Fig. 4: Observed and CESM2 model-simulated multiyear La Niña behaviour.
From: Understanding the recent increase in multiyear La Niñas
a, The observed relationship between the antecedent El Niño’s initiation in the W-CP and the WP background (31-year running mean) SST. The El Niño initiation is measured by the SST anomaly during the El Niño onset year from April to August (AMJJA). b, The observed relationship between the La Niña onset rate and its accumulative intensity. c, The observed relationship between the La Niña onset rate and the accumulative thermocline depth anomaly from the cooling onset to March of persistence year (+1). d,e, CESM2 model-simulated counterparts of a (d) and b (e). f, The relationship between the 30-year mean WP SST and the number of multiyear La Niña years simulated by ten ensemble members in the CESM2 model’s historical simulation (1901–2013). The 30-year means are made for 1901–1930 and 1981–2010 to contrast the significant mean state change.
