Run with DEBUG flag fails due to unallocated SHELFMASK

[TomasTorsvik]

If the variable SHELFMASK is not allocated, hamocc_step fails at call hamocc4bcm(..., shelfmask) as it tries to pass SHELFMASK as an argument. This fails when running in DEBUG mode.

I suggest not to pass allocatable variables as arguments. Instead, I would opt for passing this directly from the mo_read_shelfmask.F90 module.

Actually, I would prefer to only have one module shelfsea.F90 containing both the ini_read_shelfmask and the shelfsea_residence_time subroutines, and make the SHELFMASK private to this module.

@jmaerz - If you agree, I can implement this.

[JorgSchwinger]

The reason to separate the two routines is, is to keep the "core HAMOCC" and and the interface between the ocean model and HAMOCC separated. Reading the shelf-mask depends on the ocean model grid and has therefore to happen outside core HAMOCC.

I would suggest to just make SHELFMASK a non allocatable variable as omask. From my perspective, one could also just calculate the shelf residence time as a default and remove the logical switch (it's just a 2d field and negligible cost to calculate the residence time).

[TomasTorsvik]

Alternatively, if this is purely an age tracer, perhaps it doesn't need to be in iHAMOCC?

Unless at some stage someone wants to introduce, e.g. residence time for PO4 in shelf region, or something similar.

[JorgSchwinger]

Yes, it could probably be in BLOM instead of HAMOCC, but now it is already where it is...

[TomasTorsvik]

OK, I just re-arrange the ini_read_shelfmask so that the shelfmask array will be allocated before the first return statement.