| SCI-package {SCI} | R Documentation |
Standardized Climate Indices Such as SPI, SRI or SPEI
Description
Functions for generating Standardized Climate Indices (SCI). SCI is a transformation of (smoothed) climate (or environmental) time series that removes seasonality and forces the data to take values of the standard normal distribution. SCI was originally developed for precipitation. In this case it is known as the Standardized Precipitation Index (SPI).
Details
| Package: | SCI |
| Type: | Package |
| Version: | 1.0-2 |
| Date: | 2016-05-02 |
| License: | GPL (>= 2) |
Author(s)
Lukas Gudmundsson & James Stagge
Maintainer: Lukas Gudmundsson <lukas.gudmundsson@env.ethz.ch>
References
Stagee, J.H. ; Tallaksen, L.M.; Gudmundsson, L.; van Loon, A.; Stahl, K.: Candidate Distributions for Climatological Drought Indices (SPI and SPEI), 2015, International Journal of Climatology, 35, 4027-4040, doi:10.1002/joc.4267.
Stagee, J.H. ; Tallaksen, L.M.; Gudmundsson, L.; van Loon, A.; Stahl, K.: Response to comment on "Candidate Distributions for Climatological Drought Indices (SPI and SPEI)", 2016, International Journal of Climatology, 36, 2132-2138, doi:10.1002/joc.4564.
Examples
## create artificial data, resembling precipitation
set.seed(101)
n.years <- 60
date <- rep(1:n.years,each=12) + 1950 + rep((0:11)/12,times=n.years)
PRECIP <- (0.25*sin( 2 * pi * date) + 0.3)*rgamma(n.years*12, shape = 3, scale = 1)
PRECIP[PRECIP<0.1] <- 0
## apply SCI transformation
spi.para <- fitSCI(PRECIP,first.mon=1,time.scale=6,distr="gamma",p0=TRUE)
spi <- transformSCI(PRECIP,first.mon=1,obj=spi.para)
plot(date,spi,t="l")