open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello all,
I am trying to run a telemac2D model, with TPXO forcing at the border. I noticed that at the first time step, a large area near the coast has a constant value of 0 for surface elevation, while both BOTTOM and WATER DEPTH variables look fine.

This 0 area makes my model crash when I try to modify COEFFICIENT TO CALIBRATE SEA LEVEL in order to calibrate my model mean sea level value, or when I try to begin the simulation during medium or high tide (low tide does not crash).

Do you have an idea of the origin of this big patch of constant surface elevation ? I'll join all my files below.

Note : my mesh has been shifted using run_telfile.py alter --orig I_ORIGIN J_ORIGIN old_geo.slf new_geo.slf -b old_geo.cli, following recommandations on this topic : www.opentelemac.org/index.php/kunena/blu...oblem?start=30#43829.

Thank you very much,
Coline

Edit : result slf file was too heavy, here is a link to download it : creocean.fromsmash.com/result-file

Hello again,
After some additional research, I noticed that my simulations work fine when I use :instead of :
My supposition is then that the area of null value at 1st step was the result of TPXO initial condition. Could this be an internal TPXO problem ?

My area is located in Normandy, between Asnelles and Arromanches-les-Bains.

Coline

Hi
Not necessarily a TPXO problem but maybe linked to the spatial interpolation of TPXO results.
You could test with other TPXO solutions
You could also check if the coordinates conversion is OK
See with location on TPXO solutions

Regards

Hello,

I have already seen this issue when the tidal solution used from Oregon State University does not cover the area close to the coast of your local model. The interpolation is then dummy at those nodes. In your case, Atlantic Ocean is not as refined as European Shelf that was available a few years ago e.g.

You can try to switch to other tidal solutions (tpxo 9 perhaps?) and see if it better works or not.

Or as you did, use another initial condition.

Another idea is to implement a dedicated initial conditions in the areas where you have those dummy values, using e.g. INPOLY to define polygones where you will define other elevation values, e.g. in the USER_CONDIN subroutine (not the USER_CONDIN_H subroutine) as called after CONDI_TPXO subroutine in CONDIN subroutine. It needs to implement a little bit of Fortran but may be better than starting from constant elevation + velocities = 0.

Hope this helps,

Chi-Tuan