Chapter 3
Climate

Links for Enrichment and Further Learning

• RealClimate.org
• NOAA Climate Prediction Center
• NOAA Climate page
• ClimatePrediction.net
• Google Climate News
• NOAA El Nino page

Student Learning Outcomes

Given the properties of electromagnetic energy, the students will be able to:

• describe and illustrate the electromagnetic spectrum in terms of light, infrared and ultraviolet
• specify the fate of solar radiation as it passes through the Earth's atmosphere
• Define "climate" and differentiate this term from "weather"

Given Earth's seasonal changes, the students will be able to:

• explain the seasonal changes in terms of the Earth's axial tilt, orbital path around the sun, and changes in hemispherical sunlight exposure
• differentiate seasons between the northern hemisphere and southern hemisphere

Given photographic scenarios of the Earth in space, the students will be able to:

• analyze the photo and determine seasons in northern and southern hemispheres
• distinguish between photos depicting the first day of fall in the northern hemisphere and the first day of fall in the southern hemisphere

Given the state of vertical circulation patterns in the Earth's atmosphere, the student will be able to:

• sketch the location of such patterns
• indicate low pressure zones and high pressure zones in terms of these vertical circulation patterns
• differentiate and generalize rainfall quantities in low pressure zones as compared to high pressure zones

Given a tall vertical column of the atmosphere, the student will:

• characterize the vertical column of the atmosphere in terms of density, air pressure, heat content, and temperature
• generalize the water-holding capacity of air at different altitudes
• explain adiabatic cooling in terms of air density, heat content and temperature
• explain how adiabatic cooling combines with mountain ranges to produce the rain shadow effect

Given a mountain range and prevailing wind patterns, the student will:

• predict the location of the rain shadow

Given a history of climate anomalies such as the Dust Bowl and el nino, the student will:

• explain their causes
• generalize about natural variability of regional climates

Study Questions / Quiz Prep. (Consult Required Reading and lecture notes for answers.)

1. What is solar radiation in terms of electromagnetic radiation?
2. How do scientists conceptualize solar radiation?
3. Of the solar radiation that reaches the top of the earth's atmosphere, only 51% of it reaches the Earth's surface. What happens to the rest of it?
4. Of the 51% of incoming solar radiation that reaches the Earth's surface, how does it influence the Earth's surface?
5. The Earth's surface continuously emits long wave radiation. What happens to this radiation as it makes its way toward space?
6. Label the drawing of the electromagnetic spectrum below.

7. Intercepted solar radiation. Give two reasons why high latitudes receive less solar radiation than low latitudes.
8. What causes the seasons? (incidentally, Figure 3.6 implies that the Earth rocks back and forth on its axis over the course of a year -- which is completely false. Look at [this] picture instead.
9. Is the Earth's north pole pointing toward the sun or away from the sun at the vernal equinox?
10. Is the Earth's north pole pointing toward the sun or away from the sun at the autumnal equinox?
11. Is the Earth's north pole pointing toward the sun or away from the sun at the summer solstice?
12. Is the Earth's north pole pointing toward the sun or away from the sun at the winter solstice?
13. Determine the seasons in the pictures below...

a. Look at the picture below. What season is it in the northern hemisphere?		b. Look at the picture below. What season is it in the northern hemisphere?

14. As air travels up and over these mountains, adiabatic cooling occurs. What is the process of adiabatic cooling?

15. ____________ air has a greater capacity for water vapor than does ____________ air.
16. Label the regions of the atmosphere on the picture below.

17. In which atmospheric layer does weather occur?
18. In which air mass is there a natural, ozone-rich layer?
19. In the drawing below, label the indicated mountain ranges and deserts.

20. Explain how the "rain shadow effect" works.
21. How does the rain shadow effect influence the development of deserts?
22. Describe the Little Ice Age. When was it? What caused it?
23. Describe the Dust Bowl. When was it? What caused it?
24. Describe El Nino-Southern Oscillation. When does it occur?

Synthesis (These are not official study questions. But you should try to answer them on your own.)
There is something odd about the situations described below. See if you can identify the problem(s).

1. "What is the climate going to be like tomorrow?"
2. "Sunlight is brighter in summer because the Earth is closer to the Earth then."
3. Doesn't the earth wobble back-and-forth every six months? Isn't that what causes the seasons?
4. Imagine a stationary point in space 500 million miles directly above the sun's north pole. Imagine the Earth's north pole always pointed to that point. It's winter where you live now. Come on summer...
5. Imagine that you take a ride on a helium-filled balloon. You fill the balloon. with so much helium that it is on the verge of bursting. Then off you go...
6. Stoned hippies lay on the beach in 1963 and stare at the sun. "Far out, man. Light is light and light is love."
7. A rice farmer decides he can't pass up cheap land in the continental interior of South America 30 degrees south of the equator.
8. A tree farmer wants a mountain to fully develop a tree farm. He has two to choose from. Both mountains ar at 45 degrees north, stretch in a east-west line and are made up mainly of north-facing slopes and south-facing slopes. The prevailing winds for Mountain A are moisture-laden, coming from the south. The prevailing winds for Mountain B are moisture-laden, coming from the north.
9. Washed ashore on a tiny island in the Pacific Ocean 28 degrees south and about 1000 miles west of Chile, a desperate castaway places a note in a bottle and tosses it into the sea.

Light

The turbulent sun.

Electromagnetic Spectrum

Seasons

The seasons are caused by the earth's axial tilt and the planet's orbit around the sun.
Winter in the northern hemisphere, summer in the southern hemisphere.

Winter in the northern hemisphere.	Summer in the northern hemisphere.

Circulation Patterns

A simplified model of vertical air circulation patterns.

Rainfall as a function of latitude. Note that rainfall is greatest at latitudes where air masses are rising, and less where air masses are descending.

Global ocean circulation patterns.

Global Climate Distribution

Global rainfall; mountain ranges and rain shadow; and ocean currents.

Rain Shadow Effect

Rain Shadow. Mountains force moisture out of clouds.

Sahara Desert. In the rain shadow of the Atlas Mountains of Morocco.

Los Angeles basin. The San Gabriel Mountains and the San Bernardino Mountains contribute to the rain shadow that keeps moisture from the Mojave desert.

California. Rain shadows of coastal ranges and Sierra Nevada the Great Basin Desert and the Mojave Desert.

Rain shadow on Molokai Island, Hawaii.

Irregular Variations in Climate

Little Ice Age

Scene on the Ice. Painting by Hendrick Avercamp (1585-1634) portrays an unusually cold winter in Holland in the year 1608. A period of cooling called "the Little Ice Age" lasted from the 14th century to the mid 19th century.

Reconstruction of global temperature trends over the last 2000 years. Note Little Ice Age.

Dust Bowl

Dust storm approaching farm house in Stratford, Texas during the Dust Bowl. The Dust Bowl occurred in the American prairie states between 1930 and 1941. It was caused by a combination of repeated droughts and poor soil management by farmers.

El Niño

Under normal conditions in the equatorial Pacific Ocean, the equatorial current moves westward, delivering rain and warm water to the western equatorial Pacific basin (equatorial Asia).

During El Niño conditions, the equatorial current reverses. This delivers warm water and rain to the eastern Pacific basin (equatorial South America), and resulting in drought in the western equatorial Pacific basin.