Figure 4
From: A distinct and reproducible teleconnection pattern over North America during extreme El Niño events
Composites of December–February (DJF) tropical Pacific rainfall anomalies (shading, mm/day/\(^\circ\)C) from the ensemble mean CTL experiment over the 1979–2019 period for: (top row) moderate Central Pacific (CP), (middle row) moderate Eastern Pacific (EP) and (bottom row) Extreme El Niño events. Composites (shading, mm/day/\(^\circ\)C) have been obtained after normalizing fields by the average [5\(^\circ\)N/S, 170\(^\circ\)E–130\(^\circ\)W] SST anomalies (considered the main forcing region, see “Methods” section), in order to highlight the pattern rather than the amplitude differences. The left column displays the total anomaly from our 6-member ensemble simulation, while the middle and right column respectively display the linear and nonlinear response to SST contributions (see “Methods” section for details). Dots in the left column indicate areas where anomalies exceed the 97.5% confidence level based on a bootstrap test with 10,000 resamples. On middle panels, contours (red for positive, blue for negative, with a 0.2 \(^\circ\)C contour interval) indicate the corresponding SST composites. Hatching in the right column indicates when the SST anomaly brings total SST from below to above the deep convection threshold (27.5\(^\circ\)C). On the middle (right) column, r indicates the pattern correlation between the total anomaly and the linear (nonlinear) SST contribution to the rainfall anomaly. Black continuous boxes encompass the Niño3 and Niño4 regions. The black dashed box highlights the Niño3.4 region.
