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i.evapo.pt.1grass - Man Page

Computes evapotranspiration calculation Priestley and Taylor formulation, 1972.


imagery, evapotranspiration


i.evapo.pt --help
i.evapo.pt [-z] net_radiation=name soil_heatflux=name air_temperature=name atmospheric_pressure=name priestley_taylor_coeff=float output=name  [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]



Set negative ETa to zero


Allow output files to overwrite existing files


Print usage summary


Verbose module output


Quiet module output


Force launching GUI dialog


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]


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.


RNETD optional output from i.evapo.potrad is giving good results as input for net radiation in this module.

Alpha values:

Alpha values extracted from: Watflood manual.

See Also

i.evapo.mh, i.evapo.pm, i.evapo.time, i.eb.netrad, r.sun


Yann Chemin, GRASS Development Team, 2007-08

Source Code

Available at: i.evapo.pt source code (history)

Accessed: Tuesday May 14 13:41:41 2024

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