pism/pism — Issue #9: create option -tauc_to_tillphi
Author: bueler
Created: 2011-11-04 21:36:53+00:00
State: open
Labels: task

This task created based on conversation 4 Nov with [David](https://github.com/damaxwell).

The inversion procedure for the SSA will involve a python script which will used David's [siple](https://github.com/damaxwell/siple) package. I'm guessing it is called `vel2tauc.py`. It will allow a `-a` option to append the results of the inversion into a PISM NetCDF file.

There will generically be a PISM spinup run before inversion. To be useful, it generates a `tauc` field in its output file. The inversion will take that `tauc` and invert surface velocities from another file and then generate a new tauc. The old `tauc` will still be present as `tauc_prior` I think.

The option `-tauc_to_phi` will be used in the PISM run after the inversion. It will identify the file from which PISM should get a `tauc` field. Thus the sequence looks something like this:

pismr -boot_file originaldata.nc -y 1e4 -ssa_sliding -topg_to_tillphi a,b,c,d,e \
-o spinupresult.nc [other options]

vel2tauc.py -a spinupresult.nc -inv_data vel-obs.nc [other options]

pismr -i spinupresult.nc -ssa_sliding -tauc_to_tillphi -y 100 [other options]

Note that if we see `-tauc_to_tillphi foo.nc` then that is the file from which to extract the field `tauc` to calculate the basal hydrology model state variable `tillphi`. But if we see `-tauc_to_tillphi` without a file name we may assume that the `-i` file has the `tauc` variable.

Note that the inversion script `vel2tauc.py` *does* generically know about the power law used in the sliding model, and `tauc` means the coefficient in that power law. But it *does not* need to know about the state variable of the basal hydrology model (i.e. `tillphi`). A hydrology model can be arbitrarily complicated and can have a ridiculously big state. On the other hand, the current default hydrology is really preliminary and should change. Both of these are reasons why the inversion need not know about the hydrology state variable(s).