Generalised extreme value distribution estimates from parameters

Estimated quantiles as function of return period (RP) and vice versa, from user input parameters

Usage

GEVEst(loc, scale, shape, q = NULL, RP = 100)

Arguments

loc

location parameter

scale

scale parameter

shape

shape parameter

q

quantile. magnitude of the variable under consideration

RP

return period

Value

quantile as a function of RP or vice versa

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.

This function applies a probability distribution model which assumes that the sample data is independent and identical, i.e. the assumption is that all observations in the sample would not impact or depend on any other. Furthermore, all observations are from the same underlying process which has not changed over the period of record (stationarity).

Author

Anthony Hammond

Examples

# Get an annual maximum sample, estimate the parameters, and estimate the 50-year RP
am_27090 <- GetAM(27090)
GEVPars(am_27090$Flow)
#>        Loc    Scale     Shape
#> 1 264.4741 89.29227 0.2407794

# Store the parameters in an object
pars <- as.numeric(GEVPars(am_27090$Flow))

# Get an estimate of 50-year flow
GEVEst(pars[1], pars[2], pars[3], RP = 50)
#> [1] 490.3863

# Estimate the RP for a 600 m^3/s discharge
GEVEst(pars[1], pars[2], pars[3], q = 600)
#> [1] 17421.37