Nino indices, North Atlantic Oscillation (NAO), Souther Oscillation Index (SOI)

Overview

The goal of this diagnostic is to compute indices based on area averages.

In recipe_combined_indices.yml, after defining the period (historical or future projection), the variable is selected. The predefined areas are:

Nino 3
Nino 3.4
Nino 4
North Atlantic Oscillation (NAO)
Southern Oscillation Index (SOI)

Available recipes and diagnostics

Recipes are stored in recipes/

recipe_combined_indices.yml

Diagnostics are stored in diag_scripts/magic_bsc/

combined_indices.R : calculates the area-weighted means and multi-model means, with or without weights

User settings

User setting files are stored in recipes/

recipe_combined_indices.yml

Required settings for script

region: one of the following strings Nino3, Nino3.4, Nino4, NAO, SOI

running_mean: an integer specifying the length of the window (in months) to be used for computing the running mean.

moninf: an integer can be given to determine the first month of the seasonal mean to be computed (from 1 to 12, corresponding to January to December respectively).

monsup: an integer specifying the last month to be computed (from 1 to 12, corresponding to January to December respectively).

standardized: ‘true’ or ‘false’ to specify whether to compute the standarization of the variable.

Required settings for preprocessor (only for 3D variables)

extract_levels:

levels: [50000] # e.g. for 500 hPa level

scheme: nearest

Variables

all variables (atmos/ocean, monthly, longitude, latitude, time)

Observations and reformat scripts

None

References

Trenberth, Kevin & National Center for Atmospheric Research Staff (Eds). Last modified 11 Jan 2019. “The Climate Data Guide: Nino SST Indices (Nino 1+2, 3, 3.4, 4; ONI and TNI).” Retrieved from https://climatedataguide.ucar.edu/climate-data/nino-sst-indices-nino-12-3-34-4-oni-and-tni.

Example plots

../_images/Nino3.4_tos_Dec-Feb_running-mean__1950-2005.png

Time series of the standardized sea surface temperature (tos) area averaged over the Nino 3.4 region during the boreal winter (December-January-February). The time series correspond to the MPI-ESM-MR (red) and BCC-CSM1-1 (blue) models and their mean (black) during the period 1950-2005 for the ensemble r1p1i1 of the historical simulations.