blowing up when plus tide

[leon]

Dear all,
I got a problem.
When I didn't plus tide, my model can run for a long time. But when I plus tide, it just blows up after a few time steps. Why? I add my *.h file with 'UV_TIDES, SSH_TIDES, ADD_FSOBC, ADD_M2OBC'. Am I right? What's the most possible problem? Any suggestion is ok. Thank you in advance.

[kate]

First, try a shorter timestep. Second, find out if it is blowing up due to total depth going negative. Third, are you using quadratic bottom drag? That could cause it to blow up too. I wrote to the roms blog about the trouble with tides: https://www.myroms.org/blog/?p=165