Description Usage Arguments Value Author(s) References See Also Examples

This function takes an annual exceedance probability and converts it to a “partial-duration series” (a term in Hydrology) nonexceedance probability through a simple assumption that the Poisson distribution is appropriate for arrive modeling. The relation between the cumulative distribution function *G(x)* for the partial-duration series is related to the cumulative distribution function *F(x)* of the annual series (data on an annual basis and quite common in Hydrology) by

*G(x) = [\log(F(x)) + η]/η\mathrm{.}*

The core assumption is that successive events in the partial-duration series can be considered as *independent*. The *η* term is the arrival rate of the events. For example, suppose that 21 events have occurred in 15 years, then *η = 21/15 = 1.4* events per year.

A comprehensive demonstration is shown in the example for `fpds2f`

. That function performs the opposite conversion. Lastly, the cross reference to `x2xlo`

is made because the example contained therein provides another demonstration of partial-duration and annual series frequency analysis.

1 |

`f` |
A vector of annual nonexceedance probabilities. |

`rate` |
The number of events per year. |

A vector of converted nonexceedance probabilities.

W.H. Asquith

Stedinger, J.R., Vogel, R.M., Foufoula-Georgiou, E., 1993, Frequency analysis of extreme events: *in* Handbook of Hydrology, ed. Maidment, D.R., McGraw-Hill, Section 18.6 Partial duration series, mixtures, and censored data, pp. 18.37–18.39.

1 | ```
# See examples for fpds2f().
``` |

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