Geography 1 (41100). Prof. Dean . Wint., Jan 9, 2012 . Lect and Chp 4 . Pg 74-105
Chapter 4
Insolation and Temperature
I. The Impact of Temperature on the Landscape
a. Extreme shifts in temperature are not conducive to development of
organic life and in general organic life has adapted to specific
temperatures.
b. Inorganic materials such as soil development, buildings, etc., are also
affected by fluctuations of temperature.
II. Energy, Heat and Temperature
a. The universe is made up of matter and energy.
i. Matter: “stuff” of the universe: solids, liquids, gases that have
mass and volume.
ii. Energy: “Anything that changes the state or condition of
matter.”
1. Forms of energy: Chemical, kinetic, potential, nuclear
and others.
III. Energy
a. Cannot be destroyed but can change form.
b. Smallest units are atoms that when combined form molecules.
c. Their ability to move or “jiggle” defines their property as either a
solid, liquid or a gas.
d. The movement of atoms creates internal energy called kinetic energy,
the higher the energy the greater the temperature.
IV. Temperature and Heat
a. Temperature is an evaluation of the average kinetic energy of a
molecule.
b. Heat and Thermal energy are used interchangeable.
c. Heat is not something a molecule posses but something that is given
off from a higher energy molecule to a lower one.
V. Measuring Temperature
a. Is done by a thermometer.
VI. The Fahrenheit, Celsius and Kelvin Scale
a. Fahrenheit: used primarily in America.
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Geography 1 (41100). Prof. Dean . Wint., Jan 9, 2012 . Lect and Chp 4 . Pg 74-105
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b. Celsius: is primarily used in the world and is the chosen scale for
science.
i. Has a boiling and freezing point with 100 units/degrees.
c. Kelvin: measures in absolute temperatures, has no negatives.
VII. Solar Energy
a. Is the primary energy source of the earth and its unequal heating of
the earth puts the atmosphere in motion.
b. Uses nuclear fusion to produce energy known as Electromagnetic
Radiation.
i. The energy of the sun is given off as electromagnetic radiation
also known as radiant energy and reaches the earth in 8 min’s.
ii. Less than one two-billionth of the energy from the sun reaches
the Earth’s atmosphere.
iii. Flows in waves, “oscillating in the same rhythm as the
vibrations of the electrical charges that form them.”
Furthermore the length of the waves (crest-to-crest) are the
primary method of classification on the electromagnetic
spectrum.
1. Visible light: is visible to the human eye, makes up a
narrow band of light but approx. 47% of the total
energy from the Sun that arrives at Earth is VL.
2. Ultraviolet Radiation: 8% of suns energy arriving at the
earth, most is absorbed by Ozone layer, which would be
damaging to organic life if it reached the Earth’s surface
and are shorter wavelengths than visible light.
3. Infrared Radiation: 45% of the total energy from the
Sun to Earth and is slightly longer than VL. Makes up
sensible heat, ex. Standing in front of a fire.
c. Insolation: total incoming solar radiation
i. Solar constant: avg. of 1372 watts per square meter
VIII. Basic Heating and Cooling Processes in the Atmosphere
a. Radiation/Emission
i. Process by which electromagnetic energy is emitted.
ii. The higher the heat the greater the emission of
electromagnetic energy and the shorter the waves.
Geography 1 (41100). Prof. Dean . Wint., Jan 9, 2012 . Lect and Chp 4 . Pg 74-105
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iii. Blackbody radiators: reflects perfectly the heat that it absorbs
b. Absorption
i. Process by which electromagnetic energy is assimilated into an
object and is affected by an objects texture, color, etc.
ii. A good radiator is a good absorber.
c. Reflection
i. Process by which electromagnetic waves are repelled but do
not affect the waves or the object.
d. Scattering
i. Process by which molecules and some matter deflect light into
random angles but do not shorten the wavelength. Because the
light is sent in random directions, some can affect atmospheric
heating because the light is sent back into space.
ii. The light that still strikes the Earth is called “diffuse radiation.”
iii. Without this process you would have black skies.
e. Transmission
i. Degree and process by which electromagnetic waves pass
through a medium.
ii. Different substances transmit different wavelengths more
effectively.
f. Greenhouse Effect
i. Process by which the specific greenhouse gases in the
atmosphere readily transmits shortwave radiation in but do
not allow longwave radiation out. Light is absorbed and heat is
generated.
ii. Is responsible for keeping the Earth’s surface and the
Troposphere around an avg. of 15C or 59F
g. Conduction
i. Process by which heat-energy is transferred from a hot
molecule to a cooler one and vice-versa, until both molecules
become even.
ii. Air is a poor conductor because its molecules are arranged
further apart.
h. Convection
Geography 1 (41100). Prof. Dean . Wint., Jan 9, 2012 . Lect and Chp 4 . Pg 74-105
i. Process by which molecules that are warmer than their
surrounding molecules physically move location and colder
molecules fill their space.
ii. Convection Cell: is when heated expands and rises to lower
pressure and colder air takes its place.
i.
Advection
i. When the dominate direction of the transfer of heat is
horizontal.
j.
Adiabatic Cooling and Warming
i. The temperature of air changes as it ascends or descends but
no heat transfer is involved in either process.
k. Expansion: Adiabatic Cooling
i. Is cooling by the rise and expansion of air as it moves into
areas of less pressure, therefore its molecular collisions
decrease and so its temperature declines.
l.
Compression: Adiabatic Warming
i. Warming of air as it moves to areas of greater pressure, its
molecules being forced to collide more frequently cause an
increase in temperature.
m. Latent Heating
i. Deals with the process by which heat is either released or
stored during the phase change of water in the atmosphere.
1. Evaporation: is a cooling process
2. Condensation: is a warming process
IX. The Heating of the Atmosphere
a. The process by which shortwave solar radiation enters the earth, is
distributed, is reflected and longwave radiation is emitted into space.
b. Albedo: level of reflection of solar radiation
c. Global Energy Budget: is a map that lays out incoming and outgoing
solar energy.
i. 100 units of shortwave solar radiation enter the earth and on
average a 100 units of longwave radiation leave the earth into
space. This process thereby heats and cools the earth.
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Geography 1 (41100). Prof. Dean . Wint., Jan 9, 2012 . Lect and Chp 4 . Pg 74-105
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ii. The earth through its heating process generates a surplus of
heat, which is what creates a state of permanent convection or
the circulation of air.
X. Variations in Heating by Latitude and Season
a. In part because of imbalances of the vertical and latitudinal heating of
the Earth’s atmosphere weather and climate differences exist.
b. Factors
i. Angle of Incidence: the angle at which light from the sun
strikes the plane of Earth.
ii. Atmospheric Obstruction: any molecule or substance that
scatters light from directly striking the Earth’s surface. This
includes, clouds, gases, greater degrees of threshold in crossing
through the atmosphere because of Angle of Incidence.
iii. Day Length: the longer the day the greater the amount of
absorbed solar energy
c. Latitudinal Radiation Balance
XI. Land and Water Contrasts
a. Different surfaces absorb, reflect, project, warm and cool at different
rates. Water generally takes longer to heat and cool.
i. Heating
1. Water takes longer to heat or cool because
a. Specific heat: is the amount of energy required
for the temperature of water to rise, which is 5
times greater than land.
b. Transmission: solar energy penetrates many
layers of water and thereby greatly distributes
its heat transmission, the opposite of land.
c. Mobility: Water is in constant motion and
thereby distributes heat whereas land is for the
most part immobile.
d. Evaporating Cooling: Water can evaporate and
take the solar energy with it, land cannot.
ii. Implications
Geography 1 (41100). Prof. Dean . Wint., Jan 9, 2012 . Lect and Chp 4 . Pg 74-105
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1. The hottest and coldest areas of Earth are in the interior
of the continents, away from the influence of bodies of
water.
XII. Mechanisms of Heat Transfer
a. Without the transfer of heat colder regions would get progressively
colder and warm regions would progressively get hotter until the
amount of heat energy absorbed equaled the amount radiated from
the Earth.
b. Atmospheric Circulation
i. 75 to 80 percent of all heat distribution is done through the
movement of the Atmosphere.
c. Oceanic Circulation
i. Respond to average wind conditions over long time scales.
ii. A series of elongated elliptical loops from east-west and
centered approximately at 30 degrees of latitude. These loops
flow clockwise in the Northern Hemisphere and
counterclockwise in the Southern Hemisphere and are called
subtropical gyres.
iii. Northern and Southern Variations
iv. Current Temperatures
1. Different currents have different temperatures
2. “The general circulation of the oceans is a poleward
flow of warm tropical water along the east coasts of
continents and an equator-ward movement of cool
high-latitude water along the west coasts of continents.
v. Western Intensification
vi. Rounding out the pattern
XIII. Vertical Temperature Patterns
a. Environmental Lapse Rate
b. Average Lapse Rate
c. Temperature Inversions
d. Surface Inversions
e. Upper-Air Inversions
XIV. Global Temperature Patterns
Geography 1 (41100). Prof. Dean . Wint., Jan 9, 2012 . Lect and Chp 4 . Pg 74-105
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a. “Temperature distribution is shown by means of isotherms, lines
joining points of equal temperature.”
b. Prominent Controls of Temperature
i. Altitude
ii. Latitude: insolation is the primary factor in temperature
variation and is governed by latitude.
iii. Land-Water Contrasts
iv. Ocean Currents
c. Seasonal Patterns
d. Annual Temperature Range
XV. Global Warming and the Greenhouse Effect
a. While the greenhouse effect is responsible for life on Earth it has been
steadily increasing with anthropogenic (human-induced) factors.
b. The largest contributor gas to the greenhouse effect is carbon dioxide
(CO2) which is the by-product of the combustion of anything
containing carbon.
c. The temperature increase over the last 100 years is greater than any
other century in the last 1000 years.