EARTH SCIENCE > CLIMATE INDICATORS > ATMOSPHERIC/OCEAN INDICATORS > TELECONNECTIONS > PACIFIC DECADAL OSCILLATION
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
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.