Last data update: 2014.03.03

R: EMOS modeling
ensembleMOSR Documentation

EMOS modeling

Description

Fits a EMOS model to ensemble forecasts. Allows specification of a model, training rule, and forecasting dates.

Usage

ensembleMOS(ensembleData, trainingDays, consecutive = FALSE,
            dates = NULL, control = NULL, warmStart = FALSE,
            model = NULL, exchangeable = NULL)

Arguments

ensembleData

An ensembleData object including ensemble forecasts with the corresponding verifying observations and their dates. Missing values (indicated by NA) are allowed.

trainingDays

An integer giving the number of time steps (e.g. days) in the training period. There is no default.

consecutive

If TRUE then the sequence of dates in the training set are treated as consecutive, i.e. date gaps are ignored

dates

The dates for which EMOS forecasting models are desired. By default, this will be all dates in ensembleData for which modeling is allowed given the training rule.

control

A list of control values for the fitting functions. The default is controlMOSnormal() for Gaussian (normal) models.

warmStart

If TRUE, then starting values for parameters in optimization are set to the estimates of the preceding date's fit.

model

A character string describing the EMOS model to be fit. Current choices are "normal", typically used for temperature or pressure data. For specific details on model fitting see ensembleMOSnormal

exchangeable

A numeric or character vector or factor indicating groups of ensemble members that are exchangeable (indistinguishable). The model fit will have equal weights and parameters within each group. The default determines exchangeability from ensembleData.

Details

If dates are specified in dates that cannot be forecast with the training rule, the corresponding EMOS model parameter outputs will be missing (NA) but not NULL.
The training rule uses the number of days corresponding to its length regardless of whether or not the dates are consecutive.

Value

A list with the following output components:

training

A list containing information on the training length and lag and the number of instances used for training for each modeling date.

a

A vector of fitted EMOS intercept parameters for each date.

B

A matrix of fitted EMOS coefficients for each date.

c,d

Vectors of the fitted variance parameters for each date, see ensembleMOSnormal for details.

References

T. Gneiting, A. E. Raftery, A. H. Westveld and T. Goldman, Calibrated probabilistic forecasting using ensemble model output statistics and minimum CRPS estimation. Monthly Weather Review 133:1098–1118, 2005.

See Also

trainingData, ensembleMOSnormal, controlMOSnormal,

Examples

  data(ensMOStest)

  ensMemNames <- c("gfs","cmcg","eta","gasp","jma","ngps","tcwb","ukmo")

  tempTestData <- ensembleData( forecasts = ensMOStest[,ensMemNames],
                                dates = ensMOStest[,"vdate"],
                                observations = ensMOStest[,"obs"],
                                station = ensMOStest[,"station"],
                                forecastHour = 48,
                                initializationTime = "00")

  tempTestFit <- ensembleMOS( tempTestData, trainingDays = 30,
                               model = "normal")

 ## Same as
 ## tempTestFit <- ensembleMOSnormal( tempTestData, trainingDays = 30)

Results