Sub-daily PET calculation inside of mHM

Background

PET routine inside of mHM (options 1 - Hargreaves-Sammani, 2 - Priestley-Taylor, 3 - Penman) all calculate daily values (mm d-1)
When mHM is forced with subdaily forcings, mo_mhm still calculates PET at daily but skips temporal disaggregation (at this line) of the calculated daily PET

(Probable) Solution

Enable the functions pet_priestly, pet_penman to calculate PET at subdaily resolution by adjusting daysecs term. pet_hargreaves is based on function extraterr_rad_approx where again the term daysecs can be adjusted.

Issue with the solution

Whenever the forcings resolution is subdaily but not hourly, temporal disaggregation would be required nonetheless as mhm runs at hourly timestep. But the temporal disaggregation currently in place is Taylor-made for daily to hourly rescaling.

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information