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In the News:
Record low for Oct. 10-11
10 ˚F in 1985
Record low-high for Oct. 10-11
39 ˚F in 1946
Source: National Weather Service
www.noaa.gov
g
http://forecast.weather.gov/MapClick.php?site=tfx&smap=1&textField1=45.67972&textField2=-111.03778
Exam I: Where we’ve been
Composition of
the Atmosphere
Structure
St
t
off th
the
Atmosphere
Solar Radiation
Earth-Sun
Geometry,
Season
ƒ What are we working with? How does composition
affect weather and climate?
ƒ What are we working with? How is the atmosphere
organized, and how does this affect weather and
climate?
ƒ Sun = our ultimate energy source. What’s the
nature of this energy and how does the distribution of
solar radiation affect weather and climate on Earth?
Earth’s Energy
gy
Balance
Pressure and
Winds
Moisture
ƒ What happens to Sun’s energy once it reaches
Earth? How are input and output balanced?
ƒ The balance of energy drives winds. What
is the pattern and impacts of winds, on the
surface and in the upper atmosphere?
ƒ How does moisture move through the
atmosphere?
Exam I: True False
1. Water vapor is a gas and an important
component of Earth’s atmosphere.
2. Variable gasses account for only a small
percentage of the total mass of the atmosphere,
atmosphere
but they have important impacts of the behavior
of the atmosphere.
atmosphere
Exam I: Multiple Choice
1. At what latitude would the Tropic of Cancer occur, if
Earth’s axis were tilted 20°?
a.
b.
c.
d.
e.
15° S latitude
23° N latitude
20° N llatitude
tit d
70° N latitude
70° S latitude
Exam I: Matching
Questions are in figures, choices are grouped from
a-e.
a. Net longwave radiation loss
b. Absorbed solar radiation
c. Energy gained
d. Energy lost
e. Temperature
.
1.
2
2.
3.
.
.
d. Forms of Condensation
Dew:
ƒ
Liquid condensation on a surface
ƒ
Forms on clear, windless nights
ƒ
Surface cools diabatically
Frost:
ƒ
Frozen dew (hoar frost)
ƒ
From gas to solid = deposition
ƒ
Separate ice crystals
Frozen Dew:
ƒ
Dew that later freezes as T
drops: black ice
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d. Forms of Condensation
Fog:
ƒ
Precipitation
p
and Steam Fog
ƒ
Result from
adding water
vapor to the air
ƒ
e.g. cold dry air
mixes with warm
moist air
Gallatin River: ca 0°C
Air temperature: -26°C
26 C
January 2007
Steam fog from mixing of relatively warm,
“moist” air above the water with cool, dry air
(Jan. 2007, Gallatin River, MT).
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d. Forms of Condensation
Fog:
ƒ
Radiation Fog
g
ƒ
Result when
radiative cooling
g
drops temp. to
dew point, and
light winds exist
(5 km/hr; 3 mph).
ƒ
Formed by
diabatic cooling
Radiation fog is common in the Central Valley
of California from the combination of a cool,
clear nights
nights, which lower the temperature to
the dew point, and light surface winds. (A&B
8
Fig. 5-19)
d. Forms of Condensation
Fog:
ƒ
Advection Fog
g
ƒ
Results when warm,
moist air moves
horizontally (advection =
horizontal movement) over a
cooler surface
ƒ
Can be advected
long distances,
persisting well
downwind of the
area of formation
Advection fog commonly forms in the summer
In the Pacific Northwest, often when warm,
moist marine air drifts over a cold inland area
that have experienced radiational cooling.
9
(July 2001, Glacier Peak, WA).
d. Forms of Condensation
Fog:
ƒ
Upslope
p p Fog
g
ƒ
Result adiabatic
cooling, as moist air
moves up in
elevation
ƒ
Common along
Rocky Mountain
front
Upslope fog forms by adiabadic cooling, as
warm, moist air ascends up-valley (Dec.,
2007, Absaroka Range and the Paradise
Valley, MT).
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d. Forms of Condensation
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d. Forms of Condensation
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