Southern Oscillation Index

Source: R/soi.R

soi is a data frame containing the Southern Oscillation Index with columns named year for decimal year (sampled monthly and represented at mid-month) and index for the index.

data(soi, package="ocedata")

Details

The data were downloaded on August 11, 2017, and processed as follows.

library(ncdf4)
url <- "https://www.cgd.ucar.edu/cas/catalog/climind/SOI.nc"
download.file(url, "SOI.nc")
f <- nc_open("SOI.nc")
year <- as.vector(ncvar_get(f, "TIME"))
index <- as.vector(ncvar_get(f, "SOI_SIGNAL"))
ok <- is.finite(index)
year <- year[ok]
index <- index[ok]
soi <- data.frame(year=year, index=index)

Examples

data(soi, package="ocedata")
recent <- subset(soi, year > 1950)
plot(recent$year, recent$index, type='l', xlab="Year", ylab="SOI")