HR: 11:25h
AN: OS11B-05    [PDF]
TI: From NAO to AO: A distinctive process between two phenomena
AU: * Watanabe, M
EM: hiro@ees.hokudai.ac.jp
AF: Graduate School of Environmental Earth Science, Hokkaido University, Nishi 5 Kita 10, Sapporo, Hk 060-0810 Japan
AU: Jin, F
EM: jff@soest.hawaii.edu
AF: Department of Meteorology, University of Hawaii at Manoa, 2525 Correa Road, Honolulu, HI 96822 United States
AB: Toward understanding the physical origin of the so-called Arctic Oscillation (AO), we performed a singular vector analysis to the dynamical operator of the primitive model linearized about winter 3D state. The leading singular mode having the longest lifetime resembles, though not perfectly, the AO in many aspect, suggesting that the AO is a dynamical mode of the northern winter atmosphere. Furthermore, the evolution of the mode reveals the Atlantic signal rapidly propagating to East Asia along the jetstream, reminiscent of stationary Rossby waves trapped on the jet waveguide. Analysis of monthly observed fields does indicate that the North Atlantic Oscillation (NAO) accompanies such a zonally oriented wavetrain in late winter, when the NAO is virtually indistinguishable from AO. Thus the energy propagation along the Asian jet waveguide appears one of processes which realize the regional NAO extending toward the hemispheric AO.
DE: 1610 Atmosphere (0315, 0325)
DE: 1620 Climate dynamics (3309)
DE: 1635 Oceans (4203)
DE: 3344 Paleoclimatology
DE: 3349 Polar meteorology
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting