make MLD_003 computation available to mixedlayer_restrat_Bodner

[alperaltuntas]

This PR introduces the calculate_mld_003 subroutine, previously a code black in mixedlayer_restrat_OM4, so as to make it available in mixedlayer_restrat_bodner as well. The newly added flag BODNER_USE_MLD_003 determines whether mld_003 is indeed used in mixedlayer_restrat_bodner.

Fixes: #326

[gustavo-marques]

MLE_DENSITY_DIFF and MLE_MLD_STRETCH need to be defined when BODNER_USE_MLD_003=True.

if (CS%Bodner_use_MLD_003) then
      call get_param(param_file, mdl, "MLE_DENSITY_DIFF", CS%MLE_density_diff, &
           "Density difference used to detect the mixed-layer "//&
           "depth used for the mixed-layer eddy parameterization "//&
           "by Fox-Kemper et al. (2010)", units="kg/m3", default=0.03, scale=US%kg_m3_to_R)
      call get_param(param_file, mdl, "MLE_MLD_STRETCH", CS%MLE_MLD_stretch, &
             "A scaling coefficient for stretching/shrinking the MLD "//&
             "used in the MLE scheme. This simply multiplies MLD wherever used.",&
             units="nondim", default=1.0)
    endif

[gustavo-marques]

Thanks for the PR!

In addition to the comment above, I suggest we rename calculate_mld_003 to calculate_mld because the user can set the MLD criteria (MLE_DENSITY_DIFF). Similar for Bodner_use_MLD_003, which should be Bodner_use_MLD.

I suggest we remove this. call to avoid confusion. (#328)

[alperaltuntas]

@gustavo-marques the newly pushed commit should address your comments but let me know otherwise. Note that I renamed the subroutine calculate_mld_003 as detect_mld and the parameter BODNER_USE_MLD_003 as BODNER_DETECT_MLD.

[gustavo-marques]

Thank you! The last commit addresses all my comments. I approve this PR.