The usage of the frac_nobio variable in ORCHIDEE

frac_nobio is the variable which describes the fraction of the grid box which will never (in the foreseeable future !) be covered with vegetation. These fraction can be covered by glaciers, cities lakes or any other surface type where no biological activity (transpiration, assimilation, decomposition, ...) will happen.

This variable has 2 dimensions : kjpindex and nnobio, in other words the number of land grid points in ORCHIDEE and the number of no-bio classes. For the moment nnobio=1.

In the following we will go through each of the modules and detail where the frac_nobio is used and with which intention.

slowproc

diffuco

enerbil

Here frac_nobio is not used. The information about the fraction of the grid box which is not covered by vegetation or bare soil is integrated in the various surface parameters provided to enerbil (vbeta?, soilflx, soilcap, ...).

hydrol

thermosoil