.TH i.eb.netrad 1grass "" "GRASS 7.8.5" "GRASS GIS User's Manual"
.SH NAME
\fI\fBi.eb.netrad\fR\fR  \- Net radiation approximation (Bastiaanssen, 1995).
.SH KEYWORDS
imagery, energy balance, net radiation, SEBAL
.SH SYNOPSIS
\fBi.eb.netrad\fR
.br
\fBi.eb.netrad \-\-help\fR
.br
\fBi.eb.netrad\fR \fBalbedo\fR=\fIname\fR \fBndvi\fR=\fIname\fR \fBtemperature\fR=\fIname\fR \fBlocalutctime\fR=\fIname\fR \fBtemperaturedifference2m\fR=\fIname\fR \fBemissivity\fR=\fIname\fR \fBtransmissivity_singleway\fR=\fIname\fR \fBdayofyear\fR=\fIname\fR \fBsunzenithangle\fR=\fIname\fR \fBoutput\fR=\fIname\fR  [\-\-\fBoverwrite\fR]  [\-\-\fBhelp\fR]  [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR]  [\-\-\fBui\fR]
.SS Flags:
.IP "\fB\-\-overwrite\fR" 4m
.br
Allow output files to overwrite existing files
.IP "\fB\-\-help\fR" 4m
.br
Print usage summary
.IP "\fB\-\-verbose\fR" 4m
.br
Verbose module output
.IP "\fB\-\-quiet\fR" 4m
.br
Quiet module output
.IP "\fB\-\-ui\fR" 4m
.br
Force launching GUI dialog
.SS Parameters:
.IP "\fBalbedo\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of albedo raster map [0.0;1.0]
.IP "\fBndvi\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of NDVI raster map [\-1.0;+1.0]
.IP "\fBtemperature\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of surface temperature raster map [K]
.IP "\fBlocalutctime\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of time of satellite overpass raster map [local time in UTC]
.IP "\fBtemperaturedifference2m\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of the difference map of temperature from surface skin to about 2 m height [K]
.IP "\fBemissivity\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of the emissivity map [\-]
.IP "\fBtransmissivity_singleway\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of the single\-way atmospheric transmissivitymap [\-]
.IP "\fBdayofyear\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of the Day Of Year (DOY) map [\-]
.IP "\fBsunzenithangle\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of the sun zenith angle map [degrees]
.IP "\fBoutput\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of the output net radiation layer
.SH DESCRIPTION
\fIi.eb.netrad\fR calculates the net radiation at the time of satellite
overpass, the way it is in the SEBAL model of Bastiaanssen (1995).
It takes input of Albedo, NDVI, Surface Skin temperature, time of satellite
overpass, surface emissivity, difference of temperature from surface skin and
about 2 m height (dT), instantaneous satellite overpass single\-way atmospheric
transmissivity (tsw), Day of Year (DOY), and sun zenith angle.
.SH NOTES
In the old methods, dT was taken as flat images (dT=5.0), if you don\(cqt have a dT
map from ground data, you would want to try something in this line, this is to
calculate atmospherical energy balance. In the same way, a standard tsw is used
in those equations. Refer to r_net.c for that and for other non\-used equations,
but stored in there for further research convenience.
.SH TODO
Add more explanations.
.SH SEE ALSO
\fI
i.eb.soilheatflux,
i.eb.hsebal01,
i.albedo
\fR
.SH REFERENCES
.RS 4n
.IP \(bu 4n
Bastiaanssen, W.G.M., 1995. Regionalization of surface flux
densities and moisture indicators in composite terrain; a remote
sensing approach under clear skies in mediterranean climates. PhD
thesis, Wageningen Agricultural Univ., The Netherland, 271 pp.
(PDF)
.IP \(bu 4n
Chemin, Y., 2012.
A Distributed Benchmarking Framework for Actual ET Models,
in: Irmak, A. (Ed.), Evapotranspiration \- Remote Sensing and Modeling. InTech.
(PDF)
.RE
.SH AUTHOR
Yann Chemin, International Rice Research Institute, The Philippines
.SH SOURCE CODE
.PP
Available at: i.eb.netrad source code (history)
.PP
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.PP
© 2003\-2020
GRASS Development Team,
GRASS GIS 7.8.5 Reference Manual