Ocean Modeling Discussion

Eugen

Dear Julia,

Thanks a lot for the explanation !

This model is exactly what we need, I'm very glad this implementation exists.

Evgeny

Eugen

Dear Katja,

Many thanks for the response and the articles ! This is exactly what we were looking for

Evgeny

Eugen

Dear ROMS community,

For the purpose of a project I need to couple the sediment and a biological model (to account for detritus that settles down and (partially) being buried and removed from the chemical cycles).

Based on my search through the ROMS code, there is by far no coupling.

Several bio ...

Eugen

Thank John !

I've actually tried that as well (by another formula though), and it worked, but I thought there was a more direct way without conversion.

Gonna continue using relative humidity then.

Eugen

Dear ROMS community,

I have to run a long-term hindcast.

ECMWF has recently discontinued ERA-Interim atmospheric forcing data and replaced it with ERA5.

I used Kate's python scripts to download ERA5 forcing, and I have noticed that the relative humidity is replaced with the specific humidity ...

Eugen

Hi everyone,

I have a question about lateral diffusion coefficients of sediment tracers "MUD_TNU2" and "SAND_TNU2".

I looked through the test-cases, but they seem to be set to zero everywhere in the input files.

But it doesn't mean, that suspended sediments are not being diffused? There are some ...

Eugen

John,

Unfortunately, I didn't succeed to eliminate this error while playing with the ROMS time step, nor with the SWAN time step or with the coupling time step.

Could it be due to a mask mismatch? I made some significant changes in the mask inside of the domain (not in the contact point layer ...

Eugen

John,

The SWAN itself works fine now. But, coupled with ROMS, the nested grid gives a weird numerical error along the upper boundary.

It is not deadly anymore, but it is definitely a patch to be eliminated.

Could you guess please, why does it appear?

Eugen

Thanks a lot, John !

I'll try your suggestions and soon tell the results of the coupled run.

Eugen

John,

I've decided to make an experiment.
I've turned both grids of the Sandy test-case on 180 degrees. Then, I've created .grd and .bot files and have run SWAN (without coupling with ROMS). And then I've compared it with the run on the normal (non-reversed) grid.

I've switched off the winds on ...

Eugen

Thanks, John,

I've sent you a message.

Did I mention that my ROMS grids have an angle of 120 degrees?
Can it be a reason, why the configuration works such bad?

SWAN does not read the southern nested boundary at all, and the western boundary it reads with a numerical error...

Eugen

I compared indexes of child grid edge points compared to the corresponding parent grid cells in the scrip interpolation weight logs.

For Sandy hurricane it is:

ROMS starting i & j index of parent w.r.t child grid
23 27
ending i & j index of parent w.r.t child grid--
60 54

And ncdump says ...

Eugen

Yes, sure

Eugen

Dear John,

1) SWAN only (results after 5 days):
https://psv4.userapi.com/c848428/u51965391/docs/d10/2cb18d9148ad/Only_SWAN.png?extra=FNDXxVQY47FTy_rVekXjUy7jvAMXbssQ9Cm9V00vhn2TQrl-S1sWARXrsNLEWH4Eyfcfu4tv2BdopV1uhMc3Bw_GQsNY9hDOHklOb74PC19WH_6FzadoxkSDpcRvxK4rd-TQly05XObiW4vd5VOqbw

3) If I run ...

Eugen

Hi John,

1) I run SWAN grids without ROMS. No numerical errors and "zero" boundaries are found;

2) Currents are continuous, yes;

3) I've run the coupled system for one day and then have rerun with HOTFILEs. The error is still on both ROMS grids, while both SWAN grids look OK.

I suspect an ...

Eugen

Thanks, John !

I'll try your suggestions and tell the result

Eugen

Thanks John,

Here they are:

Eugen

Hi, John.

This is a snapshot after 11 hours.

But the model can go 30 days without explosion, just the results on the child grid have a little connection to the parent.

About winds: I use the same regular ECMWF grid with winds for both of my grids. I tried to run with having winds on both grids ...

Eugen

Dear ROMS users,

I run ROMS + SWAN in coupling using MCT library on two grids, one inside of another, in two way nesting.

I'm sure about the wave results on the coarse grid. However, the fine resolution grid does not behave on the way I expect it.

Here is a picture of the significant wave height ...

Eugen

Thanks, John !

Eugen

Dear ROMS users,

I have a short question.

I couple online ROMS and SWAN on the same grid. Should I correct wave directions in my TPAR boundary files on the ROMS grid angle?

To make TPAR files, I used a standard MATLAB scrip, which seemed to interpolate wave directions from the global wave product ...

Eugen

Sorry for the necroposting.
I had exactly the same problem.

The reason was the name of my test case. I named it 'NS' (i.e. North Sea), and it overlapped with a variable inside of the SWAN code with the same name.

I renamed my test case and solved the problem.

Eugen

Thanks, arango !

I tested all proposed solutions, and found out, that the source of the problem was the time step , which was five times smaller for the child grid, than for the parent, due to a grid cell size ratio of 1:5.

With the advection schemes TS_C4VADVECTION and TS_U3HADVECTION I always ...

Eugen

Dear Farshid ,

Thank you for these suggestions !

1) I undefined UV_SADVECTION, but the result is almost the same.

2) Surprisingly One-Way nesting works fine (I knew it before), but for our study we need the two-way, to prove its superiority compare to the one-way.

3) I scaled the bottom drag ...

Eugen

Dear ROMS users,

I have a bizarre problem at the contact point layer in the configuration of a coarse grid and a fine grid, nested inside of the domain with TWO-WAY interaction.

I've spotted bizarre residual currents across the grid frame in my highly tidal region (North Sea). I had a close look ...

Eugen

Dear all,

I have a problem with tidal forcing on my domain. The tidal amplitudes are too big in semi-closed bays.

How to define a boundary condition type at river point sources (like we have to do for open boundaries), to make the tides propagate?

The image below is a bias in [m]: M2 tidal ...

Eugen

Dear ROMS users,

For validation of tides at the domain of the North Sea, I decomposed SSH and U, V- velocity components from the results by using the pytides python tool.
Then I compared tidal amplitudes from the results at the points in the center of the domain with the amplitudes from the in-situ ...

Eugen

Thank you, wilkin

Yes, I confirm , that the Forcing file for the parent grid is being read twice: for the parent and for the child grids.

But how can I make ROMS reading the Forcing file for the child grid ?

This experience suggests that for added clarity we should have stdout explicitly report ...

Eugen

Thanks, John ,

I can assume this, on the basis of netcdf pictures. For example, short-wave radiation, the variable I have to define.
On the left hand-side - how it does look in the Forcing file. On the right hand-side - how it does look at the history outputs.
https://pp.userapi.com/c837232 ...

Eugen

Hello, everyone!

For my nesting simulations, I made a forcing files for both, the parent and the child grids.
However, I noticed, that ROMS, instead of reading and processing the child forcing file, interpolates data from the parent forcing file into the child grid.

What could be the reason?

Here ...

Eugen

Thank you, Kate !

Btw, we found two possible ways to overcome this problem.

First way : the subroutine LIMIT_STFLX_COOLING , which prevents temperature of going too low. It works fine, but it is a rude way.

Second way : the added a condition into the subroutine step3D_t to keep temperature the ...

Eugen

jcwarner wrote:can you put that rmask_wet in pre_step3d.F that i showed above?
-j

I'm sorry, but isn't it already there?

Eugen

Yes, I use BULK_FLUXES subroutine. And in its code I saw the multiplication on rmask_wet for longwave , sensible , latent and heat fluxes , and the wind stress .

Here is a complete list of subroutines, which I use:

#define ROMS_MODEL
#undef NESTING
#define MASKING

#define UV_ADV
#define UV ...

Eugen

Hello, everyone,

As a continuation of this topic (https://www.myroms.org/forum/viewtopic.php?f=19&t=4423), we decided to output all model variables at the 'problematic' point of model’s explosion (during long-time simulations), in order to investigate why.

It seems, that temperature goes randomly ...

Eugen

kate , thank you for the answer!

The error remains again, also during interannual (10 years) real-data run.

We think, that anomalous low temperatures could be a reason of this numerical error. I have many of them occasionally occurring time-by-time along the grid mask. But most of the time, the ...

Eugen

Hi,

I have a strange problem with the climatological multi-year simulation in ROMS.

I force the model by a climatological atmospheric forcing, climatological boundary conditions and climatological nudging at the open boundaries. And also with climatological river point sources and tides. So all ...

Ocean Modeling Discussion

Search found 36 matches

Re: Bio-sediment coupling to represent detritus (how to implement)

Re: Bio-sediment coupling to represent detritus (how to implement)

Bio-sediment coupling to represent detritus (how to implement)

Re: Specific humidity performs worse than the relative

Specific humidity performs worse than the relative

Diffusion of sediment tracers in the water column

Re: ROMS + SWAN with nesting : error on the child grid

Re: ROMS + SWAN with nesting : error on the child grid

Re: ROMS + SWAN with nesting : error on the child grid

Re: ROMS + SWAN with nesting : error on the child grid

Re: ROMS + SWAN with nesting : error on the child grid

Re: ROMS + SWAN with nesting : error on the child grid

Re: ROMS + SWAN with nesting : error on the child grid

Re: ROMS + SWAN with nesting : error on the child grid

Re: ROMS + SWAN with nesting : error on the child grid

Re: ROMS + SWAN with nesting : error on the child grid

Re: ROMS + SWAN with nesting : error on the child grid

Re: ROMS + SWAN with nesting : error on the child grid

ROMS + SWAN with nesting : error on the child grid

Re: TPAR wave directions: correct or not on the ROMS grid an

TPAR wave directions: correct or not on the ROMS grid angle

Re: Problem with SWAN

Re: Contact point problem with salinity in Two Way Nesting r

Re: Contact point problem with salinity in Two Way Nesting r

Contact point problem with salinity in Two Way Nesting run

Boundary condition type definition at river point sources

Tidal modes twice bigger in the results, than in the forcing

Re: The model does not read the Forcing file for the Child g

Re: The model does not read the Forcing file for the Child g

The model does not read the Forcing file for the Child grid

Re: WET-DRY points initialization, how they go from DRY to W

Re: WET-DRY points initialization, how they go from DRY to W

Re: WET-DRY points initialization, how they go from DRY to W

WET-DRY points initialization, how they go from DRY to WET?

Re: Climatological run error: temperature vanishing

Climatological run error: temperature vanishing