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ESCOMP / CTSM

Community Terrestrial Systems Model (includes the Community Land Model of CESM)
http://www.cesm.ucar.edu/models/cesm2.0/land/
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Implement water tracers for BareGroundFluxes #722

Open billsacks opened 5 years ago

billsacks commented 5 years ago

Note that BareGroundFluxes is the first place where we need to deal with fractionation.

billsacks commented 5 years ago

A note from David Noone:

Just took a quick look at the Bareground fluxes (canopyfluxes are similar)

The original code is:

! compute latent heat fluxes individually
qflx_ev_soil(p) = -raiw*(forc_q(c) - qg_soil(c))

For the tracers, one could write (excuse my pseudo code, and variable names):

Rtopsoil = tracer_h2osoi(p,1)/tracer_h2osoi(p,1)

if (water_isotopes) then  ! proper fractionation
  raiwt = raiw*alpha_kinetic    ! different conductance
  tr_soil = qg_soil(c) * Rtopsoil/alpha_equilibrium  ! different saturation

  ! Same expression as above, but for isotope
  tracer_qflx_ev_soil(p) = -raiwt*(tracer_forc_q(c) - tr_soil)

else  ! donor ratio.
  tracer_qflx_ev_soil(p) = Rtopsoil*qflx_ev_soil(p)
endif

What I had in mind was setting up the code infrustructure to allow this type of calculation, with the elegance of the way you're coding it up.

billsacks commented 3 years ago

I will also reach out to @rfiorella as we start working on fractionation parameterizations.