2AFC For Ordinal Polychotomous Observations And Ensemble Forecasts

Routine to calculate the Generalized Discrimination Score (aka Two-Alternatives Forced Choice Score 2AFC) for the situation of polychotomous observations (ordinal) and ensemble forecasts

Usage

afc.me(obsv, fcst, m = 3, na.rm = FALSE)

Arguments

obsv: vector with polychotomous observations (values in {1,..,m})
fcst: two-dimensional array with ensemble forecasts; dim(fcst)[1] = length(obsv); dim(fcst)[2] = ensemble size
m: number of observation categories (default = 3)
na.rm: logical; if TRUE pairs where obsv or fcst is NA are removed before scoring. Default FALSE returns NA if any input contains NA.

Value

p.afc: Value of Generalized Discrimination (2AFC) Score

Details

This routine first ranks the ensemble forecasts (see rank.ensembles) and then calculates the 2AFC-score with Eq.18 of Mason and Weigel (2009).

References

S.J. Mason and A.P. Weigel, 2009. A generic verification framework for administrative purposes. Mon. Wea. Rev., 137, 331-349

Author

Andreas Weigel, Federal Office of Meteorology and Climatology, MeteoSwiss, Zurich, Switzerland

Examples

  data(cnrm.nino34.me)
  obsv = cnrm.nino34.me$obsv
  fcst = cnrm.nino34.me$fcst
  afc.me(obsv,fcst,4)
#> [1] 0.9261863