MeteorologyThe Study of the Atmosphere

© 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password- protected website for classroom use.Chapter 1 Earth’s Atmosphere Chapter Outline The Atmosphere and the Scientific Method Weather, Climate, and Meteorology Meteorology—The Study of the Atmosphere A Glimpse at a Weather Map Weather and Climate in Our Lives Focus on a Special Topic Components of Earth’s Atmosphere The Early Atmosphere Composition of Today’s Atmosphere Vertical Structure of the Atmosphere A Brief Look at Air Pressure and Air Density Layers of the Atmosphere Focus on an Observation Summary Key Terms Questions for Review Questions for Thought and Exploration

Learning Objectives

1.1. Outline the scientific method and describe how it can be applied to studying the atmosphere and

weather.

1.2. Differentiate between weather and climate, and briefly discuss the history of meteorology and its

most important milestones.

1.3. Interpret and describe a weather map, applying weather patterns and concepts such as low, high,

front, and storm types.

1.4. List the positive and negative effects of climate and weather on human health, agriculture,

infrastructure, environment, and economy.

1.5. Compare and contrast the composition of Earth’s atmosphere over the course of its evolution.

1.6. Explain the role of gases (including water vapor, carbon dioxide, oxygen, and other greenhouse

gases) and pollutants in Earth’s atmosphere and assess their impact on Earth’s climate.

1.7. State the terms and calculations for density and air pressure, and explain their importance with

regard to Earth’s atmosphere.

1.8. Label the layers of the atmosphere and their altitudes, and classify their respective temperatures,

compositions, and functions.

Summary This introductory chapter presents a broad overview of Earth’s atmosphere and the many ways weather and climate influence our lives. We look briefly at the weather map and a satellite image so that we can observe that storms and clouds of all sizes and shapes are dispersed throughout the atmosphere. The movement, intensification, and weakening of these systems, as well as the dynamic nature of air itself, produce a variety of weather events that we describe in terms of weather elements. The sum total of (Essentials of Meteorology An Invitation to the Atmosphere, 8e Donald Ahrens) (Solution Manual all Chapters) 1 / 4

© 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password- protected website for classroom use.weather and its extremes over a long period of time is what we call weather. Although sudden changes in weather may occur in a moment, climatic change takes place gradually over many years. The study of the atmosphere and all of its related phenomena is called meteorology, a term whose origin dates back to the days of Aristotle. Weather and climate influence the clothes we wear, the food we eat, and many other parts of our lives. Extreme weather can cause severe damage and major disruption to society.

We learn that our atmosphere is one rich in nitrogen and oxygen as well as smaller amounts of other gases, such as water vapor, carbon dioxide, and other greenhouse gases whose increasing levels may result in additional global warming and climate change. We examine Earth’s early atmosphere and found it to be much different from the air we breathe today.

We investigate the various layers of the atmosphere: the troposphere (the lowest layer), where almost all weather events occur, and the stratosphere, where ozone protects us from a portion of the sun’s harmful rays. Above the stratosphere lies the mesosphere, where the air temperature drops dramatically with height. Above the mesosphere lies the warmest part of the atmosphere, the thermosphere. At the top of the thermosphere is the exosphere, where collisions between gas molecules and atoms are so infrequent that fast-moving lighter molecules can actually escape Earth’s gravitational pull, and shoot off into space.Finally, we look at the ionosphere, that portion of the upper atmosphere where large numbers of ions and free electrons exist.

Teaching Suggestions, Demonstrations, and Visual Aids

• A large classroom demonstration vacuum chamber can be used to show that sound does not travel

through a vacuum (place an alarm clock or buzzer in the vacuum chamber). Heat can’t be transported via conduction and convection through a vacuum either. The rates of cooling of a warm object inside and outside the vacuum chamber could be compared to reinforce this fact (a third object could be placed in a large container of water at room temperature to illustrate the higher thermal conductivity of water). Students might become more aware of the importance of radiant energy transport between Earth and sun.

• Chapter 1 in Hands-On Meteorology by Zbigniew Sorbjan (American Meteorological Society, 1996,

ISBN 1-878220-20-9) discusses some of the early theories about air and early determinations of the chemical composition of air.

• Place a candle in the center of a dish and partially fill the dish with water. Light the candle and then

cover it with a large jar or beaker. The flame will consume the oxygen inside the jar and reduce the pressure. Water will slowly flow into the jar to re-establish pressure balance. The change in volume should be close to 20%, the volume originally occupied by the oxygen in the air. This demonstration can be used to illustrate the concept of partial pressure, which is later used in the chapter on humidity. The students should also be asked what they think the products of the combustion might be and why these gases do not replace the oxygen and maintain the original pressure in jar. One of the combustion products is water vapor, which condenses as the air in the jar cools. Another combustion product is carbon dioxide, which presumably goes into solution.Students should be asked what effect the heat generated by the burning candle might have on the results of the experiment.

• Students often confuse water vapor with liquid water. Students should understand that water vapor is

an invisible gas. Haze, fog, clouds, and the steam from a boiling pot all become visible when water vapor condenses and forms small drops of liquid water.

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© 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password- protected website for classroom use.

• Some of the atmospheric pressure demonstrations described in Chapter 6 could be performed

here also.

• Fill a wine glass completely with water and cover it with a piece of plastic (such as the lid from a

margarine container), being careful to remove any air. Invert the glass. The water remains in the glass because the upward force on the cover due to the pressure of the air is much stronger than the downward gravitational force on the water. The demonstration can be made much more convincing if a 4000 mL flask is used instead of the wine glass. When full of water, the flask weighs approximately 10 pounds.

• Photographs showing the flat tops of thunderstorms taken from the ground or an airplane often mark

the top of the troposphere. Shadows will often be apparent on visible satellite photographs taken when the sun is at a low angle in the sky. This creates the appearance of depth reinforces the fact that Earth’s atmosphere is thin.

• The discussion of surface air motions in Chapter 1 is a good place to introduce satellite images,

loops, and surface weather maps. Being able to observe and understand weather phenomena on their own may heighten students’ interest in the subject.

• Challenge students to speculate on how we know the chemical composition of Earth’s early

atmosphere.

• Use the University of Wyoming’s Department of Atmospheric Science’s website (Atmospheric

Soundings) to demonstrate that most of the water vapor in the entire atmosphere is in the lower half of the troposphere. (Look at the “MIXR” column—this is water vapor mixing ratio, with units of g/kg—grams of water vapor per kilogram of dry air.)

Student Projects

• Have the students mark the positions of fronts and pressure systems for each day on an outline map

of the United States. (This information can be obtained, among other places, from the NOAA Advanced Hydrologic Prediction Service.)

• Have students compose a one-week blog or journal, including daily weather maps and weather

forecasts. Have the students provide a commentary for each day as to the coincidence of actual and predicted weather.

• Have students keep a daily record of weather observations, especially significant changes in the

weather. Then, periodically, the instructor can supply mean daily data such as high and low temperatures, pressure, dew point, wind speed, cloud cover, and precipitation amounts. The students should plot these data and annotate the graph with their observations. Students can use their graphs to experimentally test concepts developed in class. After studying Chapter 1, for example, students might try to determine whether periods of stormy weather really are associated with lower-than- average surface pressure.

• Students could attempt to repeat some of the experiments in Hands-On Meteorology.

• Use the University of Wyoming’s Department of Atmospheric Science’s website (Atmospheric

Soundings) to identify the altitude of the tropopause at locations on three different continents. 3 / 4

© 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password- protected website for classroom use.Answers to Questions for Review

• Radiant energy from the sun.

• Investigators use the scientific method by posing a question, putting forth a hypothesis, predicting

what the hypothesis would imply if it were true, and carrying out tests to see if the prediction is accurate. To be accepted, a hypothesis has to be shown to be correct through a series of quantitative tests. Studying atmosphere, however, is somewhat different, because our Earth has only one atmosphere. Despite this limitation, scientists have made vast progress by studying the physics and chemistry of air in the laboratory (for instance, studying the way in which molecules absorb energy) and by extending those understandings to the atmosphere as a whole. Observations using weather instruments allow us to quantify how the atmosphere behaves and to determine whether a prediction is accurate. If a particular kind of weather is being studied, such as hurricanes or snowstorms, a field study can gather additional observations to test specific hypotheses.

3. Seven common weather elements are:

(1) air temperature—the degree of hotness or coldness of the air; (2) air pressure—the force of the air above an area; (3) humidity—a measure of the amount of water vapor in the air; (4) clouds—a visible mass of tiny water droplets and/or ice crystals that are above Earth’s surface; (5) precipitation—any form of water, either liquid or solid (rain or snow), that falls from clouds and reaches the ground; (6) visibility—the greatest distance one can see; (7) wind—the horizontal movement of air.

• Weather describes the condition of the atmosphere at any particular time and place. Climate

describes weather conditions averaged over a region or over a time period.

• Meteorology is the study of the atmosphere and its phenomena. The term itself goes back to the

Greek philosopher Aristotle who, about 340 B.C., wrote a book on natural philosophy entitled Meteorologica.

• Middle-latitude cyclonic storm, hurricane, thunderstorm, and tornado.

• From the south.

• From west to east.

• High and low-pressure systems, fronts, wind speed and direction, cloud cover, and temperatures.

• Low-pressure systems: counterclockwise. High-pressure systems: clockwise.

• Weather and climate dictate the type of clothing we buy and wear, the types of crops we plant and

harvest, and homes we build. Even if we have appropriate clothing and shelter weather and climate can greatly impact and affect our comfort, well-being, and overall health (e.g., arthritic pain is linked to high humidity and falling air pressures, heart attack incidences are higher after the passage of warm fronts, when rain and wind are common, and after the passage of cold fronts, when an abrupt change takes place as showery precipitation is accompanied by cold gusty winds, and headaches are common on days when we are forced to squint, often due to hazy skies or a thin, bright overcast layer of high clouds). Weather and climate can have dramatic economic impacts, either by saving heating costs in warm winters or by increasing them in cold years.

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