afc.me {afc}

2AFC For Ordinal Polychotomous Observations And Ensemble Forecasts

Description

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)

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)

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).

Value

p.afc

Value of Generalized Discrimination (2AFC) Score

Author(s)

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

References

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

See Also

afc rank.ensembles

Examples

  #Forecasts and observations of Nino-3.4 index
  #Load set of polychotomous observations (4 categories) and 9-member ensemble forecasts
  data(cnrm.nino34.me)
  obsv = cnrm.nino34.me$obsv
  fcst = cnrm.nino34.me$fcst

  #Calculate skill score
  afc.me(obsv,fcst,4)