Ocean Modeling Discussion

an ncdump of a netcdf history file shows the units of omega to be cubic meters per second, however in wrt_his.F the routine scale_omega is called before omega is written. This routine multiplies omega by pn and pm, so the units of omega on output are actually m/s.

Shchepetkin and McWilliams (2005) give the discrete continuity equation as:

dV(t2,k,j,i) = dV(t1,k,j,i) - dt*{U(k,j,i+1/2) - U(k,j,i-1/2) + V(k,j+1/2,i) - V(k,j-1/2,i) + W(k+1/2,j,i) - W(k-1/2,j,i)}

where U = u*dy*dz, V = v*dx*dz (W is defined separately but appears to be W = omega*dy*dz ...

I'd like to be able to balance integral{(divergence of u).dV} with integral(u.dA) over some volume; for this I need to know what the layer thickness is at u (and v) points.

I had first thought that it would be the average of the Hz's at the adjoining rho points, but if, as Kate noted in another ...

doesn't look like I've updated. Both log files say:

SVN Root URL : https://www.myroms.org/svn/src/trunk
SVN Revision : 154M


Just to make sure I wasn't crazy, I just tried doing two identical runs (different history file output name and different log file name, but otherwise the same) and the ...

I just realized I wasn't completely clear in my first post. I meant the only difference in the log headers are the Haney number and the basin volumes. The history file output is definitely different between the two runs, otherwise I wouldn't bother with checking into this. After thirty model days ...

I recently redid an old run, this time with diagnostics turned on. I output the history files as well, just to be sure I haven't changed anything in the meantime and have found that the results are slightly different.

From looking at the log files, the only difference between the old run and the ...

Thanks for all of the information. I gave the problem to one of the computer guys here to explore what the limitations of our machine are. He has asked me to post the following:

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I am running into a "segmentation fault" with this ocean_upwelling.in file :

Lm == 504 ! Number of I ...

Hi Kate, thanks for the suggestions. I tried compiling with the -bmaxdata option, but got the error:

ld: invalid BFD target: 'maxdata:0x70000000'
I don't really understand this (and google didn't help); my knowledge in this area is a bit slim, but the computer guy here said that that flag is for ...

I've been getting a segmentation fault when I try to run my ROMS application, but have always been able to run the upwelling example without difficulty, so I tried adjusting the upwelling example to see where the problem lay. I've found that by only changing the horizontal dimensions of the grid in ...

thanks for getting back to me; to answer your questions:

-I am initializing with u, v, ubar, vbar and zeta all =0

-I am using the GLS. k-epsilon turbulence closure

-Sorry about that, I mean w is large at k=0 and then decreases at k=1....

-Omega is small! Omega is zero at k=0 and at the surface ...

I am still having this problem; I appreciate that it is nobody's job to help me sort out my issues, but if someone could tell me if this is a normal occurence and to be expected from the model, or if this is abnormal and I should continue to look for the problem, it would be so helpful!

To ...

thank you for your reply, that is very helpful!

The suggested maximum rvalue, or Beckmann and Haidvogel number, has been previously discussed on this forum, but what about the Haney number? Shchepetkin and McWilliams (2003) test with a value just under 4; is that considered a reasonable maximum?

Before doing any realistic runs, I am trying initializing with a horizontally uniform (but vertically varying) stratification appropriate to my modelling region to find optimal theta_s and theta_b for minimizing spurious currents. I've found that theta_s = 3 and theta_b = 0.7 works reasonably well ...

Error in ==> mexcdf at 121
[varargout{:}] = feval(fcn, varargin{:});


Check your mexcdf.m file. In my version, the variable fcn is created at the top of the file based on the version of Matlab you have, and 7 isn't an option, so the variable is never set:

v=version;
if v(1) == '6'
fcn ...