R/triangular_chill_2.R

In EduardoFernandezC/dormancyR: Functions to Compute Chill Metrics

#' Triangular chilling model (Legave \emph{et al.} 2008, 2013)
#'
#' This function computes the chill according to the triangular function proposed by Legave \emph{et al.} (2008) and
#' Legave \emph{et al.} (2013). This model, which uses Tmean as input, was selected as one of the "bests" over several
#' models proposed by the same authors.
#'
#' @param ExtrDailyTemp Dataframe containing columns \emph{"Tmax"} and \emph{"Tmin"}. These values must correspond to daily
#' records
#' 
#' @param summ Boolean parameter indicating whether the computed metric should be provided as cumulative values
#' over the period or as the actual accumulation for each hour
#'
#' @references Legave J., Farrera I., Almeras T. and Calleja M. 2008. Selecting models of apple flowering time
#' and understanding how global warming has had and impact on this trait. J. Horticult. Sci. Biotechnol. 83(1):
#' 76 - 84. \href{https://www.tandfonline.com/doi/abs/10.1080/14620316.2008.11512350}{doi:10.1080/14620316.2008.11512350}
#' 
#' Legave J., Blanke M., Christen D., Giovannini D, Mathieu V. and Oger R. 2013. A comprehensive overview of the
#' spatial and temporal variability of apple bud dormancy release and blooming phenology in Western Europe.
#' Int. J. Biometeorol. 57(2): 317 - 331. \href{https://link.springer.com/article/10.1007/s00484-012-0551-9}{doi:10.1007/s00484-012-0551-9}
#' 
#' @examples 
#' library(chillR)
#' 
#' tempResponse_daily(KA_weather, Start_JDay = 345, End_JDay = 58, 
#'                    models = list(Triangular_Chill_Legave = triangular_chill_2))
#' 
#' @export triangular_chill_2

triangular_chill_2 <- function (ExtrDailyTemp, summ = TRUE) {
  
  #Computing Tmean from Tmin and Tmax
  
    if (!("Tmean" %in% names(ExtrDailyTemp)))
      ExtrDailyTemp[,"Tmean"] <- (ExtrDailyTemp["Tmax"] + ExtrDailyTemp["Tmin"]) / 2
  
  #Threshold (Tc)reported in the paper
    
    threshold <- 1
  
  #Temperature interval (Ic) define the range of efficient temperatures around Threshold
  
    temp_interval <- 24 
  
  #Giving a value of 0 to the whole record 
  
    ExtrDailyTemp[,"Triang_Chill_Legave"] <- 0
  
  #Selecting those days which fit the condition 2: TC-Ic < Tmean < TC+Ic
  
    rel_days_cond2 <- which(threshold - temp_interval < ExtrDailyTemp$Tmean & 
                            threshold + temp_interval > ExtrDailyTemp$Tmean)
  
    #Computing the chill value for such condition
  
      ExtrDailyTemp[rel_days_cond2, "Triang_Chill_Legave"] <- 1 - (abs(ExtrDailyTemp[rel_days_cond2, "Tmean"] - 
                                                                     threshold) / temp_interval)
  
  #End of the function    
      
    if (summ == TRUE)
      return(cumsum(ExtrDailyTemp$Triang_Chill_Legave)) else return(ExtrDailyTemp$Triang_Chill_Legave)
}