| computeG {RLeafAngle} | R Documentation |
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.
Author(s)
Wei-Min Wang (wmwang AT gmail.com)
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))
}