i.evapo.pt
Computes evapotranspiration calculation Priestley and Taylor formulation, 1972.
i.evapo.pt [-z] net_radiation=name soil_heatflux=name air_temperature=name atmospheric_pressure=name priestley_taylor_coeff=float output=name [--overwrite] [--verbose] [--quiet] [--qq] [--ui]
Example:
i.evapo.pt net_radiation=name soil_heatflux=name air_temperature=name atmospheric_pressure=name priestley_taylor_coeff=1.26 output=name
grass.script.run_command("i.evapo.pt", net_radiation, soil_heatflux, air_temperature, atmospheric_pressure, priestley_taylor_coeff=1.26, output, flags=None, overwrite=False, verbose=False, quiet=False, superquiet=False)
Example:
gs.run_command("i.evapo.pt", net_radiation="name", soil_heatflux="name", air_temperature="name", atmospheric_pressure="name", priestley_taylor_coeff=1.26, output="name")
Parameters
net_radiation=name [required]
Name of input net radiation raster map [W/m2]
soil_heatflux=name [required]
Name of input soil heat flux raster map [W/m2]
air_temperature=name [required]
Name of input air temperature raster map [K]
atmospheric_pressure=name [required]
Name of input atmospheric pressure raster map [millibars]
priestley_taylor_coeff=float [required]
Priestley-Taylor coefficient
Default: 1.26
output=name [required]
Name of output evapotranspiration raster map [mm/d]
-z
Set negative ETa to zero
--overwrite
Allow output files to overwrite existing files
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--qq
Very quiet module output
--ui
Force launching GUI dialog
net_radiation : str, required
Name of input net radiation raster map [W/m2]
Used as: input, raster, name
soil_heatflux : str, required
Name of input soil heat flux raster map [W/m2]
Used as: input, raster, name
air_temperature : str, required
Name of input air temperature raster map [K]
Used as: input, raster, name
atmospheric_pressure : str, required
Name of input atmospheric pressure raster map [millibars]
Used as: input, raster, name
priestley_taylor_coeff : float, required
Priestley-Taylor coefficient
Default: 1.26
output : str, required
Name of output evapotranspiration raster map [mm/d]
Used as: output, raster, name
flags : str, optional
Allowed values: z
z
Set negative ETa to zero
overwrite: bool, optional
Allow output files to overwrite existing files
Default: False
verbose: bool, optional
Verbose module output
Default: False
quiet: bool, optional
Quiet module output
Default: False
superquiet: bool, optional
Very quiet module output
Default: False
DESCRIPTION
i.evapo.pt Calculates the diurnal evapotranspiration after Prestley and Taylor (1972). The Priestley-Taylor model (Priestley and Taylor, 1972) is a modification of Penman's more theoretical equation.
NOTES
RNETD optional output from i.evapo.potrad is giving good results as input for net radiation in this module.
Alpha values:
- 1.32 for estimates from vegetated areas as a result of the increase in surface roughness (Morton, 1983; Brutsaert and Stricker, 1979)
- 1.26 is applicable in humid climates (De Bruin and Keijman, 1979; Stewart and Rouse, 1976; Shuttleworth and Calder, 1979), and temperate hardwood swamps (Munro, 1979)
- 1.74 has been recommended for estimating potential evapotranspiration in more arid regions (ASCE, 1990). This worked well in Greece with University of Thessaloniki.
Alpha values extracted from: Watflood manual.
SEE ALSO
i.evapo.mh, i.evapo.pm, i.evapo.time, i.eb.netrad, r.sun
AUTHOR
Yann Chemin, GRASS Development Team, 2007-08
SOURCE CODE
Available at: i.evapo.pt source code
(history)
Latest change: Friday Feb 07 19:16:09 2025 in commit a82a39f