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NAME
i.evapo.potrad - Potential evapotranspiration, radiative method after Bastiaanssen (1995)
KEYWORDS
Potential ET,
evapotranspiration
SYNOPSIS
i.evapo.potrad
i.evapo.potrad --help
i.evapo.potrad [-rdb] albedo=name temperature=name latitude=name dayofyear=name transmissivitysingleway=name waterdensity=float [slope=name] [aspect=name] [atmosphericemissivity=float] [airtemperature=name] [surfaceemissivity=name] output=name [rnetd=name] [--overwrite] [--help] [--verbose] [--quiet] [--ui]
Flags:
- -r
- Output Diurnal Net Radiation (for i.eb.eta)
- -d
- Slope/Aspect correction
- -b
- Net Radiation Bandara (1998), generic Longwave calculation, need apparent atmospheric emissivity, Air temperature and surface emissivity inputs
- --overwrite
- Allow output files to overwrite existing files
- --help
- Print usage summary
- --verbose
- Verbose module output
- --quiet
- Quiet module output
- --ui
- Force launching GUI dialog
Parameters:
- albedo=name [required]
- Name of the Albedo layer [0.0-1.0]
- temperature=name [required]
- Name of the temperature layer [Degree Kelvin]
- latitude=name [required]
- Name of the degree latitude layer [dd.ddd]
- dayofyear=name [required]
- Name of the Day of Year layer [0.0-366.0]
- transmissivitysingleway=name [required]
- Name of the single-way transmissivity layer [0.05-1.0], defaults to 1.0 if no input file
- waterdensity=float [required]
- Value of the density of fresh water ~[1000-1020]
- Default: 1005.0
- slope=name
- Name of the Slope layer ~[0-90]
- aspect=name
- Name of the Aspect layer ~[0-360]
- atmosphericemissivity=float
- Value of the apparent atmospheric emissivity (Bandara, 1998 used 0.845 for Sri Lanka)
- Default: 0.845
- airtemperature=name
- Name of the Air Temperature layer [Kelvin], use with -b
- surfaceemissivity=name
- Name of the Surface Emissivity layer [-], use with -b
- output=name [required]
- OUTPUT: Name of the Potential ET layer
- rnetd=name
- OUTPUT: Name of the Diurnal Net Radiation layer
i.evapo.potrad calculates the diurnal potential
evapotranspiration after Bastiaanssen (1995). This is converting all
Net radiation from the diurnal period into ET. It takes input maps
of Albedo, surface skin temperature, latitude, day of year,
single-way transmissivity and takes input value of the density of
fresh water.
The "-r" flag permits output map of Diurnal net radiation to use in r.eb.eta.
The "-b" flag permits a generic longwave balance calculation from
surface emissivity, Air Temperature and a value of apparent
atmospheric emissivity.
The "-d" flag is a slope/aspect correction, not really tested,
reports and tests are most welcome.
Slope/aspect correction to be screened and tested by somebody in the known.
r.sun
i.albedo
i.eb.eta
- 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)
Chemin, Y., 2012.
A Distributed Benchmarking Framework for Actual ET Models,
in: Irmak, A. (Ed.), Evapotranspiration - Remote Sensing and Modeling. InTech.
(PDF)
Yann Chemin, International Rice Research Institute, The Philippines
SOURCE CODE
Available at:
i.evapo.potrad source code
(history)
Latest change: Monday Jun 28 07:54:09 2021 in commit: 1cfc0af029a35a5d6c7dae5ca7204d0eb85dbc55
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GRASS Development Team,
GRASS GIS 7.8.9dev Reference Manual