nadim(1)

NAME
nadim - semi-discrete canopy reflectance model

SYNOPSIS
nadim [-LAI n] [-lad n] [-lrad n] [-hc n] [-rl n] [-tl n] [-rs n] [-rsl[1/2/3/4] n] [-cAb n] [-cW n] [-cP n] [-cC n] [-N n] < in_file

DESCRIPTION
NADIM is a semi-discrete canopy reflectance model. First order scattering is dealt with explicitly and succesive orders of scattering are represented by a turbid medium model. The version of the code documented in this manual page has been coupled with prospect(1) (to provide leaf reflectance) and the soil reflectance functions described by Price. The input file has been adapted to that it has the same format as the kuusk(1) CRM code.

PROGRAM OTIONS

-u  Print a brief usage message.

NADIM MODEL OPTIONS

-LAI n
    Set the canopy Leaf Area Index to n.

-lad n
    Set the canopy leaf angle distribution to n, where valid options are:
    1 - Planophile
    2 - Erectophile
    3 - Plagiophile
    4 - Extremeophile
    5 - Uniform

-hc n
    Set the height of the canopy, in meters, to n.

-lrad n
    Set the leaf radius, in meters, to n.

-rl n
    Set the leaf reflectance to n. This option switches prospect OFF: any prospect options passed are ignored.

-tl n
    Set the leaf transimittance to n. This option switches prospect OFF: any prospect options passed are ignored.

-rl n
    Set the soil reflectance to n. This option switches the calculation of the soil reflectance from the Price vectors OFF: any Price options will be ignored.

PRICE SOIL OPTIONS

-rslN n
    Set the weight of the Nth soil reflectance vector to n. Valid values of N are {1,2,3,4}.

PROSPECT OPTIONS

-cab n
    Set the leaf chlorophyl concentration (ug/cm2) to n.

-cw n
    Set the equivelant water thickness of the leaf (cm) to n.

-cp n
    Set the leaf protein content to (g/cm2) to n.

-cc n
    Set the leaf cellulose + lignin content (g/cm2) to n.

-N n
    Set effective number of layer insde the leaf to n.

ADDITIONAL OUPUT OPTIONS
The following options print their parameters after the directional reflectances, on the same line, for each set of angles. They are always printed out in the order albedo, fapar, transmission regardless of the order they appear on the command line. For each, one value is output per wavelength. So, for example, with two wavelengths and the fapar and transmission options set the output for one line would be: vza vaa sza saa rho1 rho1 fapar1 fapar2 trans1 trans2.

-albedo
    Output the spectral albedo for each wavelength.

-fapar
    output the spectral fAPAR (fAR?) for each wavelength.

-trans
    output the transmission below the canopy for each wavelength.

INPUT FILE FORMAT
The input file contains on the first line, the number of angular samples, followed (on the same line) by the number of wavelengths for which reflectance is to be simulated, followed by the wavelengths in nm. The following lines should contain the viewing and illumination angles for each sample in degrees, in the order vzen vaz szen saz. The output is then the same as input, but with the simulated reflectance in each of the specified bands e.g. for 9 samples, at 2 wavelengths (550 and 850nm), with vz varying between -40 and 40 in 10 degree steps, we have an input file as follows:
9 2 550 850
-40 0 0 0
-30 0 0 0
-20 0 0 0
-10 0 0 0
0 0 0 0
10 0 0 0
20 0 0 0
30 0 0 0
40 0 0 0
Currently comments are not supported in nadim. This means that some kuusk(1) input (i.e. those with comments in) files file not work.

REFERENCES
Gobron N., Pinty B., Verstraete M., Govaerts Y. (1997) A semidiscrete model for the scattering of light by vegetation. Journal of Geophysical Research. vol 102. no D8. 9431-9446.
Jacquemoud S., Baret F. (1990), Prospect: a model of leaf optical properties spectra, Remote Sens. Environ., 34:75-91.
Jacquemoud S., Ustin S.L., Verdebout J., Schmuck G., Andreoli G., Hosgood B. (1995), PROSPECT return, Remote Sens, Environ., in preparation.
Kuusk, A. (1996) A computer-efficient plant canopy reflectance model, Computers and Geosciencees, 22(2), pp. 149-163. Price, J. (1990) On the Information Content of Soil Reflectance Spectra, Rem. Sens. Environ. 33:113-121.

BUGS
Probably loads...

SEE ALSO
kuusk(1), prospect(1)

AUTHOR/COPYRIGHT
Model and (FORTRAN) code:
Nadine Gobron
C interface, coupling with prospect and Price, and man page:
Tristan Quaife
Remote Sensing Unit
Department of Geography, UCL
Chandler House
2 Wakefield Street
London WC1N 1PG
(C) University College London, 2004
tquaife@geog.ucl.ac.uk