Transcript
Page 1: Chapter 4: Insolation and Temperature

Chapter 4: Insolation and Temperature

Page 2: Chapter 4: Insolation and Temperature

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

Page 3: Chapter 4: Insolation and Temperature

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

Page 4: Chapter 4: Insolation and Temperature

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

Page 5: Chapter 4: Insolation and Temperature

Energy, Heat, and Temperature

• 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• Too short to be seen by the

human eye

Figure 4-5

Figure 4-4

Page 6: Chapter 4: Insolation and Temperature

• Insolation– Incoming solar radiation– Shortwave energy

• Terrestrial Energy– Longwave

energy– “Earth’s”

energy

Energy, Heat, and Temperature

Figure 4-16

Page 7: Chapter 4: Insolation and Temperature

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

Page 8: Chapter 4: Insolation and Temperature

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

Page 9: Chapter 4: Insolation and Temperature

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

Page 10: Chapter 4: Insolation and Temperature

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

Page 11: Chapter 4: Insolation and Temperature

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

Page 12: Chapter 4: Insolation and Temperature

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

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Radiation, Conduction & Convection Operating Simultaneously

Page 14: Chapter 4: Insolation and Temperature

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

Page 15: Chapter 4: Insolation and Temperature

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

Page 16: Chapter 4: Insolation and Temperature

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

Page 17: Chapter 4: Insolation and Temperature

The Heating of the Atmosphere: Global Energy Budget

• Energy in = Energy out

Figure 4-17

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• Earth does not distribute heat evenly through space & time– Cause of weather and climate

The Heating of the Atmosphere: Global Energy Budget

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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

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Variations in Heating by Latitude and Season

• Atmospheric obstructions– Clouds, haze, particulates, etc. decrease insolation

Figure 4-20

Figure 3-4

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Variations in Heating by Latitude and Season

• Day length– The longer the day, the more

insolation is received

Figure 4-19

Page 22: Chapter 4: Insolation and Temperature

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

Page 23: Chapter 4: Insolation and Temperature

Land and Water Contrasts

• Land heats and cools more rapidly than water due to:– Specific heat– Transmission– Mobility– Evaporative

cooling

Figure 4-23

Page 24: Chapter 4: Insolation and Temperature

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

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Mechanisms of Heat Transfer

• Need heat transfer to prevent constant warming at tropics & cooling at poles

• Circulation patterns in atmosphere and oceans transfer heat

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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

Page 27: Chapter 4: Insolation and Temperature

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)

Page 28: Chapter 4: Insolation and Temperature

Mechanisms of Heat Transfer

• Temperature patterns– Poleward currents transfer warm water poleward– Equatorial currents transfer cool water equatorward

Figure 4-25

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Mechanisms of Heat Transfer

• 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

Figure 4-26

Page 30: Chapter 4: Insolation and Temperature

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

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• Global temperature maps– Seasonal extremes

• January & July– BROAD

understanding of temperature patterns

– Isotherm: line connecting points of equal temperature

Global Temperature

Patterns

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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

Page 33: Chapter 4: Insolation and Temperature

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

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Global Temperature Patterns

• Annual temperature range– Difference in average temperature of warmest and

coldest months (usually Jan & July)

Figure 4-32

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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 ChangeFigure 4-33

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Global Warming and the Greenhouse Effect

• Relationship between carbon dioxide and temperature

Figure 4-35

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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

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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


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