climpred.metrics._std_ratio#

climpred.metrics._std_ratio(forecast: xarray.Dataset, verif: xarray.Dataset, dim: Optional[Union[str, List[str]]] = None, **metric_kwargs: Any) → xarray.Dataset[source]#

Ratio of standard deviations of the forecast over the verification data.

\text{std ratio} = \frac{\sigma_f}{\sigma_o},

where \sigma_{f} and \sigma_{o} are the standard deviations of the forecast and the verification data over the experimental period, respectively.

Parameters

  • forecast – Forecast.

  • verif – Verification data.

  • dim – Dimension(s) to perform metric over.

  • metric_kwargs – see xarray.std

Notes

minimum

0.0

maximum

∞

perfect

1.0

orientation

N/A

References

Example

>>> HindcastEnsemble.verify(
...     metric="std_ratio",
...     comparison="e2o",
...     alignment="same_verifs",
...     dim="init",
... )
<xarray.Dataset>
Dimensions:  (lead: 10)
Coordinates:
  * lead     (lead) int32 1 2 3 4 5 6 7 8 9 10
    skill    <U11 'initialized'
Data variables:
    SST      (lead) float64 0.7567 0.8801 0.9726 1.055 ... 1.075 1.094 1.055
Attributes:
    prediction_skill_software:     climpred https://climpred.readthedocs.io/
    skill_calculated_by_function:  HindcastEnsemble.verify()
    number_of_initializations:     64
    number_of_members:             10
    alignment:                     same_verifs
    metric:                        std_ratio
    comparison:                    e2o
    dim:                           init
    reference:                     []