1. Chapter 4: Insolation and Temperature

2. The Impact of Temperature on the Landscape
All living things influenced by temperature
Adaptation to temperature extremes
Temperature affects human-built landscape
Temperature affects inorganic landscape components
Soil and bedrock exposure
Figure 4-1a & 4-1b

3. Energy, Heat, and Temperature
Energy: ability to do work
Forms of energy
Kinetic – energy of movement
Chemical, Potential, Nuclear, etc.
Temperature
Heat
Movement of atoms
Temperature:
Measurement of heat
Temperature scales
Celsius
Fahrenheit
Kelvin
Figure 4-2

4. Energy, Heat, and Temperature
The Sun
Primary source of energy for Earth’s atmosphere
Properties of Sun
Average size star
Nuclear fusion
Magnitude of Sun’s energy
Energy spreads as it leaves the Sun
Travels through voids in space without loss of energy
Figure 4-3

5. Energy, Heat, and Temperature
Figure 4-4
Electromagnetic (EM) energy
EM spectrum
Wavelength
Distance between two wave crests
3 important areas of EM spectrum
Visible radiation
Ultraviolet radiation
Too short to be seen by the human eye
Infrared radiation
Figure 4-5

6. Energy, Heat, and Temperature
Insolation
Incoming solar radiation
Shortwave energy
Terrestrial Energy
Longwave energy
“Earth’s” energy
Figure 4-16

7. Basic Heating and Cooling Processes in the Atmosphere
Radiation
When objects emit EM energy
AKA Heat energy emitted from a body
Warmer objects radiate more effectively
Warmer objects emit at shorter wavelengths
Figure 4-6

8. Basic Heating and Cooling Processes in the Atmosphere
Absorption
Body absorbs radiation
Good radiator, good absorber
Reflection
Objects repel electromagnetic waves
Opposite of absorption
Figure 4-7

9. Basic Heating and Cooling Processes in the Atmosphere
Scattering
Deflection of light waves by molecules and particles
Transmission
Electromagnetic waves pass completely through a medium
Sunsets
Figure 4-9

10. Basic Heating and Cooling Processes in the Atmosphere
Greenhouse effect
Some atmospheric gases transmit shortwave radiation, but not Earth’s longwave radiation
Earth radiation held in by atmosphere
Atmospheric blanket
Figures 4-11 & 4-12

11. Basic Heating and Cooling Processes in the Atmosphere
Conduction
Transfer of heat energy across a medium
Energy moves from molecule to another one without changing molecular positions
AKA direct heat transfer by contact
Molecules become agitated, then vibrate & collide with cooler molecules, transferring heat energy
Figure 4-13

12. Basic Heating and Cooling Processes in the Atmosphere
Convection
Heat transfer by vertical circulation in a moving substance
Vertical convection cell
Warm air gains heat, expands & rises
Cool air loses heat, contracts & sinks
Advection
Horizontal transfer of heat in a moving fluid
AKA wind
Figure 4-14

13. Radiation, Conduction & Convection Operating Simultaneously

14. Basic Heating and Cooling Processes in the Atmosphere
Adiabatic Cooling and Warming
Change in pressure & thus temperature of rising or descending air
Adiabatic cooling
Air rises and expands, molecular collisions decrease, so temperature decreases
Adiabatic warming
Air sinks and compresses, collisions increase so temperatures increase
Figure 4-15

15. Basic Heating and Cooling Processes in the Atmosphere
Latent heat
Heat released or absorbed during a phase change
AKA “hidden heat” since latent heat is not felt
Evaporation: liquid water is converted to water vapor
Cooling process
Condensation: water vapor is converted to liquid water
Warming process

16. The Heating of the Atmosphere
Balance between shortwave incoming solar radiation & outgoing longwave solar radiation
Albedo
The higher the albedo, the more radiation the object reflects
Figure 4-16

17. The Heating of the Atmosphere: Global Energy Budget
Energy in = Energy out
Figure 4-17

18. The Heating of the Atmosphere: Global Energy Budget
Earth does not distribute heat evenly through space & time
Cause of weather and climate

19. Variations in Heating by Latitude and Season
Angle of incidence
Angle the Sun’s rays strike Earth’s surface
The higher the angle, the more intense the radiation
Figure 4-18

20. Variations in Heating by Latitude and Season
Atmospheric obstructions
Clouds, haze, particulates, etc. decrease insolation
Figure 3-4
Figure 4-20

21. Variations in Heating by Latitude and Season
Day length
The longer the day, the more insolation is received
Figure 4-19

22. Variations in Heating by Latitude and Season
Latitudinal radiation balance and the world distribution of insolation
Belt of max solar energy that moves through the tropics following the Sun’s direct rays
Figure 4-21

23. Land and Water Contrasts
Land heats and cools more rapidly than water due to:
Specific heat
Transmission
Mobility
Evaporative cooling
Figure 4-23

24. Land and Water Contrast Implications
Oceans = more moderate climates
Hottest & coldest places on Earth are interiors of continents
N. (land) vs. S. (water) Hemisphere
Figure 4-24

25. Mechanisms of Heat Transfer
Need heat transfer to prevent constant warming at tropics & cooling at poles
Circulation patterns in atmosphere and oceans transfer heat

26. Mechanisms of Heat Transfer
2 mechanisms move heat poleward in both hemispheres, driven by latitudinal imbalance of heat
Atmospheric circulation (Ch 5)
Oceanic circulation
Direct relationship between atmospheric and oceanic circulation
Air blowing over the ocean creates major surface ocean currents
Heat energy stored by oceans affects atmospheric circulation

27. Mechanisms of Heat Transfer
Northern and southern variations
Near N. Hemisphere pole, landmasses lie so close that little flow can enter the Arctic Ocean
In S. Hemisphere, little land mass allows for constant westward belt of ocean circulation called West Wind Drift
Southern Ocean
(AKA the 5th Ocean)

28. Mechanisms of Heat Transfer
Temperature patterns
Poleward currents transfer warm water poleward
Equatorial currents transfer cool water equatorward
Figure 4-25

29. Mechanisms of Heat Transfer
Figure 4-26
Rounding out the pattern
NW portions of N. Hemisphere receive cool water from Arctic Ocean
Water pulled away from western coasts of continents = upwelling
Deep ocean circulation
Global conveyor belt
Tied to short-term climate change

30. Vertical Temperature Patterns
Environmental lapse rate
Normal vertical temperature gradient
Average lapse rate
6.5°C/km or 6.5°C/1000m)
Temperature inversions
Surface inversions
Upper air inversions
Figures 4-27 & 4-28

31. Global Temperature Patterns
Global temperature maps
Seasonal extremes
January & July
BROAD understanding of temperature patterns
Isotherm: line connecting points of equal temperature

32. Global Temperature Patterns
Primary controls on global temperature
Altitude
Temperature decreases with altitude
Latitude
Fundamental cause of temperature variation
Temperature with latitude
Land–Water contrasts
Continents have higher summer & lower winter temps than oceans
Ocean currents
Cool currents push isotherms equatorward; warm currents push isotherms poleward
Figure 4-29 – average January temperature
Figure 4-30 – average July temperature

33. Global Temperature Patterns
Seasonal patterns
Latitudinal shift in isotherms from one season to another
More pronounced over continents than water and over high latitudes than low latitudes
Figure 4-31

34. Global Temperature Patterns
Annual temperature range
Difference in average temperature of warmest and coldest months (usually Jan & July)
Figure 4-32

35. Global Warming and the Greenhouse Effect
Climate of Earth is becoming warmer, known as global warming
Air temp increases when atmospheric gases trap longwave radiation
Human-enhanced greenhouse effect
Carbon dioxide main culprit
Also methane, nitrous oxide, CFC’s
Intergovermental Panel on Climate Change
Figure 4-33

36. Global Warming and the Greenhouse Effect
Relationship between carbon dioxide and temperature
Figure 4-35

37. Summary
Temperature affects both living and nonliving aspects of Earth’s landscape
Energy exists in many different forms, but cannot be created or destroyed
Temperature is a measure of the amount of kinetic energy in the molecules of a substance
Temperature is measured on three primary scales
The Sun is the primary source of energy for Earth’s atmosphere
Electromagnetic radiation is classified by wavelength
The Sun emits three important types of electromagnetic radiation: visible, infrared, and ultraviolet
Insolation refers to incoming solar radiation
Radiation is the process by which electromagnetic radiation is emitted by an object
Radiation can undergo several processes, including absorption, reflection, transmission, and scattering
The greenhouse effect makes Earth able to support life

38. Summary Conduction is the transfer of heat through molecular collision
Convection is a vertical transport of heat in a fluid
Advection is the horizontal transport of heat
Adiabatic cooling and warming processes do not release or absorb heat
The global radiation budget describes the latitudinal distribution of temperature
Land surfaces heat and cool faster than water surfaces
Heat is transferred globally through atmospheric and oceanic circulations
The vertical temperature patterns in the atmosphere help describe vertical circulations
Global warming is the observed warming of the atmosphere
Temperature and carbon dioxide show a close relationship