How is surface temperature computed ?

In dealing with surface pool evaporation, I need to understand how is the surface temperature computed by CS.
When I force it through a user formula Ts(t) in the IHM, it seems to be recomputed and doesn't correspond to the imposed one.
When I try to force a Dirichlet value for the variable itempb (ground temperature) in a rough Wall boundary condition, CS refuses to run.
Thanks for clarifying this point !
Stephane Burkhart

Start by tracing how surface temperature is computed for surface pool evaporation and how the IHM user formula Ts(t) interacts with that computation. Check the handling of itempb in a rough Wall boundary condition; done means documenting the computation, override behavior, and why the proposed Dirichlet value is rejected.

Written by the indexing model from the issue text.