Define SSH_TIDES and undef UV_TIDES

[crisalas]

Hi all,

I have a problem with tides in my ROMS models, when are defining SSH_TIDES and UV_TIDES, the tides that I obtain are over-estimate, but when define SSH_TIDES and undef UV_TIDES, the tides are more similar to in-situ data of tides from the study area.

In the figure:
FULL_DEFINE : SSH_TIDES and UV_TIDES define

DEFINE UV_TIDES: and undef SSH_TIDES

DEFINE_SSH TIDES: and undef UV_TIDES

FORCING MODEL: zeta values of the model that use to create forcing file through make_roms2roms.

My questions is about the meaning of SSH_TIDES and UV_TIDES, if undef for example UV_TIDES (the better combination to fit with the data), Does ROMS model calculates this missing values? Is it a good approaches undef UV_TIDES?

I will appreciate any comment about it.

Thanks in advance

[wilkin]

Can you give us a bit more background on the information that went in to building the tidal harmonic boundary forcing file? Looking quickly at the Xtide prediction for Puerto Montt http://tides.mobilegeographics.com/locations/5140.html I see a tidal range of about 4 to 5 m, whereas your full SSH_TIDES and UV_TIDES result is about twice that (though with a significant spring/neap cycle which is not conspicuous in the Xtide prediction).

Could you possibly have interpreted tidal range data as tidal amplitude in your forcing file? That would give a factor of 2.

Your SSH_TIDES-only solution seems very low, which I would expect because the way the boundary forcing enters in ROMS it is the tidal velocity volume flux that really drives the response.

[crisalas]

Can you give us a bit more background on the information that went in to building the tidal harmonic boundary forcing file?

I used a ROMS model output of an area bigger than my area (father domain) , which was forcing with NCEP2 and ECCO data, and the zeta values was recorded daily (Incorporating aliasing effect I guess, in the last figure this values is FORCING MODEL). With roms2roms process I got the roms_bry and roms_ini files. Then using nestgui tools I create roms_frc (that contain tides information) and roms_blk files from the roms_frc and roms_blk of father domain which were created previously using make_NCEP.m The tides are forcing with TPXO7, number of tide component = 10. When I compile the code, define TIDES and define OBC_M2FLATHER scheme.

Looking quickly at the Xtide prediction for Puerto Montt http://tides.mobilegeographics.com/locations/5140.html I see a tidal range of about 4 to 5 m, whereas your full SSH_TIDES and UV_TIDES result is about twice that (though with a significant spring/neap cycle which is not conspicuous in the Xtide prediction).

Could you possibly have interpreted tidal range data as tidal amplitude in your forcing file? That would give a factor of 2.

I don't know if there is a bad interpretation between tidal range and tidal amplitude, I don't know how to know. Perhaps the variable zeta that give ROMS I'm misinterpreting, Do you know it's meaning?, if it represents tidal amplitude or tidal range or otherwise...

Any comment will be hopeful

Thanks in advance

Cristian