R/EnsCorr.R

In easyVerification: Ensemble Forecast Verification for Large Data Sets

# EnsCorr.R Correlation with Ensemble Mean
#
#     Copyright (C) 2016 MeteoSwiss
#
#     This program is free software: you can redistribute it and/or modify
#     it under the terms of the GNU General Public License as published by
#     the Free Software Foundation, either version 3 of the License, or
#     (at your option) any later version.
#
#     This program is distributed in the hope that it will be useful,
#     but WITHOUT ANY WARRANTY; without even the implied warranty of
#     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#     GNU General Public License for more details.
#
#     You should have received a copy of the GNU General Public License
#     along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

#' Correlation with Ensemble Mean
#'
#' Computes the ensemble mean correlation (Pearson) with the verifying
#' observations.
#'
#' @param ens n x k matrix of n forecasts from k ensemble members
#' @param obs n verifying observations
#'
#' @examples
#' tm <- toymodel()
#'
#' ## compute correlation directly
#' EnsCorr(tm$fcst, tm$obs)
#'
#' ## compute correlation using veriApply
#' veriApply("EnsCorr", tm$fcst, tm$obs)
#'
#' @seealso \code{\link{veriApply}}
#'
#' @export
EnsCorr <- function(ens, obs) {
  stopifnot(is.matrix(ens), is.vector(obs), length(obs) == nrow(ens))
  return(cor(rowMeans(ens), obs, use = "p"))
}