The Pacific Decadal Oscillation, or PDO, is a long-lived El Niño-like pattern of Pacific climate variability. The PDO pattern [is] marked by widespread variations in Pacific Basin and 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.

Alaska Climate and PDO

BRIAN HARTMANN AND GERD WENDLER The Significance of the 1976 Pacific Climate Shift in the Climatology of Alaska BRIAN HARTMANN AND GERD WENDLER Geophysical Institute, University of Alaska, Fairbanks, Fairbanks, Alaska Journal of Climate, 18, 4834, 2005

The Significance of the 1976 Pacific Climate Shift in the Climatology of Alaska 1) The intensification of the Aleutian low during the winter and spring causes warming due to advection from the south. 2) Additional moisture is also advected into high latitudes resulting in increased cloudiness and precipitation. 3) The increase in the frequency of higher wind speeds results in a decrease in the intensity and frequency of temperature inversions, which generally raises temperatures. 4) The increase in winter and spring mean temperatures Results in a decrease in total snowfall, despite an increase in the total precipitation.

Pacific Northwest and PDO

A third order polygon works okay, though.

Snowpack in the Pacific Northwest

“A study of springtime mountain snowpack in the Pacific Northwest showed widespread declines in snowpack since 1950 at most locations with largest declines at lower elevations indicating temperature effects.” “Substantial declines (some in excess of 50%) were common in the Cascades, especially in Oregon.” Mote, Philip W., Martyn Clark, and Alan F. Hamlet, 2004. Variability and Trends in Mountain Snowpack in Western North America. 15th Symposium on Global Change and Climate Variations, Seattle, Washington.

Bumping Lake is an older station Bumping Lake is an older station. Would anyone fit a linear trend to this?

A third order polygon works okay, though.

Fisheries

Columbia River Salmon

The Arctic Let’s look at trends in the last century, as reported in refereed journal articles….

Polyakov, et al, 2003

The Glaciers of Glacier Park

Pederson, G. T. , Fagre, D. B. , Gray, S. T. and Graumlich, L. J. 2004 Pederson, G.T., Fagre, D.B., Gray, S.T. and Graumlich, L.J. 2004. Decadal-scale climate drivers for glacial dynamics in Glacier National Park, Montana, USA. Geophysical Research Letters 31: 10.1029/2004GL019770.

“snowpack fluctuations in GNP exhibit a significant relationship with the PDO. PDO and local May 1st SWE are negatively correlated (r = 0.764; p < 0.001).”

North Cascades Glaciers vs. PDO

Conclusions 1. The PDO signal seems to be a permanent feature of Earth’s climate system. 2. Typical period is about 50 years, though this varies. 3. There is a close tie-in with ENSO phases. 4. There is a strong regional signal. 5. PDO changes correlate well with the variation in temperatures over the last century

Combining PDO and AMO The Atlantic multidecadal oscillation (AMO) is a mode of natural variability occurring in the North Atlantic Ocean and which has its principal expression in the sea surface temperature (SST) field.