BrierScore: Compute Brier Score And Its Decomposition And Brier Skill...

In s2dverification: Set of Common Tools for Forecast Verification

Compute Brier Score And Its Decomposition And Brier Skill Score

Description

Computes the Brier score (BS) and the components of its standard decomposition as well with the two within-bin components described in Stephenson et al., (2008). It also returns the bias-corrected decomposition of the BS (Ferro and Fricker, 2012). BSS having the climatology as the reference forecast.

.BrierScore provides the same functionality, but taking a matrix of ensemble members (exp) as input.

Usage

BrierScore(obs, pred, thresholds = seq(0, 1, 0.1))

.BrierScore(exp, obs, thresholds = seq(0, 1, 0.1))

Arguments

obs	Vector of binary observations (1 or 0).
pred	Vector of probablistic predictions with values in the range [0,1].
thresholds	Values used to bin the forecasts. By default the bins are [0,0.1), [0.1, 0.2), ... [0.9, 1].
exp	Matrix of predictions with values in the range [0,1] for the .BrierScore function

Value

Both BrierScore and .Brier score provide the same outputs:

• $relstandard reliability

• $resstandard resolution

• $uncstandard uncertainty

• $bsBrier score

• $bs_check_resrel-res+unc

• $bss_resres-rel/unc

• $gresgeneralized resolution

• $bs_check_gresrel-gres+unc

• $bss_gresgres-rel/unc

• $rel_bias_correctedbias-corrected rel

• $gres_bias_correctedbias-corrected gres

• $unc_bias_correctedbias-corrected unc

• $bss_bias_correctedgres_bias_corrected-rel_bias_corrected/unc_bias_corrected

• $nknumber of forecast in each bin

• $fkbaraverage probability of each bin

• $okbarrelative frequency that the observed event occurred

• $binsbins used

• $predvalues with which the forecasts are verified

• $obsprobability forecasts of the event

Author(s)

History:
0.1 - 2012-04 (L. Rodrigues) - Original code
0.2 - 2017-02 (A. Hunter) - Adapted to veriApply()

References

Wilks (2006) Statistical Methods in the Atmospheric Sciences.
Stephenson et al. (2008). Two extra components in the Brier score decomposition. Weather and Forecasting, 23: 752-757.
Ferro and Fricker (2012). A bias-corrected decomposition of the BS. Quarterly Journal of the Royal Meteorological Society, DOI: 10.1002/qj.1924.

Examples

# Minimalist examples with BrierScore
a <- runif(10)
b <- round(a)
x <- BrierScore(b, a)
x$bs - x$bs_check_res
x$bs - x$bs_check_gres
x$rel_bias_corrected - x$gres_bias_corrected + x$unc_bias_corrected
 ## Not run: 
a <- runif(10)
b <- cbind(round(a),round(a)) # matrix containing 2 identical ensemble members...
x2 <- BrierScore(a, b)
 
## End(Not run)

# Example of BrierScore using UltimateBrier
# See ?UltimateBrier for more information
example(Load)
clim <- Clim(sampleData$mod, sampleData$obs)
ano_exp <- Ano(sampleData$mod, clim$clim_exp)
ano_obs <- Ano(sampleData$obs, clim$clim_obs)
bs <- UltimateBrier(ano_exp, ano_obs, thr = c(1/3, 2/3))

 ## Not run: 
# Example of .BrierScore with veriApply
require(easyVerification)
BrierScore2 <- s2dverification:::.BrierScore
bins_ano_exp <- ProbBins(ano_exp, thr = c(1/3, 2/3), posdates = 3, posdim = 2)
bins_ano_obs <- ProbBins(ano_obs, thr = c(1/3, 2/3), posdates = 3, posdim = 2)
bs2 <- veriApply("BrierScore2", bins_ano_exp, Mean1Dim(bins_ano_ob,s 3), 
                tdim = 2, ensdim = 3)
 
## End(Not run)

s2dverification documentation built on April 20, 2022, 9:06 a.m.