Opened 18 months ago

#735 new defect

Potential issues in the way transmitted light is calculated

Reported by: gmarie Owned by: Matthew Mcgrath
Priority: minor Milestone: ORCHIDEE 4.3
Component: Physical processes Version: trunc
Keywords: transmitted light, diffuse light, albedo Cc:

Description

In the file where transmitted light is calculated : albedo_surface.f90

at line 945, the following equation is used to calculate transmitted light from one layer to another one.

Light_Tran_Tot(ipts,ivm,:) = direct_light_weight*(Isotrop_Tran_Coll(:) + Isotrop_Tran_Uncoll(:)) + (un-direct_light_weight)*(Isotrop_Tran_Coll(:) + Isotrop_Tran_Uncoll(:))

direct_light_weight equal 0.5 meaning that the source is composed by 50% of direct and 50% of diffuse light.

But the minimum value obtain for Light_Tran_Tot is 0.5 for a very dense canopy. It seems that Isotrop_Tran_Coll and Isotrop_Tran_Uncoll have been use twice instead of Collim_Tran_Coll and Collim_Tran_UnColl.

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