Exploring El Niño

Kevin Theissen, University of St. Thomas (MN)
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Initial Publication Date: June 13, 2014 | Reviewed: June 24, 2014


In this introductory-level lab activity, students first view a 20-minute portion of an informative video to learn about the operation of an array of moored buoys that is used to detect changes in the El Niño Southern Oscillation (El Niño, "normal", and La Niña conditions)in the equatorial Pacific Ocean. Students then directly access, display, and work with recent and present data collected from the buoy system using the Tropical Atmosphere Ocean project website. Finally, students examine data from a coral geochemical record to infer past ENSO events.

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Introductory-level course in paleoclimatology. Majority of the students are non-majors.

Skills and concepts that students must have mastered

  • Basic understanding of ocean stratification and the factors that influence it.
  • Ability to make and neatly format a data plot in Microsoft Excel.
  • Understand the influence of seawater temperature on oxygen isotopic values.

How the activity is situated in the course

This lab activity is done in tandem with a portion of a lecture on ENSO. Students will have had previous instruction on ocean circulation and stratification and oxygen isotopes in the course.


Content/concepts goals for this activity

  • Explore the oceanographic conditions that are characteristic of various ENSO modes in the equatorial Pacific Ocean and how these conditions are monitored and tracked.
  • Understand the concept of an anomaly and its significance in monitoring present climate conditions as well as past ones.
  • Recognize the socioeconomic impacts of ENSO (and especially El Niño events) around the world.

Higher order thinking skills goals for this activity

Reading and interpreting various types of data plots (contoured surface, cross-section, and time series plots; anomaly plots).

Comparing and evaluating data to make a diagnosis (i.e. are current conditions indicative of a developing El Niño event?)

Other skills goals for this activity

  • "Web-mining" for data using the internet.
  • Using Excel as a tool to work with data.

Description and Teaching Materials

The video clip that I use to begin the exercise (Part A) comes from the NOVA program "Chasing El Niño". The video is available on YouTube (https://www.youtube.com/watch?v=TYR3GcSLHco) if you don't have access to a copy. I make use of approximately the first 20 minutes of the program. Students then have an opportunity to ask follow-up questions before we walk through the characteristics of El Niño and "normal" and La Niña conditions in the equatorial Pacific ocean. Students will need to access the Tropical Atmosphere Ocean project (TAO) website (http://www.pmel.noaa.gov/tao/) to complete Part B of the exercise. The lab handout gives "cookbook" instructions to students to carry out the touring and data display tasks I have set for them. Part C of the exercise requires that students access an excel file and then plot a time-series record of oxygen isotopic data from coral collected in the Galapagos islands which is in many ways the sweet spot for detecting ENSO events.
Student handout for Exploring El Nino lab exercise (Acrobat (PDF) 707kB Jun12 14)

Urvina Bay coral oxygen isotope data set (Excel 27kB Jun12 14)

Example TAO data plots (Acrobat (PDF) 231kB Jun12 14)

Teaching Notes and Tips

I encourage folks who are interested in using data from the TAO project (buoy data) to first play with the features of the website a bit. I have found it to be very user-friendly and yet also really powerful in terms of data display capabilities.

The lab as shown in the exercise handout should take most students about 2 hours to complete. In an intermediate-level Oceanograpy course that I also teach, I do a longer variation on this lab in which the students use data from the buoy array to explore a specific ENSO event more closely and then make a brief presentation to their peers and instructor.

The video portion of the activity could alternatively be done as a pre-lab assignment allowing the instructor to begin the lab with a discussion and review of the characteristics of various ENSO modes -or- more time to play with data.


  1. The exercise is graded for quality of the responses on the student handout.
  2. Students are later given questions showing ENSO data from the TAO buoy array on an exam to assess their learning and retention.

References and Resources