Make additional ecosystem parameters available via marbl_settings_mod or namelist

[jessluo]

A few parameters are encoded in the source files and should be made available for modification via marbl_settings_mod.F90 or as namelist parameters:

1. Power of the 'quadratic' loss term for autotrophs and zooplankton. For autotrophs, the value is 1.75 (e.g. Pprime(auto_ind)**1.75_r8) and for zooplankton the value is 1.5 (e.g. Zprime(zoo_ind)**1.5_r8).
   It may not be necessary to allow for individual variations in the 'power loss power' term. One value for autotrophs and one value for zooplankton may be sufficient.

2. Power of the 'quadratic' term on the implicit calcifier routing to POC. Within the marbl_compute_grazing subroutine, the routing of autotroph grazing (of implicit calcifiers) to POC has a power of 1.6. Should that be a parameter within marbl_settings_mod as well? Also, should this portion of the subroutine be more general to include autotrophs that are neither implicit calcifiers nor diatoms?

3. Maximum CaCO3 : C ratio (QCaCO3_max) should be flexible by autotroph PFT. Currently, since there is only one implicit calcifier in the default CESM2 parameter set, there is no need for variations in QCaCO3_max. However, under cases where there is more than 1 implicit calcifier, it would be nice to adjust the maximum CaCO3 : C ratio per implicit calcifier.

4. Similarly, should f_photosp_CaCO3 be changed as well to allow for variations between implicit calcifiers (if implicit calcifier > 1)? Right now it appears that f_photosp_CaCO3 is the same value as QCaCO3_max, so if QCaCO3_max changes, then f_photosp_CaCO3 should as well.

[mnlevy1981]

For point 4, f_graze_sp_poc_lim and spc_poc_fac should also be moved to autotroph_type (and it's not entirely clear that "if QCaCO3_max changes, then f_photosp_CaCO3 should as well" is true, need to look into it)

[matt-long]

I think we should remove sp from the names of parameters associated with implicit calcification and replace with something like imp_calcifier or imp_calc. Additionally, the following parameters might be renamed to be more informative.

• parm_f_prod_sp_CaCO3 is really a minimum or base rate, so could be parm_f_imp_calc_photo_CaCO3_min
• f_photosp_CaCO3 is really a max rate, so could be parm_f_imp_calc_photo_CaCO3_max

[mnlevy1981]

#328 added auto_mort2_exp, zoo_mort2_exp, and QCaCO3_max but there are other variables in this issue ticket that still need to be moved into the settings file.

[mangelesg]

I have not been able to find the value of zooplankton_settings(:)%Tref.

I didn't find it in marbl_settings_mod.F90 nor in the MARBL documentation chrome-extension://oemmndcbldboiebfnladdacbdfmadadm/https://marbl.readthedocs.io/_/downloads/en/latest/pdf/

I would appreciate any help in this matter

[mnlevy1981]

@angeles2013 -- for both autotroph_settings(:) and zooplankton_settings(:), Tref is determined by the correspondingtemp_func_form_opt in marbl_settings_mod::set_derived_from_temp_func_form().

For the q_10 functional form (the default for zooplankton_settings(1)%temp_func_form_opt), Tref is 30. For the arrhenius functional form Tref is 25, and for power functions Tref is 0.

[mangelesg]

Thank you!