reanalysis datasets54,55,56. The time series is scaled by ONDJF s.d. of Niño3.4 SST in 1900–1999 and smoothed with a three-month running-mean filter. The red and blue dashed lines indicate the 0.5 s.d. and −0.5 s.d. thresholds for identifying El Niño (red) and La Niña (blue) events, respectively. The vertical blue shadings mark the years of multi-year La Niña events. b,c, Time–longitude evolution of equatorial (5° N–5° S average) SST (°C; colouring), depth of 20 °C isotherm (m; contours; positive in green and negative in white, with an interval of 3 m) and surface zonal wind stress (N m−2; vectors) anomalies, composited for single-year (b) and multi-year (c) La Niña events, respectively. Ocean temperature and surface wind data are from IAP58 and NCEP/NCAR reanalysis57, respectively, in 1948–2021.
