tide error

[Suhuiyangy]

After using the boundary addition tidal method, the amplitude of M2 is too high, and changing the bottom friction is useless. After adding tides using a tidal file, if the. h file calculates the tidal amplitude correctly using # define ANA_SSOBC and # define ANA_S2OBC, but using # define add_SSOBC # define add_S2OBC, the overall amplitude will be raised. Adding tides to the boundary is higher during high tide and lower during low tide. May I ask how to solve this? Eternally grateful.

[jcwarner-usgs]

maybe the amplitudes of the tidal constituents in the tidal forcing file are too high?
you could do a harmonic analysis of the model tide and compare to analysis of observed tide. then adjust those components along the boundary.

[Suhuiyangy]

Thank you. Do you mean to compare the tidal component harmonic constant output from the ROMS model with the measured value, and then adjust the boundary file? I am using tidal ubar, vbar, zeta, etc. extracted from TMD.

[Suhuiyangy]

[Suhuiyangy]

Why does zeta show a range of -40 meters when I #define wet_dry?

[jcwarner-usgs]

The wet_dry will drape a water level over all the topography. At locations well above sea level, like at -40, there will be a thin film of water draped over the hills. That will make zeta be at -40 (negative above sea level). What i do is set where wetdry_mask_rho=0 to = nan
wetdry_mask_rho(wetdry_mask_rho==0)=NaN
then use zeta.*wetdry_mask_rho

[Suhuiyangy]

Thank you very much!I finally changed the grid and added tides using boundaries, but this situation occurred again. It seems that the climax is right, but the low tide is not. May I ask what is the general reason for this.

[Suhuiyangy]

This is my simulation area.

[Suhuiyangy]

tide result

[Suhuiyangy]

result.txtThis is the running process.

[jcwarner-usgs]

It is very difficult for me to explain why your tide is not exactly correct.
The phases look great, but the amplitude is slightly too large at certain times. This could be from too large of amplitude for a longer tidal component. I am not sure. As i suggested earlier, you could do a tidal harmonic analysis of the observed and of the model and see which constituents are different, then modify the boundary tide file.

[Suhuiyangy]

Thanks.
Accurate during high tide, high during low tide What is the usual reason for this?

[Suhuiyangy]

When I use SWAN simulation and find that the wave height is low, how should I change it? My boundary is based on the WW3 data method provided in the COAWST manual, and the wind field is ERA5.

[Suhuiyangy]

swan.txt

[Suhuiyangy]

PRINT.txtresult

[jcwarner-usgs]

If the waves from SWAN are too low, it could be from several things:
-winds are not accurate enough
-boundary conditions are not accurate enough
-wave growth formulation ( ie Komen vs ST6 etc) is not accurate enough
-dissipation mechanisms not accurate enough (wcap and or depth induced breaking)
etc

Try to make some adjustments in these items and see what works.
Did you compare your winds to any nearby meteorological stations?