tidal forcing not showing up

[asujrpv]

Hello all,

I have added tidal forcing (I think) to my roms simulation. The area is rather small and it is driven by the tidal potential. I made the tidal forcing using both, PM_make_tides from prof. MacCready and also following the instructions in the roms forum https://www.myroms.org/wiki/index.php/Tidal_Forcing.

I am interested in retrieving the tidal forcing starting at September 1, 2006 and run the simulation for 5 days. So in my cdw.h file I have the following definitions
DSTART = -5366.0d0 ! days
TIDE_START = -5366.0d0 ! days
TIME_REF = 20060901.0d0 ! yyyymmdd.dd

TIDE_START = datenum(1992,1,1(-datenum(2006,9,1).
Is this the proper way to set up these variables?
One of the problems is that the velocities due to the tidal forcing from TPX07 are in the order of tens of centimiters/s (30-40 cm/s) but the velocities I obtain from the simulations are in the order of 0.1cm/s which is impossible if I am imposing the tidal forcing correctly.

I will appreciate your help.
thanks!
Rafael
PS More information on what I defined in my simulations:

#define SOLVE3D
#define UV_ADV
#define UV_COR
#define SALINITY
#define ANA_INITIAL
#define SSH_TIDES /* use if imposing tidal elevation */
#define UV_TIDES /* use if imposing tidal currents */
#define RAMP_TIDES /* ramping (over one day) tidal forcing */
/* #define MASKING */
/* Surface boundary conditions*/
#define ANA_SMFLUX
#define ANA_STFLUX
#define ANA_SSFLUX
/* Bottom boundary conditions*/
#define UV_LOGDRAG
#define ANA_BTFLUX
#define ANA_BSFLUX
/* Lateral boundary conditions*/
#define EAST_VOLCONS
#define WEST_VOLCONS
#define SOUTH_VOLCONS
#define NORTH_VOLCONS

[kate]

/* Lateral boundary conditions*/
#define EAST_VOLCONS
#define WEST_VOLCONS
#define SOUTH_VOLCONS
#define NORTH_VOLCONS

Try turning these off. Tides by their very nature do not conserve volume in a small domain.

Also, what are your boundary conditions? If you don't specify any open ones, it will assume closed walls.

[asujrpv]

/* Lateral boundary conditions*/
#define EAST_VOLCONS
#define WEST_VOLCONS
#define SOUTH_VOLCONS
#define NORTH_VOLCONS

Try turning these off. Tides by their very nature do not conserve volume in a small domain.

Also, what are your boundary conditions? If you don't specify any open ones, it will assume closed walls.

Kate,
here is what I use, and attached is a profile of the u_bar velocity, these should be in the order of tens of centimeters... I do not know how to check if the input from tidal forcing is correct...

#define SOLVE3D
#define UV_ADV
#define UV_COR
#define SALINITY
#define ANA_INITIAL
#define SSH_TIDES /* use if imposing tidal elevation */
#define UV_TIDES /* use if imposing tidal currents */
#define ADD_FSOBC /* use to add tidal elevation to processed OBC data */
#define ADD_M2OBC /* use to add tidal currents to processed OBC data */
#define MIX_S_UV /* use if mixing along constant S-surfaces */
/* #define RAMP_TIDES */
/* #define MASKING */
/* Surface boundary conditions*/
#define ANA_SMFLUX
#define ANA_STFLUX
#define ANA_SSFLUX
/* Bottom boundary conditions*/
#define UV_LOGDRAG
#define ANA_BTFLUX
#define ANA_BSFLUX
/* Lateral boundary conditions*/
/*
#define EAST_VOLCONS
#define WEST_VOLCONS
#define SOUTH_VOLCONS
#define NORTH_VOLCONS
*/
#define EAST_FSCHAPMAN
#define WEST_FSCHAPMAN
#define SOUTH_FSCHAPMAN
#define NORTH_FSCHAPMAN

/* Lateral boundary conditions*/
/* #define EAST_FSRADIATION /* use if free-surface radiation condition */
#define EAST_M3RADIATION /* use if 3D momentum radiation condition */
#define EAST_KRADIATION /* use if TKE fields radiation condition */
#define EAST_TRADIATION /* use if tracers radiation condition */
/* #define WEST_FSRADIATION /* use if free-surface radiation condition */
#define WEST_M3RADIATION /* use if 3D momentum radiation condition */
#define WEST_KRADIATION /* use if TKE fields radiation condition */
#define WEST_TRADIATION /* use if tracers radiation condition */
/* #define NORTH_FSRADIATION /* use if free-surface radiation condition */
#define NORTH_M3RADIATION /* use if 3D momentum radiation condition */
#define NORTH_KRADIATION /* use if TKE fields radiation condition */
#define NORTH_TRADIATION /* use if tracers radiation condition */
/* #define SOUTH_FSRADIATION /* use if free-surface radiation condition */
#define SOUTH_M3RADIATION /* use if 3D momentum radiation condition */
#define SOUTH_KRADIATION /* use if TKE fields radiation condition */
#define SOUTH_TRADIATION /* use if tracers radiation condition */

By the way, I got these parameters from the tidal forcing nc file:

GET_NGFLD - tidal period
(Min = 4.32000000E+04 Max = 9.29496301E+04)
GET_2DFLD - tidal elevation amplitude
(Min = 1.79808629E-01 Max = 1.13754682E+00)
GET_2DFLD - tidal elevation phase angle
(Min = 1.19593738E+00 Max = 4.42787901E+00)
GET_2DFLD - tidal current inclination angle
(Min = 4.99600361E-16 Max = 6.28318531E+00)
GET_2DFLD - tidal current phase angle
(Min = 6.29543824E-04 Max = 6.27993607E+00)
GET_2DFLD - maximum tidal current, ellipse major axis
(Min = 2.60039070E-03 Max = 2.06806635E+00)
GET_2DFLD - minimum tidal current, ellipse minor axis
(Min = -1.05285788E+00 Max = 4.76676267E-03)

[kate]

Try adding:

Code: Select all

#define EAST_M2FLATHER
#define WEST_M2FLATHER
#define NORTH_M2FLATHER
#define SOUTH_M2FLATHER

[asujrpv]

Try adding:

Code: Select all

#define EAST_M2FLATHER
#define WEST_M2FLATHER
#define NORTH_M2FLATHER
#define SOUTH_M2FLATHER

Kate,
will the above ask for a climatology input file?

[kate]

No, it shouldn't. It should want a boundary condition file which I believe you are OK with since you have:

Code: Select all

#define ADD_FSOBC /* use to add tidal elevation to processed OBC data */
#define ADD_M2OBC /* use to add tidal currents to processed OBC data */

Again, you need to specify some open condition on 2-D momentum or it will impose a wall.

[asujrpv]

No, it shouldn't. It should want a boundary condition file which I believe you are OK with since you have:

Code: Select all

#define ADD_FSOBC /* use to add tidal elevation to processed OBC data */
#define ADD_M2OBC /* use to add tidal currents to processed OBC data */

Again, you need to specify some open condition on 2-D momentum or it will impose a wall.

Kate, thanks, I will do that. I do not have a boundary file, all I have is grid file and forcing file... I hope this will not create a problem, i.e. I hope it will not ask me for a bry file, but if it does, I gather the bry file should be obtained from the tidal forcing, is this correct?
Rafael

[kate]

You probably want to turn off those ADD_XXOBC options. They tell it to add the tides to the other open boundary information.

It could still tell you that you need a boundary file, depending on the logic within globaldefs.h. Sometimes you have to beat it over the head and say I don't need a boundary file because the tides are enough. You will just have to try it and see.

[asujrpv]

You probably want to turn off those ADD_XXOBC options. They tell it to add the tides to the other open boundary information.

It could still tell you that you need a boundary file, depending on the logic within globaldefs.h. Sometimes you have to beat it over the head and say I don't need a boundary file because the tides are enough. You will just have to try it and see.

The only way this code is not asking for a bry file is by defining ANA_M2OBC and ANA_FSOBC... I am running it now to see if this works.

On the other hand, can I just use ana_m2obc.f and do not set the boundary conditions? by default, it will set the BC to zero, but what if I left these BC intact?

Thanks
R

[kate]

You will just have to try it and see.

I think it should work, but I usually hack globaldefs.h instead. That's why Hernan doesn't always like my approach to things...

[asujrpv]

You probably want to turn off those ADD_XXOBC options. They tell it to add the tides to the other open boundary information.

It could still tell you that you need a boundary file, depending on the logic within globaldefs.h. Sometimes you have to beat it over the head and say I don't need a boundary file because the tides are enough. You will just have to try it and see.

The only way this code is not asking for a bry file is by defining ANA_M2OBC and ANA_FSOBC... I am running it now to see if this works.

On the other hand, can I just use ana_m2obc.f and do not set the boundary conditions? by default, it will set the BC to zero, but what if I left these BC intact?

Thanks
R

It seems to work, I am quite happy! thanks!