|The Pacific Decadal Oscillation (PDO) is a pattern of Pacific
climate variability similar to ENSO in character, but which
varies over a much longer time scale. The PDO can remain in the
same phase for 20 to 30 years, while ENSO cycles typically only
last 6 to 18 months. The PDO, like ENSO, consists of a warm and
cool phase which alters upper level atmospheric winds. Shifts in
the PDO phase can have significant implications for global
climate, affecting Pacific and Atlantic hurricane activity,
droughts and flooding around the Pacific basin, the productivity
of marine ecosystems, and global land temperature patterns.
Experts also believe the PDO can intensify or diminish the
impacts of ENSO according to its phase. If both ENSO and the PDO
are in the same phase, it is believed that El NiĆ±o/La Nina
impacts may be magnified. Conversely, if ENSO and the PDO are
out of phase, it has been proposed that they may offset one
another, preventing "true" ENSO impacts from occurring.
Researchers have found evidence for ju