R/eto_hs.R

In BrazilMet: Download and Processing of Automatic Weather Stations (AWS) Data of INMET-Brazil

#' Hargreaves - Samani ETo
#' @param tmin A dataframe with Maximum daily air temperature (°C)
#' @param tmean A dataframe with Minimum daily air temperature (°C)
#' @param tmax A dataframe with Maximum daily air temperature (°C)
#' @param ra A dataframe of extraterrestrial radiation (MJ m-2 day-1)
#' @examples
#' \dontrun{
#' eto_hs <- eto_hs(tmin, tmean, tmax, ra)
#' }
#' @export
#' @return Returns a data.frame object with the ETo HS data
#' @author Roberto Filgueiras, Luan P. Venancio, Catariny C. Aleman and Fernando F. da Cunha

eto_hs <- function(tmin, tmean, tmax, ra) {
  HS <- as.data.frame(0.0023 * (tmean + 17.8) * ((tmax - tmin)^0.5) * (0.408 * ra))
  colnames(HS)[1] <- "Eto_HS"
  return(HS)
}