East Asia and Western Pacific METEOROLOGY AND CLIMATE

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A primitive equation model was used in this study to simulate the topographic and
diurnal heating/cooling effects on the airflow pattern and precipitation. The simulation
started at 0500 LSI on June 20, 1987 and ended at 0500 LST on June 21, 1987,
completing a 24-hour cycle. Section 2 gives a brief description of the model Section 3
describes the large-scale and initial conditions. The results and discussions are in section
4 and the conclusions and future work in section 5.
2. THE MODEL
The model framework is based on the Quasi-Lagrangian Nested Grid Model
(QNGM) developed by Mathur (1983). The quasi-Lagrangian scheme used in this model
evaluates the horizontal advections by tracing back the original position of a grid point
using a nine point interpolation scheme. This scheme is second order in nature but it also
considers the acceleration on the path during advection to increase the computation
accuracy (Mathur, 1983).
The model uses the 0 coordinate in the vertical For this study, 22 vertical layers
are used with an interval of Aa = 0.05 from a= 0 to 0.95. A better resolution is used in
the lowest 3 layers where Aa= 0.01 for the lowest layer and ACT = 0.02 for the next two
layers. There are 31 by 31 horizontal grid points and the horizontal grid spacing is 20
km. The model domain and the topography are shown in Fig. 1.
r / / / / /• / / / / // >>>>>>>> sv '/ / s */ '/ '/ V-'/.
/ /• //////////// /'X + * , ,\, t
//////////// /''/ /
////////////// ,
* /'
xl
•//•/// y A.
, -1 / //////.
. / i / ////// , t V f / /;///// A
//;/// ///////.
_/V/ /////////A
' //.//,//•
Ff^. J T/ze wotfe/ domain and the
topography of Taiwan. The contour
interval zs 500 m.
Fi^. 2 r/ze .srea^y state airflow in the
lowest layer after 12 hours simulation.
The maximwnwind vector is 95 mis.