537: Masking Settings

Two types of masking can be applied to exclude variables (i.e., gridpoints, stations or indices) either from the analysis or from the forecasting:

  • Dry-masking excludes all variables that have an average value of less than the threshold indicated by "dry mask". It is designed to act as a dry-mask, but in practice it can be applied to any variable. The dry mask can only be set before running Actions ~ Calculate . The average used to apply the mask is calculated using all data from the training period rather than the climatological average, so any variables that are omitted are consistently omitted regardless of the climatological period. These variables are treated as if they were missing values.
  • Skill-masking applies only when calculating retroactive forecasts and when running Tools ~ Forecast . If the skill is less than the threshold indicated by "skill mask" then climatological forecasts will be issued. The skill can be measured using:
    • Pearson's correlation
    • Spearman's correlation
    • Kendall's tau
    • Kendall's tau-c
    The skill is calculated using either the
    • cross-validated hindcasts, or
    • retroactive hindcasts, or
    • fitted values

    depending upon how the forecast error variance (as set in Options ~ Forecast ) is calculated. The skill masking can be reset after running Actions ~ Calculate .

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