Fig. 1: Increasing in the low-frequency VM variability in observations.
From: Enhanced North Pacific Victoria mode in a warming climate
a The 23-year running root-mean-square (RMS) of the boreal winter–spring (December–May, DJFMAM) low-frequency PDO (blue line) and VM (red line) indices for the period 1920–2021. b The secular variations in the ratio of the RMS of the VM and PDO indices. c The 23-year running mean of the PDO (blue line) and VM (red line) event frequencies. d The 23-year running mean pattern correlation coefficients of the DJFMAM SST anomalies with PDO (blue line) and VM (red line) patterns in the North Pacific (20°N–70°N, 120°E–100°W). In d the horizontal dashed line indicates the 95% significance level for the running pattern correlations. Linear fits are displayed together with p values based on the Mann–Kendall test. The shaded areas in all panels indicate the two-sided 95% confidence levels of the slopes.
