The two-stream model tends to overestimate the amount of radiation absorbed by vegetation. The degree of the overestimation varies with the background albedo. Based on these analyses, a parameterization is proposed to include the effect of 3-D structure on radiation regimes. This parameterization explicitly accounts for the between-crown gap probability. The within-crown gap probability is parameterized by a clumping factor.
Good agreement is reached for both winter or summer data.