R/PET_fromTemp.R

In EcoHydRology: A Community Modeling Foundation for EcoHydrology

PET_fromTemp <- function (Jday, Tmax_C, Tmin_C, lat_radians, AvgT = (Tmax_C + Tmin_C)/2, albedo = 0.18, TerrestEmiss = 0.97, aspect = 0, slope = 0, forest = 0, PTconstant=1.26, AEparams=list(vp=NULL, opt="linear")) 
{
    if (length(Jday) != length(Tmax_C) | length(Jday) != length(Tmin_C)) {
        cat("Warning, input vectors unequal length:  Longer data sets truncated.\n")
        length(Jday) <- min(length(Jday), length(Tmax_C), length(Tmin_C))
        length(Tmax_C) <- min(length(Jday), length(Tmax_C), length(Tmin_C))
        length(Tmin_C) <- min(length(Jday), length(Tmax_C), length(Tmin_C))
    }
    cloudiness <- EstCloudiness(Tmax_C, Tmin_C)
	DailyRad <- NetRad(lat_radians, Jday, Tmax_C, Tmin_C, albedo, forest, slope, aspect, AvgT, cloudiness, TerrestEmiss, AvgT, AEparams=AEparams)
      
	potentialET <- PTpet(DailyRad, AvgT, PTconstant)
	potentialET[which(potentialET < 0)] <- 0
    potentialET[which(Tmax_C == -999 | Tmin_C == -999)] <- (-999)
    return(potentialET)
}