Extremes | R Documentation |

This function returns the number of spells of more than
`min.length`

days which exceed or are below the given `threshold`

from daily data.

```
Extremes(
data,
threshold,
op = ">",
min.length = 6,
spells.can.span.years = TRUE,
max.missing.days = 5,
dates = NULL,
timedim = NULL,
calendar = NULL,
ncores = NULL
)
```

`data` |
A n-dimensional array containing daily data. |

`threshold` |
A n-dimensional array with the threshold to be/not to be
reach, usually given by the a percentile computed with the |

`op` |
The operator to use to compare data to threshold. |

`min.length` |
The minimum spell length to be considered. |

`spells.can.span.years` |
Whether spells can span years. |

`max.missing.days` |
Maximum number of NA values per time period. |

`dates` |
A vector of dates with a calendar attributes. If NULL (by default), the 'time' attributes of parameter 'data' are considered. |

`timedim` |
An integer number indicating the position of the time dimension
in the parameter |

`calendar` |
A character indicating the calendar type. |

`ncores` |
The number of cores to be used when computing the extreme. |

This routine compares data to the thresholds using the given
operator, generating a series of TRUE or FALSE values; these values are then
filtered to remove any sequences of less than `min.length`

days of TRUE
values. It then computes the lengths of the remaining sequences of TRUE values
(spells) and sums their lengths. The `spells.can.spa .years`

option
controls whether spells must always terminate at the end of a period, or
whether they may continue until the criteria ceases to be met or the end of
the data is reached. The default for fclimdex is FALSE.

A list of length 2:

`$output1`

, an array with the same dimensions as the original`data`

, except the time dimension which is reduced to annual resolution given a timeseries of maximum spell lengths for each year.`$year`

, a vector indicating the corresponding years.

```
##Example synthetic data:
data <- 1:(2 * 3 * 310 * 1)
dim(data) <- c(time = 310, lon = 2, lat = 3, model = 1)
time <- as.POSIXct(paste(sort(rep(1902:1911, 31)), 1, 1:31, sep = "-"), tz = "CET")
metadata <- list(time = list(standard_name = 'time', long_name = 'time',
calendar = 'noleap',
units = 'days since 1970-01-01 00:00:00',
prec = 'double',
dim = list(list(name = 'time', unlim = FALSE))))
attr(time, "variables") <- metadata
attr(data, 'Variables')$dat1$time <- time
threshold <- Threshold(data, dates = NULL, base.range = NULL, qtiles = 0.9,
ncores = NULL)
res <- Extremes(data, threshold = threshold, op = ">", min.length = 6,
spells.can.span.years = TRUE, max.missing.days = 5,
ncores = NULL)
str(res)
```

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