climdex.spi6: Standardized Precipitation Index 6-mon

View source: R/indices.R

climdex.spi6R Documentation

Standardized Precipitation Index 6-mon

Description

Adapted by ClimPACT2 and SPEI (arguments taken from here) libraries. Given a timeseries of daily precipitation amounts [mm], the function calculates the Standardized Precipitation Index (SPI) as it is created and defined by the SPEI library. This function computes the climdex index spi at multiple scales.

Usage

climdex.spi6(ci, freq = c("monthly"), scale = 6, distribution = "Gamma",
  fit = "ub-pwm", kernal = list(type = "rectangular", shift = 1),
  ref.start = NULL, ref.end = NULL)

Arguments

ci

Object of type climdexInput (representing the daily precipitation [mm])

freq

Time frequency to aggregate to. Allowed only monthly

scale

an integer, representing the time scale at which the SPI will be computed. Default is 3

distribution

name of the distribution function to be used for computing the SPI (default ’Gamma’)

fit

name of the method used for computing the distribution function parameters (default 'ub-pwm')

ref.start

optional, starting point of the reference period used for computing the index. Defaults to NULL, indicating that the first value in data will be used as starting point.

ref.end

optional, ending point of the reference period used for computing the index. Defaults to NULL, indicating that the last value in data will be used as ending point.

kernel

optional, a list defining the type of kernel used for computing the SPI atscales higher than one. Defaults to unshifted rectangular kernel.

...

For more details please refer to the SPEI

Value

A vector containing a monthly SPI at the selected scale

Author(s)

Christiana Photiadou (KNMI)

References

http://www.ecad.eu/documents/atbd.pdf

https://cran.r-project.org/web/packages/SPEI/SPEI.pdf


ECA-D/climind documentation built on Nov. 26, 2022, 10:20 a.m.