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The prediction of ocean tide is important for oceangraphic
research and applications in the fishery and military. The
conventional ground-based method has been largely dependent on
tide gauge data and the prediction is done on a point-by-point
basis. Since the development of satellite altimetry, it is
ssible to predict ocean tide on a global scale and the area
cover can be a continous two-dimensional surface. In this
study, the residual M2 tide caculated fromPEX/POSEIDON(T/P) and
ERS-1 altimeter data is used to improve Csr3.0 tidemodel which
is developed by the Center of Space Research, University of
Texas, Austin. Te studied area covers the Western Pacific,
ranging from 0°∼50°north and 100°∼ 150°east. First, we
use a crossover adjustment to reduce orbit errors. Then the
residual M2 tide is determined from the residual sea surface
height obtain by subtracting a mean sea surface from the sea
surface from individual cycles. The caculation of residual M2
tide is based on the spherical harmonic expansions for
amplitude and phase. harmonic expansions for amplitude and
phase. The mean sea surface of T/P was constructed from 36
10-day repeat cycles, while 18 35-day repeat cycles were used
for the ERS-1 mean sea surface The comparison using 13 tide
gauge data shows that the results derived from ERS-1 alitmeter
data are better than that from T/P altimeter data. Moreover,
the best result is obtained when we use the spherical harmonic
expansion to degree 20. The RMS error is reduced to 1.6 cm when
we add the residual M2 tide to the CSR3.0 tide model This is
better than the 1.2 cm improvement derived in other research
institutions.
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