Extending an inversion

Two cases are covered here:

• an inversion that stopped unexpectedly, e.g. due to a timeout, a full disk, or another such failure

• an inversion that stopped normally but needs to be extended, e.g. because the maximum number of simulations was reached or tighter convergence is required

1. If the inversion stopped unexpectedly, remove the last directory generated by the CTM (e.g. for CHIMERE with 24-hour periods, remove the last day’s directory).

2. Modify the YAML to reuse the valid computations:

   • in obsoperator, set autorestart to True

   • in simulator, set reload_from_previous to True. If simulator is not specified in the YAML (which is the usual case when using the default cost function), add it as shown in the example below.

mode:
  minimizer:
    df1: 0.5
    epsg: 0.1
    maxiter: 10
    nsim: 25
    plugin:
      name: M1QN3
      version: std
    simulator:
      plugin:
        name: gausscost
        version: std
      reload_from_previous: true
  plugin:
    name: 4dvar
    version: std
  save_out_netcdf: true
obsoperator:
  plugin:
    name: standard
    version: std
    type: obsoperator
  autorestart: True

3. To extend the inversion, adjust the minimizer’s stopping criteria. For M1QN3, decrease epsg and increase maxiter and nsim.

4. Relaunch the job.