Lesson Title: El Nino and the Galapagos
Subject Area: Meteorology/Oceanography
Investigation Summary: Using past climate data from the Galapagos Islands, students will construct and
interpret climatograms to recognize patterns in precipitation, ocean temperature, and mean air
temperature in order to classify years as El Nino years.
Approximate Time Needed: 50 to 60 minutes on day 2 of the unit.
Enduring Understandings:
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
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Understanding of relationships between precipitation, sea surface temperature, and air
temperature and their indication of ENSO event.
Scientific Endeavor Knowledge (specific knowledge regarding nature of science or science
process skills): Analysis and interpretation of weather data in order to read and create a
climatogram.
Assessment – what will students do to show they have achieved the enduring understandings?
o Creation of climatogram graphs
o Analysis and understanding questions, detailed notes from reading
 Labeled as “Part C” questions in the unit overview.
Short term understandings:
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SOL’s Addressed: ES.1abcf, ES.2ac, ES.12ab
Learning Targets: Weather data collection/analysis/interpretation, weather forecasting
Assessment – what will students do to show they have achieved the short-term understandings?
o Students will complete the reading, will interpret climatograms, will create two
climatograms, and will answer analysis and understanding questions.
Lesson Overview :
 Materials needed:
o Reading material (below)
o Climatograms for 1965-1998 (below)
o Graph Paper or Excel
o Data collection and graphing can be done in Excel
Detailed Lessons:

See below
Methodology for the student Research
Data: provided in the lesson (below)
Conclusions: Students will recognize relationship between precipitation, sea surface temperature, and
mean air temperature and ENSO conditions
Background Knowledge: Provided in reading (below).
Effects of El Nino
An El Nino is a global weather or climate event that affects populations of organisms and ecosystems in
many areas of Earth. El Nino is a disruption of the ocean/atmospheric system in the tropical Pacific that
has important consequences for weather around the globe. El Nino events occur irregularly at intervals
of 2-10 years, although the average is about once every 3-4 years.
Your first task is to read about the El Nino weather patterns that affect many parts of the world and to
complete the directions and questions below. Throughout the reading, you should focus on making
good, detailed notes in order to increase your comprehension and understanding.
Part A
Read El Nino and the Galapagos. Using the data recorded over the period of 1965-1998, make a list
identifying which years an El Nino event occurred. Remember, an El Nino year is characterized by
increased rainfall, warmer air temperatures, and higher water temperatures.
Part B
On a piece of graph paper (or on Microsoft Excel), using the data below from the years 1993-94 and
1997-98, make climatograms for each set of data (Rain, Air Temperature, Water Temperature) as
modeled for you in the 30-year examples.
Months
Rain
(cm)
Air
Temp
(C)
Water
Temp
(C)
Months
Rain
(cm)
Air
Temp
(C)
Water
Temp
(C)
1993-94, Santa Cruz Island
May
Jun
Jul
Aug
0.2
0.6
1.1
0.6
Jan
3.3
Feb
0.7
Mar
0.0
Apr
0.0
27.6
28.7
27.9
25.9
26.0
24.5
24.0
24.6
25.2
23.5
22.3
22.5
23.1
22.1
Sep
1.0
Oct
0.2
Nov
0.2
Dec
10.6
22.2
22.3
23.9
24.8
26.0
21.3
21.0
22.1
23.5
24.5
Sep
0.5
Oct
0.8
Nov
14.6
Dec
31.7
Jan
0.4
Feb
9.7
Mar
25.3
1997-98, Santa Cruz Island
Apr
May
Jun
Jul
Aug
40.1
13.7 24.7
2.4
1.2
26.1
28.2
29.0
28.7
28.1
27.8
27.5
27.1
27.2
26.9
27.6
28.6
23.0
25.3
26.7
27.1
27.0
26.7
26.4
25.9
25.8
25.8
25.9
26.6
Which of these two years do you think is an El Nino year, and why?
El Nino and the Galapagos
An example of the close relationship between the ocean and the atmosphere is seen in the climate events known
as El Nino and La Nina. Scientists refer to these as ENSO-the El Nino Southern Oscillation.
In 1997-98, the world witnessed a major ENSO event. Near the equator, the eastern portion of the Pacific Ocean
warmed from 5-9 C above normal, resulting in changes to the jet streams in both the northern and southern
hemispheres. The end results were floods or droughts throughout much of the world’s mid-latitudes. California
received increased precipitation (usually rainfall), which led to some flooding, mudslides, and damage to lives and
property. In contrast, the northern states from the Rocky Mountains to the Great Lakes enjoyed a very mild
winter—golf was played all year in Minnesota!
Weather Events
In normal years, the winds tend to blow from east to west across the Pacific, near the equator. The easterly winds
push the surface waters westward across the ocean. In turn, this causes deeper, colder waters to rise to the
surface. This upwelling of deep ocean waters brings with it the nutrients that otherwise would remain near the
bottom. The fish populations living in the upper waters are dependent on these nutrients for survival. During El
Nino years, however, the winds weaken, stopping the upwelling of the colder deep water. As the ocean warms,
the warmer water shifts eastward, as do the clouds and thunderstorms that produce heavy rainfall along the
equator. El Nino events occur every three to five years on average.
These events happen because the relationship between the ocean and the atmosphere is disturbed. Ocean
surface temperatures have to increases by only 1 C for jet streams to bring storms to normally dry regions and
drought to humid regions.
El Nino’s Effects Around the World
The 1982-83 El Nino was very strong. The presence of unusually warm ocean water and the atmospheric changes
combine to produce an unusual increase in the quantity of rainfall along the coast of South America. In Ecuador
and northern Peru, up to 250 cm of rain fell during a six-month period, changing the coastal South American desert
into a grassland dotted with lakes. In coastal terrestrial ecosystems, such as in the Galapagos, this climate change
has important impacts on ecosystems that are linked to the ocean. Unusual wind patterns also caused monsoon
rains to fall over the central Pacific instead of its western edge, which led to droughts and terrible forest fires in
Indonesia and Australia.
Overall, the loss to the world’s economy as a result of El Nino amounted to more than $8 billion. Likewise, the
record-breaking El Nino winter of 1997-98 resulted in unusual weather in many parts of the world. In the United
States, severe weather events included flooding in the Southeast, major storms in the Northeast, and flooding in
California.
La Nina
By May 1998, the El Nino event was largely over, but rapid cooling in the eastern tropical Pacific led to a La Nina
event. La Nina causes below-normal ocean surface temperatures in the eastern equatorial Pacific; therefore, its
effects tend to be nearly opposite those of El Nino. For example, El Nino led to massive flooding in California, and
La Nina led to below-normal rainfall in the same area.
A body of open ocean, some 1240 km wide and 300 km from north to south, cooled by up to 10 C in 30 days!
Mother Nature demonstrates an enormous ability to adjust the thermostat of Planet Earth.
The Galapagos and the El Nino of 1982-83
In 1982-83, the El Nino was so strong that scientists named it “the event of the century.” Large areas of the
Ecuadorian coast suffered serious problems, including the loss of human life. The Galapagos Islands were no
exception. In 1983 the weather station of the Charles Darwin Research Station registered 201 days with
measurable rainfall, and total precipitation for 1983 was 276.9 cm. In normal years measurable rainfall occurs on
only about 50 days a year, and total yearly precipitation averages 38.5 cm. Graph 1 shows rainfall data from 19651998. The highest peak occurred in 1983 when El Nino reached its greatest intensity.
Graph 1—Rainfall in the Galapagos, 1965-98
In 1983, the average monthly ocean temperature reached 28.6 C in March, compared to normal years when the
average temperature is 25.5 C. Graph 2 shows average yearly ocean temperatures observed between 1965-1998.
The high peak in 1983 is clearly visible and is the highest average yearly ocean temperature observed during more
than 30 years of observations.
Graph 2—Ocean temperature in the Galapagos, 1965-98
Graph 3 displays changes in average annual air temperature. Again, high temperatures peaked in 1983, with a
yearly average of 25.7 C, compared to a normal yearly average of 23.8 C. The highest average air temperature
occurred in March 1983, reaching 27.8 C.
Graph 3—Air temperature in the Galapagos, 1965-98
El Nino in 1997
In the Galapagos, the second half of 1997 was marked by unusual climate conditions, with patterns more similar to
those expected early in the year rather than in July, August, or September. The year 1997 had strong rains during
the first half of the year. The increased rainfall caused a large amount of water to be soaked into the ground,
which caused the roots of many plants to rot. Large plants, such as the giant cacti and large Scalesia trees, fell over
and died because their rotted roots could not support their own weight. The air temperature in 1997 was also
above normal.
Part C—Understanding and Analysis Questions
1. What is an El Nino, and how often do they occur?
2. Give examples of how the El Nino event described affected California as opposed to the
northern states between the Rocky Mountains and the Great Lakes.
3. How did the El Nino of 1982-83 affect Ecuador and Peru?
4. What is a La Nina event, and how is it different from El Nino?
5. How does a typical El Nino affect the amount of rainfall and the water temperature in the
Galapagos?