Case study 3.1 - Predicting Patterns: What does La Niña look like?
During this activity your students will:
- Predict the local effects of La Niña based on the mechanics of El Niño.
- Create precipitation intensity maps for the three states of the El Niño Southern Oscillation.
- Predict the regional coastal effects of ENSO based on its mechanics.
- Consider the global effects of ENSO and its potential long-term impacts.
My goals in creating this activity were to:
- Encourage students to think critically about cause and effect in the climate system.
- Teach students to analyze a system using process mechanics/first principles.
- Enable students to predict system outcomes given changes in state or variables.
Context for Use
Prior to the activity some exposure to El Niño will be necessary. If you are using the rest of Unit 3, which includes lecture material, no additional instruction is necessary.
This activity takes roughly 30 min and can be used
- as a solitary activity in an introductory geology, meteorology, geography, or environmental science class,
- as a lab on ocean surface oscillations when coupled with case studies 2.1, 2.2, 3.2, 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 the first half of the activity, students demonstrate their knowledge and understanding of El Niño (ENSO+) and ENSO normal conditions by identifying their SST expressions. They then use ENSO mechanics to create a sea surface temperature map for La Niña. This exercise helps them to learn about La Niña as an expression of the ENSO system, rather than as a separate phenomenon.
In the second half, students create precipitation maps for all three ENSO conditions. This part of the activity will likely take a little more time, since they have to process the atmospheric connection between SST and precipitation in concert with three different expressions. Even if they have seen diagrams of ENSO including precipitation, students may have some difficulty making the appropriate connections. This exercise allows them to synthesize and evaluate what they've learned about climate and El Niño.
Questions embedded in the activity ask them to reflect on their projections and the nature of ENSO. Many of your students' 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 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 their predictions from this activity with real SST anomaly maps from Case study 3.2.
- Case study 3.1 student handout/assignment (Microsoft Word 113kB Aug25 13)
- Case study 3.1 student handout/assignment (Acrobat (PDF) 220kB Aug25 13)
- Case study 3.1 instructor notes (Microsoft Word 114kB Aug25 13)
- Case study 3.1 instructor notes (Acrobat (PDF) 222kB Aug25 13)
Teaching Notes and Tips
Some students may have difficulty projecting La Niña.
- First ask them to review and perhaps diagram the El Niño and normal conditions. From there ask them to increase wind strength and predict how the process diagram would change, then it should be easier to progress to a temperature map.
- If they still do not grasp the mechanics, ask them to consider what happens when wind strength decreases, which they should already know from El Niño, and simply ask what they think would happen if the opposite occurred.
Depending on the rest of your course material and your students' experience, you may have to approach the projection of precipitation intensity differently.
- Because of the nature of tropical precipitation and the structure of my climate course, I build the discussion on convection, which they have already learned in the context of both plate tectonics and the Coriolis effect.
- Once they have made a connection between SST and precipitation, the task is simply to translate the three temperature maps they have into precipitation intensity maps.
- If you prefer, you can simplify the assignment by telling them only to mark areas of high precipitation, rather than filling in the whole map.
References and Resources
- NOAA: La Niña
- film: Australia - Eye of the Storm - La Niña
- article: Are more frequent or intense La Niñas in our future?
- article: Missouri River Flood Drama Likely Took Direction from La Niña
- article: 2010 Climate Events Connected to El Niño or La Niña
- article: Winter Temperatures Influenced by North Atlantic Oscillation, La Niña
- article: Innovative Farmers Look to Climate Forecasts for an Edge
- 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