Two
main characteristics distinguish PDO from El Niño / Southern Oscillation (ENSO): first, 20th century PDO «events» persisted for 20 - to - 30 years, while typical ENSO events persisted for 6 to 18 months; second, the climatic fingerprints of the PDO are most visible in the North Pacific / North American sector, while secondary signatures exist in the tropics — the opposite is true for ENSO.