East Asia and Western Pacific METEOROLOGY AND CLIMATE

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In another experiment, the heating sources is located
at the eastern tropical Pacific Ocean(5*N, 130°W) where is
so-called " key region lf by Pan and Oort(1983). The
result of simulation illustrated that the spiral structure
anomalous perturbations are covered the whole Northern
Hemisphere at 500 hPa . And it is also shown that the
atmospheric circulation of the Northern Hemisphere is
characterized by anomalous wavetrains across the Pacific
and Northern America continent, which is somewhat similar
to PNA pattern. In Fig.5. the anomalous wavetrains are
denoted by duble thick line, and the spiral shaped
perturbation are linked by single thick line.
On the other hand, we set three heating sources in the
Eastern Tropical Pacific Ocean (2 N°- 10°N , 125*W - 135°W
, (3 a c)), Western Tropical Pacific Ocean (2°N - 10*N , 125°W
- 155°W / ( ~1.2°c)) , and the Indian Ocean (5*N - 15°N ,
83° E - 91°E ,(l.8°c)) , respectively, which are referred
to the patterns of anomalous SST fields in January 1973.
The response of 500 hPa GPH to these three heating sources
are shown in Fig. 6 . The observational 500 hPa anomalous
GPH for January, 1973 is shown in Fig. 7 . It shows that
the main features of Fig. 6 is closed to Fig. 7 .
3. TROPICAL UNSTABLE ATMOSPHERE INTERACTION
To apply above model to the tropics, we should firstly
discuss the tropical atmosphere - ocean interaction. Some
authors (e.g. Philander et al, 1984) constructed models to
investigate air - sea interactions using so called
"slavery atmosphere", i.e., the atmosphere model is
steady, only the ocean model is time - dependent. Ji
(1987) argued that this kind of coupling is actually to
parameterilze the forcing of wind stress in an ocean
model. Here we will set up an analytical coupled model, in
which the motion equations of the atmosphere and ocean
are all time - dependent, and explore coupling mechanism
of atmosphere - ocean system (AOS).
The basic equations of the atmosphere and ocean
are similar the ones derived by Anderson and Gill(1975),
which are shallow water equations and inertial gravity
waves are filtered. Chao and Ji (1985, 1986) used these
equations to discussed the tropical oceanic waves. The
coupling between the atmosphere and ocean are similar to
Philander et al 's (1984), i.e., changes in the depth of
the thermocline affects the SST which, in turn, heats (or
cools) the atmosphere. Atmospheric winds ar^ assumed to
act as a body force in the ocean. Parabolic cylinder
functions are used to solve the equations. It is a simple
truncated filtered model. The detailed descriptions of
this model are given inseparate papers (Ji and Chao, 1989
Chao and Zhang, 1988).