Ocean Modeling Discussion

hpd14thu

The explaination in wikiroms is confusing. And the issuse is that if you set the right river_Xposition and river_Eposition. Maybe you can read #5 of this post https://www.myroms.org/forum/viewtopic.php?t=2200 Update: Wilkin reminded me that my answer is problematic. And here is his advice, which is ...

hpd14thu

Peida, The shared folder just had things like mexcdf and the seawater routines, which are publicly available. However, I am not supporting that code at all any more and I strongly urge you to write your own from scratch. Cheers, Parker Parker, Thanks, I will take a try. :D Have a good day！ Peida

hpd14thu

Reiner, We recently published a paper which gives a method for complete energy budgets in ROMS: MacCready, P., and S. N. Giddings (2016) The Mechanical Energy Budget of a Regional Ocean Model. J. Phys. Oceanogr., 46, 2719–2733, doi:10.1175/JPO-D-16-0086.1. http://journals.ametsoc.org/doi/10.1175/J ...

hpd14thu

From your .h file, I find you use ANA_SMFLUX, but you undefine ANA_SSFLUX and STFLUX. Well, define ana_.. means you use anaytical functions in ROMS/fucntions to calculate this variable. However, it seems that you want to calculate them by Monin-Obukhov similarities method in bulk.F but not anaytical ...

hpd14thu

Hi all,

I want to know that can we run two projects at the same time in ROMS to improve efficiency? How to achieve this?

Thanks

hpd14thu

Thank you, Hoty:

After some trials, I found I could expand the area to decrease the influence of boundary reflection.

And I use:

hpd14thu

If your barotropic solution is working for you, don't change that. Using Rad alone will not require external fields. You may or may not do better with RADIATION_2D. Just try it and see if it helps. If you want more specific advice, you should probably tell us more about what you are trying to do ...

hpd14thu

This is a classic problem with regional ocean models. You can try the radiation boundary conditions instead, if you like. However, what is working for us in practice is using values from a global ocean model on the boundaries to keep things behaving better (if not entirely well). Thanks Kate, I ...

hpd14thu

After checking more closely, I found that the blowup occurred at a time very close to when a typhoon passed my study area. In my initial simulation, the blowup occurred just a few days after my start time, during which the approaching typhoon already seemed to be influencing the conditions in my ...

hpd14thu

Hi all, I used OpenFOAM recently and ran a case with wave absorption boundary condition. When I turn to ROMS, I found that they were no wave absorption boundary condition. I don't have open boundary data, and I only want to absorb wave of open boudary and avoid reflection. I tried cha for 2dzeta ...

hpd14thu

I heard when using ROMS simulated tyhoon process, the over-mixing often happens which results over-cooling. Maybe you can try to adjust parameters in ROMS mixing scheme.

hpd14thu

You don't mention the point or the place model blows up, maybe it helps.

And if you activate WET_DRY. If -100m palce always be dry, or sometimes be wet?

hpd14thu

Thanks for your suggestion, I will have a try.

Peida

hpd14thu

Hi all,

I am trying to add a time-varing horizontal acceleration, but I don't find any introduction about control eqution code in wikiROMS, I wonder that if someone have achieved this before and could share that how to deal with the code.

Thanks and look forward to your reply!

hpd14thu

You are telling the model that it can never have less than 10 m water depth in the "wet" parts. You might try something rather smaller for DCRIT, like 0.5 m. Then you'd have to have 9.5 m of water leaving due to the storm surge before a spot became "dry". Thank you for your reply, Kate! I ...

hpd14thu

wilkin wrote:There is a detailed explanation of the conventions for specifying river sources here in WikiROMS:

https://www.myroms.org/wiki/River_Runof ... _Eposition

Thank you! It's very helpful!

hpd14thu

According to rtoste's suggestion, I recreated the initial and boundary files from CMIP for my simulation, then it works well without blow-up problem. Good evening, I have the same question. I wonder that if your inition data and boundary data are from different database, which cause this problem ...

hpd14thu

Hello everyone, I am runing a costal area case and I just force it by wind stress.The running time is 16days. I set hmin as 10m and turn on the WET_DRY option( I set WET_DRY parameter as 10m , too). But I don't know why there are too much land mask generated in the last half of my calculation time ...

hpd14thu

Maybe some variables are not consistent in your input files(.in file and some input nc files). You can try CPP options kate told you, I think it works well

hpd14thu

With a minimum grid cell size of ~4 km you should be well within CFL stability with such a small time step, so that's not your problem. The log indicates a 3rd record was written to the restart file on blow-up, so you should plot what's in there and look for a location that is causes trouble. It ...

hpd14thu

Now, I have created several forcing files according to the script of D_ECMWF2ROMS. However, when i generate the initial and boundary files using d_mercator2roms.m and D_OBC_MERCATOR.m, I can not find the source dataset of mercator ocean data. So my problem is how to download the mercator ocean data ...

hpd14thu

Dear all, I'm trying to run ROMs by bulk forcing,and initial condition, but it blows up. Because my area is near the coast and my blow-up point is in the shallow water area(~10m), I try to decrease my dt from 300s to 10s and decrease my N from 36 to 25. It does work but it just delay the time of ...

hpd14thu

Dear all, I'm trying to run ROMs by bulk forcing, river forcing and boundary values, but it blows up from the beginning. And ROMS doesn't show the details. I wonder that which problems can result in this blow-up, then I can have a check. Thank you! ---------------------------- mab Operating system ...

hpd14thu

It depends on which vertical "transform" function you use. The old one needed Tcline <= hmin, but the new one does not. I'm sure there's plenty of code still around from the bad old days. I use: Vtransform == 2 ! transformation equation Vstretching == 4 ! stretching function THETA_S == 7.0d0 ...

hpd14thu

Hello everyone,

I found that in init.matlab pre-processing file, people set hc=min(hmin,Tcline), but my hmin is very small(2m), so I want to set a bigger hc=Tcline(50m)(change the code hc=min(hmin,Tcline) to hc=Tcline). I wonder that if it's OK?

Thank you!!

hpd14thu

kate wrote:It refers to i, j. The western-most u-point is at i=1.

Thank you so much!

hpd14thu

Hello everyone, I have a question about the xi_position and eta_position of rivers.nc input. I wonder the xi_position and eta_position refer to the internal grid or the rho grid(contains two more external columns). If it refers to the rho grid, we can use i and j But if it refers to the internal ...

hpd14thu

wilkin wrote:The parameters Tcline and hc are explained here:
https://www.myroms.org/wiki/Vertical_S-coordinate

The page concludes with some example stretching generated with scoord.m which is in the Matlab repository available on myroms.org.

Thank you for your reply

Peida

hpd14thu

Hi Peida, It sounds like being able to specify exact corner coordinates would be a useful feature to add, I'll try and put something together. In the meantime you can import custom reference points in a text file as comma deliminated x,y pairs. These points will plot as small black + symbols on the ...

hpd14thu

Hi all, I am writing the matlab code to generate init.nc file now. But I am not clear about the physical significance of parameter hc and Tcline . I try to Goole that but I did not find the answer. I would so appreciate if if someone can explain these parameters. Thanks for your attention and your ...

hpd14thu

Hi Victor, Unfortunately I haven't added support for creating multiple nested grids into GruidBuilder since I've only done off-line nesting. For now you'll have to add the nesting attributes manually to the attributes in the new grid to use contact.m. I'll look into it for the next time I update ...

hpd14thu

But, are you only using ROMS why use the COAWST ? I agree with Ivica, if you do not use the functions of a coupled model, it does not make sense to use it. Do you use the tidal forcing and river data? What atmospheric and ocean forcing are you using? On what machine do you perform your simulations ...

hpd14thu

I suggest you first to read a few papers related to the wind stress formulations in extreme events like TC, many of them are John's papers using COAWST and many Hurricane cases etc. Not to just blindly run ROMS model and then expect to get result that is perfect. For example: Bryant & Akbar in JMSE ...

hpd14thu

Hi hpd14thu, Thanks for your questions. 1) Are the wind speeds also overestimated compared to the data? 2) There has been an observed rolloff of drag at high wind speeds that is not coded into the current version of bulk fluxes. This will be included in the next COAWST version, but you can send me ...

hpd14thu

Are you using COAWST or ROMS? Hello， I wonder that the magnitute of the wind speed you used. I also met the problem that the currents were too strong. My wind speed is up tp 58m/s. I don't know that if the scheme in ROMS can adapt to the 58m/s-wind speed, or if there is something wrong in my cpps. ...

hpd14thu

lalvarez wrote:Hello there

You have to look at your files timelength, or how you set the order in your *.in file configuration

Thank you for your reply, the problems are solved!

hpd14thu

I use the hurricane to force the upper ocean, and the wind speed is up to 55m/s. And there is a problem, the upper ocean's currents is too strong compared to the data. I wonder that if I have choose some cppoptions when I try the high-speed wind cases?

hpd14thu

Hello， I wonder that the magnitute of the wind speed you used.

I also met the problem that the currents were too strong. My wind speed is up tp 58m/s. I don't know that if the scheme in ROMS can adapt to the 58m/s-wind speed, or if there is something wrong in my cpps.

hpd14thu

Hello, I try to generate force.nc file by Matlab, and the variables in this file are Uwind, Vwind, Pair.... But the matrix of variables is too big and Matlab show that 'one or more variables sizes violate format'. So I generate two force.nc, which are corresponding to different period of time. But ...

hpd14thu

kate wrote:Maybe you need a shorter timestep when the winds ramp up. What is the nature of your blow-up?

Thank you for your reply , I set a shorter timestep and the problem was solved.o(∩_∩)o

hpd14thu

I set the U-wind and V-wind as input forcing file, when the lateral gradient of these two variales increase, the project blow-up.
So how can I solve this problem if I want to run the high lateral gradient case? Thank you!

hpd14thu

s_rho is not the final dimensional vertical coordinate. s_rho depends on the choice of TRANSFORM and the final z depths depend on the STRETCHING applied to s_rho. Read https://www.myroms.org/wiki/Vertical_S-coordinate There are Matlab and Python routines to compute z offline from the Vtransform ...

hpd14thu

I set theta s=5 and theta b=0.4 , these parameters should work on the spacing of near-surface.
But the value of s_rho shows that the grid is still equidistant.

I wonder how to solve this problems, look forward to your reply.

hpd14thu

Look at the examples in ana_grid.h (which you are presumably using to create your x/y grid). Follow one of these, like UPWELLING: Xsize=1000.0_r8*REAL(Lm(ng),r8) Esize=1000.0_r8*REAL(Mm(ng),r8) depth=150.0_r8 f0=-8.26E-05_r8 beta=0.0_r8 and set f0 to the value you want. Then there is code later in ...

hpd14thu

Hello, I want to use x-y coordinate instead lat-lon coordinate, but I don't know where can I set the value of parameter f. I wonder that if I should set the value in grid.nc or other place .

Hope your reply.Thanks~

hpd14thu

Hello，here is the part about reading the forcing file in result.out. I wonder that if there is any problems in reading part. I just set one variable : Uwind = 8, all of other values =0 LM: GET_STATE - Read state initial conditions, t = 0 00:00:00 (Grid 01, File: zfirst_init_cco.nc, Rec=0001, Index=1) ...

hpd14thu

You probably set all sea grids as land pixels. So all the velocity/kinetic energy are zeros, but total potential energy and volume are not since the calculation of these diagnostics are not masked off. Can you make a plot your land/sea masks to check? -Bin Hello,Bin Thank you for your help and ...

hpd14thu

And here is my matlab file which used to write values into forcing.nc file: %1) Enter start time of forcing file, in seconds. % This time needs to be consistent with model time (ie dstart and time_ref). % See *.in files for more detail. time = [0 1 2]; sms_time = [0 1 2]; %4) Obtain grid information ...

hpd14thu

Reading the log file output your quoted WRT_HIS - wrote history fields (Index=2,2) into time record = 0000082 82 0 00:00:01 0.000000E+00 9.608405E+01 9.608405E+01 4.601201E ... that says to me the model has run for only 1 second of simulated time. If so, you're not going to see much action. What is ...

hpd14thu

And here is my frc_uvstress.cdl netcdf frc_uvstress { dimensions: xi_rho = 100 ; xi_u = 99 ; xi_v = 100 ; eta_rho = 200 ; eta_u = 200 ; eta_v = 199 ; sms_time = UNLIMITED ; // (0 currently) variables: float sms_time(sms_time) ; sms_time:long_name = "surface momentum stress time" ; sms_time:units ...

hpd14thu

I'm a beginner at computer programming. I use the frc_uvstress.cdl file in ".../trunk/Data/ROMS/CDL" , and I transfered it into forcing netcdf file. Then I use a matlab file(which named str_cdl_nc.m) to write values(sms time, sustr, svstr) into the ncfile. But when I check the forcing.nc file. The ...

hpd14thu

Dear, Your attached file is completely wrong :shock: and it's not really readable for the ROMS, such attributions, dimensions and time format. I suggest you that follow directory :arrow: ".../trunk/Data/ROMS/CDL" it can help you to find your questions :?: . Good luck to you Farshid Thanks a lot! I ...

hpd14thu

To add to Kate's suggestion, I would run this model for about 10 time steps having compiled with debug on in the compile script (however you compile the model). Run in scalar mode (one processor). Make sure that you turn on array bounds checking. This makes sure that arrays are defined and indexes ...

hpd14thu

Dear, As stated by Katherine and John, such errors :arrow: (GET_2DFLD - error while reading variable: or GET_3DFLD - error while reading variable:) are due to the definition of input variables. To avoid encountering such a problem is essential check consistency of the variables in ".nc" file with ...

hpd14thu

Gridded: LonMin = -13.6075 LonMax = 35.9397 LatMin = 97.6335 LatMax = 146.0208 Model: LonMin = 0.0000 LonMax = 0.0000 LatMin = 0.0000 LatMax = 0.0000 Your model grid doesn't appear to have lat,lon values in it. The gridded forcing does have them, though one might question your latitude values. Are ...

hpd14thu

Given the values in the wind forcing file (10^34), I think these are all "missing values" for netcdf. Are you sure that you assigned variables to the forcing file? I would plot the wind speeds in the forcing file to see that they are what you wanted. If the forcing file is ok, then make sure that ...

hpd14thu

Gridded: LonMin = -13.6075 LonMax = 35.9397 LatMin = 97.6335 LatMax = 146.0208 Model: LonMin = 0.0000 LonMax = 0.0000 LatMin = 0.0000 LatMax = 0.0000 your forcing file does not have any grid data. each field needs an attribute of lon and lat. see here https://www.myroms.org/forum/viewtopic.php?f=1 ...

hpd14thu

you basically have this set: /* Forcing */ # ifdef WRF_MODEL ... # else /*# define BULK_FLUXES/* # define ANA_SMFLUX # endif so you have ana_smflux on. that will look for analytical values and they are most likely set to 0. so you would want to use #undef ANA_SMFLUX and then it will look for su ...

hpd14thu

kate wrote:I don't know what to check either, but you need to be looking at the values in all the input and output files. Where is that weird 1e34 coming from? I like ncview for viewing these files.

hpd14thu

My force file contains sustr and svstr , but when I run it , I find that these two variable has not been read. I consider that there are some problems in my head file , but I don't know which CPP option I should add into head file. Here is my head file: /* ** svn $Id: sandy.h 25 2007-04-09 23:43:58Z ...

hpd14thu

【and when I checked the calculation process in his file , I found that the sus ,the svs..in each step is 10^34, I don't know if it means that the calculation is blow out.】 It means you have some serious problems. I'm not sure what, but I'd look carefully at all the inputs and outputs. And here is my ...

hpd14thu

Here is the file which used to generae force.nc : %1) Enter name of netcdf forcing file to be created. % If it already exists it will be overwritten!!. % fn='zfirst_wind_cco.nc'; fn='zfirst_wind_cco.nc'; %2) If you want to read the forcing data from another netcdf file, then % enter read_forcing=1 ...

hpd14thu

【and when I checked the calculation process in his file , I found that the sus ,the svs..in each step is 10^34, I don't know if it means that the calculation is blow out.】 It means you have some serious problems. I'm not sure what, but I'd look carefully at all the inputs and outputs. Thank you for ...

hpd14thu

The forcing file just contains frc_bulk variables:
Uwind , Vwind , Pair..
But I don't use ustress adn vstress

hpd14thu

And here is my result: Lateral Boundary Conditions: NLM ============================ Variable Grid West Edge South Edge East Edge North Edge --------- ---- ---------- ---------- ---------- ---------- zeta 1 Closed Closed Closed Closed ubar 1 Closed Closed Closed Closed vbar 1 Closed Closed Closed ...

hpd14thu

/* ** svn $Id: sandy.h 25 2007-04-09 23:43:58Z jcwarner $ ******************************************************************************* ** Copyright (c) 2002-2007 The ROMS/TOMS Group ** ** Licensed under a MIT/X style license ** ** See License_ROMS.txt ...

hpd14thu

! Application title. TITLE = ZFIRST ! C-preprocessing Flag. MyAppCPP = ZFIRST ! Input variable information file name. This file needs to be processed ! first so all information arrays can be initialized properly. VARNAME = /home/hpd14/Documents/COAWST_V3.2/ROMS/External/varinfo.dat ! Number of ...

hpd14thu

Hello ,every one,I just use a grid file, a initial file and a easy wind file, in order to calculate the flow forced by the wind. But the result( u,v ,salt...) is zero. I tried a lot ,but it didn't work. I really need your help, thank you!

Here is my in.file and headfile

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