Topic Guide:  El Nino


In this activity you will form groups, conduct research into the El Nino phenomenon, and report back to your lab section in the form of a presentation. At the end of this activity you will find suggestions for the format of the presentation. You will use the data you investigate as evidence for your statements. Please use these suggestions and the “How to make a class presentation” (Resource 1) as guidelines for your presentation.



The El-Nino affects the weather in nearly every nation. It is interesting that a phenomenona that occur primarily in the equatorial region would have such widespread impacts. Not only are fisheries affected, but there are rainfall increases in some location and droughts in others. A great deal of research, including a lotof data acquisition, has been conducted and scientists now have some confidence that they understand the El-Nino and can predict it about a year in advance.


A phenomena related to the El-Nino (or ENSO), is the La-Nina, a period of colder than normal equatorial waters that follows El-Nino. These phenomena illustrate the importance of sea surface temperatures on the global weather patterns.


Key processes and concepts to review before beginning:



After completing this investigation you should be able to:

1) Explain the El Nino phenomena

2) Predict the development of the El Nino

3) Understand the beneficial as well as negative effects of El Nino


You can go straight into exploring the data, but if you need more background information about paleoclimate, please review the websites that provide background information (found after the data section).


Background Information and Data:

It is important that you understand what the El Nino, which is sometimes referred to as ENSO (El Nino - Southern Oscillation), and La Nina cyclic phenomena are.

This site will help you answer the basic questions about El Nino. Be sure to notice how El Nino affects your Earth Summit country.


What is the El Nino phenomenon?


What is La Nina?


How is La Nina different than El Nino?


What happens to upwelling and primary productivity during an El Nino event?


While patterns evident in the data you can use this table to keep track of the physical changes that occur as the El Nino and La Nina phenomena cycle.


Conditions             Trade winds            SST                         SSL                   Primary productivity










El Nino






La Nina




Carefully examine the three graphics, of sea surface temperatures (SST) for La Nina, normal conditions, and El Nino.

What are the differences between the sea surface temperatures for the three conditions?


Access Ferret Live Access Server: 

(link: on using Ferrett Live Access Server:

In the left hand panel, find “Atlas of Surface Marine Data 1994.” Click on the (+) sign at the left of the entry. Next, click on “sea surface temperature anomaly.” Now you will need to limit the area to the Pacific Ocean region by pulling the data box smaller. You can also go to the pull down menu under the red “get data” button and choose South Pacific region, but you will need to change the latitude constraints the box slightly to include the area from Southern California to Central South America. Access the data for January 1982 by using the pull down menu. The exact day doesn’t matter, but pick a day mid-month. Hit the red “get data” button. You will need to download the image to the desktop as this interface doesn’t allow two (or more) images to be show simultaneously. To save the image on a Mac, under “file” pull down menu, chose “save as.” On a PC, use the right mouse to save the image. You will need to label the figure (i.e.: Jan1982). Access and download the data for September 1982 so you can compare the two months and see the changes that occurred in SST as the 1982 El Nino grew.


Describe major changes in the pattern of SST occurring off the South American coast?


Models of El-Nino:

Idealized ENSO Simulation

This animation takes into account changes in sea surface temperature and height during El Nino/La Nina cycles. Be sure to identify the axes of the graph to understand what is happening in the animation. You already know what happens to SST during an El Nino, but what happens to sea surface levels (SSL)?

What is the relationship between the Trade Winds and El Nino? What affect do these winds have on sea surface height? Why is it that during non-El Nino years, the water off South America is cooler than during El Nino years?


Are we currently in an El Nino?



What are some of the global effects of El-Nino on precipitation?

Additional Data:

The Worldwatcher software also contains numerous datasets pertinent to the study of El-Nino. For example, monthly global precipation data are available for the years 1982 to 1994. You can access these by clicking on “Geography” at  the WorldWatcher Welcome window, then “Atmosphere”, then choose data from the precipitation menu.


More background information:

Please take some time to browse the links for information on the topic of El Nino. If you learn something new and interesting, please share it with the lab in your presentation.


Presentation Framework

Your presentation should include a brief overview explaining the significance of El Nino. You should then choose as many of the following topics as is necessary to explain the concept. Choose topics that you think might be relevant to understanding the El Nino phenomena. Your presentation should include interesting findings from your investigations, backed up with data. You must use the physical data in your presentation.


You may choose from the following list of topics, or investigate a topic of your own. The topics in the list are examples of investigations that could be made using the data available at the URL’s listed above.


Data driven topics : 


Overview type topics:


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