Ocean Modeling Discussion

Hi, I can find how to compute density in rho_eos.F, but how about density equation?
I mean drho/dt= advection + diffusion

Hi，does anyone know that how to get the density equation in ROMS ? Can I use linear EOS function combining the tracer equations (temp and salt) to derive the density equaiton when I define NONLINEAR_EOS?

I suspect that in the vertical interpolation either the new surface or bottom level is outside the range of the old levels and extrapolation creates NANs. You might need to create a rule to catch this, or explicitly set the extrapolation method to 'nearest'


Hi, it is weird that there is no NaN ...

Hi，is anyone tried to diagnose buoyancy equation in ROMS？
can I use Linear EOS to put temp equation and salt equation together？

Hi, I have a parent restart file (theta_s=8 and theta_b=0.1). And I want to modified stretching, so I change parameters(theta_s=7, theta_b=2) by using code "roms2roms". After that, I spin up model with the modified version restart files.

First step like:

TIME-STEP YYYY-MM-DD hh:mm:ss.ss KINETIC ...

It must be something wrong when you using "get_roms_grid" or "roms2roms". You can search words such as "vertical process" in these codes, and modified it.

No, no, no MIX_S_TS! It's a terrible thing to do with a sigma coordinate. Why wouldn't MIX_GEO work? My biggest problems with it
involve wetting and drying and realistic bathymetry. I don't know what you are trying.

I'm just suggesting trying a shorter timestep so that you can rule out CFL ...

Yes, there's a CFL condition. There's also the timescale of damping on the scales you want to damp (2 dx) and the timescale of damping on scales you don't want to damp. A CFL of 1.0 will be unstable. What are you shooting for?


But my case can run with the same condition except I use VIS2 and ...

kate wrote: ↑Tue Apr 12, 2022 4:39 pm They have different timestep constraints, depending on dx. You could try a shorter timestep to see if it runs.

Is it CFL condition? Or the t<(Δx/pi).^4./v4? I am confused because I get visc4' s value through the latter

kate wrote: ↑Mon Apr 11, 2022 4:51 pm Does it run with TNU2? Is this a new domain? Are you sure you have a small enough timestep?

Thanks, kate!
But it can run with TNU2; the domain is a curve orthogonal grid made by myself; and my dt=90, I think it is small enough.

Dear ROMS user,
As a beginner I meet some problem that: firstly I defined smagorinsky option and I want to define VISC4' and TNU4' s value, so I caculate these parameter with the (ΔX./pi).^4./dt.
The model is always blow-up in Max speed and Max rho, no matter how I change the value of VISC4 and ...