UKFE (version 0.1.1)

GEVAM: Generalised extreme value distribution - estimates directly from sample

Description

Estimated quantiles as function of return period (RP) and vice versa, directly from the data

Usage

GEVAM(x, RP = 100, q = NULL, trend = FALSE)

Arguments

x

numeric vector (block maxima sample)

RP

return period (default = 100)

q

quantile (magnitude of variable)

trend

logical argument with default of FALSE. If TRUE, a linear adjustment to the location parameter is made to account for non-stationarity

Value

quantile as a function of RP or vice versa, with the option of accounting for the linear trend in the sample

Details

If the argument q is used, it overrides RP and provides RP as a function of q (magnitude of variable) as opposed to q as a function of RP. The parameters are estimated by the method of L-moments, as detailed in 'Hosking J. Wallis J. 1997 Regional Frequency Analysis: An Approach Based on L-moments. Cambridge University Press, New York'. The trend argument allows the location parameter to move in line with the observed linear trend of the sample

Examples

# NOT RUN {
#Get an annual maximum sample and estimate the 50-year RP
AM.27090 <- GetAM(27090)
GEVAM(AM.27090$Flow, RP = 50)
#Estimate the RP for a 600m3/s discharge
GEVAM(AM.27090$Flow, q = 600)
#Estimate the 50-year RP allowing for non-stationarity in the location parameter
GEVAM(AM.27090$Flow, RP = 50, trend = TRUE)
# }