2. Earth’s Energy Balance
or:
What comes in must go out!
The sun is the power source that drives
many of Earth’s flow systems (storms,
waves, ocean and wind currents)
When the sun’s energy (sunlight) enters
our atmosphere, its inputs must be
balanced by equal outputs
This energy must be redistributed over the
globe to maintain the conditions of our
current lifelayer
2
3. Surplus vs. Deficit
A surplus in your checkbook is a good
thing!
A surplus of energy within Earth’s systems
generally means an increase in
temperature and changes in Earth’s
systems’ circulations
(NOT such a good thing!)
3
4. Net Radiation
Net radiation is the difference between the
radiation energy surplus and deficit
Can be measured daily, monthly, yearly, even
by century, in order to help us answer the
question, “Are we heating up or cooling
down?”
Determining net radiation begins with a
number of insolation losses in the
atmosphere…
17. Sensible Heat
Sensible heat is heat that can be felt and
measured
Moved by conduction; transferred by global
winds and ocean currents
18. Latent Heat
Latent heat cannot be sensed or directly
measured
Heat that is stored or released during the change of
state of solids, liquids, and gases
Movement occurs most often through condensation
and evaporation (Ex.: the formation of clouds or the
evaporation of ocean water)
Water in the atmosphere is the most important mover
of latent heat, which ultimately helps to balance
Earth’s energy budget
19. Review
1.What is the power source that
drives Earth’s flow systems?
2.What happens if Earth’s energy
inputs and outputs are unbalanced?
3.Describe the different ways
incoming solar radiation is balanced
by outgoing radiation (draw a
diagram, if that makes it easier to
explain).
20. 4.What is albedo? What kinds of
surfaces have a high albedo?
What surfaces have a low albedo?
5.Describe convection.
6.What is counterradiation? What
kinds of gases contribute to
counterradiation? What is the
greenhouse effect?
7.What is the difference between
sensible heat and latent heat?
21. Temperature
Temperature—a measure of the level of
sensible heat of matter; an expression of
atomic motion
Heat moves from substances of higher temp.
to substances of lower temp. until their
temperatures equalize
22. Fahrenheit, Celsius, and Kelvin
Three systems of temperature
measurement in use internationally:
Fahrenheit, Celsius, and Kelvin
In order to convert from Fahrenheit
to Celsius and back, use these
formulae:
C° = 5/9 (F-32°)
F° = 9/5 C + 32°
0°K = absolute zero—the point at
which all molecular motion ceases
-273.15°C or -459.67°F
Room temperature is about 295K
Converting K to °C only requires
adding 273° (e.g. 3°C = 276K)
Especially useful when dealing with
very low temperatures, as there are
no negative numbers
23. Isotherms
Isotherms—
lines on a
map that
connect
points of
equal
temperature
24. Daily and Seasonal
Temperature Changes
Daily temperatures are influenced by
patterns of sunrise and sunset, which are
the result of seasonal changes,
themselves the result of latitude.
26. Temperature Inversions
Temperatures are generally
hotter during the day at the
surface and cooler above.
A temperature inversion
occurs when surface
temperatures are cooler than
the air above for some
vertical distance.
Once a temperature
inversion occurs, it tends to
persist until all heat has
been transferred back out to
space.
There are four common
types of temperature
inversions….
27. Subsidence Inversion
Subsidence inversions
Occur in the upper atmosphere
Result of air slowly descending due to a high
pressure cell
As the air descends, it compresses and warms, and
this warm layer sits atop cooler air below
Most common in the subtropics year-round and in the
Northern Hemisphere in winter
Do not sink lower than a few hundred meters above
sea level due to low-level turbulence
28. Radiational Inversion
Radiational inversions—the result of rapid
radiational cooling
Most common in high latitudes, especially at
night
Long wave radiation (heat) is radiated back
out to space and has left the lower portion of
the troposphere, but has not yet entirely left
the air above.
29. Advectional Inversion
Advection = “wind” (any horizontal
movement of air, usually in response to
atmospheric pressure differences)
Advectional inversions—a horizontal flow
of air displaces warmer air upward
Especiallycommon along coasts, as air
moves out of high pressure zones over the
water and into a low pressure zone over land.
31. Cold-air-drainage Inversion
Cold-air-drainage inversions—cooler air on mountain
slopes sinks into a valley below, forcing the warmer air in
the valley to rise upward
Most common in the midlatitudes, especially in winter
32.
33. Daily Temperature Lags
Insolation levels rise as the sun rises, reach a
maximum at noon, then decrease and end at
sunset
The coldest time of day is actually after the sun
has risen
The hottest time of day is a few hours after noon
The hottest time of day (maximum daily
temperature) varies based on such factors as
cloudiness, windiness, proximity to a large body
of water, and even storms.
34. Seasonal Temperature Lags
In summer, monthly insolation is highest
In winter, monthly insolation is lowest
In between, during the equinoxes, insolation levels are in
the middle
Highest monthly temperatures tend to be one month
after the summer solstice
Lowest monthly temperatures also follow one month
after the winter solstice
Although radiation levels are similar for both the fall
(autumnal) and spring (vernal) equinoxes, temperatures
are considerably warmer following the summer months
than following winter. The temperatures of the equinoxes
are not the same because each reflects the
temperatures of previous seasonal conditions.
35. Factors influencing differences in
temperature
Latitude
Elevation/Altitude
Cloud Cover and Albedo
Proximity to a Water Body
Differential
heating of land and water
Ocean currents
Proximity to an urban area
49. Global Temperature Patterns: Mini Quiz!
Which will be colder? Highland areas (areas of higher elevation)
or lowland areas in the same region?
Highlands are colder than surrounding lowlands.
Does temperature increase or decrease with latitude (as you get
closer to the poles)?
It decreases.
True or False? Seasonal isotherm shifts are more dramatic over
land areas than over oceans.
True
Which influences temperatures on the edges of continents: warm
or cold ocean currents?
Both warm and cold currents affect temperatures on nearby
land
Equatorial locations receive a roughly even amount of insolation
all year round. How does that affect their temperature patterns?
They tend to have more even temperature patterns
50. Review
1.What is the difference between heat and
temperature?
2.True or False? Heat flows from the hot
object toward the cold object until both
objects are the same temperature.
3.Lines on a map that connect points of
equal temperature are called...
4.Draw two graphs: one showing a normal
atmospheric temperature condition and
one showing a temperature inversion.
5.Describe the 4 temperature inversions.
51. 6.The hottest time of day is just after
noon and the coldest time is just after
sunrise. Why?
7.Name the 5 factors influencing the
temperature of any location.
8.Why does being near a body of water
make a location warmer in winter and
cooler in summer than locations further
inland? (Remember the properties of
land vs. water!)
9.What is an urban heat island?
52. What is the difference between
Weather and Climate?
• Weather • Climate
53. What is the difference between
Weather and Climate?
• Weather • Climate
Short-term
atmospheric
conditions
(A storm or warm front)
54. What is the difference between
Weather and Climate?
• Weather • Climate
Short-term
atmospheric
conditions
(A storm or warm front)
55. What is the difference between
Weather and Climate?
• Weather • Climate
Short-term An average of
atmospheric weather conditions
conditions over a long period of
(A storm or warm front) time
(minimum of 30 yrs.)
56. What is the difference between
Weather and Climate?
• Weather • Climate
Short-term An average of
atmospheric weather conditions
conditions over a long period of
(A storm or warm front) time
(minimum of 30 yrs.)
57. “Choosing shorts or long underwear on a
particular day is about weather; the ratio
of shorts to long underwear in the drawer
is about climate."
--Charles Wohlforth, The whale and the supercomputer:
On the northern front of climate change, p. 150
Climate is what entices you to go
there on vacation…weather is what
drives you to come home.
58. The 4 Basic Elements of
Weather and Climate
Temperature
Moisture Content (Precipitation)
Atmospheric Pressure
Wind (strength, direction, constancy)
59. The 7 Controls of
Weather and Climate
Latitude
Distribution of land and water
General circulation of the
atmosphere
General circulation of the oceans
Elevation
Topographic barriers
Storms
69. Global Warming: An Informed Opinion
• An Inconvenient Truth
• IPCC—Intergovernmental Panel on Climate Change
• NRDC—Natural Resources Defense Council
• EPA, NOAA, NESDIS—National Environmental
Satellite, Data and Information Service, etc.
vs.
• CEI—Competitive Enterprises Institute
(GlobalWarming.org)
• Global corporations—esp. carbon-based energy
74. Review
1.What is the difference between
weather and climate?
2.What are the 4 basic elements of
weather and climate that we
measure? Which 2 are easiest to
track?
3.Name the 7 controls of weather and
climate.
4.What does “IPCC” stand for? What
does it do?
75. Homework this week:
Work on study guides (Ex. credit!)
Draw and label the hypothetical radiation
balance diagram
Read through class notes
Highlight anything you don’t understand.
Try to find the answer in the chapters.
Ask for help if you still don’t get it
Review the class slides
Watch a Khan Academy video
