sunML: Sunlit shaded multi-layer model

Description Usage Arguments Value Examples

Description

Simulates the light microenvironment in the canopy based on the sunlit-shade model and the multiple layers.

Usage

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sunML(Idir,Idiff,LAI=8,nlayers=8,cos.theta=0.5,kd=0.7,chi.l=1,heightf=3,
  maxIdir = 2235, maxIdiff = 119)

Arguments

Idir

direct light (quantum flux), (micro mol /m2/s).

Idiff

indirect light (diffuse), (micro mol /m2/s).

LAI

leaf area index, default 8.

nlayers

number of layers in which the canopy is partitioned, default 8.

cos.theta

cosine of theta, solar zenith angle.

kd

extinction coefficient for diffuse light.

chi.l

The ratio of horizontal:vertical projected area of leaves in the canopy segment.

heightf

height factor. simple empirical relationship between LAI and height of a canopy.

maxIdir

Maximum direct irradiance

maxIdiff

Maximum diffuse irradiance

Value

a data.frame structure with components

row number equal to the number of layers.

layIdir

direct solar radiation.

layIdiff

difusse solar radiation.

layItotal

total solar radiation.

layFsun

proportion of the leaf area in each layer which is in direct light.

layFshade

proportion of the leaf area in each layer which is in indirect light.

layHeight

layer height.

Examples

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res2 <- sunML(1500,200,3,10)

xyplot(layFsun + layFshade ~ c(1:10), data=res2,
       ylab="LAI",
       xlab="layer",
       type="l",lwd=2,col=c("blue","green"),
       lty=c(1,2),
       key=list(text=list(c("Direct","Diffuse")),lty=c(1,2),
                cex=1.2,lwd=2,lines=TRUE,x=0.7,y=0.5,
                col=c("blue","green")))

BioCro documentation built on May 2, 2019, 6:15 p.m.