The Azimuth Project
Experiments in El Niño analysis and prediction (Rev #7)

Background

A short video explains El Niño issues in a simple way:

Tutorial information on climate networks, and their application to El Niño signal processing:

This paper explains how climate networks can be used to recognize when El Niño events are occurring:

This paper on El Niño prediction created a stir:

A lot of the methodology seems to come from this free paper:

This paper is also relevant:

Action plan for improving on the paper

The paper (WHICH PAPER???) is based on data available from the National Centers for Environmental Prediction and the National Center for Atmospheric Research Reanalysis I Project:

More precisely, there’s a bunch of files here containing worldwide daily average temperatures on a 2.5 degree latitude × 2.5 degree longitude grid (144 × 73 grid points), from 1948 to 2010. If you go here the website will help you get data from within a chosen rectangle in a grid, for a chosen time interval.

The paper (WHICH PAPER) uses daily temperature data for “14 grid points in the El Niño basin and 193 grid points outside this domain” from 1981 to 2014. That’s 207 locations and 34 years. The paper starts by taking these temperatures, computing the average temperature at each day of the year at each location, and subtracting this from the actual temperatures to obtain “temperature anomalies”. In other words, they use a big array of numbers like this: the temperature on March 21st 1990 at some location, minus the average temperature on all March 21sts from 1981 to 2014 at that location. Then they process this array of numbers in various ways, which I can explain… They consider all pairs of locations, so at some point they are working with 207 × 207 × 365 × 34 numbers.

A first look at some of the data

This shows surface air temperatues over the Pacific for 1951.

Yearly mean temperatures over the pacific in 1951

To see how this image was made: R code for pacific1951 image

Second look

To see how this image was made: R code to display 6 years of Pacific temperatures

Third look

Temperatures in the pacific in early 1957 and 1958

The rectangle is roughly the area where the El Niño index NINO3.4 is defined.

category: climate, experiments