calculateET0 {PMEvapotranspiration}

PMEvapotranspiration

Description

FAO-56 Penman-Monteith evapotranspiration

Usage

calculateET0(T_max, T_min, Latitude, altitude, RH_min, RH_max, u2, n, J)

Arguments

T_max

Maximum temperature in degree Celsius

T_min

Minimum temperature in degree Celsius

Latitude

Latitude in decimal degree

altitude

altitude in meter

RH_min

Minimum Relative humidity in percentage

RH_max

Maximum Relative humidity in percentage

u2

The average wind speed (m/s) measured at 2 m above the ground level

n

Actual daily sunshine duration

J

number of the day in the year between 1 (1 January) and 365 or 366 (31 December)

Value

Returns a list containing the calculated reference evapotranspiration (ET0) and other intermediate values used in the calculation. The list includes:

• ET0: Reference evapotranspiration calculated using FAO-56 Penman-Monteith Equation.

• T_mean: Mean temperature.

• P: Atmospheric pressure.

• gamma: Psychrometric constant.

• delta: Slope of vapor pressure curve.

• e_s: Saturation vapor pressure.

• e_a: Actual vapor pressure.

• Ra: Extraterrestrial radiation.

• Rso: Clear sky solar radiation.

• Rs: Solar radiation.

• Rns: Net shortwave radiation.

• Rnl: Net longwave radiation.

• Rn: Net radiation.

References

#'

• Córdova, M., Carrillo-Rojas, G., Crespo, P., Wilcox, B., and Célleri, R. (2015). Evaluation of the Penman-Monteith (FAO 56 PM) method for calculating reference evapotranspiration using limited data. Mountain Research and Development, 35(3), 230-239.

• Debnath, S., Adamala, S., and Raghuwanshi, N. S. (2015). Sensitivity analysis of FAO-56 Penman-Monteith method for different agro-ecological regions of India. Environmental Processes, 2, 689-704.

Examples

{
calculateET0(T_max = 25, T_min = 15, Latitude = 45,
 altitude = 100, RH_min = 20,
 RH_max = 80, u2 = 2, n = 10, J = 150)
}