Recently, Bradbury et al. (2002) noted that the position
and orientation of the North American trough axis
represent important features of midtropospheric flow.
They suggested that the regional climate in New England
is much more strongly dependent on the features
related to the axis position–orientation rather than on
those related to the intensity of the trough. They also
claimed that similar results may exist in other midlatitude
regions. Although the emphasis of their study is on
the synoptic-scale investigation, the method they used is
illuminating for climate research. Therefore, the purpose
of this paper is to investigate the climate characteristics
related to the features of the EAT axis in boreal
winter. We will further compare the roles of the EAT
axis tilt on the regional climate to those of the intensity
of the EAT.
The datasets used in this study are described in section
2. The dominant modes and the corresponding indices
of the EAT are derived and explained in section 3.
Section 4 then presents the possible influence of the
EAT axis tilt on the pathway of the EAWM. In section
5, we demonstrate the modulation of the EAT axis on
the regional climate in extreme EAWM winters. Finally,
we discuss the potential of the EAT axis tilt for
prediction of the East Asian climate in the following
seasons in section 6, and give a summary in section 7.