Welcome to the new DiscussCESM forum!
We are still working on the website migration, so you may experience downtime during this process.

Existing users, please reset your password before logging in here: https://xenforo.cgd.ucar.edu/cesm/index.php?lost-password/

sunlit and shaded quantities when Plant Hydraulic Stress (PHS) is inactive


Nicholas Herold
Hi, are the shaded and sunlit values for gs that are produced by the Photosynthesis subroutine purely diagnostic? I see that in PhotosynthesisHydraulicStress shaded and sunlit versions of several variables are calculated and used (as is described in the technote) but the Photosynthesis subroutine doesn't seem to distinguish shaded and sunlit canopy in its calculations - though shaded and sunlit gs are written out. Can I confirm that these are just diagnostic values. And is it correct to interpret values from the Photosynthesis subroutine (for gs, cs, an etc.) as an average over sunlit and shaded canopies?



Keith Oleson
CSEG and Liaisons
Staff member
Photosynthesis is called twice, once with the argument phase='sun' and once with the argument phase='sha'.
The variable arrays are mostly generic within subroutine Photosynthesis, but they point to appropriate sun/sha variables, e.g.,

if (phase == 'sun') then
par_z => solarabs_inst%parsun_z_patch

else if (phase == 'sha') then
par_z => solarabs_inst%parsha_z_patch