2.9
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. .
Session 2, Climate Predictions on Seasonal and Interannual Time Scales: 1(parallel with Session 1)
Monday, 10 January 2005, 1:30 PM-5:30 PM
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