Ocean Modeling Discussion

Hi all, i am still assimilating my HF radar currents with more or less success. i use daily assimilation window with 30 min data (2km model 6km data). But although it works relatively well, sometimes i do not recognize the assimilated data in my solution. I am using W4DPSAS with WEAK_CONSTRAINT (ROM...

Hi, thanks for your answer

Indeed i was using varinfo.dat coming with the test case (svn 999) instead of the one coming with the source code.

Hi , i recently upgraded my ROMS code to SVN Revision 1036. But i get the following error when running RBL4DVAR simulation. did i missed any changes in the inputs (.in) files ? Thanks Found Error: ** Line: 140 Source: ROMS/Utility/def_var.F DEF_VAR - Grid 01, unable to define variable: ^@^@^@^@^@^@^...

thanks a lot for your fast answer
guess i got it on my way too:
CALL netcdf_get_fvar (ng, model, OBS(ng)%name, Vname(1,idOerr)

Hello,
Playing with some grep i realized that "obs_error" variable is never used in the code. Therefore i wonder where i should introduce observation error when known ?
Thanks

†hanks

I was rather looking any paper/report but it could indeed also be a DOI

All in the subject .
X.

did you try
#define TS_DIF4

# define MIX_GEO_TS/UV
#define TS_DIF4/UV
I know this should be not activated with SU3 but from my little experience with this branch of ROMS it helps solving this kind of trouble.
You may also try TKE or GLS

Hello, i lately upgrade ROMS to the following version: ROMS 3.9 GIT Root URL : https://www.myroms.org/git/src GIT Revision : ef5d653689eff77de5a2302b0a00e2fd840506e4 SVN Root URL : https://www.myroms.org/svn/src/trunk SVN Revision : 1002 Still with some trouble with my HF radar data i stepped back t...

thanks for your answer Jivica,

unfortunately even by reducing drastically by 90% my standard deviation i don't solve it. Plus i did not compile with -DADJUST_STFLUX.

i think the problems come from the data i assimilate, which are not divergence free and therefore may induce some spurious upwelling.

Capture d’écran 2020-01-30 à 10.58.13.png Hi, I am running some I4DVAR experiments where i assimilate surface velocities from radar measurement. But while i tend to improve my surface current i am inducing a strong cooling of the SST as illustrated in the attached figure. This is after a 24 hour ru...

OK, found the day2sec in Utility/wrt_ini.F

trying with ocean_time in seconds from the begining (but i am queing... )

Hi, I am running some I4DVAR experiments, but at the end of the inner loop when initializing the final non linear run it initialise (blow up) with a bad time. To be clear, i start my run with a roms_ini.nc whom time is 175464 hours since 2000-01-01 (ie 7 of jan 2020) . But then the roms_ini.nc is re...

Hi, I am running quite successively some I4DVAR experiments. Also i am still working on understanding all the subtleties of 4DVAR, i am reasonably happy with my results. I made 3 runs (same domain, same forcing ) with 3 differents datasets (surface velocities) i run it daily with 8 inner loop and 1 ...

I guess it is zeta related and that obs_depth is absolute and not relative to zeta.

Hi all, I am assimilating near surface current data with I4DVAR capability of ROMS. I noticed that the rejection of my data is strongly dependent from the depth i put them: i.e -pure surface (obs_depth=0) i get 100% data rejected -obs_depth=-7 i get almost 100% of data accepted -obs_depth=-1 i get a...

Hello,
thanks for your answsers, still have to try GLS or MY2.5, but I managed to try the "easy one" suggested by kate and i got a strong improvments of my solution. With some presistent noise only very near coast.

c.drinkorn wrote:Hi Xavier,

I switched from MIX_GEO_TS to MIX_S_TS in order to solve a similar problem at the bottom. Maybe it also helps you.

//Cate

Thanks a lot for your answer Cate. I just made a try, but no sucess once again...

Hello, I am doing some ROMS modelling and although it goes quite smooth, i have some noise on the temperature field, mainly at the surface, as you can see on the figure attached. I am using #define UV_ADV #define TS_U3ADV_SPLIT advections schemes (but i have tried others without any success) and i h...

Thanks Kate,
I kind of tried that and in the best scenario i had a window on which i could click e to activate/desactivate toogle.

Tried again and it is now working (may because i used the zoom)

Thanks for your answer.
Xavier

Hi all, I went through severe stability problems during the last few days fighting with really intense eddies blowing up the model. I happens that this was solved by increasing the LIMIT_VDIFF and LIMIT_VVISC from 1e-3 to 1e-1 . i also had some success with 1e-2 but with a reduced time step. Where d...

Hi, I am a bit lost with the use of the sponge layer through visc_factor in the grid file. Basically it modifies visc4 variable. But since i am using diffusive advection scheme i do not understand which values are in visc4 (which should be 0). Any one could give me any insight about proper sponge se...

Hello,
Quite experienced with Agrif or NEMO i am new in using ROMS-rutgers. I would like to edit and correct my mask, but i don't really understand if and how i can do that with pyroms (i don't have matlab).
Any one could help with that ?
Thanks