Time-dependent species concentration function

[LaurieNovak]

Ask a question about KPP:

I am trying to use KPP to build a boxmodel simulation of chamber experiments. To this end, I want to use a function which describes the concentration of reactant A, which is added a various timesteps.
e.g. Limonene = 2 ppb at t = 0, then at t = 2h, I want to raise Limonene to 4 ppb.
I saw in the KPP guide that a function of
CO2 = MyCO2Func() is possible, however I cannot find any further information as to where to define MyCO2Func.
Do you have suggestions how to handle this?
Thanks in advance!

[RolfSander]

This is only an example showing that you can use your own Fortran90
SUBROUTINE to define initial values. The actual code of MyCO2Func()
could be in any Fortran90 file that is linked into your boxmodel.

If you only need a step function (i.e., a sudden increase from 2 to 4
nmol/mol, it's easiest to change the limonene concentration outside of
KPP.

In my CAABA/MECCA boxmodel, you can find something like this in
SUBROUTINE injection in messy_semidep_box.f90:

https://gitlab.com/RolfSander/caaba-mecca/-/blob/develop/caaba/messy_semidep_box.f90