Uncertainty: Uncertainty quantification for gauged and ungauged pooled...

In UKFE: UK Flood Estimation

Uncertainty quantification for gauged and ungauged pooled estimates

Description

Quantification of uncertainty for pooling results for the gauged and ungauged case

Usage

Uncertainty(
  x,
  Gauged = FALSE,
  qmed = NULL,
  Dist = "GenLog",
  Conf = 0.95,
  fseQMED = 1.55,
  UrbAdj = FALSE,
  URBEXT = NULL,
  Plot = TRUE,
  IncAMest = TRUE,
  Parametric = TRUE
)

Arguments

x	the pooled group derived from the Pool() or PoolSmall function
Gauged	a logical argument with a default of FALSE. If FALSE the uncertainty intervals are calculated for the ungauged case. If TRUE they are calculated for the gauged case
qmed	the QMED estimate for the ungauged case. It is derived from the observed AMAX if Gauged equals TRUE.
Dist	a choice of distribution to use for the estimates. Choices are "GEV", "GenLog" ,"Gumbel", or "Kappa3". The default is "GenLog"
Conf	the confidence level of the uncertainty intervals. Default is 0.95. Must be between 0 and 1.
fseQMED	The factorial standard error of the QMED estimate for an ungauged assessment. The default is 1.55.
UrbAdj	applies an urban adjustment to the growth curves
URBEXT	URBEXT value for the site of interest. This is necessary if a UrbAdj equals TRUE.
Plot	logical argument with a default of TRUE. If TRUE a return level plot with results and margin of error is plotted. If FALSE, it is not.
IncAMest	logical argument with a default of TRUE. Sometimes when doing gauged (enhanced single site analysis), the central estimate of the single site estimate is outside the intervals of the ESS estimate. When this argument is true the confidence interval is expanded to include the central estimate for the single site. If FALSE, it is not.
Parametric	logical argument with a default of TRUE. If TRUE, the bootsrapping is done by simulation with the distribution of choice. If FALSE the bootsrapping is done by resampling with replacement.

Details

Uncertainty for both the gauged (enhanced single site) and ungauged case are quantified according to the bootstrapping procedures, which account for weights in the pooling group, detailed in Hammond, A. (2021). Sampling uncertainty of UK design flood estimation. Hydrology Research. 1357-1371. 52 (6).

Value

A dataframe with 10 rows and four columns. Return period in the first column, central estimate in the second, lower in the third, and upper in the fourth. If Plot = TRUE, a return level plot is also returned.

Author(s)

Anthony Hammond

Examples

#Get an ungauged pooling group:
Pool.203018 <- Pool(GetCDs(203018), exclude = 203018)
#Use the function to quantify the central estimate and uncertainty
Uncertainty(Pool.203018, qmed  = QMED(GetCDs(203018)))
#Form a pooling group with subject site included.
 Pool.203018 <- Pool(GetCDs(203018))
#Quantify the central estimate and uncertainty
 Uncertainty(Pool.203018, Gauged = TRUE)

UKFE documentation built on April 4, 2025, 12:55 a.m.