R/buildup_effect.r

In nrcan-cfs-fire/cffdrs: Canadian Forest Fire Danger Rating System

#' Build Up Effect Calculator
#'
#' @description Computes the Buildup Effect on Fire Spread Rate. All variables
#' names are laid out in the same manner as Forestry Canada Fire Danger Group
#' (FCFDG)(1992).
#'
#' @references \url{https://cfs.nrcan.gc.ca/publications/download-pdf/10068}
#' Development and Structure of the Canadian Forest Fire Behavior Prediction
#' System." Technical Report ST-X-3, Forestry Canada, Ottawa, Ontario.
#'
#' @param FUELTYPE The Fire Behaviour Prediction FuelType
#' @param BUI The Buildup Index value
#'
#' @return BE: Build up effect
#' @noRd

buildup_effect <- function(FUELTYPE, BUI) {
  # Fuel Type String represenations
  d <- c(
    "C1", "C2", "C3", "C4", "C5", "C6", "C7",
    "D1", "M1", "M2", "M3", "M4", "S1", "S2", "S3", "O1A", "O1B"
  )
  # The average BUI for the fuel type - as referenced by the "d" list above
  BUIo <- c(
    72, 64, 62, 66, 56, 62, 106,
    32, 50, 50, 50, 50, 38, 63, 31, 01, 01
  )
  # Proportion of maximum possible spread rate that is reached at a standard BUI
  Q <- c(
    0.9, 0.7, 0.75, 0.8, 0.8, 0.8, 0.85,
    0.9, 0.8, 0.8, 0.8, 0.8, 0.75, 0.75, 0.75, 1.0, 1.0
  )
  names(BUIo) <- names(Q) <- d
  # Eq. 54 (FCFDG 1992) The Buildup Effect
  BE <- ifelse(
    BUI > 0 & BUIo[FUELTYPE] > 0,
    exp(50 * log(Q[FUELTYPE]) * (1 / BUI - 1 / BUIo[FUELTYPE])),
    1
  )
  return(as.numeric(BE))
}

.BEcalc <- function(...) {
  .Deprecated("buildup_effect")
  return(buildup_effect(...))
}