Hi Maosier,
From the looks of the code, the two seem to be redundant in the case of isoprene. If you look at module_bioemi_megan2.F, you'll see that:
mebio_isop (i,j) = E_megan2 ( is_isoprene )
which is the emissions coming out of the MEGAN scheme after all the adjustments/gammas have been applied.
whereas:
ebio_iso(i,j) = ebio_iso(i,j) + gas_emis, with the term "gas_emis" equal to, e.g.:
gas_emis = mozcart_per_megan(icount) * E_megan2(p_of_megan2mozcart(icount))
with the *_per_megan = 1.0 for isoprene.
If they are not equal, then it looks like ebio_iso is an accumulated diagnostic. You could check this by running a 1 hour test simulation with a biogenic emission timestep = 30 minutes and seeing if they are scaled by 2.
Jordan
