Fix: uninitialised variables in cable_canopy.F90

[ccarouge]

CABLE

Thank you for submitting a pull request to the CABLE Project.

Description

Fixes #351.

Move the definition of sum_rad_gradis and sum_rad_rniso out of the NITER loop in define_canopy() since these variables do not change in the loop. Having a quick comparison between the outputs before and after this commit the effect is negligeable.

Use sum_rad_gradis and sum_rad_rniso as calculated in define_canopy() everywhere in define_canopy(), dryLeaf() and wetLeaf(), instead of recalculating them sometimes.

Move the initialisation of canopy%DvLitt and canopy%kthLitt to the top of define_canopy() since these variables are constant throughout the run. We also want these variables to be defined in all cases to avoid errors in function calls, but only used with cable_user%litter turned on.

Type of change

Please delete options that are not relevant.

• Bug fix

Testing

benchcab/me.org analysis: https://modelevaluation.org/analyses/anywhere/BPLvifw3DyARokYdg/s6k22L3WajmiS9uGv/CJGXP5GQWhGf3nH28/all

Tested in benchcab the changes for DvLitt and kthLitt on their own. benchcab showed bitwise identical results when moving the initialisation compared to the previous implementation with the litter option on.

Please add a reviewer when ready for review.

---

📚 Documentation preview 📚: https://cable--352.org.readthedocs.build/en/352/

[ccarouge]

Since we are introducing 2 changes that will break reproducibility I have decided to document some of the differences separately.
In the first commit we only move the calculation of sum_rad_gradis before calling wetLeaf. benchcab shows differences in the results compared to the main branch but these are minimal. Here are the timeseries for Qle and Qh for the start of the runs for a random flux site:

[rml599gh]

Also noting that my tests showed that without the sum_rad_gradis bug fixed, site runs were not consistently reproducible.

[rml599gh]

Reference at line 192. Matthews not Mathews. Title is 'of fine fuel' not 'of offine fuel'. Probably useful to include the doi (https://doi.org/10.1071/WF05063)