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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