[R-pkgs] Introducing the rsoi package

[Sam Albers]

Hi folks,

I am pleased to announce that the rsoi is now up on CRAN (v0.2.1
https://CRAN.R-project.org/package=rsoi). rsoi is a minimal but
hopefully useful package to folks that are looking for easy access in
R to Southern Oscillation Index and Oceanic Nino Index data.

rsoi uses data collected by the National Oceanic Atmospheric
Administration. Their data are usually updated monthly. Data are
downloaded and formatted for use in R by the `download_enso()`
function. El Nino, La Nina and neutral periods of ENSO are categorized
by temperature anomalies from a 30 year base period in the Central
South Pacific Ocean.

Suggestions and contributions are very much welcome at the rsoi github
page: https://github.com/boshek/rsoi

-Sam