HeatAccumulation: calculate BK curve

getAccumExposure.R

getAcumExposure = function(ts, tmin=27.5, tinc=1){
  ## calculate accumulated exposure
  ## this version does not have gaps in temp bins
  ## ts is a times series of daily values
  ## tmin is the starint temp to accumulate
  ## tinc is the number of decimal places to round temperature
  ## removes NA's
  ts = ts[!is.na(ts)]
  ts = ts[ts>=tmin]
  if (length(ts)==0){
    return(NA)  ## this is the case when tmin is higher than ts max
  }
  ts = round(ts, tinc)
  
  tsDF <- data.frame(temp = seq(tmin, max(ts, na.rm=T), by=10^-tinc), nDays=NA)
  for (i in 1:nrow(tsDF)){
    tsDF$nDays[i] <- sum(ts >= tsDF$temp[i])
  }
  ## add last temp with zero days
  tsDF <- rbind(tsDF, data.frame(temp=max(tsDF$temp+10^-tinc), nDays=0))
  
  return(tsDF)
}