East Asia and Western Pacific METEOROLOGY AND CLIMATE

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grid, and time level respectively.
To be brief, here we only present the computation of free surface by
continuity equation and the momentum equation in the x direction.
Equations for y-momentum, salinity (s), temperature (T), SGS energy (e),
pollutant (P) are similar.
In the present model, the horizontal grid conforms to the earth's
ellipsodial coordinates and the arbitrary vertical grid spacing approximates
the bottom topography of the modeled area. The results are subsequently
transformed into the Universal Mercator projection for graphical
representation.
The vertical momentum, mass, heat, and turbulent energy
closures are computed implicitly. In the horizontal direction, the exchange
coefficients are computed in two parts as a function of the local vorticity
gradient and the local grid dimension.
The second part represents the
contribution from the homogeneous subgrid scale turbulence above the
spatial Nyquist frequency, which is computed according to the turbulence
spectrum theory (i.e.,proportional to the four-third power of the gridsize).
The model detail can be found in Liu (1983, 1985, 1988) and Liu and
Leendertse (1978, 1987).
The-five-layer China Sea model covers the area from 110°E to 129°E,
and from 19°N to 45°N with a 1/4 x 1/4 degree grid resolution (Fig. 1). For
the Southern China Sea area, a 1/8 x 1/8 degree model covers up to 29°N.
The areas surounding Taiwan are covered by a high resolution model of 1/24
by 1/24 degree resolution.
To establish the initial and boundary data bank for these models, a
substantial effort has been undertaken since the summer of 1980. These data
include depth, salinity, monthly temperature, and tidal prediction
coefficients at the models open boundaries.
made for the China Sea model.
After adjustments have been
It is then used for prescribing the open
boundary conditions for the nested models. In the process, interpolations
were made in the frequency domain by the cross-spectral analysis and
transfer function technique. These statistical methods were applied because
field data usually contain errors.
After the initial adjustment phase, the
model gives reasonably good results in making astronomical tidal
predictions The model has also been used for generalting co-tidal charts for