El Nino/Southern Oscillation (ENSO) and Related Climate Indices

Description

Downloads Southern Oscillation Index, Oceanic Nino Index, North Pacific Gyre Oscillation data, North Atlantic Oscillation and Arctic Oscillation. Data sources are described in the help files for each function.

Author(s)

Maintainer: Sam Albers sam.albers@gmail.com

Other contributors:

• Elio Campitelli elio.campitelli@cima.fcen.uba.ar [contributor]

See Also

Useful links:

• https://boshek.github.io/rsoi/

• https://github.com/boshek/rsoi

• Report bugs at https://github.com/boshek/rsoi/issues

Download Antarctic Oscillation data

Description

Projection of the monthly 700 hPa anomaly height field south of 20°S on the first EOF obtained from the monthly 700 hPa height anomaly.

Usage

download_aao(use_cache = FALSE, file = NULL)

Arguments

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

• AAO: Antarctic Oscillation

References

https://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/aao/aao.shtml

Examples

## Not run: 
aao <- download_aao()

## End(Not run)

Download Arctic Oscillation data

Description

Projection of the daily 1000 hPa anomaly height field north of 20°N on the first EOF obtained from the monthly 1000 hPa height anomaly.

Usage

download_ao(use_cache = FALSE, file = NULL)

Arguments

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

• AO: Arctic Oscillation

References

https://www.ncei.noaa.gov/access/monitoring/ao/

Examples

## Not run: 
ao <- download_ao()

## End(Not run)

Download Asymmetric and Symmetric SAM indices

Description

Deprecated. The upstream API for the Asymmetric and Symmetric SAM indices is no longer available. These functions now return NULL with a warning.

Usage

download_asymsam_monthly(use_cache = FALSE, file = NULL)

download_asymsam_daily(use_cache = FALSE, file = NULL)

Arguments

Value

NULL (invisibly). A warning is issued.

References

Campitelli, E., Diaz, L. B., & Vera, C. (2022). Assessment of zonally symmetric and asymmetric components of the Southern Annular Mode using a novel approach. Climate Dynamics, 58(1), 161-178. doi:10.1007/s00382-021-05896-5

Examples

## Not run: 
asymsam <- download_asymsam_monthly()

## End(Not run)

Download Dipole Mode Index (DMI)

Description

Intensity of the IOD is represented by anomalous SST gradient between the western equatorial Indian Ocean (50E-70E and 10S-10N) and the south eastern equatorial Indian Ocean (90E-110E and 10S-0N). This gradient is named as Dipole Mode Index (DMI). When the DMI is positive then, the phenomenon is refereed as the positive IOD and when it is negative, it is refereed as negative IOD.

Usage

download_dmi(use_cache = FALSE, file = NULL)

Arguments

Value

• Year: Year of record

• Month: Month of record

• 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

• DMI: Dipole Mode Index

References

https://psl.noaa.gov/gcos_wgsp/Timeseries/DMI/

Examples

## Not run: 
dmi <- download_dmi()

## End(Not run)

Download Southern Oscillation Index and Oceanic Nino Index data

Description

The Southern Oscillation Index is defined as the standardized difference between barometric readings at Darwin, Australia and Tahiti. 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

Usage

download_enso(climate_idx = c("all", "soi", "oni", "npgo"), create_csv = FALSE)

Arguments

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: Oceanic Oscillation Index

• phase: ENSO phase

• SOI: Southern Oscillation Index

• NPGO: North Pacific Gyre Oscillation

Examples

## Not run: 
enso <- download_enso()

## End(Not run)

Download Multivariate ENSO Index Version 2 (MEI.v2)

Description

MEI.v2 is based on EOF analysis of level pressure, sea surface temperature, surface zonal winds, surface meridional winds, and Outgoing Longwave Radiation. The analysis is conducted for 12 partially overlapping 2-month "seasons".

Warm phase is defined as MEI index greater or equal to 0.5. Cold phase is defined as MEI index lesser or equal to -0.5.

Usage

download_mei(use_cache = FALSE, file = NULL)

Arguments

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: Bi-moonthly season of record

• Year: Year of record

• MEI: Multivariate ENSO Index Version 2

• Phase: ENSO phase

References

https://psl.noaa.gov/enso/mei/

Examples

## Not run: 
mei <- download_mei()

## End(Not run)

Download North Atlantic Oscillation data

Description

surface sea-level pressure difference between the Subtropical (Azores) High and the Subpolar Low.

Usage

download_nao(use_cache = FALSE, file = NULL)

Arguments

Value

• Month: Month of record

• Year: Year of record

• NAO: North Atlantic Oscillation

References

https://www.ncei.noaa.gov/access/monitoring/nao/

Examples

## Not run: 
nao <- download_nao()

## End(Not run)

Download North Pacific Gyre Oscillation data

Description

North Pacific Gyre Oscillation data also known as the Victoria mode

Usage

download_npgo(use_cache = FALSE, file = NULL)

Arguments

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

• Year: Year of Record

• Month: Month of record

• NPGO: North Pacific Gyre Oscillation

References

https://www.oces.us/npgo/

Examples

## Not run: 
npgo <- download_npgo()

## End(Not run)

Download Oceanic Nino Index data

Description

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

Usage

download_oni(use_cache = FALSE, file = NULL)

Arguments

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

https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/enso.shtml

Examples

## Not run: 
oni <- download_oni()

## End(Not run)

Download Pacific Decadal Oscillation Data

Description

The PDO index is derived as the leading principal of monthly SST anomalies in the North Pacific Ocean, poleward of 20N. The monthly mean global average SST anomalies are removed to separate this pattern of variability from any "global warming" signal that may be present in the data.

The NCEI PDO index is based on NOAA's extended reconstruction of SSTs (ERSST Version 4). It is constructed by regressing the ERSST anomalies against the Mantua PDO index for their overlap period, to compute a PDO regression map for the North Pacific ERSST anomalies. The ERSST anomalies are then projected onto that map to compute the NCEI index. The NCEI PDO index closely follows the Mantua PDO index.

Usage

download_pdo(use_cache = FALSE, file = NULL)

Arguments

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

• PDO: Pacific Decadal Oscillation index

References

Original PDO: https://www.ncei.noaa.gov/access/monitoring/pdo/

Examples

## Not run: 
pdo <- download_pdo()

## End(Not run)

Download Relative Oceanic Nino Index data

Description

El Niño–Southern Oscillation (ENSO) is often characterized through the use of sea surface temperature (SST) departures from their climatological values, as in the Niño-3.4 index. However, this approach is problematic in a changing climate when the climatology itself is varying. To address this issue, van Oldenborgh et al. proposed a relative Niño-3.4 SST index, which subtracts the tropical mean SST anomaly from the Niño-3.4 index and multiplies by a scaling factor.

• The cold phase was defined as periods in which the RONI values within a sliding five-season window were all below -0.5 degC

• The warm phase was defined as periods in which the RONI values within a sliding five-season window were all above 0.5 degC

• The neutral phase was defined as the situation outside the definitions of warm phase and cold phase

Usage

download_roni(use_cache = FALSE, file = NULL)

Arguments

Value

• Year: Year of record

• Season: Season of record

• roni: Relative Oceanic Niño Index, using the 1991–2020 base period "3 month running mean of ERSST.v5 SST anomalies in the Niño 3.4 region (5°N–5°S, 120°–170°W) with average tropical mean (20°N–20°S) SST anomalies subtracted. The difference is then adjusted so the variance equals the original Niño 3.4 index".

• Start_Month: Start month of record

• End_Month: End month of record

• phase: ENSO phase

References

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso/roni/#latest-data doi:10.1175/JCLI-D-23-0406.1

Examples

## Not run: 
roni <- download_roni()

## End(Not run)

Download Southern Oscillation Index data

Description

The Southern Oscillation Index is defined as the standardized difference between barometric readings at Darwin, Australia and Tahiti.

Usage

download_soi(use_cache = FALSE, file = NULL)

Arguments

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

• SOI: Southern Oscillation Index

• SOI_3MON_AVG: 3 Month Average Southern Oscillation Index

References

https://www.cpc.ncep.noaa.gov/data/indices/soi

Examples

## Not run: 
soi <- download_soi()

## End(Not run)