PenmanMonteithv

PenmanMonteithv is a name encountered in some software tools, datasets, and educational materials to denote a versioned or variant implementation of the Penman–Monteith evapotranspiration model. In its common interpretation, the Penman–Monteith framework estimates reference evapotranspiration (ET0) for a hypothetical well-watered crop by combining an energy-balance component with aerodynamic resistance to compute evapotranspiration from meteorological data.

The standard form, often associated with FAO-56 guidelines, uses inputs such as net radiation, soil heat flux (typically small for daily time steps), mean air temperature, wind speed at a reference height, saturation vapor pressure, actual vapor pressure, and the slope of the saturation vapor pressure curve. A variant labeled “v” may indicate specific adjustments or parameter choices, such as different values for the psychrometric constant, alternative vapor pressure deficit formulations, modified canopy or surface resistances, or other empirically tuned elements. Because there is no universal definition for “PenmanMonteithv,” users should consult the source documentation or code to understand the exact modifications.

Applications of this approach include estimating reference evapotranspiration for irrigation scheduling, hydrological modeling, and climate studies. The method remains widely used due to its physical basis and performance across diverse climates, provided high-quality meteorological data are available.

See also: Penman–Monteith equation; FAO-56; evapotranspiration; reference evapotranspiration (ET0).