Search found 21 matches

by xavierC
Thu Apr 02, 2020 7:09 pm
Forum: ROMS Adjoint
Topic: Where to introduce obs error
Replies: 2
Views: 72

Re: Where to introduce obs error

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)
by xavierC
Thu Apr 02, 2020 6:50 pm
Forum: ROMS Adjoint
Topic: Where to introduce obs error
Replies: 2
Views: 72

Where to introduce obs error

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
by xavierC
Thu Mar 26, 2020 7:39 am
Forum: ROMS Tools and Techniques
Topic: How to cite pyroms ?
Replies: 4
Views: 142

Re: How to cite pyroms ?

†hanks
by xavierC
Wed Mar 25, 2020 8:24 pm
Forum: ROMS Tools and Techniques
Topic: How to cite pyroms ?
Replies: 4
Views: 142

Re: How to cite pyroms ?

I was rather looking any paper/report but it could indeed also be a DOI
by xavierC
Wed Mar 25, 2020 8:48 am
Forum: ROMS Tools and Techniques
Topic: How to cite pyroms ?
Replies: 4
Views: 142

How to cite pyroms ?

All in the subject .
X.
by xavierC
Wed Mar 25, 2020 8:28 am
Forum: ROMS Results
Topic: strange velocity results (need some ideas to correct them)
Replies: 5
Views: 191

Re: strange velocity results (need some ideas to correct them)

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
by xavierC
Wed Feb 26, 2020 4:07 pm
Forum: ROMS Adjoint
Topic: Adjoint compilation error with define VISC4 and DIFF4
Replies: 1
Views: 162

Adjoint compilation error with define VISC4 and DIFF4

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...
by xavierC
Thu Feb 06, 2020 1:40 pm
Forum: ROMS Adjoint
Topic: 4DVAR assimilation of surface velocities destroy sst
Replies: 3
Views: 341

Re: 4DVAR assimilation of surface velocities destroy sst

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.
by xavierC
Thu Jan 30, 2020 10:07 am
Forum: ROMS Adjoint
Topic: 4DVAR assimilation of surface velocities destroy sst
Replies: 3
Views: 341

4DVAR assimilation of surface velocities destroy sst

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...
by xavierC
Thu Jan 09, 2020 4:47 pm
Forum: ROMS Adjoint
Topic: I4DVAR rewriting roms_ini.nc with new time unit
Replies: 1
Views: 85

Re: I4DVAR rewriting roms_ini.nc with new time unit

OK, found the day2sec in Utility/wrt_ini.F

trying with ocean_time in seconds from the begining (but i am queing... )
by xavierC
Thu Jan 09, 2020 3:30 pm
Forum: ROMS Adjoint
Topic: I4DVAR rewriting roms_ini.nc with new time unit
Replies: 1
Views: 85

I4DVAR rewriting roms_ini.nc with new time unit

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...
by xavierC
Wed Jul 10, 2019 8:29 am
Forum: ROMS Adjoint
Topic: CG_DELTA not positive OR Negative Ritz value found.
Replies: 0
Views: 232

CG_DELTA not positive OR Negative Ritz value found.

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 ...
by xavierC
Thu Jun 20, 2019 9:58 am
Forum: ROMS Adjoint
Topic: depth of assimilated data
Replies: 2
Views: 480

Re: depth of assimilated data

I guess it is zeta related and that obs_depth is absolute and not relative to zeta.
by xavierC
Thu Jun 20, 2019 8:30 am
Forum: ROMS Adjoint
Topic: depth of assimilated data
Replies: 2
Views: 480

depth of assimilated data

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...
by xavierC
Wed May 29, 2019 2:31 pm
Forum: ROMS Problems
Topic: Noisy SST
Replies: 8
Views: 610

Re: Noisy SST

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.
by xavierC
Tue May 28, 2019 12:32 pm
Forum: ROMS Problems
Topic: Noisy SST
Replies: 8
Views: 610

Re: Noisy SST

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...
by xavierC
Tue May 28, 2019 11:52 am
Forum: ROMS Problems
Topic: Noisy SST
Replies: 8
Views: 610

Noisy SST

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...
by xavierC
Mon Apr 15, 2019 7:13 am
Forum: ROMS Tools and Techniques
Topic: How to edit a mask with pyroms
Replies: 2
Views: 594

Re: How to edit a mask with pyroms

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
by xavierC
Fri Apr 12, 2019 3:20 pm
Forum: ROMS Usage
Topic: #define LIMIT_VDIFF #define LIMIT_VVISC
Replies: 0
Views: 283

#define LIMIT_VDIFF #define LIMIT_VVISC

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...
by xavierC
Fri Apr 12, 2019 8:47 am
Forum: ROMS Tools and Techniques
Topic: sponge layer and diffusive advection schemes
Replies: 1
Views: 396

sponge layer and diffusive advection schemes

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...
by xavierC
Fri Apr 12, 2019 8:06 am
Forum: ROMS Tools and Techniques
Topic: How to edit a mask with pyroms
Replies: 2
Views: 594

How to edit a mask with pyroms

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