Physical utility functions

Set of functions used in the calculation of physical variables.

utils_saturationVP(temperature)

utils_averageDailyVP(Tmin, Tmax, RHmin, RHmax)

utils_atmosphericPressure(elevation)

utils_airDensity(temperature, Patm)

utils_averageDaylightTemperature(Tmin, Tmax)

utils_latentHeatVaporisation(temperature)

utils_latentHeatVaporisationMol(temperature)

utils_psychrometricConstant(temperature, Patm)

utils_saturationVaporPressureCurveSlope(temperature)

Arguments

temperature

Air temperature (ºC).

Tmin, Tmax

Minimum and maximum daily temperature (ºC).

RHmin, RHmax

Minimum and maximum relative humidity (%).

elevation

Elevation above sea level (in m).

Patm

Atmospheric air pressure (in kPa).

Value

Values returned for each function are:

  • utils_airDensity: air density (in kg·m-3).

  • utils_atmosphericPressure: Air atmospheric pressure (in kPa).

  • utils_averageDailyVP: average (actual) vapour pressure (in kPa).

  • utils_averageDaylightTemperature: average daylight air temperature (in ºC). utils_latentHeatVaporisation: Latent heat of vaporisation (MJ·kg-1). utils_latentHeatVaporisationMol: Latent heat of vaporisation (J·mol-1).

  • utils_psychrometricConstant: Psychrometric constant (kPa·ºC-1).

  • utils_saturationVP: saturation vapour pressure (in kPa).

  • utils_saturationVaporPressureCurveSlope: Slope of the saturation vapor pressure curve (kPa·ºC-1).

Functions

  • utils_averageDailyVP(): Average daily VP

  • utils_atmosphericPressure(): Atmospheric pressure

  • utils_airDensity(): Air density

  • utils_averageDaylightTemperature(): Daylight temperature

  • utils_latentHeatVaporisation(): latent heat vaporisation

  • utils_latentHeatVaporisationMol(): Heat vaporisation mol

  • utils_psychrometricConstant(): psychrometric constant

  • utils_saturationVaporPressureCurveSlope(): Saturation VP curve slope

References

McMurtrie, R. E., D. A. Rook, and F. M. Kelliher. 1990. Modelling the yield of Pinus radiata on a site limited by water and nitrogen. Forest Ecology and Management 30:381–413.

McMahon, T. A., M. C. Peel, L. Lowe, R. Srikanthan, and T. R. McVicar. 2013. Estimating actual, potential, reference crop and pan evaporation using standard meteorological data: a pragmatic synthesis. Hydrology & Earth System Sciences 17:1331–1363. See also: http://www.fao.org/docrep/x0490e/x0490e06.htm

Author

Miquel De Cáceres Ainsa, CREAF