rfa {lfstat}

Regional Frequency Analysis

Description

This function uses J.R.M. Hosking's package produce an object of class 'rfd', containing the specification of the regional frequency distribution.

Usage

rfa(lflist, n = 7, event = 100, dist = c("wei", "gev", "ln3", "gum", "pe3"))

Arguments

lflist

A list of 'lfobj's.

n

MAM-n is used (e.g. n=7 means MAM7).

event

A value for T, e.g. event = 100 means the 100 years extreme low flow event.

dist

A vector of distribution to fit, the names are according to Hosking's in his lmom package. Can be an of "wei", "gev", "ln3", "gum", "pe3".

Value

An object of class "rfd", containing the specification of the regional frequency distribution: It is a list with the following elements:

dist

The character string dist.

para

Vector containing the parameters of the fitted regional distribution.

qfunc

The quantile function of distribution dist. It is a function that takes a single argument, a vector of probabilities, and returns a vector of quantiles.

rmom

The regional average L-moments.

index

Index flood values at each site. This is a named vector whose values are the index flood values at each site, from regdata[[3]], and whose names are the site names, from regdata[[1]].

References

Gustard, A. & Demuth, S. (2009) (Eds) Manual on Low-flow Estimation and Prediction. Operational Hydrology Report No. 50, WNO-No. 1029, 136p. https://library.wmo.int/doc_num.php?explnum_id=7699

See Also

regfit and lmom-package which this function wraps.

Examples

data(ngaruroro)
# Toy example to get some more "rivers"
seventies <- subset(ngaruroro, hyear %in% 1970:1979)
eighties <- subset(ngaruroro, hyear %in% 1980:1989)
nineties <- subset(ngaruroro, hyear %in% 1990:1999)

toyrfa <- rfa(list(seventies,eighties,nineties), n=3,dist = "gev")

require(lmomRFA)
regquant(c(1/1000,1/100),toyrfa)
sitequant(1/100,toyrfa)