East Asia and Western Pacific METEOROLOGY AND CLIMATE

195
Case 1: Squall line
Fig. 1 is the reflectivity
chart at
0122L May 17, 1987.
It showes that the
squall line formed at
the northern Taiwan
strait and passed through
the northwestern
Taiwan. Wide-spreading
thunderstorms/ rainshowers
with local heavy
rainfall were observed
at the northwestern
Taiwan when the squall Fig 2.Squall line of horizontal wind
line passing through.
field(m/s) in Doppler mode on May
Fig. 2 is the radial
wind field at the
17,1987
same time as fig.l . From this chart, we can find all
the wind blowing to the radar station at the quadrant
from northwest to southwest. The maximum wind area located
at the southwest, it reached to 20m/s ( severe turbulence).
Case 2: Typhoon
The tropical storm ALEX ( July 27, 1987 ) circulation
center can be easily defined when it approaching to the
northern Taiwan due to the circulation pattern is perfect.
The circulation center is located at the cyclonic vortex
center in the weak reflectivity area indicated by green
(see Fig.3). The circulation center can't be defined easily
in Fig.3-(4),(5), due to the circulation is destroyed
by the topography and the title vertical center structure
after the circulation center makes a landfall in the
northern Taiwan. We can also define the circulation center
by using the zero isodop and the core of the maximum plus