The OASIS Coupler Forum

  HOME

v_cfl problem when coupling with OASIS

Up to Specific issues in real coupled models

Posted by Anonymous at June 11 2025

Hi,

I am trying to run WRF+NEMO coupled with oasis on a global run.

I keep having this error right at the beginning:

Timing for main: time 2024-12-15_06:00:20 on domain   1:    7.16088 elapsed seconds    

         9340  points exceeded v_cfl = 2 in domain d01 at time 2024-12-15_06:00:20 hours

Max   W:    343      1     33 W: *******  w-cfl: *******  dETA:    0.01

Followed by a segmentation fault.

I set a very little time_step (20).

What is strange is that if I run the exact same case without coupling (with wrf non coupled executable) without changing anything it runs fine at this point. 

My namcouple part for ocean-> atmosphere is:

O_SSTSST WRF_d01_EXT_d01_SST  1 10800  1  fdocn1.nc EXPOUT

180 148 361 181 ocnt  atmt  LAG=10800

P 2 P 0

SCRIPR

BILINEAR LR SCALAR LATLON 1

# Ocean X-velocity (o->a 2)

O_OCurx1 WRF_d01_EXT_d01_UOCE 1 10800  1 fdocn1.nc EXPOUT

180 148 361 181 ocnt  atmt  LAG=10800

P 2 P 0

SCRIPR

BILINEAR LR SCALAR LATLON 1

# Ocean surface Y-velocity (o->a 3)

O_OCury1 WRF_d01_EXT_d01_VOCE 1 10800  1 fdocn1.nc EXPOUT

180 148 361 181 ocnt  atmt  LAG=10800

P 2 P 0

SCRIPR

BILINEAR LR SCALAR LATLON 1


I set all fields in the restart files to 0.

Thanks for insights, maybe this is a WRF problem and not a oasis problem....

Best regards

Posted by Anonymous at June 11 2025

Hi,
Your OCE very low resolution, and ATM little bit high resolution. check your damping parameter in the ATM. if you use the "DISTWGT" or "CONSERV" instead of BILINEAR it will work ? 
and also check wrapping artifacts poles (what you already tried).
Best,

Posted by Anonymous at June 11 2025

Hi,

Thank for your reply,
I have w_damping set to 1.
Changing to DISTWGT does not change anything (haven't tried CONSERV yet). 
What do you mean by : "check wrapping artifacts poles ".

Best

Posted by Anonymous at June 11 2025

Hi,
In poles it accelerates it? 
maybe that is why? BILINEAR will also work. your "resolution" is too poor.  so find the "butterfly effect". your work does not show CONSERV. 
Best,
*.*
Reply to this