Changes between Version 70 and Version 71 of Doc/FAQ

Timestamp:

06/10/22 12:02:18 (2 years ago)

Author:

omamce

Comment:

--

Doc/FAQ

@@ -261 +261 @@
 [[BR]][[BR]]
 '''Warning: you'll need to get parameter files and maybe some forcing ones corresponding to the resolution.'''
+
+
+## Restarting the model after a crash ##
+
+Sometimes the coupled model crashes. Most common crashes occurs either in LMDZ or NEMO. 
+
+LMDZ triggers an emergency stop when the temperature reaches values outside an acceptable range. It is mainly due to instabilities in the convection scheme. High resolutions are more prone to crash.
+
+NEMO triggers an emergency stop when the salinity becomes negative, or when the current is larger than 10 m/s. It happens mostly in ice covered regions. This is mainly due to and instable vertical advection scheme when a high vertical resolution is used (dz=1 m).
+
+### What can I do ? ###
+
+Often, it is possible to restart the model. The procedure consists of adding a small perturbation to the coupler restarts. You can use a procedure that will add a random perturbation to a selected field. Generally, with perturb the sea surface temperature. It will change the trajectoire of the model and, hopfully, avoid  the crash. If the models crashes often, you better discuss with some model specialist(s)
+
+### Procedure ###
+* In the model launching directory, run .`./../../libIGCM/clean_PeriodLength.job` to cleanup the last period.
+* In the file `COMP/oasis.driver`, add in the `[UserChoices]` section the lines : 
+{{{
+ByPass_addnoise_sst=y
+ByPass_PerturbExe=AddNoise
+ByPass_FileOut=sstoc
+ByPass_PerturbVar=O_SSTSST
+ByPass_PerturbAmp=0.1
+}}}
+
+Note that the model will run `AddNoise` only once, and switch automatically to `ByPass_addnoise_sst=n`