Meteorology
Chap. 12
Air Masses
Weather Systems
Gathering Weather Data
Weather Analysis
Air Masses – 12.1
Objectives
• Compare and
contrast
weather and
climate
• Analyze how
imbalances in
the heating of
Earth’s surface
create weather
• Describe how
and where air
masses form
The Weather Channel
I. Meteorology
I. Meteorology
Meteor- means ‘high in the air’
Meteorology is the study of atmospheric
phenomena.
I. Meteorology
A. Hydrometeors
Any form of water in the atmosphere
I. Meteorology
A. Hydrometeors
B. Lithometeors
Solid material in the atmosphere: smoke, dust,
condensation nuclei
I. Meteorology
A. Hydrometeors
B. Lithometeors
C. Electrometeors
Electricity in the atmosphere: thunder and
lightning
II. Weather vs. Climate
II. Weather vs. Climate
Weather is the
current state of the
atmosphere (shortterm)
II. Weather vs. Climate
Weather is the
current state of the
atmosphere (shortterm)
Climate is long-term
variation of the
atmosphere
III. Energy to Earth
III. Energy to Earth
A. Energy gets to Earth via
Energy is transmitted through space via light
.
III. Energy to Earth
A. Energy gets to Earth via radiation.
B. Some energy is absorbed, while
some is
.
III. Energy to Earth
A. Energy gets to Earth via radiation.
B. Some energy is absorbed, while
some is reflected.
III. Energy to Earth
A. Energy gets to Earth via radiation.
B. Some energy is absorbed, while
some is reflected.
C. Not all places receive equal
radiation.
Why not ??
III. Energy to Earth
A. Energy gets to Earth via radiation.
B. Some energy is absorbed, while
some is reflected.
C. Not all places receive equal
radiation.
1. When the sunlight strikes the Earth
perpendicularly the maximum
energy is transferred.
Unequal distribution of Sun’s radiation
III. Energy to Earth
A. Energy gets to Earth via radiation.
B. Some energy is absorbed, while
some is reflected.
C. Not all places receive equal
radiation.
1. When the sunlight strikes the Earth
perpendicularly the maximum
energy is transferred.
2. Implications
Implications
More heat is transmitted from the sun in ____.
a. the morning
b. the afternoon
c. the evening
Implications
More heat is transmitted from the sun in ____.
a. the morning
b. the afternoon
c. the evening
More heat is transmitted from the sun at____.
a. the equator
b. the poles
c. the point between the equator and the poles
Implications
More heat is transmitted from the sun in ____.
a. the morning
b. the afternoon
c. the evening
More heat is transmitted from the sun at____.
a. the equator
b. the poles
c. the point between the equator and the poles
III. Energy to Earth
A. Energy gets to Earth via radiation.
B. Some energy is absorbed, which
some is reflected.
C. Not all places receive equal
radiation.
D. Energy that reaches the Earth is
moved by the _____ and .
III. Energy to Earth
A. Energy gets to Earth via radiation.
B. Some energy is absorbed, which
some is reflected.
C. Not all places receive equal
radiation.
D. Energy that reaches the Earth is
moved by the water and air.
IV. Air Masses
A large dome of air having similar horizontal
temperature and moisture properties.
IV. Air Masses
A. Source Region
IV. Air Masses
A. Source Region
1. An air mass that forms over a polar
region will be ____.
IV. Air Masses
A. Source Region
1. An air mass that forms over a polar
region will be cold.
2. An air mass that forms over a tropic
region will be _____ and __ _.
IV. Air Masses
A. Source Region
1. An air mass that forms over a polar
region will be cold.
2. An air mass that forms over a tropic
region will be warm and humid.
IV. Air Masses
A. Source Region
B. Classifying Air Masses
IV. Air Masses
A. Source Region
B. Classifying Air Masses
1. cT – Continental Tropic
Warm and dry
IV. Air Masses
A. Source Region
B. Classifying Air Masses
1. cT – Continental Tropic
2. mT – Maritime Tropic
Warm and humid
IV. Air Masses
A. Source Region
B. Classifying Air Masses
1. cT – Continental Tropic
2. mT – Maritime Tropic
3. cP – Continental Polar
Cold and dry
IV. Air Masses
A. Source Region
B. Classifying Air Masses
1. cT – Continental Tropic
2. mT – Maritime Tropic
3. cP – Continental Polar
4. mP – Maritime Polar
Cold and humid
IV. Air Masses
A. Source Region
B. Classifying Air Masses
1. cT – Continental Tropic
2. mT – Maritime Tropic
3. cP – Continental Polar
4. mP – Maritime Polar
5. A - Arctic
Cold and dry
Air Masses over the U.S.
IV. Air Masses
A. Source Region
B. Classifying Air Masses
C. Air masses are also classified by air
mass stability
Stability is the resistance to vertical movement
of air particles
IV. Air Masses
A. Source Region
B. Classifying Air Masses
C. Air masses are also classified by air
mass stability
D. Air masses are modified while they
move.
Eventually they lose their original
characteristics
The End
Air Masses – 12.1
Objectives
• Describe how
the rotation of
Earth affects the
movement of air
• Compare and
contrast wind
systems
• Identify the
various types
of fronts
http://calspace.ucsd.edu/virtualmuseum/climatechange1/08_1.shtml
I. A Global Illustration
I. A Global Illustration
A. Vertical movement of air
I. A Global Illustration
A. Vertical movement of air
1. Warm air
.
This is observed in the location that receives
the greatest amount of solar radiation
I. A Global Illustration
A. Vertical movement of air
1. Warm air rises.
2. Cool air
.
This occurs as air loses energy in the upper
troposphere.
I. A Global Illustration
A. Vertical movement of air
1. Warm air rises.
2. Cool air falls.
This occurs as air loses energy in the upper
troposphere.
I. A Global Illustration
A. Vertical movement of air
B. Movement of air across the
Earth’s surface
I. A Global Illustration
A. Vertical movement of air
B. Movement of air across the
Earth’s surface
1. Air moves North or South in various
Hadley cells
I. A Global Illustration
A. Vertical movement of air
B. Movement of air across the
Earth’s surface
1. Air moves North or South in various
Hadley cells
2. The location where air comes
together between the tropics is called
the
zone
(ITCZ)
I. A Global Illustration
A. Vertical movement of air
B. Movement of air across the
Earth’s surface
1. Air moves North or South in various
Hadley cells
2. The location where air comes
together between the tropics is called
the intertropical convergence zone
(ITCZ)
Intertropical Convergence Zone
http://calspace.ucsd.edu/virtualmuseum/climatechange1
I. A Global Illustration
A. Vertical movement of air
B. Movement of air across the
Earth’s surface
C. Movement of air relative to
Earth’s motion
I. A Global Illustration
A. Vertical movement of air
B. Movement of air across the
Earth’s surface
C. Movement of air relative to
Earth’s motion
1. Air doesn’t travel straight
I. A Global Illustration
A. Vertical movement of air
B. Movement of air across the
Earth’s surface
C. Movement of air relative to
Earth’s motion
1. Air doesn’t travel straight
2. It turns due to the Coriolis effect
Coriolis effect
Perception of an East or West deflection of air
currents due to the rotation of the Earth.
In the Northern
hemisphere air
currents are
deflected
.
In the Southern
hemisphere air
currents are
deflected
.
Coriolis effect
Perception of an East or West deflection of air
currents due to the rotation of the Earth.
In the Northern
hemisphere air
currents are
deflected right.
In the Southern
hemisphere air
currents are
deflected left.
I. A Global Illustration
D. Global wind systems
I. A Global Illustration
D. Global wind systems
1. Trade winds (Northeast & Southeast)
Occur between the equator and 30ºN or 30ºS
I. A Global Illustration
D. Global wind systems
1. Trade winds (Northeast & Southeast)
2. Westerlies
Occur between 30º and 60º (in North & South).
They blow toward the
.
I. A Global Illustration
D. Global wind systems
1. Trade winds (Northeast & Southeast)
2. Westerlies
Occur between 30º and 60º (in North & South).
They blow toward the East. (From the West)
I. A Global Illustration
D. Global wind systems
1. Trade winds (Northeast & Southeast)
2. Westerlies
3. Polar Easterlies
Occur between 60º and 90º (in North & South).
They blow toward the ______.
I. A Global Illustration
D. Global wind systems
1. Trade winds (Northeast & Southeast)
2. Westerlies
3. Polar Easterlies
4. Doldrums
It’s pretty depressing to sail here.
I. A Global Illustration
D. Global wind systems
1. Trade winds (Northeast & Southeast)
2. Westerlies
3. Polar Easterlies
4. Doldrums
5. Horse Latitudes
Watch out for horses!
I. A Global Illustration
D. Global wind systems
E. Moisture
I. A Global Illustration
D. Global wind systems
E. Moisture
1. In areas of
pressure there is rain.
I. A Global Illustration
D. Global wind systems
E. Moisture
1. In areas of low pressure there is rain.
2. In areas of high pressure it is
.
I. A Global Illustration
D. Global wind systems
E. Moisture
1. In areas of low pressure there is rain.
2. In areas of high pressure it is dry.
I. A Global Illustration
D. Global wind systems
E. Moisture
F. Jet Streams
Jet Stream
Upper-level air winds
Caused by difference in temp. & pressure
between equator and poles
High speed (some over 110 mph)
Move from West to East
II. Fronts
Boundary between air masses with different
densities.
II. Fronts
A. Cold Front
Symbol:
direction
1. Cold air displaces warm air
II. Fronts
A. Cold Front
Symbol:
direction
1. Cold air displaces warm air
2. Warm air rises the steep boundary
II. Fronts
A. Cold Front
Symbol:
direction
1. Cold air displaces warm air
2. Warm air rises the steep boundary
3. Brings thunderstorms/rain
II. Fronts
A. Cold Front
B. Warm Front
Symbol:
direction
II. Fronts
A. Cold Front
B. Warm Front
Symbol:
direction
1. Warm air moves slowly over cold air mass
II. Fronts
A. Cold Front
B. Warm Front
Symbol:
direction
1. Warm air moves slowly over cold air mass
2. Extensive clouds formed with precipitation
II. Fronts
A. Cold Front
B. Warm Front
C. Stationary Front
II. Fronts
A. Cold Front
B. Warm Front
C. Stationary Front
1. Warm air mass collides with cold mass
II. Fronts
A. Cold Front
B. Warm Front
C. Stationary Front
1. Warm air mass collides with cold mass
2. Neither air mass pushes harder than the
other
II. Fronts
A. Cold Front
B. Warm Front
C. Stationary Front
1. Warm air mass collides with cold mass
2. Neither air mass pushes harder than the
other
3. May bring days of cloudy/rainy weather
II. Fronts
A. Cold Front
B. Warm Front
C. Stationary Front
D. Occluded Front
Symbol:
direction
II. Fronts
A. Cold Front
B. Warm Front
C. Stationary Front
D. Occluded Front
Symbol:
direction
1. Cold air overtakes another cold front
II. Fronts
A. Cold Front
B. Warm Front
C. Stationary Front
D. Occluded Front
Symbol:
direction
1. Cold air overtakes another cold front
2. Often occurs in later stages of storm
II. Fronts
A. Cold Front
B. Warm Front
C. Stationary Front
D. Occluded Front
Symbol:
direction
1. Cold air overtakes another cold front
2. Often occurs in later stages of storm
3. Precipitation may occur on both sides
III. Pressure
A. High Pressure
III. Pressure
A. High Pressure
1. Indicates air is _____
III. Pressure
A. High Pressure
1. Indicates air is falling
2. Coriolis effect turns air ________
III. Pressure
A. High Pressure
1. Indicates air is falling
2. Coriolis effect turns air clockwise
3. Symbol
III. Pressure
A. High Pressure
1. Indicates air is falling
2. Coriolis effect turns air clockwise
3. Symbol
III. Pressure
A. High Pressure
B. Low Pressure
III. Pressure
A. High Pressure
B. Low Pressure
1. Indicates air is _____
III. Pressure
A. High Pressure
B. Low Pressure
1. Indicates air is rising
2. Coriolis effect turns air
______________
III. Pressure
A. High Pressure
B. Low Pressure
1. Indicates air is rising
2. Coriolis effect turns air
counterclockwise
3. Symbol
III. Pressure
A. High Pressure
B. Low Pressure
1. Indicates air is rising
2. Coriolis effect turns air
counterclockwise
3. Symbol
The End
Gathering Weather Data – 12.3
Objectives
• Recognize the
importance of accurate
weather data
• Describe the technology
used to collect weather
data.
• Analyze the strengths
and weaknesses of
weather observation
systems
A balloon launch
from the S. Pole.
I. Surface Data
I. Surface Data
A. Thermometer
I. Surface Data
A. Thermometer
1. Indicates the
of the air.
I. Surface Data
A. Thermometer
1. Indicates the temperature of the air.
2. How does it work?
I. Surface Data
A. Thermometer
B. Barometer
I. Surface Data
A. Thermometer
B. Barometer
1. Indicates the
_______ of the air.
I. Surface Data
A. Thermometer
B. Barometer
1. Indicates the
pressure of the air.
2. How does it work?
I. Surface Data
A. Thermometer
B. Barometer
C. Anemometer
I. Surface Data
A. Thermometer
B. Barometer
C. Anemometer
1. Indicates the speed
of the
.
2. How does it work?
I. Surface Data
A. Thermometer
B. Barometer
C. Anemometer
1. Indicates the speed
of the wind.
2. How does it work?
I. Surface Data
A. Thermometer
B. Barometer
C. Anemometer
D. Hygrometer
I. Surface Data
A. Thermometer
B. Barometer
C. Anemometer
D. Hygrometer
1. Indicates the ______
_______ of the air.
I. Surface Data
A. Thermometer
B. Barometer
C. Anemometer
D. Hygrometer
1. Indicates the relative
humidity of the air.
2. How does it work?
I. Surface Data
A. Thermometer
B. Barometer
C. Anemometer
D. Hygrometer
E. Ceilometer
I. Surface Data
A. Thermometer
B. Barometer
C. Anemometer
D. Hygrometer
E. Ceilometer
1. Indicates the height of
.
I. Surface Data
A. Thermometer
B. Barometer
C. Anemometer
D. Hygrometer
E. Ceilometer
1. Indicates the height of clouds.
2. How does it work?
II. Upper-level Data
II. Upper-level Data
A. Weather balloons
II. Upper-level Data
A. Weather balloons
B. Radiosonde
A package of sensors that collect atmospheric
information in the upper atmosphere
II. Upper-level Data
A. Weather balloons
B. Radiosonde
Measures:
II. Upper-level Data
A. Weather balloons
B. Radiosonde
Measures:
1. Temperature
II. Upper-level Data
A. Weather balloons
B. Radiosonde
Measures:
1. Temperature
2. Pressure
II. Upper-level Data
A. Weather balloons
B. Radiosonde
Measures:
1. Temperature
2. Pressure
3. Humidity
II. Upper-level Data
A. Weather balloons
B. Radiosonde
Measures:
1. Temperature
2. Pressure
3. Humidity
4. Wind speed & direction
II. Upper-level Data
A. Weather balloons
B. Radiosonde
C. Radar
Radio detecting and ranging
II. Upper-level Data
A. Weather balloons
B. Radiosonde
C. Radar
D. Doppler Radar
Detect the speed of rain drops as they move
toward/away from station
Doppler Effect
Doppler Effect
1. The waves ahead of a moving object are
compressed, and wavelength is
shortened.
Doppler Effect
1. The waves ahead of a moving object are
compressed, and wavelength is
shortened.
2. The waves behind a moving object are
depressed or elongated.
II. Upper-level Data
A. Weather balloons
B. Radiosonde
C. Radar
D. Doppler Radar
E. Weather Satellites
Take photos (visible and infrared light) of
Earth.
The End
Weather Analysis – 12.4
Objectives
• Analyze a
basic surface
weather chart
• Distinguish
between analog
and digital
forecasting
• Describe
problems with
long-term
forecasts
I. Station Model
A condensed compilation of a variety of
weather data.
I. Station Model
See page 915
I. Station Model
A. Temperature
I. Station Model
A. Temperature
B. Dew point
Temperature at which water vapor condenses
I. Station Model
A. Temperature
B. Dew point
C. Precipitation
Rain, Snow, Drizzle, Showers, Fog,
Thunderstorm, etc.
I. Station Model
A. Temperature
B. Dew point
C. Precipitation
D. Cloud cover
Fraction of the sky that is covered.
I. Station Model
A. Temperature
B. Dew point
C. Precipitation
D. Cloud cover
E. Wind
This shows a wind that is 25 knots FROM the
southwest
I. Station Model
A. Temperature
B. Dew point
C. Precipitation
10 + 10 + 5 knots
D. Cloud cover
E. Wind
This shows a wind that is 25 knots FROM the
southwest
II. Surface Analysis
II. Surface Analysis
A. Isopleths
Lines connecting point of equal value
II. Surface Analysis
A. Isopleths
1. Isobars
“same
”
II. Surface Analysis
A. Isopleths
1. Isobars
“same pressure”
II. Surface Analysis
A. Isopleths
1. Isobars
2. Isotherms
“same
”
II. Surface Analysis
A. Isopleths
1. Isobars
2. Isotherms
“same temperature”
II. Surface Analysis
A. Isopleths
1. Isobars
2. Isotherms
3. These lines are like lines of elevation
II. Surface Analysis
A. Isopleths
1. Isobars
2. Isotherms
3. These lines are like lines of elevation
4. Many lines close together represent
steep transition
III. Forecasting
Predicting the future weather
III. Forecasting
A. Historically
III. Forecasting
A. Historically
1. Data was extrapolated from the
weather of the past few days
III. Forecasting
A. Historically
1. Data was extrapolated from the
weather of the past few days
2. Not very accurate
III. Forecasting
A. Historically
B. Digital Forecasting
III. Forecasting
A. Historically
B. Digital Forecasting
1. Uses computers to analyze lots of
variables.
III. Forecasting
A. Historically
B. Digital Forecasting
1. Uses computers to analyze lots of
variables.
2. The higher the density, the better
the forecast.
III. Forecasting
A. Historically
B. Digital Forecasting
C. Analog Forecasting
Looks for analogous conditions.
III. Forecasting
A. Historically
B. Digital Forecasting
C. Analog Forecasting
1. Compares data to past weather that
had similar characteristics.
III. Forecasting
A. Historically
B. Digital Forecasting
C. Analog Forecasting
1. Compares data to past weather that
had similar characteristics.
2. Use to create broad, season
forecasts.
III. Forecasting
D. Long-term forecasting
III. Forecasting
D. Long-term forecasting
1. Accuracy of a forecast decreases
with time.
III. Forecasting
D. Long-term forecasting
1. Accuracy of a forecast decreases
with time.
2. There are too many variable to
create a good forecast
The End