The PDO and El Niño occur in slightly different regions of the Pacific – the PDO is a northern Pacific phenomenon; El Niño is centered in the tropics.
They also behave differently. PDO phases last decades. Because each PDO phase is long, and the air-sea interactions require many years to adjust, the effects of PDO phase changes, or ‘regime shifts”, are predictable for up to 10 years. During warm (positive) phases of the PDO, warmer than average ocean water sits very near the western coast of North America. During cool (negative) phases, cooler waters are present there.
The Pacific Decadal Oscillation (PDO) is often described as a long-lived El Niño-like pattern of Pacific climate variability (Zhang et al. 1997). As seen with the better-known El Niño/Southern Oscillation (ENSO), extremes in the PDO pattern are marked by widespread variations in the Pacific Basin and the North American climate. In parallel with the ENSO phenomenon, the extreme phases of the PDO have been classified as being either warm or cool, as defined by ocean temperature anomalies in the northeast and tropical Pacific Ocean. When SSTs are anomalously cool in the interior North Pacific and warm along the Pacific Coast, and when sea level pressures are below average over the North Pacific, the PDO has a positive value. When the climate anomaly patterns are reversed, with warm SST anomalies in the interior and cool SST anomalies along the North American coast, or above average sea level pressures over the North Pacific, the PDO has a negative value (Courtesy of Mantua, 1999).
The PDO and El Niño occur in slightly different regions of the Pacific – the PDO is a northern Pacific phenomenon; El Niño is centered in the tropics.They also behave differently. PDO phases last decades. Because each PDO phase is long, and the air-sea interactions require many years to adjust, the effects of PDO phase changes, or ‘regime shifts”, are predictable for up to 10 years. During warm (positive) phases of the PDO, warmer than average ocean water sits very near the western coast of North America. During cool (negative) phases, cooler waters are present there.The Pacific Decadal Oscillation (PDO) is often described as a long-lived El Niño-like pattern of Pacific climate variability (Zhang et al. 1997). As seen with the better-known El Niño/Southern Oscillation (ENSO), extremes in the PDO pattern are marked by widespread variations in the Pacific Basin and the North American climate. In parallel with the ENSO phenomenon, the extreme phases of the PDO have been classified as being either warm or cool, as defined by ocean temperature anomalies in the northeast and tropical Pacific Ocean. When SSTs are anomalously cool in the interior North Pacific and warm along the Pacific Coast, and when sea level pressures are below average over the North Pacific, the PDO has a positive value. When the climate anomaly patterns are reversed, with warm SST anomalies in the interior and cool SST anomalies along the North American coast, or above average sea level pressures over the North Pacific, the PDO has a negative value (Courtesy of Mantua, 1999).
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