Correct rain gauge precipitation data for wind and evaporation errors after Richter (1995)

correct_prec(month, tavg, prec, station.exposure = "mg", full_output = FALSE)

Arguments

month: Vector of months.
tavg: Vector of air temperature values (deg C). Same length as month.
prec: Vector of measured rainfall vales (mm). Same length as month.
station.exposure: Situation of the weather station where prec was measured: one of 'frei', 'lg', 'mg', 'sg' (corresponding to full exposure, low protected, moderate protected, strong protected situation).
full_output: Logical wether to return the full data set additionally including input data, correction coefficients.

Value

A vector of corrected rainfall data, or (if full_output == TRUE) a data.table containing the input objects, the month, the precipitation type ('N4So': liquid rain, summer; 'N4Wi' liquid rain, winter; 'N8' = sleet, 'N7' = snow), correction coefficients epsilon and b, and the corrected rainfall.

References

Richter, D. (1995) Ergebnisse methodischer Untersuchungen zur Korrektur des systematischen Messfehlers des Hellmann-Niederschlagsmessers. Berichte des Deutschen Wetterdienstes, 194, 93 pp, Offenbach, Germany

Examples

clim <- slb1_meteo[as.integer(format(slb1_meteo$dates,"%Y")) %in% 2001:2005,]
clim$month <- as.integer(format(clim$dates, "%m"))

prec_meas <- clim$prec
correct_prec_frei <- with(clim,
                       correct_prec(month, tmean, prec, station.exposure = "frei"))
correct_prec_lg <- with(clim,
                     correct_prec(month, tmean, prec, station.exposure = "lg"))
correct_prec_mg <- with(clim,
                     correct_prec(month, tmean, prec, station.exposure = "mg"))
correct_prec_sg <- with(clim,
                     correct_prec(month, tmean, prec, station.exposure = "sg"))

plot(clim$dates, cumsum(correct_prec_frei),
type = "l", col = "violet", xlab = "dates", ylab = "cum. precipitation (mm)")
lines(clim$dates, cumsum(correct_prec_lg), col = "blue")
lines(clim$dates, cumsum(correct_prec_mg), col = "green")
lines(clim$dates, cumsum(correct_prec_sg), col = "red")
lines(clim$dates, cumsum(prec_meas))
legend('bottomright', c('frei', "lg", "mg", "sg"),
       col = c("violet", "blue", "green", "red", "black"),
       lty = 1, pch = NULL )