3.3: Review and Additional Resources

Summary

Assess your learning. Start with the "Important Terms and Concepts" to ensure you know the terminology related to the topic of the chapter and concepts discussed. Then, test your overall understanding by taking the "Self-assessment quiz".

Important Terms and Concepts \(\PageIndex{1}\)

• Energy

  the ability to do work on matter

• Potential Energy

  the energy of position

• Kinetic Energy

  the energy of motion

• Heat

  aka thermal energy; the total energy associated with random atomic and molecular motions of a substance

• Calorie

  a unit of measurement for heat. A calorie is the amount of heat required to raise the temperature of one gram of water through 1^oC.

• Specific Heat

  the heat required to raise the temperature of one unit substance (e.g., gram) through a particular temperature interval.

• Joule

  unit of measurement for energy. One joule is the equivalent of one watt of power radiated or dissipated for one second.

• Conduction

  the transfer of heat from warmer to colder portions of the mass in a solid

• Convection

  heat is transferred by the circulation of molecules in fluids

• Radiation

  the transfer of energy via electromagnetic waves.

  Net radiation

  the difference between incoming (i.e., S and L↓) and outgoing components of radiation (S+D)a and L↑: Q*= [(S+D) - (S+D)a] + L↓ - L↑

• Advection

  a term that is applied to the horizontal transfer of heat by the wind

• Temperature

  a measure of the average kinetic energy level of a substance, the degree of hotness or coldness

• Amplitude

  the height of the wave

• Wavelength

  the distance between successive crests

• Photon

  a bundle of energy

• selective absorber

  absorbs only particular wavelengths of light

• Shortwave radiation

  ultraviolet, visible, and a portion of infrared energy

• Longwave radiation

  infrared, (like microwave, TV, radio waves)

• Direct shortwave radiation

  shortwave radiation able to penetrate through the atmosphere without having been affected by constituents of the atmosphere in any way.

• Diffuse Shortwave radiation

  shortwave radiation that has been scattered by gases in the atmosphere

• Insolation

  the total incoming solar radiation

• Albedo

  The proportion of light reflected from a surface

• Net shortwave radiation

  the difference between incoming and outgoing shortwave radiation. K= (S+D) - (S+D)a

• Terrestrial longwave radiation

  The energy absorbed by the surface is radiated from the Earth

• Atmospheric counter-radiation

  long-wave radiation emitted from the earth to the atmosphere after it has absorbed the shorter-wave radiation of the sun.

• Sensible heat transfer

  heat energy transferred between the surface and air when there is a difference in temperature between them

• Latent heat transfer

  transfer of energy where temperature does not change/cannot be sensed

• Ground heat transfer

  The transfer of energy to and from the surface

• Fahrenheit scale

  scale used for measuring temperature; mainly in the US; based on body temperature

• Celsius scale

  an accepted international system of measurement because it is based on a decimal scale having 100 units between the freezing and boiling points of water.

• Kelvin scale

  It is an absolute scale given that at absolute zero all molecular movement ceases.

• Daily temperature range

  the difference between the highest and lowest temperatures over a 24 hour period

• Average daily temperature

  the sum of highest and lowest temperature of the day divided 2

• Average monthly temperature

  the sum of the average daily temperature divided by the number of days in the month

• Annual temperature range

  the difference between the highest and lowest monthly temperature for a place

• Average annual temperature

  the sum of the mean monthly temperature divide by 12.

• Daily temperature lag

  The amount of time between maximum incoming energy and maximum temperature over the day

• Annual or Seasonal temperature lag

  the amount of time between the highest incoming insolation and highest temperature on an annual basis

• Land/Sea contrasts

  Water is a transparent medium and land is opaque. Water allows light to penetrate to depth, leaving the surface layers cooler than they would be if the surface was opaque. A cooler water surface results in cooler air temperatures above.

• Continentality

  The impact of continental location on weather and climate characteristics of a place

• Specific heat

  the amount of heat required to raise the temperature of one unit of mass of a substance by one degree celsius

• Air mass

  vast pool of air, covering thousands of square kilometers, having about the same humidity and temperature characteristics over its horizontal extent

• mT air mass

  Maritime Tropical - originates over the tropical oceans; warm and moist

• cP air mass

  Continental Polar - originates over high latitude continents; cold and dry

• mP air mass

  Maritime Polar - originates over mid to high latitude oceans; cool and moist

• Air mass trajectory and temperature

  The influence that air masses have on the temperature of a place depends the location with respect to the source of the air mass and the trajectory of the air mass as it moves from its source region.

• Radiation inversion

  commonly occurs when the evening air is still and there are no clouds to trap heat.

• Sea breeze inversion

  occur along windward coasts bordered by cold ocean currents

• Subsidence inversion

  form when subsiding air undergoes adiabatic heating aloft, while air in contact with the surface remains cooler.

• Isotherm

  lines connecting points of equal air temperature are used to map the geographic pattern of temperature across the earth's surface.

• Global warming

  Increasing levels of greenhouse gases results in rising global air temperatures

Self-assessment Quiz \(\PageIndex{1}\)

Short Answer  

Generally speaking, where is the highest and lowest amounts of insolation and net radiation on a global basis?

Answer

Insolation: highest amount in the tropical/subtropical deserts; minimum at the poles. Net radiation: maximum in the tropical/subtropical oceans; minimum at the poles.

What is albedo and what determines the albedo of a surface?

Answer

Albedo is the proportion of light reflected from the surface. It is mostly determined by the color of the surface though sun angle influences albedo for some surfaces like water.

What determines the amount of radiation emitted by a body?

Answer

The amount of radiation emitted by a body depends on the temperature of the emitting body.

What determines sun angle at a place?

Answer

Sun angle is a largely determined by the tilt of Earth's axis. The sun angle varies by latitude, time of day. time of year, and slope of the surface.

Why do physical geographers refer to the gasses of the atmosphere as a "selective absorber" of radiation?

Answer

A gas that is a selective absorber is one that absorbs only particular wavelengths of light. The gasses of Earth's atmosphere are considered selective absorbers as they tend to allow shortwave solar radiation through but absorbs longwave radiation emitted by the surface.

Compare and contrast conduction, convection, and radiation.

Answer

Conduction is the heat transfer via molecular collisions. Convection is heat transfer by circulation. Radiation is heat transfer via electromagnetic radiation.

Explain why the maximum wavelength of emission for the Sun is different than that of the Earth.

Answer

The maximum wavelength of emission depends on the temperature of the emitting body, the hotter the body the shorter the maximum wavelength of emission. The Sun being much warmer than the Earth emits most of its energy in the shortwave end of the electromagnetic spectrum while the Earth emits its energy in the longwave end of the electromagnetic spectrum.

Briefly describe how the vertical rays of the sun at noon change throughout the year.

Answer

• March 21 and Sept 23: 0^o latitude
• June 22: 23.5^o North latitude
• Dec 22: 23.5^o degrees South latitude

How do clouds affect solar radiation?

Answer

They block incoming solar radiation reflecting it of their top and back out to space. They diffuse incoming solar radiation as well.

What is net radiation?

Answer

Net radiation is an accounting of incoming and outgoing components of radiation. It also is the amount of energy used to do work in the earth system.

Briefly describe the latitudinal variation of the radiation balance.

Answer

There is a net gain of radiation between about 38^o North and South latitude. Poleward of these latitudes there is a net loss of radiation.

Compare and contrast latent heat transfer in humid and arid regions.

Answer

There is more latent heat flux in a humid region because there is more water available than in a desert region.

Multiple Choice Questions  

1. The earth is closest to the sun on about
   1. January 4th
   2. March 21st
   3. July 4th
   4. June 21st
2. Latent heat is transferred into the air by
   1. conduction
   2. convection
   3. radiation
   4. none of the above
3. Which place likely receives the most insolation at noon (barring any effect of clouds)?
   1. 90 N on June 22nd
   2. 45 N on June 22nd
   3. 23.5 N on June 22nd
   4. 0 on June 22nd
4. The highest amount of net radiation is found
   1. over polar seas
   2. over midlatitude continents
   3. over subtropical deserts
   4. over tropical oceans
5. The earth's maximum wavelength of emission is about
   1. .5 micrometers
   2. 1.0 micrometers
   3. 10 micrometers
   4. 100 micrometers
6. The sun is directly overhead of 23.5 S at noon on
   1. March 21st
   2. June 22nd
   3. Sept. 23rd
   4. Dec. 22
7. The hotter the emitting body
   1. the shorter the wavelength of maximum emission
   2. the longer the wavelength of maximum emission
   3. the less energy it will emit
   4. the more latent heat it will store
8. Clouds are good absorbers of radiation at a wavelength of about
   1. .5 micrometers
   2. 1 micrometers
   3. 10 micrometers
   4. at all the above wavelengths
9. ________ is the total energy associated with random atomic and molecular motions of a substance.
   1. radiation
   2. temperature
   3. potential energy
   4. heat
10. Where would I expect to find the largest amount of latent heat transfer into the air?
    1. The west coast of the United States near Los Angeles
    2. The east coast of the United States near New York
    3. In the middle of the Sonoran Desert of Mexico
    4. In the tropical rain forest of Brazil
11. The annual temperature range is greatest
    1. in the east coast of the United States (Washington D.C. for example)
    2. in the interior of the continent (Kansas City, KS, for example)
    3. the west coast of the United States (Los Angeles, CA, for example)
    4. near the equator.
12. The air temperature of a large body of water does not change as much as nearby land because
    1. most of the net radiation is used for latent heat transfer rather than sensible heat.
    2. mixing of the water occurs
    3. the specific heat of land is lower than that of water
    4. all the above are true
13. The coldest temperature over the course of the day normally occurs
    1. at midnight
    2. at sunset
    3. just after sunrise
    4. at 8:00 pm
14. The daily range of temperature is greatest
    1. when skies remain cloudless during the day and night
    2. when the sky remains cloudy all day and night
    3. when the sky is cloudy during the day but cloudless at night
    4. when the sky is cloudless during the day but cloudy at night.
15. The seasonal lag of temperature
    1. is greater for places located on the coast
    2. is greater for places located in the interior of a continent
    3. is not any different if you are located on a coast or in the interior of the continent
    4. is nonexistent along a coast
16. Which of the following air masses is the coldest during the winter?
    1. mP
    2. cP
    3. mT
    4. they are all equally cold during the winter but not during the summer
17. Isotherms
    1. in the Northern Hemisphere bend towards the north when passing over passing over the Gulf Stream current during the winter.
    2. tend to be linear in form in the Southern Hemisphere.
    3. are more closely spaced over the North American continent in winter than summer.
    4. exhibit all the above.
18. Which of the following statements is false?
    1. Maximum outgoing radiation and maximum incoming solar radiation generally occur at the same time.
    2. Maximum outgoing radiation generally occurs at the same time as maximum daily temperature.
    3. Maximum daily temperature lags behind maximum daily incoming solar radiation.
    4. Maximum outgoing radiation generally lags behind maximum incoming solar radiation.
19. Which of the following energy balance components has the most significant impact on the temperature of the air above the surface?
    1. sensible heat transfer
    2. latent heat transfer
    3. ground heat transfer
    4. none of the above affect the temperature of the air.
20. Heat transfer into the air is most efficient
    1. when there is turbulent mixing
    2. when the air is still
    3. when there is no difference in the temperature between the air and the surface
    4. none of the above

Answer

1. A
2. B
3. C
4. D
5. C
6. D
7. A
8. C
9. D
10. B
11. B
12. D
13. C
14. A
15. A
16. B
17. D
18. A
19. A
20. A

Additional Resources

Citations

• OpenAI. (2026). ChatGPT (GPT-4o version) [Large language model]. https://chatgpt.com
• Google. (2026). Gemini (Gemini 1.5 Pro version) [Large language model]. google.com
• Kious, W. J., & Tilling, R. I. (1996). This dynamic earth: The story of plate tectonics. U.S. Geological Survey.
• Scudder, R. (2020, August 28). Geodesy: The size and shape of planet Earth. ThoughtCo.
• National Oceanic and Atmospheric Administration (NOAA). (2024, June 16) What is geodesy? 
• National Oceanic and Atmospheric Administration (NOAA). (2021). Is the Earth a perfect sphere? National Ocean Service.
• Ritter, M. E. (2020). The physical environment: An introduction to physical geography. (L. Pitts, Ed.).
• Williams, D. R. (2024, January 11). Earth fact sheet. NASA Goddard Space Flight Center.
• Wikipedia. (2026, May 22). Empirical evidence for the spherical shape of Earth. 

Suggested Readings

Use these resources to further explore the world of geography 

• Focus on The Physical Environment: "Arbiters of Energy" (NASA Earth Observatory)
• World of Change: Solar Activity
• Connections: "Warming Oceans". (NPR) All Things Considered
• Oblack, Rachelle. "The 5 Layers of the Atmosphere." ThoughtCo. Last modified May 15, 2025. 
• Scispectrum. "Liquid-in-Glass Thermometers: A Look at the Classic Temperature Gauge." 22 Aug. 2025.
• Association for Canadian Educational Resources. (n.d.). Proximity to water bodies. ACER.
• National Weather Service. (n.d.). JetStream - Clouds. National Oceanic and Atmospheric Administration.
• Buis, A. (2022, February 8). Steamy relationships: How atmospheric water vapor amplifies Earth's greenhouse effect. NASA Science.