Tidal Forcing in ROMS

[taowang]

I am a beginner to learn ROMS. Now I want to simulate the tide in an ideal rectangle bay. But I don't know how to add the tidal information at the open boundary. My model is an ideal model. Should I download the desired tidal constituent database and associated software,yet?Or I just need to modify the codes in some fortran files?
Thanks for any point of view.
-Tao

[fdaryabor]

Hi,Taowang,

For your case after make surface forcings and boundary conditions of domain, add tidal elevation (m) and tidal currents (m/s) to sea surface height and 2D momentum climatologies, respectively. Furthermore, you must be careful when add tidal forcings, since tidal forcings (TPXO6/TPXO7) are in UT time the simulated harmonics are in UT, otherwise before add convert it to local time.


Hope can help you,
Good luck

[wilkin]

Look at the example code in Functional/ana_fsobc.h Functional/ana_m2obc.h
for the test case ESTUARY_TEST:

In ana_fsobc.h:

Code: Select all

#elif defined ESTUARY_TEST
      IF (LBC(iwest,isFsur,ng)%acquire.and.                             &
     &    DOMAIN(ng)%Western_Edge(tile)) THEN
        cff=1.0_r8*SIN(2.0_r8*pi*time(ng)/(12.0_r8*3600.0_r8))
        DO j=JstrR,JendR
          BOUNDARY(ng)%zeta_west(j)=cff
        END DO
      END IF

This is one way to add tidal harmonic variability as an analytical function. Note that some care is required with amplitude and phase to make the free surface and velocity dynamically consistent.

You will want to use this in conjunction with the Flather and Chapman open boundary conditions so that the reflected wave inside the domain has some chance to escape through the open boundary.

[taowang]

Thank you for your advices. I will have a try.