The Oceanic Nino Index is average sea surface temperature in the Nino 3.4 region (120W to 170W) averaged over three months. Phases are categorized by Oceanic Nino Index:

  • Warm phase of El Nino/ Southern Oscillation when 3-month average sea-surface temperature departure of positive 0.5 degC

  • Cool phase of La Nina/ Southern Oscillation when 3-month average sea-surface temperature departure of negative 0.5 degC

  • Neutral phase is defined as when the three month temperature average is between +0.5 and -0.5 degC

download_oni(use_cache = FALSE, file = NULL)

Arguments

use_cache

logical option to save and load from cache. If `TRUE`, results will be cached in memory if `file` is `NULL` or on disk if `file` is not `NULL`.

file

optional character with the full path of a file to save the data. If `cache` is `FALSE` but `file` is not `NULL`, the results will be downloaded from the internet and saved on disk.

Value

  • Date: Date object that uses the first of the month as a placeholder. Date formatted as date on the first of the month because R only supports one partial of date time

  • Month: Month of record

  • Year: Year of record

  • ONI: Oneanic Oscillation Index

  • ONI_month_window: 3 month period over which the Oneanic Oscillation Index is calculated

  • phase: ENSO phase

References

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/detrend.nino34.ascii.txt

Examples

if (FALSE) { oni <- download_oni() }