Update icedrv_init.F90 to read in dynamics_nml

[Marek-Muchow]

PR checklist

• Short (1 sentence) summary of your PR:
  This fixes loading the dynamics_nml, which was defined in icedrv_init.F90, but not loaded from icepack_in (in the stand-alone version).
• Developer(s): Marek-Muchow
• Suggest PR reviewers from list in the column to the right.
• Please copy the PR test results link or provide a summary of testing completed below.
  I only tested it locally, results did not change as expected as only driver script for stand-alone case was adapted.
• How much do the PR code changes differ from the unmodified code?
  • bit for bit
  • different at roundoff level
  • more substantial
• Does this PR create or have dependencies on CICE or any other models?
  • Yes
  • No
• Does this PR add any new test cases?
  • Yes
  • No
• Is the documentation being updated? ("Documentation" includes information on the wiki or in the .rst files from doc/source/, which are used to create the online technical docs at https://readthedocs.org/projects/cice-consortium-cice/.)
  • Yes
  • No, does the documentation need to be updated at a later time?
    • Yes
    • No
• Please document the changes in detail, including why the changes are made. This will become part of the PR commit log.

The dynamics_nml was defined, but not loaded from icepack_in (when using icepack in the stand alone version). Thus, the variables in dynamics_nml were always set to the default parameters and flexibility in the code (for example switching between the ice strength parametrisations (kstrength = 1 or 0) and ridging schemes (krdg_redist = 1 or 0) was not possible via icepack_in).

Problem was also mentioned in the Forum (https://bb.cgd.ucar.edu/cesm/threads/icepack-stand-alone-dynamics_nml-from-icepack_in-get-overwritten-by-default-parameters.12290/).

[apcraig]

In standalone Icepack, there is no dynamics. That's probably why it's not read in. Are there namelist settings in dyn_nml that matter for standalone Icepack?

[eclare108213]

Good catch. It would be helpful to have results from Icepack's base_suite, which includes tests with different values of the dynamics options. If I understand the problem correctly, some of the base_suite results will be non-BFB, indicative of the error. Instructions for running test suites can be found here. Let us know if you have questions or need other help with this. Thank you for finding and fixing the problem!

[eclare108213]

In standalone Icepack, there is no dynamics. That's probably why it's not read in. Are there namelist settings in dyn_nml that matter for standalone Icepack?

Icepack owns some dynamics-related things like ice strength, ridging, and surface stress calculations, even though it does not calculate internal stress / momentum / advection.