Parameter Tree:
EARTH SCIENCE > CLIMATE INDICATORS > ATMOSPHERIC/OCEAN INDICATORS > TELECONNECTIONS > PACIFIC DECADAL OSCILLATION

Definition:
Fisheries scientist Steven Hare coined the term "Pacific Decadal
Oscillation" (PDO) in 1996 while researching connections between
Alaska salmon production cycles and Pacific climate. PDO has since
been described as a long-lived El Nino-like pattern of Pacific
climate variability because the two climate oscillations have similar
spatial climate fingerprints, but very different temporal behavior.
Two main characteristics distinguish PDO from El Nino/ 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.
Several independent studies find evidence for just two full PDO cycles
in the past century: "cool" PDO regimes prevailed from 1890-1924 and
again from 1947-1976 while"warm" PDO regimes dominated from 1925-1946
and from 1977 through (at least) the mid-1990's. Shoshiro Minobe; has
shown that 20th century PDO fluctuations were most energetic in two
general periodicities, one from 15-to-25 years, and the other from
50-to-70 years.


Reference:
Hare, S.R. and R.C. Francis. 1995. Climate Change and Salmon
Production in the Northeast Pacific Ocean. In: R.J. Beamish [ed.]
Ocean climate and northern fish populations. Can. spec. Pub. Fish. Aquat. Sci.
121, pp. 357-372.
http://ww2.wrh.noaa.gov/climate_info/PDO_page.htm