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I am trying to run a backwards simulation but I keep running into the following error:

[2018/05/22 14:31:55]$INFO: ===== Simulation started =====

[2018/05/22 14:31:55]$INFO: {Simulation} Run 1 / 1

[2018/05/22 14:31:55]$INFO: {Simulation} Setting up...

[2018/05/22 14:31:55]$INFO: Opened dataset D:\2016\HISTORY\NEATL_2015060100.nc

[2018/05/22 14:31:58]$INFO: Release manager setup [OK]

[2018/05/22 14:31:58]$INFO: Time manager setup [OK]

[2018/05/22 14:31:58]$INFO: Instantiated action "Advanced/Transport/Advection"

[2018/05/22 14:31:58]$INFO: Instantiated system action "org.previmer.ichthyop.action.SysActionAgeMonitoring"

[2018/05/22 14:31:58]$INFO: Instantiated system action "org.previmer.ichthyop.action.SysActionMove"

[2018/05/22 14:31:58]$INFO: Action manager setup [OK]

[2018/05/22 14:31:58]$INFO: Output manager setup [OK]

[2018/05/22 14:31:58]$INFO: {Simulation} Setup [OK]

[2018/05/22 14:31:58]$INFO: {Simulation} Intializing...

[2018/05/22 14:33:19]$INFO: Opened dataset D:\2016\HISTORY\NEATL_2016080403.nc

[2018/05/22 14:33:25]$INFO: Release manager initialization [OK]

[2018/05/22 14:33:25]$INFO: Time manager initialization [OK]

[2018/05/22 14:33:25]$INFO: Zone manager initialization [OK]

[2018/05/22 14:33:25]$INFO: Created output file C:\Users\12708235\Desktop\ichthyop-3.2\output\roms3d_ichthyop-run201805221431.nc.part

[2018/05/22 14:33:25]$INFO: Output manager initialization [OK]

[2018/05/22 14:33:25]$INFO: {Simulation} Initialization [OK]

[2018/05/22 14:33:25]$INFO: Opened dataset D:\2016\HISTORY\NEATL_2016080400.nc

[2018/05/22 14:33:32]$INFO: Release event (ReleaseManager) time = 1521072000 seconds. Released 200 particles.

[2018/05/22 14:33:32]$INFO: NetCDF output file, writing record 0 - time 2016/08/04 00:00:00

[2018/05/22 14:33:32]$SEVERE: -1


The forward simulation works fine, and so does the backwards simulation when I disable advection which is not ideal. I have tried both Forward Euler and Runge Kutta 4 to no avail. I have also tried Ichthyop Version 3.3 and versions older than 3.2.


My configuration is attached to this post.


Any suggestions?

Ichthyop version: 
Ichthyop 3.2
Hydrodynamic dataset: 
Java version: 
Java SE 6
Operating system: 
Windows 7

Hi Jasmine

I think I have found the issue. In your configuration file ("ROMS3D" window), you deactivated NetCDF sorting.

It must be activated in backward simulations. Furthermore, in backward runs, the "Time" window, the beginning of the simulation must me set equal to the last time value in your NetCDF file.

I was able to run the model backward with the files that you sent me (using Ichthyop 3.3) without any CFL warnings.

Tell me if it works now


Hi Nicolas,
It runs perfectly now in version 3.3. without any CFL warnings or issues with the backwards simulation.
Thanks for your help,