Description Usage Arguments Value Types References See Also Examples

Using plotting positions as described in Wilks (2011), counts of occurrences per forecast category are converted to probabilities of occurrence. For ensembles of size 1 (e.g. verifying observations), the count vector is returned unaltered (corresponding to occurrence probabilities of 0 or 1).

1 | ```
count2prob(x, type = 3)
``` |

`x` |
input matrix of counts from |

`type` |
selection of plotting positions (default to 3, see Types) |

Matrix of probabilities per category

The types characterize the plotting positions as specified in Wilks (2011). The plotting positions are computed using the following relationship:

*p(x_i) = (i + 1 - a)/(n + 1 - a)*

where i is the number of ensemble members not exceeding x, and n is the number of ensemble members. The types are characterized as follows:

type | description | a |

1 | Weibull | 0 |

2 | Bernard and Bos-Levenbach | 0.3 |

3 | Tukey | 1/3 |

4 | Gumbel | 1 |

5 | Hazen | 1/2 |

6 | Cunnane | 2/5 |

Wilks, D.S. (2011). Statistical methods in the atmospheric sciences (Third Edition). Academic press.

`convert2prob`

for conversion of continuous forecasts to ensemble counts

1 2 3 4 5 | ```
tm <- toymodel()
## convert to tercile forecasts (only display first forecast and obs)
count2prob(convert2prob(tm$fcst, prob=1:2/3))[1,]
count2prob(convert2prob(tm$obs, prob=1:2/3))[1,]
``` |

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