Bidecadal and pentadecadal climatic oscillations over the North Pacific and North America.
Shoshiro Minobe
Division of Earth and Planetary Sciences, Graduate School of Science,
Hokkaido University, 060-0810 Sapporo, Japan
Tel: 81-11-706-2644
Fax: 81-11-706-4907
minobe@geophys.hokudai.ac.jp
Climatic variations on bidecadal(about 20 years) and pentadecadal (50-70 years) time scales are analyzed in terms of their seasonal and regional dependencies in the North Pacific and North American sector. The both bidecadal and pentadecadal variations are evident in SLP fields associated with the strength changes of the Aleutian low. The bidecadal variability is found only in winter, but the penal signal exists in winter mad spring. Bidecadal air-temperature variability is evident in winter in Alaska and western and eastern North America.
The Alaska temperature and Aleutian low strength exhibit a prominent out-of-phase relationship throughout the present century. On the other hand, an out-of-phase relationship between the Aleutian low strength and air-temperature in western North America on bidecadal time scale is detectable only after the 1930s, suggesting that the linkage between the atmospheric circulation in the North Pacific and temperature change over North America be modulated on a century timescale.
