Feedback on the application of CROCO with tidal forcing

Dear all,

Please, I need your support to improve my tidal forcing model. My study area is in the north of the yucatan peninsula. It is a shallow region with a micro-tidal tidal range.
My model has a spatial resolution of 2.7km. My simulations are interannual with glorys and ERA5 forcings. The harmonic tidal components are generated by “make_interannual_tides”. When I compare the velocities and water levels simulated by my model with ADCP data, I find that my model overestimates the velocities and water levels. Adjustments to bottom drag or viscosity parameters have little effect. If you look at the following figure, it is evident that my model does not reproduce well the tidal wave. In order to have a fairer comparison, I made a tidal component analysis of the measured levels using the T_TIDE package. Another test I did was to reduce the Hmin up to 10m depth (the ADCP is located at a depth ~10.4 m).

The blue line is the measured tide level; the solid black line is the predicted tide level after harmonic analysis;
the red, green and thin black dashed line are some tests in CROCO changing viscosity and hmin.

I am using CROCO v1.3. In cppdefs I have defined the following:

ifdef TIDES
define SSH_TIDES
define UV_TIDES
define POT_TIDES
undef TIDES_MAS
ifndef UV_TIDES
define OBC_REDUCED_PHYSICS
endif
define TIDERAMP
endif
define OBC_M2CHARACT
undef OBC_M2ORLANSKI
define OBC_M3ORLANSKI
define OBC_TORLANSKI
undef OBC_M2SPECIFIED
undef OBC_M3SPECIFIED
undef OBC_TSPECIFIED

Please let me know your feedback to understand the model running in my study area and eventually improve its performance.
Best regards,
César.

Hi Cesar
Are you using define Average option in cppdef.h ? I think you should consider instantaneous velocity profile for comparing your result by undef Average then, your result might converge.

Regards
Manmeet Singh

Hello Cesar.

If your simulation is interannual and you are simulating several months you must take into account that the option:

#define TIDERAMP

It would only be used for the first month (or first days); in the following months where the RST file is used as start condition you should disable the TIDERAM option.

“This implies that the tidal wave will be attenuated for the first three days, in order to avoid numerical instabilities in the simulation”

I hope the information is useful.