PROSAIL2R: Simulate canopy spectrum

In hsdar: Manage, Analyse and Simulate Hyperspectral Data

Simulate canopy spectrum

Description

Simulate a canopy spectrum using PROSAIL 5B

Usage

PROSAIL(N = 1.5, Cab = 40, Car = 8, Cbrown = 0.0,
        Cw = 0.01, Cm = 0.009, psoil = 0, LAI = 1, 
        TypeLidf = 1, lidfa = -0.35, lidfb = -0.15,
        hspot = 0.01, tts = 30, tto = 10, psi = 0,
        parameterList = NULL, rsoil = NULL)

Arguments

N	Structure parameter
Cab	Chlorophyll content
Car	Carotenoid content
Cbrown	Brown pigment content
Cw	Equivalent water thickness
Cm	Dry matter content
psoil	Dry/Wet soil factor
LAI	Leaf area index
TypeLidf	Type of leaf angle distribution. See details section
lidfa	Leaf angle distribution. See details section
lidfb	Leaf angle distribution. See details section
hspot	Hotspot parameter
tts	Solar zenith angle
tto	Observer zenith angle
psi	Relative azimuth angle
parameterList	An optional object of class 'data.frame'. Function will iterate over rows of parameterList setting missing entries to default values. See examples section.
rsoil	An optional object of class 'Speclib' containing the background (soil) reflectance. Note that reflectance values must be in range [0...1].

Details

This function uses the FORTRAN code of PROSAIL model (Version 5B). For a general introduction see following web page and the links to articles provided there:

http://teledetection.ipgp.jussieu.fr/prosail/

The following table summarises the abbreviations of parameters and gives their units as used in PROSAIL. Please note that default values of all parameters were included with the intention to provide an easy access to the model and should be used with care in any scientific approach!

Parameter	Description of parameter	Units
N	Leaf structure parameter	NA
Cab	Chlorophyll a+b concentration	ug/cm2
Car	Carotenoid concentration	ug/cm2
Caw	Equivalent water thickness	cm
Cbrown	Brown pigment	NA
Cm	Dry matter content	g/cm2
LAI	Leaf Area Index	NA
psoil	Dry/Wet soil factor	NA
hspot	Hotspot parameter	NA
tts	Solar zenith angle	deg
tto	Observer zenith angle	deg
psi	Relative azimuth angle	deg

Functions for distribution of leaf angles within the canopy may work in two modes, which is controlled via TypeLidf:

1. TypeLidf == 1 (default): lidfa is the average leaf slope and lidfb describes bimodality of leaf distribution. The following list gives an overview on typical settings:

   LIDF type	lidfa	lidfb
   Planophile	1	0
   Erectophile	-1	0
   Plagiophile	0	-1
   Extremophile	0	1
   Spherical (default)	-0.35	-0.15

2. TypeLidf != 1: lidfa is the average leaf angle in degree (0 = planophile / 90 = erectophile); lidfb is 0

Value

An object of class Speclib. If parameterList is used, the parameter are stored in SI table of Speclib.

Note

The function is based on the FORTRAN version of the PROSAIL-code initially developed by Stephane JACQUEMOUD, Jean-Baptiste FERET, Christophe FRANCOIS and Eben BROADBENT. SAIL component has been developed by Wout VERHOEF.

Author(s)

Lukas Lehnert

References

Jacquemoud, S., Verhoef, W., Baret, F., Bacour, C., Zarco-Tejada, P.J., Asner, G.P., Francois, C., and Ustin, S.L. (2009): PROSPECT + SAIL models: a review of use for vegetation characterization, Remote Sensing of Environment, 113, S56-S66.

See Also

PROSPECT, Speclib

Examples

## Single spectrum
spectrum <- PROSAIL(N = 1.3)
plot(spectrum)

## Example using parameterList
## Test effect of leaf structure and LAI on spectra
parameter <- data.frame(N = c(rep.int(seq(0.5, 1.5, 0.5), 2)),
                        LAI = c(rep.int(0.5, 3), rep.int(1, 3)))
spectra <- PROSAIL(parameterList = parameter)

## Print SI table
SI(spectra)

## Plot spectra
plot(subset(spectra, LAI == 0.5), col = "red", ylim = c(0, 0.3))
plot(subset(spectra, LAI == 1), col = "green", new = FALSE)

hsdar documentation built on March 18, 2022, 6:35 p.m.