Ocean Modeling Discussion

The College of Earth, Ocean, and Atmospheric Sciences invites applications for a Research Associate position As part of the NASA-sponsored Ocean Surface Salinity Team project, the Research Associate will lead the development, testing, and analysis of a high-resolution coupled ice-ocean circulation ...

Sad news...

I will always remember Dale as one of the pioneers of coastal ocean modeling, a great mentor and a good listener. He was part of a great epoch in physical oceanography, and the great leader.

The College of Earth, Ocean, and Atmospheric Sciences invites applications for a Research Associate position As part of the NASA-sponsored Ocean Surface Salinity Team project, the Research Associate will lead the development, testing, and analysis of a high-resolution coupled ice-ocean circulation ...

Dear colleagues, We are happy to offer again our successful session - please consider submitting an abstract (submission now open with a deadline of 6 September). Go to session OM001 (ID: 26761) under "Ocean Modeling": https://agu.confex.com/agu/os18/preliminaryview.cgi/Session26761 Advances in ...

This does help a lot.. and hopefully solves the problem in my case...

Thank you for checking!

I am running a coastal application in ROMS providing wind velocities (and other forcing) as multiple files (one file per year, 2008, 2009, 2010, 2011, 2012). Because of the wall clock limit on the supercomputer I can run it for about 3 model months at a time. It runs fine (with restarts roughly ...

Research Associate (Postdoctoral), College of Oceanic and Atmospheric Sciences, Oregon State University, to work on modeling, data assimilation, and analysis of ocean processes that determine shelf-open ocean exchange off Oregon. The successful applicant will participate in an NSF-sponsored research ...

Ban, -- Thanks for interesting statistics. Did you run ROMS test in OpenMP or MPI regime?
-- Alex

I am trying to run a roms application as OpenMP. I use ROMS version 3.1 and compile it as OMP using a pgi compiler on a Sun station (linux, 4 proc) and obtain executable oceanO. I set env variable OMP_NUM_THREADS to 2 and set the number of tiles to 2 in the roms .in file. I am trying to run the ...

bzhang: your comment makes sense. Thanks!

I've been trying to do fancy momentum term balance analysis, doing this by post-processing of ROMS output. I've translated the roms pressure grad term in Matlab and stumbled upon the following detail. In the code, the barotropic pressure gradient, e.g., at level N, is apparently twice the value that ...

CLASSIFIED ADVERTISEMENT Research Associate (Postdoctoral), College of Oceanic and Atmospheric Sciences, Oregon State University. The successful applicant will lead research in areas of development and implementation of algorithms for variational data assimilation in a nonlinear model of circulation ...

Re: U = sqrt(g/H)*exp(-f*y/sqrt(g*H))*cos(omega*time).

Anybody looking into that, check dimensions. Is U a velocity (m/s)?
sqrt(g/H) has units of (1/s). Does the wave aplitude have to be sqrt(g*H)?

Hi, I've tried to checkout the tagged roms version, roms-3.1, which is shown as revision 167 in the roms-svn repository (https://www.myroms.org/projects/src/browser/tags). I run, from the linux machine: >> svn checkout https://www.myroms.org/svn/src/tags/roms-3.1 MyDir The download has been ...

Good poi`nt, about the diagnostic. Dig it and keep us updated.

Double-check your open boundary files. We've seen the statements like "I've checked the boundary files and they were fine". And then, later "sorry, there was a NaN at one point in one snapshot". NaN does not appear for no reason. Something has been set NaN. You obtained your open boundary files by ...

Use a better resolution. Try to resolve the boundary layer. Or, for the sake of experiment,
increase Akv by an order of magnitude.

The Ekman layer thickness is delta=sqrt(2*Akv/f) (see Pedlosky'87, 4.3.16) Akv=1.e-3 m2/s f=1.e-4 1/s => delta= 4m So the sharp change you see in u,v in the upper 4 m is Ekman veering. Besides, sustr=Akv du/dz at the surface. You are probably trying to estimate it at the points below the surface ...

The College of Oceanic and Atmospheric Sciences (COAS) at Oregon State University announces the availability of a full-time position for a Research Associate (Postdoctoral). We seek a research colleague who will join our coastal modeling and data assimilation group to work on variational data ...

Can anybody comment on why boundary conditions are implemented for tracers in pre_step3d.F? To my understanding, pre_step3d initializes time stepping of interior variables, u(:,:,:,nnew), v(:,:,:,nnew), and t(:,:,:,nnew,:). Then, why lateral boundary conditions are implemented for the intermediate ...

Here is a question about the computation of W before time-stepping tracer fields. Let's consider a b/c time step, from time n to n+1. To time-step tracers, mass fluxes are needed at the intermediate time n+1/2 (is my interpretation correct?). Horizontal fluxes are updated in step3d_uv, and vertical ...

The wind speed scale is meters per sec, while the ocean surf currents are 1-2 orders of magnitude as small. Subtracting the ocean currents from wind currents would change the resulting atm. flux only by 1-10% (the difference would be esp. small in most important cases, when winds are strong). What ...

The underlying continuous equations (w/out dissipation) with any type of local boundary conditions used in ROMS constitute an ill-posed problem (ref: Oliger and Sundstrom, SIAM J. Appl. Math, 1978). That may mean for us that ROMS with open boundary conditions (and low enough dissipation - like ...

Sasha and Stef, Thanks for your valuable comments. I agree, it should really make sense to have b/t time step small enough to resolve the fast b/t wave in time. Here are results of experiments w/ decreased DT. The number shows the decrease in magnitude over two days (max zeta(t=48h)/ max zeta(t=0 ...

DT=240 sec
NDFAST=30
Maximum barotropic Courant Number = 1.77177877E-01

Channel depth H=100 m,
so wave_phase_speed=sqrt(gH) = 31.2 m/s

wave_length_of_interest = channel length =100 km (=1.e+5 m)

2*pi * dt * wave_phase_speed / wave_length_of_interest = 0.47

Any comments?

Colleagues, Thank you for your informative and thoughtful replies. I'll check on these and let you know. Meanwhile, can you answer the simple question? In the 3D case, does rhs3d (specifically, prsgrd) compute the total pressure (- g d zeta/ dx + (g/rho0) int_{z}^{zeta} [d rho / dx] dz') or only its ...

I verified that in the 3D test v is the same at every level. Also T and S are not changed.
In the output, svstr=0, bvstr=0, AKv=0, AKt=0.

I have tried to use roms (Feb. 2007 version) to reproduce the barotropic linear wave solution in the periodic channel. I presumed this could be done both in the 2D set-up (#undef SOLVE3D) and in the 3D set-up (#define SOLVE3D) if unstratified water is used in the second case. Surprisingly, the 2D ...

Re: I consider 3D rectangular basin with uniform wind forcing on the top in E-W direction. I put periodic boundary conditions in E-W direction and WALL boundary conditions on the North and South. So I put no slip condition GAMMA2 = -1.0d0 in the .in file. And the result was that the horizontal along ...