enso: Ocean Climate Indices
In eeholmes/SardineForecast: Indian Oil Sardine Data, Code and References for Papers on Forecasting

Description Usage Format Details References

Oceanic Nino Index, Equatorial Southern Oscillation Index and Dipole Mode Index

enso

A data frame with variables:

Year
Month: For ONI and SOI, this is a 3-month average. Jan value is average of Dec-Jan-Feb. Qtr would be denoted JFM.
ONI: The ONI index value
SOI: The SOI index value
DMI: The DMI index value
MEI: The MEI index value
NAO: The NAO index value
PDO: The PDO index value
AMO: The AMO index value

The ONI index is 3 month running mean of ERSST.v5 SST anomalies in the Niño 3.4 region (5°N-5°S, 120°-170°W)], based on centered 30-year base periods updated every 5 years. The ONI was downloaded as follows:

require(XML)
require(RCurl)
require(httr)
oni=read.table("http://www.cpc.ncep.noaa.gov/data/indices/oni.ascii.txt", stringsAsFactors=FALSE)

The SOI used is the Equatorial SOI monthly. The data were downloaded with the following code.

1	soi=read.table("http://www.cpc.ncep.noaa.gov/data/indices/reqsoi.for", stringsAsFactors=FALSE)

The DMI is the monthly Dipole Mode Index. The DMI (also IOD index) is defined by the SSTA difference between the western Indian Ocean (10°S–10°N, 50°E–70°E) and the southeastern Indian Ocean (10°S–0°, 90°E–110°E). The data were downloaded from the NOAA Earth Systems Research Laboratories with the following code.

1	dmi=read.table("https://www.esrl.noaa.gov/psd/gcos_wgsp/Timeseries/Data/dmi.long.data", skip=1, nrows=149)

The NAO is the monthly North Atlantic Oscillation Index. The North Atlantic Oscillation (NAO) index is based on the surface sea-level pressure difference between the Subtropical (Azores) High and the Subpolar Low. The data were downloaded from the NOAA Climate Prediction Center with the following code.

1	nao = read.table("ftp://ftp.cpc.ncep.noaa.gov/wd52dg/data/indices/nao_index.tim", skip=9, nrows=length(1950:2018)*12)

The PDO is the monthly Pacific Decadal Oscillation Index and the AMO is the Atlantic Multidecadal Oscillation. The PDO is an index of the sea surface temperature anomalies over the North Pacific Ocean. The AMO is based on sea-surface temperature oscillations in the North Atlantic Ocean. The data were downloaded from the NOAA Physical Sciences Laboratory with the following code.

1
2

pdo = read.table("https://psl.noaa.gov/tmp/gcos_wgsp/data.143.131.2.6.325.11.4.55", skip=0, nrows=length(1948:2017)*12)
amo <- read.table("https://psl.noaa.gov/tmp/gcos_wgsp/data.143.131.2.6.325.11.25.33", skip=0, nrows=length(1948:2017)*12)