Ocean Modeling Discussion

simion1232006

Hi there, I am trying to build a ROMS_SWAN coupling model and got some error messages.Did any one happen to see this before? I used to compile ROMS-swan on other machine and the model worked all right. The machine I am using is a Cray system. I guess it may be duo to the Cray compiler. Any ...

simion1232006

I assume this is not a bug but rather a limited functionality. As long as your nested grid would not cross the border or within few grid of the coarse model border, there should not be any issue. When doing interpolation from donor grid to receiver grid, I think you'd better allow couple of grids of ...

simion1232006

Hi everyOne， I am testing the ROMS strong constrain data assimilation model. I got a interesting error that asking me to prepare climatology inputs . This is only required for the updated ROMS version. For the version older than ROMS3.4 there is no such error. I am curious why it requires c ...

simion1232006

Good catch. I saw similar problems and did similar modifications. Still better let ROMS group to update an official version based on what we report.

simion1232006

For two way nesting model with wet-Dry on, if the fine grid treat a area as ‘dry’, it will pass a zero value to the coarse grid, even this area is considered as 'wet' in coarse grid. This somehow did not affect too much the coarse model simulation, but will leave some unpleasant dots on temperature p ...

simion1232006

The code should be correct. If my understanding is right, the phase angle should not have an a factor of period in it. Just make sure you have the correct phase angle input, and I think you will be fine.

simion1232006

Thanks a lot for your reply,Arango. I apologize for directly jumping into contact.m(Although there are couple of none essential typos mentioned by rock, the code works fine). The spherical grid also works great with the contact.m. I did not know the 659 ticket, but I do constantly update my ROMS at ...

simion1232006

Hi Warner, Thanks for your reply. Mine is svn #756, and I could not get the #659 you mentioned.I am quite curious of the ROMS version you use. I know you have developed your own branch of ROMS (forgot the name, sorry). Is that all right if I can use svn to download your version? I just looked into ...

simion1232006

I retested the lake_jersey case. With wet_dry on, the test case have the similar problem. I guess now I can have a rest (too tired). It confirms that the wet_dry option is still buggy in the newest ROMS. See below: lake_jersey_wetdry.jpg Anyone can try this out by switch on the wet_dry in lake ...

simion1232006

Thank you. That is helpful. I did a couple of tests, and the run without wet_dry looks fine, the wired results only appear with wet_dry on. I will keep updating my findings. Below is another nesting domain - twoway nesting, wet_dry. Notably there is no dry land in the domain. two_way_wetdry.jpg I ...

simion1232006

Dear ROMS users, I had a problem with the information exchange between donor and receiver grid months ago, while after the update at the end of 2014, the problem disappear. But now it comes back. I hope someone can give me a hint. Simulation with one_way nesting. Donor_grid.jpg receiver_grid.jpg The ...

simion1232006

Oh, I did not notice I need to regenerate the refined grid. That could be the problems. I actually modified the refined the batyhymetry to improve the depth, and matched them at the coarse fine boundary. I will need to recreate this grid and see how it goes. Many thanks.

simion1232006

This is my previous model output. It looks all fine. Note that I have also updated the matlab repository, created an new contact input file.

simion1232006

I have no problem to use the previous ROMS version(nesting, no wet_dry), while after I updated the code yesterday,I could not run the model any more. It blows up after ~50 time step. see the attachment (SST of restart file): the SST changes a lot on the coarse fine boundary. I guess there is a bug ...

simion1232006

HI Prof arango. This is very good news to me. Thanks a lot for you hard work on ROMS.

simion1232006

I am facing the similar issue. I attempted to modified the nesting.F subroutine, while it is quite hard. I noticed that Lweight is directly taken from the contact file (created by matlab),and is constantly used to interpolate value from donor to receiver or from receiver to donor. Given that contact ...

simion1232006

simion1232006

I noticed that the ERA-interim data set has a little cooling problem near the coast. It appears that the land side gets less heat than the ocean, while the land-ocean boundary is too coarse for some coastal circulation model. Thus some areas of ocean are gridded as land area receiving less heat.

simion1232006

That is just the description, the actual name are 'eewss' and 'nsss'.

simion1232006

It is very hard to understand what you mean. Although SSH is more relevant to your netcdf driving file than to .in file, you might want to check your driving force.

simion1232006

I found a bug in obs_roms2roms.m. see code below % Receiver grid. if (isvec && D.vector_rotation ), if ( D.spherical ), Xname = 'lon_rho'; % If requested, interpolate Yname = 'lat_rho'; % U- and V-points variables else % to RHO-points instead to Xname = 'x_rho'; % facilitate the curvilinear Yname ...

simion1232006

As far as I know, roms_metadata doesn't include that variable. You need to make a little modification for your own purpose.

simion1232006

Best choice would be using the ROMS official input file generating scripts (Matlab). You can modified it for your own purpose. Those scripts guarantee an standard input and usually would not make any mistake. I personally don't recommend change anything in varinfo.dat, as it might cause confusion ...

simion1232006

#define ANA_SMFLUX and #undef BULK_FLUX. Otherwise it needs to read in the heat flux and wind forcing.

simion1232006

On behalf of ROMS users, I need to say my poster here might be misleading. Prof Wilkin sent me a message about the potential volume conservative risk of one way nesting. So it might not be the best choice. The nesting scheme is still under active development, so will wait for the newest progress.

simion1232006

I know this has been posted before. While I still have a little confusion about the humidity used in bulk flux script. IF (RH.lt.2.0_r8) THEN !RH fraction cff=cff*RH !Vapor pres (mb) Q(i)=0.62197_r8*(cff/(PairM-0.378_r8*cff)) !Spec hum (kg/kg) ELSE !RH input was actually specific humidity in g/kg Q ...

simion1232006

I have checked everything. Turning on the one_way nesting is so far the only solution.

simion1232006

For the interests of anyone who working on ROMS nesting scheme, I feel the one_way nesting is more stable than the two_way nesting. I will dig into the codes to see their differences . while if someone know the reason, I really appreciate you can post them here.

simion1232006

I just found the radiation_2D flag should be switched on. Another test with this flag is running fine for 3000 time steps already. It could be the problem.

simion1232006

I have experienced blowing up problem with ROMS nesting scheme for my application. Since the real case is complicated and hard to tell , I cleaned up all unnecessary issues by turning off the surface heat flux and wind, making the refined grid exactly the same as the master grid (the same masking ...

simion1232006

I ran the WC13 case (the strong constrained case) and got the similar log information. In the next loop, the model updated the itl file, and the value are not zero any more. In the weak constrained case, everything is normal.

There should be nothing wrong with it. Never mind.

simion1232006

I cut part of the log file, see below: The nonlinear model runs all right, while when the model switch to the tangent model, it creates a initial file with all zero values (NWS_200911_itl.nc). Does anyone have any experience on this? I am quite new in regional model data assimilation. Many thanks ...

simion1232006

Problem solved. I should not define the uv_logdrag and MB_BBL at the same time.

simion1232006

I am working on testing the newest nesting scheme for my application. It seems that the model start to ran, while stop at the initialization and configuration step. Does any of you have experiences on that? Also I found a problem to run the nesting model:The tiles specified for the coarse grid ...

simion1232006

Thanks, Kate. I will have a look. There is another issue coming with the code. It is not a bug but very annoying(see the figure). somehow the particle jump over something and the model stop to run. I mean is there a way to turn this thing off or just let the particle stop if it passed through ...

simion1232006

Thanks for your reply. The good side is it actually solved my problem. The trajectories of these particles look pretty smooth and realistic. So without further debugging of the codes, I would just use it as a temporary solution.

simion1232006

I don't know exactly what happens here. Seemingly, adding commands to print out variables on the screen can totally change the model results. The original code, in my experience, gave me unrealistic vertical motion of particles. If somebody has the same issue, I hope my post would help.

simion1232006

I added the test command because I found something wrong in the outputs. The interesting thing is I solved the problem by adding another command (see attachments).

simion1232006

Dear all, I tried to use the LTRANs version 2 for my ROMS application. It works great if I release the particles on the surface. However, I found something weird of the model outputs if I released the particle in the subsurface layer. In the attached figure, the depth of the first particle moves ...

simion1232006

I had the similar problems. I spent a whole day but still could not figure out the problems, until I saw Hadfield's reply.
Coping the uv_rotate.f to Utility folder really works. Maybe the ROMS team could do this tiny change.

simion1232006

Sincerely appreciate your favor. Yes, this is the right one. I will have a look. -------------------------------------------------------------------------------- I get a reply from Dr zhang. It works for me now.I can see the atmosphere pressure driving flow now even with periodic boundary condition ...

simion1232006

Thank you.Wilkin. Also did you post the right link? I did not see any things related to periodic boundary with along-shelf pressure gradient in this paper. Also it is in Hawaiian , not Mid Atlantic Bight. I really appreciate if you can send me a good link. Currently , I am working on the instability ...

simion1232006

First thing is why you want to nudge your baroclinic velocity to zero. I think radiation for u , v should be enough. Also, i had the similar problems when I ran a model with open boundary with no boundary value provided(you put it as zero).The flow can hardly cross the boundary when i use flather ...

simion1232006

Thank you very much. Kate.
I will reconsider it.

simion1232006

I used MIX_GEO_TS and have not found any problems yet. Maybe it is case by case.

simion1232006

Oh ,this is tricky. I simply want a channel flow driven by both pressure gradient and wind. For simplicity , it could be infinite in long-shore direction. However , seems it is very hard to put into practice

simion1232006

Periodic boundary conditions are a set of boundary conditions that are often used to simulate a large system by modelling a small part that is far from its edge. Basically on these boundaries the dynamic properties are exactly the same. It is suitable for simulating the system that is infinite in ...

simion1232006

Thank you. Kate. I think your methods will work. (flather with specified boundary at north, radiation at south, solid both east and west). Also it is a problem to decide the ubar corresponding to certain pressure gradients. Actually my case is more about pressure gradient via sloping isopycnals,so I ...

simion1232006

Hi Prof Arango, Thank you very much. However , is there a way to apply a negative pressure gradient (opposite to wind )in idealized up-welling cases. I did some hind cast simulations fully driven by global model,but it is too complicated to analyse. I would like to simplify it by using a idealized ...

simion1232006

Hi everyone. I have some questions related to the periodic boundary conditions. Does anyone have the experience in specifying a periodic boundary condition in idealized upwelling case with a pressure gradient (barotropic or baroclinic). So basically only the velocity fields are periodic, and both ...

simion1232006

Try mpiexec command see whether it works. As if you use shared memory machine and use the gforker manager, the mpirun command might not work.

simion1232006

I used to have the similar problem. You might not install the openmpi in the right way. I use mpich2, so not sure whether it is the same.

simion1232006

You need install gfortran gcc g++ first in ubuntu using synaptic package manager(fantastic feature in ubuntu). Then you probably need to install netcdf and mpich2 library. For this part you really need to figure it out by yourself as it is worth a exploration. Be careful about the flag as all the ...

simion1232006

Download it from the official website ,then use virtualbox to install it.You do not need a real CD, a ISO file is fine.
See this: http://www.ubuntu.com/download. Also Linux system is free of charge.

simion1232006

I agree with that. As long as you do not bother the multi processors, cygwin is enough to use. Virtualbox things is actually running a real linux system within window . So if you have a workstation with more than 8 core. you definitely can run the real simulation. Another thing: I am ubuntu fan ...

simion1232006

I tried to use cygwin long time ago and found it is really tricky and also not efficient to run. I have a suggestion you can install a software called virtulbox, and install a ubuntu OS in the virtualbox. Then you can run this linux system within the virtualbox under you host computer. All the other ...

simion1232006

Thank you.Dr Warner. My bathymetry is not flat.That should be the reason. Can i ask another question: If I calculate the heaflux from ROMS history file, how could I make sure the hearflux is conservative. For each grid, i can compute the hearflux to the x-direvtion, y-direction,but for vertical ...

simion1232006

Hi everyone: Is there anyone notice in ROMS output the vertical velocity at the bottom is not zero. In my study, I tried to look at the tracer transports. I integrated the vertical heat flux through the depth and found it is not zero, so I checked the vertical velocity from the history file, and ...

simion1232006

Number of State Observations Processed: ObsTime = 40124.0000 Variable IstrObs IendObs Count Rejected temp 1 33 33 32 Total 33 32 Obs Tally 33 32 Wrote NLM state at observation locations, datum = 0000001 - 0000033 Almost all of my data were rejected.Does anyone have the similar problems?

simion1232006

I heard the nesting feature has been added into ROMs. I plan to use the one way nest ,but I can not find introduction about this. I want to nest a 250m resolution small model near the coast into a 2~4 km resolution big model. Please help ! Thanks ----It seems that I can not do nesting in the ...

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