85th AMS Annual Meeting

Monday, 10 January 2005: 5:00 PM
Long-range remote impacts of the North Pacific wintertime circulation regimes
Wilbur Y. Chen, NOAA/NWS/NCEP/CPC, Camp Springs, MD
Wintertime North Pacific sea-level pressure anomalies are found to assume a few clustered circulation regimes. And, depending on the configurations of the circulation regimes, they can make distinctive impacts on many far-reaching parts of the globe: * A DJF east-west dipole configuration can make a significant impact on the ensuing MJJ subtropical western north Pacific, eastern north Pacific, central Americas, and western north Atlantic, during which times, the south Asia monsoon and north/south American monsoon take shape. * A north-south oriented dipole is found not effective in the above impacts. Depending on the orientation of a dipole, a maximum impact is found for an east-west orientation, and its influence decreases rapidly to nothing if it rotates towards a north-south orientated dipole circulation regime. * The most frequently developed circulation regimes are single pole large N Pacific anomalies. These winter circulation regimes do not produce the above early-summer impacts. However, they can make a significant impact a year later over the central Americas and the adjacent subtropical regions as well as resulting in a clear NAO, the North Atlantic Oscillation, over the northeastern Atlantic. Therefore, a NAO can no longer be treated as a pure naturally varying mode. It can be influenced, and therefore predicted, by a frequently occurring single pole north Pacific large circulation regime one year ahead of time.

Supplementary URL: