new diagnostic: dzt_on_rho has non-positive axis_id

[rfarneti]

Dear All, the MOM5 Google group seems to be down (perhaps because of all the recent spam messages?). I will place my question here if you don't mind. I am trying to introduce a new diagnostic, dzt_on_rho, to save dzt, and eventually other thickness quantities, on potential density surfaces. I am following what is done in src/mom5/ocean_diag/ocean_tracer_diag.F90 for diagnose_tracer_on_rho. The need for this diagnostic is to try to avoid remapping dzt onto pot_rho offline.

Changes on ocean_thickness.F90 compile, but when testing it I keep getting the following error:

diag_manager_mod::register_diag_field: module/output_field ocean_model/dzt_on_rho has non-positive axis_id

meaning that axes are not passed.

I do not seem to find the (probably obvious) mistake. Could somebody provide some advice or hint? My ocean_thickness.F90 is here:

https://github.com/rfarneti/MOM5/blob/master/src/mom5/ocean_core/ocean_thickness.F90

Thanks! Riccardo