Figure 5: PDO and ENSO compared. Strong similarity between PDO and El Nino (as measured by NINO34).
We can see how the annual PDO and ENSO (Mulitvatriate ENSO Index) tracking well since 1950.
Figure 6: Annual average PDO and MEI from 1950 to 2007. Clearly they correlate well. Note how the ENSO events amplify or diminish the favored PDO state.