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Unit 5: Atmosphere
Meteorology – Study of the
atmosphere!
Structure of the Atmosphere Notes
• Layers of the atmosphere are based on Temperature
Changes.
– Troposphere - lowest layer; thickness depends on
location; where weather occurs-clouds, precipitation…
– Stratosphere - strong steady winds; aircraft fly in the
lower stratosphere, ozone layer causes increased temp.
– Mesosphere - temperature drops
– Thermosphere - temperature rises because oxygen and
nitrogen absorb solar energy
• Ionosphere-ions and electrons reflect radio waves
• Create your model.
http://www.physicalgeography.net/fundamentals/7b.html
• Composition of the Atmosphere
– The two main gases in air are nitrogen and oxygen.
• Remaining gases: argon, carbon dioxide, hydrogen, ozone,
krypton and helium
– Water Vapor (remember the water cycle)
• Where in the atmosphere are gas molecules closer
together?
– At lower altitudes.
• Where is the air pressure greatest?
• At lower altitudes.
Measuring Temperature
• Thermometers - instruments that measure heat
(how fast molecules move)
– Thermometers work on the principle that a rise in
temperature causes molecules to move further
apart.
– Most thermometers contain a liquid such as
mercury or alcohol that expands when heated.
• Temperature Scales
– Celsius
• Freezing point=
Boiling point=
– Fahrenheit
• Freezing point=
Boiling point=
• Altitude
Changes in Temperature
– Temperature decreases as altitude increases in the
troposphere.
– Normal lapse rate: change in temperature of 1 degree for
every 160 meters (practice problems)
• Seasons and the Sun
– The sun’s rays do not heat the Earth’s surface evenly.
– Because the earth is round, only the equator gets direct
rays. (Remember the lab from astronomy! Review heat
movement!)
• Insulation
– Would the temperature range be greater on cloudy or
clear days?
REVIEW: Heating of the Atmosphere
• Radiation - waves that transfer heat energy
– hot bodies (sun) radiate short heat waves
– cooler bodies (earth) radiate longer waves
• Conduction - object receives heat when it comes
into contact with a hotter object
– Air that touches warm ground or air is heated
• Convection - steady flow of heated currents
– Ex. Heating water in a kettle
– convection is the most effective form of heat
transfer
• Normally 70% of the Sun’s energy is absorbed.
• Clouds can reflect solar energy so it never
reaches the Earth’s surface.
OR
• Clouds can keep energy from escaping back into
space.
Clouds
• Watch the video clips and answer in your
own words:
How do clouds form?
• Terms: Evaporation, Condensation (dew
point), Condensation nuclei
Cloud Activity / 2.5 / 15 pts.
• Use page 288 in your textbook to draw a cloud
diagram taking up half the page.
– Km above the Earth surface should be labeled on the side
as well as the freezing level.
– Draw and label each type of cloud.
• Below your diagram, write the following root
words:
AltoStratusCirro-
Nimbus-
Cumulus-
Cloud Questions-complete
sentences
1. What clouds are associated with rain?
2. What clouds are made primarily of ice?
3. What clouds are associated with
thunderstorms?
4. Explain “vertical development” in
reference to cloud formation.
Practice Problems Before the Quiz
• You climb to the top of a mountain that has an
altitude of 480m. The temperature at the
bottom of the mountain is 62 degrees F. What
will the approximate temperature be a the top of
the mountain?
• You are walking down a gradually sloping hill
320m. The temperature at the peak of the hill is
80 degrees F. What will be the approximate
temperature at the bottom of the hill?
Do You Know Your
Clouds?
© Copyright 2010. M. J. Krech. All rights
reserved.
Cloud Activity / 2.5 / 15 pts.
• Use page 288 in your textbook to draw a cloud
diagram taking up half the page.
– Km above the Earth surface should be labeled on the side
as well as the freezing level.
– Draw and label each type of cloud.
• Below your diagram, write the following root
words:
AltoStratusCirro-
Nimbus-
Cumulus-
Cloud Questions-complete
sentences
1. What clouds are associated with rain?
2. What clouds are made primarily of ice?
3. What clouds are associated with
thunderstorms?
4. Explain “vertical development” in
reference to cloud formation.
What else is in the Air?
• Ozone(O3) - form of oxygen forms when UV rays
from the sun react with oxygen in the upper
atmosphere
– Protects the inhabitants of Earth from harmful
ultraviolet rays. DOES NOT BLOCK HEAT!
– Good in the stratosphere. Bad at ground level!
– Chlorofluorocarbons (CFC’s) used in air conditioners
and refrigerators destroy the ozon layer.
• Dust-tiny grains of rock, dirt, pollen, salt crystals,
soot from fires, and bacteria (condensation nuclei)
• Water Vapor (Humidity)
– How does water vapor enter the air? ?
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SPECIFIC/ABSOLUTE HUMIDITY:
(expressed as grams of water vapor per cubic meter volume of air)
measure of the actual amount of water vapor (moisture)
in the air,
RELATIVE HUMIDITY:
(RH) (expressed as a percent)
Also measures water vapor, but RELATIVE to the
temperature of the air.
In other words, it is a measure of the actual amount of
water vapor in the air compared to the total amount of
vapor that the air can hold.
•
•
WARM AIR CAN HOLD MORE WATER VAPOR
THAN COLD AIR!!
Humidity
• Capacity of air is primarily a function of
temperature
• Relative Humidity (RH) =
(actual water vapor content)
(max. water vapor capacity of the air)
x 100
• Heated air becomes lower in RH because
denominator gets larger
• Cooled air becomes higher in RH
Saturation vs
Air Temperature
The actual amount of
Water air can hold changes
With air temperature
Air at 104 F can hold 3 times
As much water as 68 F air !
(47 grams vs only 15 grams)
Air at 68 F can hold 4 times
As much water as air at 0 F
(15 grams vs only 4 grams)
47 grams
15 grams
32 F
104 F
68 F
4 grams
Saturation and Dew Point
• Dew-point
– temperature to which
air must be cooled
for water vapor to
condense.
• EXAMPLES:
water on outside of
drinking glass
ice on your car
window
dew and fog
Humidity Lab / 2.5
Title: Humidity Lab
Purpose: To learn how to measure relative
humidity using a sling psychrometer.
Background: 1. Draw a sling psychrometer.
2. Problem Solving Lab pg. 283
2nd: 4/24/14
Due today: None
Review your notes from yesterday for
our quiz today.
You should review:
Layers of the atmosphere
Clouds
Temperatures Scales
Normal Lapse Rate
Humidity
Important Dates
4/17
Unit 6 Vocabulary
4/21
Water Cycle Coloring
4/24
Quiz
4/25
Reading Guide Due!
4/29
Quiz: Weather Maps
5/2
TEST!
5/5
Library: Honors Project and
Remediation
5/6
Last Current Event is due!
Source Check could be
turned in on this day (5/14)
Humidity Lab / 2.5
Title: Humidity Lab
Purpose: To learn how to measure relative
humidity using a sling psychrometer.
Background: 1. Draw a sling psychrometer.
2. Problem Solving Lab pg. 283
3. Practice Problems
• Hypothesis: What do you predict is the relative
humidity for our classroom?
Do you think the relative humidity is higher
outside or inside the school?
• Data: Copy the three tables from the lab sheet.
Air Masses & Fronts / 2.5
● defined by the temperature and water vapor
content.
● take characteristics of surface below them
● categorized by where they are from
The abbreviations used to classify air masses
use the following letters: c, m, T, P, and A.
For each letter, describe its property:
Word
c
continental
m maritime
T Tropical
P Polar
A Arctic
Means
dry
moist
warm
cold
very cold
Color Your Diagram. Answer the questions.
Fronts
A front is a boundary between two different
air masses, resulting in stormy weather.
A front usually is a line of separation
between warm and cold air masses.
Fronts are often associated with some form
of precipitation
© Copyright 2010. M. J. Krech. All rights reserved.
Four Types of Fronts
Cold Front
Occluded Front
Warm Front
Stationary Front
Cold Front
• IA cold front forms when cold, dense air moves into
a region occupied by warmer air.
• Severe Weather/Thunderstorms followed by cold
weather.
Cold front
Warm Front
• A warm front forms when warm air moves into
an area formerly covered by cooler air.
• Lots of cloud cover and rain followed by
warmer weather.
Warm Front
Stationary front
• When the flow of cold
air and warm air meet.
• prolonged rain until one
“wins”.
Occluded fronts
• A cold air mass moves quickly and overtakes a
second cold air mass. Warm air is caught
between the two cold air masses.
• Severe Weather/ Tornadoes
Fronts
• Card sort
Weather Maps / 2.5
• Weather maps show weather
• s
patterns so meteorologists
can predict and explain
upcoming weather events.
– Fronts
– Pressure systems
– Weather Stations
Wind Speed
WEATHER STATION
MODEL
Temperature
Current Weather:
Cloud Cover
(100% shown here)
Wind
Direction
Barometric
Pressure
Dew Point
Current Weather Symbols
1023
What is the temperature at
this reporting station? 76
What is the wind speed at
this reporting station?
20 mph
What type of precipitation i
occurring at this reporting
Rain
Station?
What amount of cloud cover
is at this reporting station?
100%
What the barometric
pressure at this
reporting station?
1023
What is the wind direction?
NE
What is the dew point?
55
Weather Station Activity / 16 pts.
• In your notes!
• 20 minutes
Isopleths
• Lines (remember
contour lines?) that
connect similar areas on
a map.
– Isotherms= temperature
– Isobars=air pressure
Isotherms
Isobars
Air Pressure
• Low Pressure Areas:
– Air moves up through the area. This causes air to move
counterclockwise.
– Because the air is moving up, clouds form.
– Weather is overcast and possibly rainy.
• High Pressure Areas:
– Air moves down through the area. This causes air to move
clockwise.
– Because air is moving down, no clouds form.
– Weather is clear and fair.
• Changes in pressure can be caused by fronts and/or
temperature changes.
• Measure with a barometer and recorded with isobars.
Severe weather types
• Thunderstorm
– Features
• A. cumulonimbus
clouds
• B. Heavy rainfall
• C. Lightning
• D. Occasional hail
– Occurrence
• A. 2000 in progress
at any one time
• B. 100,000 per year
in the United States
• C. Most frequent in
– 1. Florida
– 2. Eastern Gulf
Coast Region
Stages of Development
• All thunderstorms require
– Warm air
– Moist air
– Instability (lifting)
A. High surface temperatures
B. Most common in the afternoon
C. Rising air causes a change in cloud charge to
create lightening (picture)
Tornado---Features
• Local storm of short duration
• Features
– Violent windstorm
– Rotating column of air around a severe low
pressure
– Extends down from a cumulonimbus cloud
– Winds approach 480km (300 miles)per hour
Stages of Development
Occurences and Development
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Average of 780 each year in U.S.
Most frequent from April through June
Associated with Severe thunderstorms
Exact cause for tornadoes is not known
Occur most often along an occluded or cold
front
Tornado forecasting
• Difficult to forecast because of their small size
• Tornado watch
– To alert people
– Issued when the conditions are favorable
– Covers 65,000 sq km
• Tornado warning
– Issued when a funnel cloud is sighted or is indicated by
radar
Hurricanes
• Most violent storm on Earth
• To be called a hurricane
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Wind speed in excess of 119 km per hour
Rotary circulation
Wind speeds can reach 300 km per hour
Can generate 50 foot waves at sea
• Known by different names
– Typhoon in western Pacific
– Cyclone in Indian ocean
Hurricane formation and decay
A. Form in tropical waters.
B. Energy comes from warm water.
C. Develop most often in late summer when warm
water temperatures provide energy and moisture
D. Initial stage is not well understood
Tropical depression-winds below 61km per hour
Tropical storm- 61 to 119 km per hour
E. Diminish over cooler ocean water and land
Destruction from a hurricane
• Factors that affect amount of hurricane damage
– Strength of storm (the most important factor)
– Size and population density
– Shape of the ocean bottom near the shore
• Categories of hurricane damage
– Wind damage
– Storm surge-large dome of water on shore
– Inland freshwater flooding from torrential rains
Discovery Education Video / 2.6
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Answer appropriate # of questions.
In your notebook.
Complete sentences are NOT necessary.
24 min.
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Venn Diagram for Hurricanes
and Tornadoes
Low Pressure
Most Destructive
Warm Air
Tropical Waters
Watches and Warning Systems
Eye
Measured with the Fujita Scale
Named
Discovery Education Video / 2.6
•
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Answer appropriate # of questions.
In your notebook.
Complete sentences are NOT necessary.
24 min.
Climate vs. Weather / 2.6
• Weather - the state of the atmosphere at a given
time and place.
• What is the difference between weather and
climate?
– Climate is the long term weather of an area.
• Climate is determined by the overall temperature
and precipitation of an area.
Factors that affect climate.
1. Global Position
2. Bodies of water
Land changes temperature faster than water.
Sea breezes occur during the day when the land is
warmer than water and a land breeze occurs at
night when the water is warmer than land
Factors that affect climate
3. Human impact
Over production of Carbon Dioxide leads to
GLOBAL WARMING.
4. El nino
Periods of increased ocean temperature that
cause erratic weather
• Biome Activity / 2.6
Discovery Education Video / 2.6
•
•
•
•
Answer appropriate # of questions.
In your notebook.
Complete sentences are NOT necessary.
24 min.
Climate / 2.6
• Weather - the state of the atmosphere at a given
time and place.
• What is the difference between weather and
climate?
– Climate is the long term weather of an area.
• Climate is determined by the overall temperature
and precipitation of an area.
Factors that affect climate.
1. Global Position/Seasons
2. Bodies of water
Land changes temperature faster than water.
Sea breezes occur during the day when the land is
warmer than water and a land breeze occurs at
night when the water is warmer than land
Factors that affect climate
3. Human impact
Over production of Carbon Dioxide leads to
GLOBAL WARMING.
4. El nino
Periods of increased ocean temperature that
cause erratic weather