Foundations of Earth Science
Heating the Atmosphere
Chapter 11 Lecture
Natalie Bursztyn
Utah State University
Foundations of Earth Science
Eighth Edition
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1
Distinguish between weather and climate.
Name the basic elements of weather and climate.
Focus Questions 11.1
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2
Weather
Occurs over a short period of time
Constantly changing
Climate
Averaged over a long period of time
Generalized, composite of weather
Focus on the Atmosphere
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3
Elements of weather and climate
Properties that are measured regularly:
Air temperature
Humidity
Type and amount of cloudiness
Type and amount of precipitation
Air pressure
Wind speed and direction
Weather and Climate
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Weather and Climate
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List the major gases composing Earth’s atmosphere.
Identify the components that are most important to understanding weather and climate.
Focus Questions 11.2
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Air is a mixture of discrete gases
Major components of clean, dry air
78% Nitrogen (N)
21% Oxygen (O2)
Argon and other gases
0.04% Carbon dioxide (CO2)
Composition of the Atmosphere
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Major Components
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Water vapor
Up to 4% of air’s volume
Forms clouds and precipitation
Greenhouse gas
Aerosols
Tiny solid and liquid particles
Water vapor can condense on solids
Reflect sunlight
Color sunrise and sunset
Variable Components
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Variable Components
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Ozone
Three atoms of oxygen (O3)
Distribution not uniform
Concentrated between 10 and 50 km above the surface
Absorbs harmful UV radiation
Variable Components
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Interpret a graph that shows changes in air pressure from Earth’s surface to the top of the atmosphere.
Sketch and label a graph that shows atmospheric levels based on temperature.
Focus Questions 11.3
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Atmospheric pressure is the weight of the air above.
Average sea level pressure is 1000 millibars or 14.7 psi
Pressure decreases with altitude
Half of atmosphere is below 3.5 mi (5.6 km)
90% of atmosphere is below 10 mi (16 km)
Pressure Changes
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Pressure Changes
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Four atmospheric layers based on temperature
Troposphere
Lowermost layer
Temperature decreases with increasing altitude
Environmental lapse rate
Average 6.5C per km or 3.5F per 1000 feet
Thickness varies
Average height is about 12 km
Outer boundary is the tropopause
Temperature Changes
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Temperature Changes
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The environmental lapse rate is variable
Actual environmental lapse rate for any particular time and place
Measured with a radiosonde
Attached to a balloon and transmits data by radio
Temperature Changes
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Temperature Changes
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Stratosphere
12 to 50 km
Temperature increases at top
Outer boundary is the stratopause
Mesosphere
50 to 80 km
Temperature decreases
Outer boundary is the mesopause
Thermosphere
No well-defined upper limit
Fraction of atmosphere’s mass
Gases moving at high speeds
Temperature Changes
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Temperature Changes
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Explain what causes the Sun angle and length of daylight to change during the year.
Describe how these changes produce the seasons.
Focus Questions 11.4
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Earth’s motions
Rotation on its axis
Once every 24 hours
Circle of illumination is the line separating Earth’s lighted half from dark half
Orbital motion around the Sun
Seasons
Result of:
Changing Sun angle
Changing length of daylight
Earth–Sun Relationships
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Earth–Sun Relationships
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Seasons
Caused by Earth’s changing orientation to the Sun
Axis is inclined 23.5º
Axis is always pointed in the same direction
Earth–Sun Relationships
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Special days (Northern Hemisphere)
Summer solstice: June 21–22
Sun’s vertical rays located at Tropic of Cancer
23.5º N latitude
Winter solstice: December 21–22
Sun’s vertical rays located at Tropic of Capricorn
23.5º S latitude
Autumnal equinox: September 22–23
Sun’s vertical rays located at equator (0º latitude)
Spring equinox: March 21–22
Sun’s vertical rays located at equator (0º latitude)
Earth–Sun Relationships
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Earth–Sun Relationships
[insert Figure 11.15 and Table 11.1 here]
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Earth–Sun Relationships
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Distinguish between heat and temperature.
List and describe the three mechanisms of heat temperature.
Focus Questions 11.5
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Heat is synonymous with thermal energy
Temperature refers to the intensity, or degree of "hotness"
Heat is always transferred from warmer to cooler objects
Energy, Heat, and Temperature
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Mechanisms of heat transfer
Conduction
Molecular activity
Convection
Mass movement within a substance
Radiation (electromagnetic radiation)
Gamma waves, X-rays
Ultraviolet,visible, infrared
Microwaves and radio waves
Energy, Heat, and Temperature
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Energy, Heat, and Temperature
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Laws of Radiation
All objects emit radiant energy
Hotter objects radiate more total energy per unit area than colder objects
Hotter objects radiate more short-wavelength radiation than cooler objects
Good absorbers of radiation are good emitters as well
Energy, Heat, and Temperature
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Energy, Heat, and Temperature
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Sketch and label a diagram that shows the paths taken by incoming solar radiation.
Summarize the greenhouse effect.
Focus Questions 11.6
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Incoming solar radiation
Atmosphere is largely transparent to incoming solar radiation
Atmospheric effects
Reflection
Albedo (percent reflected)
Scattering
Absorption
Most visible radiation reaches the surface
About 50% absorbed at Earth’s surface
Heating the Atmosphere
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Heating the Atmosphere
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Heating the Atmosphere
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Heating the Atmosphere
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Radiation from Earth’s surface
Earth re-radiates longer wavelengths
Terrestrial radiation
Terrestrial radiation is absorbed by
Carbon dioxide and water vapor
Lower atmosphere is heated from Earth’s surface
Heating of the atmosphere is termed the greenhouse effect
Heating the Atmosphere
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Heating the Atmosphere
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Summarize the nature and cause of the atmosphere’s changing composition since around 1750.
Describe the atmosphere’s response and some possible future consequences.
Focus Questions 11.7
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CO2 levels are rising
Industrialization of the past 200 years
Burning fossil fuels
coal, natural gas, and petroleum
Deforestation
Present CO2 level is 30% higher than its highest level over at least the past 800,000 years
Human Impact on Global Climate
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Human Impact on Global Climate
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Human Impact on Global Climate
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Important impacts of human-induced global warming:
Rise in sea level
Shift in large-storm paths
Changes in precipitation distribution
Changes in occurrence of severe weather
Stronger tropical storms
Increasing frequency and intensity of heat waves and droughts
Gradual environmental shifts
Human Impact on Global Climate
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Human Impact on Global Climate
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Calculate five commonly used types of temperature data.
Interpret a map that depicts temperature data using isotherms.
Focus Questions 11.8
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For the Record: Air Temperature Data
Temperature measurement
Daily maximum and minimum
Other measurements
Daily mean temperature
Daily range
Monthly mean
Annual mean
Annual temperature range
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Isotherms used to examine distribution of air temperatures over large areas
Line that connects points of the same temperature
iso = equal, therm = temperature
Easy to visualize temperature gradient
For the Record: Air Temperature Data
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For the Record: Air Temperature Data
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Discuss the principal controls of temperature.
Use examples to describe their effects.
Focus Questions 11.9
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Temperature control – any factor that causes temperature to vary from place to place and from time to time
Receipt of solar radiation
Differential heating of land and water
Land heats more rapidly than water
Land gets hotter than water
Land cools faster than water
Land gets cooler than water
Why Temperatures Vary: The Controls of Temperature
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Specific heat is the amount of energy needed to raise the temperature of 1 gram of a substance 1 degree Celsius
Why Temperatures Vary: The Controls of Temperature
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Why Temperatures Vary: The Controls of Temperature
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Other important controls
Altitude
Geographic position
Cloud cover
Albedo
Why Temperatures Vary: The Controls of Temperature
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Why Temperatures Vary: The Controls of Temperature
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Interpret the patterns depicted on world maps of January and July temperatures.
Focus Question 11.10
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Temperature maps
Temperatures are adjusted to sea level
January and July used for analysis
Represent temperature extremes
World Distribution of Temperature
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Global temperature patterns
Temperature decreases poleward from tropics
Isotherms exhibit latitudinal shift with seasons
Warmest and coldest over land
World Distribution of Temperature
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World Distribution of Temperature
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World Distribution of Temperature
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Global temperature patterns
Southern Hemisphere
Isotherms are straighter
Isotherms are more stable
Isotherms show ocean currents
Annual temperature range
Small near equator
Increases with an increase in latitude
Greatest over continental locations
World Distribution of Temperature
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