qrel.plot {verification}

Quantile Reliability Plot

Description

The quantile reliability plot gives detailed insights into the performance of quantile forecasts. The conditional observed quantiles are plotted against the discretized quantile forecasts. For calibrated forecasts (i.e., reliability), the points should lie on a diagonal line. The interpretation concerning over or under forecasting of a quantile reliability diagram is analogous to the interpretation of a reliability diagram for probability forecasts of dichotomous events (see for example Wilks (2006), pp. 287 - 290).

Usage

qrel.plot(A, ...)

Arguments

A

A "quantile" class object from verify

...

optional arguments.

Note

This function is based on reliabiliy.plot by Matt Pocernich.

Author(s)

Sabrina Bentzien

References

Bentzien and Friederichs (2013), Decomposition and graphical portrayal of the quantile score, submitted to QJRMS.

See Also

quantileScore, reliability.plot

Examples

data(precip.ensemble)

#Observations are in column 3
obs <- precip.ensemble[,3]

#Forecast values of ensemble are in columns 4 to 54
eps <- precip.ensemble[,4:54]

#Quantile forecasts from ensemble
p <- 0.9
qf <- apply(eps,1,quantile,prob=p,type=8)

#generate equally populated binnng intervals
breaks <- quantile(qf,seq(0,1,length.out=11))

qs <- quantileScore(obs,qf,p,breaks)
qrel.plot(qs)