RLeafAngle (version 1.0)

computeG: Compute the mean projection of unit leaf area on the plane perpendicular to beam direction, namely, G parameter.

Description

Compute the mean projection of unit leaf area on the plane perpendicular to beam direction, namely, G parameter.

Usage

computeG(LeafAngleZ, FractionZ, LeafAngleA, FractionA, theta, alpha)

Arguments

LeafAngleZ

The center angles list of leaf zenith angle intervals.

FractionZ

The leaf area fraction list given leaf zenith angle intervals list.

LeafAngleA

The center angles list of leaf azimuth angle intervals.

FractionA

The leaf area fraction list given leaf azimuth angle intervals list.

theta

The zenith angle of beam direction.

alpha

The azimuth angle of beam direction.

Value

The mean projection of unit leaf area on the plane perpendicular to beam direction, namely, G value.

References

Wang, W. M., Li, Z. L., & Su, H. B. (2007). Comparison of leaf angle distribution functions: effects on extinction coefficient and fraction of sunlit foliage. Agricultural and Forest Meteorology, 143(1), 106-122.

Examples

angleZ<-c(4.5, 13.5, 22.5, 31.5, 40.5, 49.5, 58.5, 67.5, 76.5, 85.5)
angleA<-c(10,30,50,70,90,110,130,150,170,190,210,230,250,270,290,310,330,350)
sADis<-sysAziDis()
sZDis<-sphericalDis()
for(solarZenith in 10:80)
{
  print(computeG(angleZ,sZDis,angleA,sADis,solarZenith,40))
}