Opened 3 years ago

Last modified 4 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 4.2
Component: Physical processes Version: trunc
Keywords: transmitted light, diffuse light, albedo Cc:


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.

Change History (2)

comment:1 Changed 7 months ago by luyssaert

  • Milestone changed from ORCHIDEE 4.3 to ORCHIDEE 4.2

comment:2 Changed 4 months ago by xnwang

A fix is applied in the revision [8016], after a discussion between MM and XW.

Light_Tran_Tot(ipts,ivm,:) = direct_light_weight*(Collim_Tran_Coll(:) + & Collim_Tran_Uncoll(:)) + (un-direct_light_weight)*(Isotrop_Tran_Coll(:) + &


Last edited 4 months ago by jgipsl (previous) (diff)
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