Calculate daily total reference ET at a given point. Follows the steps outlined in Zotarelli et al (2010) https://unpkg.com/node-red-contrib-evapotranspiration@1.0.1/alogorithms/evapotranspiration%20ae45900.pdf.

Usage

etr_penman_monteith(
  lat,
  days,
  srad,
  ws,
  elev,
  rh_mean = NULL,
  rh_min = NULL,
  rh_max = NULL,
  t_mean = NULL,
  t_min = NULL,
  t_max = NULL,
  reference = 0.23,
  wind_height = 2
)

Arguments

lat: Latitude of ETo calculation in degrees.
days: The julian day ETo is being calculated on.
srad: Shortwave radiation in W m^-2.
ws: Wind speed at 2 meters in M s^-1.
elev: Elevation in meters.
rh_mean: Relative humidity (%).
rh_min: Minumum daily relative humidity (%).
rh_max: Maximum daily relative humidity (%).
t_mean: Air temperature in Celsius.
t_min: Minimum daily air temperature in degC.
t_max: Maximum daily air temperature in degC.
reference: The albedo of the reference surface (defaults to 0.23 for grass).
wind_height: The height of the wind observation in meters. (defaults to 2). If it is not 2 meters, the wind speed will be corrected to a 2 meter observation.

Value

Reference ET in mm per day.

Examples

etr_penman_monteith(
  t_mean = NULL,
  t_max = 21.5,
  t_min = 12.3,
  rh_mean = NULL,
  rh_max = 84,
  rh_min = 63,
  lat = 50.8,
  days = 187,
  ws = 2.77778,
  wind_height = 10,
  elev = 100,
  reference = 0.23,
  srad = 255.4398
)
#> [1] 3.88004