cre.hourly: Calculates crop reference evapotranspiration from hourly data

In ilyamaclean/ecohydrotools: hydrogical modelling for ecological applications with R

Description

cre.hourly applies the Penman-Monteith equation to derive hourly crop reference evapotranspiration

Usage

cre.hourly(Rn, tc, u1, rh, p, dn)

Arguments

Rn	a single numeric value, vector, two-dimensional array or matrix of net radiation (MJ / m^2 / hr)
tc	a single numeric value, vector, two-dimensional array or matrix of temperature (deg C)
u1	a single numeric value, vector, two-dimensional array or matrix of wind speed at one metre above the ground (m /s)
rh	a single numeric value, vector, two-dimensional array or matrix of relative humidity (percentage)
p	a single numeric value, vector, two-dimensional array or matrix of pressure (Pa)
dn	binary variable indicating whether day or night (day - 1, night = 0). Must be a single numeric value or have the same dimensions as Rn
u1	a single numeric value, vector, two-dimensional array or matrix of wind speed at one metre above the ground (m /s)

Details

Applies the method detailed in Allen et al (1998). If relatively fine-resolution spatial data are needed, radiation, temperature, wind and relative humidity can be downscaled using the microclima package. The variable dn and humidity conversions can also be obtained using this package. If only sea-level pressure is known, then p can be derived using function pressure.height(). To convert radiation from watts m^-2 to MJ m^-2 hr^-1 multiply by 0.0036.

Value

a single numeric value, vector, two-dimensional array or matrix of crop reference evapotranspiration (mm / hr)

See Also

cre.daily for deriving crop reference evapotranspiration from daily data

Examples

cre.hourly(1.1, 20, 1.3, 70, 101300, 1) # day
cre.hourly(-0.3, 5, 1.3, 100, 101300, 0) # night (cold and wet)
cre.hourly(-0.1, 30, 1.3, 60, 101300, 0) # night (hot and dry)

ilyamaclean/ecohydrotools documentation built on June 10, 2019, 5:45 a.m.