Case Study 3.2 - Exploring Patterns: ENSO on the Global Stage
- Read global sea surface temperature (SST) anomaly maps.
- Assess the state of the El Niño-Southern Oscillation from SST anomaly maps.
- Create a time line of changes in ENSO conditions.
- Assess the recurrence interval of the ENSO system.
My goals in creating this activity were to:
- Encourage students to think critically about cause and effect in the climate system.
- Help students to process the connections between different ocean surface anomalies.
- Allow students to discover both the patterns in and uncertainties of ocean-atmosphere phenomena.
- Empower students to use their observational and quantitative skills to gain deeper understanding of Earth processes.
Context for Use
Prior to the activity some discussion of ENSO will be necessary. If you are using the rest of Unit 3, no additional instruction is necessary.
For the second part of the the activity, students will need to know how or be taught to calculate recurrence intervals.
This activity takes roughly 35 minutes and can be used
- as a solitary activity in an introductory geology, meteorology, geography, or environmental science class,
- as a lab on ENSO when coupled with case studies 2.1, 2.2, 3.1, and/or your own material, or
- as part of the complete Climate of Change InTeGrate Module and/or Unit 3 during or outside class time.
Description and Teaching Materials
In this activity students analyze data maps of SST anomaly for early December of 1997 to 2011 (1 per 2 yrs) and create an ENSO time line. Not all of the maps are straightforward with regard to oscillation expression, so you should be prepared to counsel students on how to make sense of real ocean data. (See below for tips.) This exercise allows them to synthesize what they have learned and evaluate global ocean surface data.
Questions embedded in the activity ask them to reflect on their findings and the nature of ocean-atmosphere systems. Many of the responses will vary in both correctness and insight. Depending on the rest of your course material and students' experiences, you will have to gauge acceptability of some responses; so the instructor's notes are simply a guide and not a key.
The display version of the time series of SST maps is available in case you cannot print student assignments in color.
There are further opportunities for reflection and synthesis if you complete both Unit 3 activities, as students will be able to compare the real ENSO maps from this activity with their predictions from Case Study 3.1.
- Case Study 3.2 Student Handout/Assignment (Microsoft Word 4.2MB Oct21 16)
- Case Study 3.2 Student Handout/Assignment (Acrobat (PDF) 2.8MB Aug25 13)
- Case Study 3.2 Display (PowerPoint 2007 (.pptx) 3.4MB Sep15 12)
- Case Study 3.2 Display (Acrobat (PDF) 715kB Sep15 12)
Teaching Notes and Tips
- Talk about how to look at the maps—what the anomaly data really mean.
- Suggest an anchor, something that is easy to recognize, like the light yellow and blue of normal temps or a strong El Niño signature. (Notice the series starts with the intense El Niño of 1997.)
- Students may find it easiest to start the time line with the full span, mark the recognizable peaks in first, and then fill in the rest around those they see most clearly.
- If the students struggle with their initial identifications, point out an example or two to get them started.
References and Resources
- NOAA ESRL: The Global Climate during El Niño and La Niña
- ENSO-Related Rainfall Patterns over the Tropical Pacific
- Tropical Atmosphere Ocean project (TAO)
- animation: TAO ENSO Model
- video: TAO ENSO Observing System