2000.09.09 By K. Matsumoto @ National Astronomical Observatory
* Short-period ocean tide model (NAO.99b, NAO.99Jb models)
Global and regional models for major 16 constituents (M2,
S2, K1, O1, N2, P1, K2, Q1, M1, J1, OO1, 2N2, Mu2, Nu2,
L2, T2) are prepared. Model region and resolution are as
follows,
Model Region Resolution
Global model (NAO.99b model ) 0E-360E, 90S-90N 0.5deg
Regional model(NAO.99Jb model) 110E-165E, 20N-65N 1/12deg (5min)
The global model is developed by assimilating tidal
solutions from about 5 years of TOPEX/POSEIDON altimeter
data (Cycle 9-198) into hydrodynamical model. Coastal
tide gauge data are additionally assimilated for the
regional model around Japan.
Reference:
Matsumoto, K., T. Takanezawa, and M. Ooe,
Ocean Tide Models Developed by Assimilating TOPEX/POSEIDON
Altimeter Data into Hydrodynamical Model: A Global Model
and a Regional Model Around Japan,
Journal of Oceanography, 56, 567-581, 2000.
* Long-period ocean tide model (NAO.99L model)
Global models for 7 constituents (Mtm, Mf, MSf, Mm, MSm,
Ssa, Sa) are prepared. The long-period global models are
developed by T. Takanezawa (NAO). These models are purely
hydrodynamical model (T/P data not assimilated). Model
region and resolution are as follows,
Model Region Resolution
Mtm, Mf, MSf, Mm, MSm, Ssa 0E-360E, 90S-90N 0.5deg
Sa 0E-360E, 90S-90N 1.0deg
Sa model is re-sampled into 0.5 deg map for the
sake of convenient calculation, although their original
resolution is 1.0 deg.
* Loading tide model (radial displacement)
Global models for the above 23 constituents are prepared.
They are based on spherical harmonic decomposition of
ocean tidal field up to degree and order 360.
Model Region Resolution
Global model 0degE-360degE, 90degS-90degN 0.5deg
Sa loading models is developed using re-sampled
0.5deg map although their original resolution is 1.0deg
for the sake of convenient calculation.
* Loading tide model (potential perturbation)
Model region and resolution are the same as those for
radial displacement model. The potential perturbation is
the sum of the potential perturbation due to ocean
self-attraction and that due to mass redistribution in the
solid Earth caused by ocean tidal loading. Note that the
values in the file have been divided by the gravity
accerelation g.
* Format transformation
The tide models (except for the regional loading model and
the velocity model) are written in integer table format. In
order to transform them to standard (Longitude, Latitude,
Amplitude, Greenwhich phase) format, please use
nao2xyap.f such as;
% f77 (f90) -o nao2xyap nao2xyap.f
% nao2xyap < m2.nao > m2.xyap
Units are in cm for amplitude and in degrees for location
and phase.
* Extracting files
Use gunzip command for *.gz file and tar xvf command for
*.tar file
* E-mail contact
Questions about the short-period ocean tide model
should be sent to
National Astronomical Observatory
Koji MATSUMOTO
matumoto@miz.nao.ac.jp
Questions about the long-period ocean tide model should
be sent to
National Astronomical Observatory
Takashi TAKANEZAWA
takane@miz.nao.ac.jp
EOF
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