[MITgcm-support] Simple problems about the output of salinity and eta

[Terry Chen]

Hello everyone,
  Since I am a beginner of the z-coordinate model, these questions form me may be a little bit silly.
  I am using MITgcm in a coastal region, and I find some confusing problems about the eta.
  I have divided 28 layers vertically, and start my modeling with the force of tide. From the manual I learn that k=1 is for the surface layer, and k=28 is for the bottom. Then I find that during the tide period, all of the salinity and velocity outputs was for all 28 layers, while actually the total depth at that time was less than the sum thickness of the 28 layers. In other words, I can't see any changes resulted from the decline of water level in the outputs of the salinity and velocity.  
  At the ebb tide, some eta output near the land is even lower than my model depth, which may mean this point is dry or with a depth set by the hFacMin, but I can still find that the output here is more than 1 layer.
  Is that mean the z-coordinate is actually moving up and down or some extrapolation exist here ?  How should I understand the eta can be lower than my depth?


Best,
Terry
  
  


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Thank you for your reading！
 Terry Chen



Physical Oceanography School Of Marine Science

 Sun Yat-sen University
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