$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

                       森羅万象セミナー  第 69 回
                http://www.ep.sci.hokudai.ac.jp/~sinra/

                             Dr. Zhengyu Liu
    (Center for Climatic Research/IES, University of Wisconsin-Madison)


             講演(1) "Evolution of El Nino in the Holocene: 
                          Modeling, Theory and Implications"

                日時: 2002年6月11日(火) 10:45-
                場所: 地球環境科学研究科 C104講義室


             講演(2) "Dynamics of Decadal Thermocline Variability"

                日時: 2002年6月11日(火) 15:30-
                場所: 地球環境科学研究科 C104講義室


$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$


[講演(2) 要旨]

Several fundamental issues of decadal thermocline dynamics in the
extratropical ocean are studied. First, observed large scale upper ocean
variability can be understood from an unified viewpoint of planetary wave
dynamics. The variability consists of two groups of waves: the 1st
baroclinic mode, which propagates largely westward regardless of the mean
thermocline circulation (non-Doppler-shift wave) and the 2nd or higher
baroclinic modes which tend to follow the circulation. Second, the nature
of subduction is studied for an active tracer, such as temperature anomaly.
It is found that although the pathway of an active tracer tends to be
similar to a passive tracer, its amplitude and speed differ significantly
from those of the passive tracer. Third, the impact of a midlatitude Rossby
wave packet on the equatorial region is quantified using a simple mass
conservation principle. 



***
横畠徳太(Yokohata Tokuta)
060-0810 札幌市北区北 10 条西 8 丁目
北海道大学理学研究科地球惑星科学専攻
Tel     011-706-4494
e-mail  yokohata@ep.sci.hokudai.ac.jp