The
Atmosphere
AVM 303 Aviation Meteorology
CACS 209 General Meteorology
Meteorology
• The branch of science dealing with the earth’s
atmosphere and the physical processes
occurring in it.
Reasons for Studying
Meteorology
• Understand Atmospheric Processes: Gain
knowledge of the physical processes in the
atmosphere.
• Identify Meteorological Hazards:
• Learn about weather-related hazards.
• Understand their effects on aircraft.
• Learn how to minimize risks posed by these hazards.
Reasons for Studying
Meteorology
• Weather Information for Flight:
• Identify necessary weather information for each flight.
• Interpret actual and forecasted weather conditions using
provided documentation.
• Weather Analysis:
• Analyze and evaluate weather information both before
and during flight.
• Devise solutions to problems caused by weather
conditions.
Significance of Meteorology in
Aviation
• Control Over Weather: Weather remains
beyond human control, but understanding
meteorology helps aviators anticipate and
mitigate weather-related challenges.
Atmosphere
• The spheroidal gaseous envelope surrounding
the earth.
Constituents of the Atmosphere
• Nitrogen (N₂): 78.09%
• Oxygen (O₂): 20.95%
• Argon (Ar): 0.93%
• Carbon Dioxide (CO₂): 0.03%
• Trace Gases:
• Neon (Ne) • Carbon Monoxide (CO) • Methane (CH₄)
• Nitrous Oxide (N₂O) • Xenon (Xe) • Iodine (I₂)
• Helium (He) • Sulphur Dioxide (SO₂) • Ozone (O₃)
• Nitrogen Dioxide (NO₂) • Hydrogen (H₂)
• Krypton (Kr) • Ammonia (NH₃)
Properties of the Earth's
Atmosphere
The atmosphere varies vertically and horizontally
in:
• Pressure
• Temperature
• Density
• Humidity
The Structure of the
Atmosphere
The Troposphere:
• Definition: The lowest layer of the Earth's
atmosphere.
• Characteristics:
• Temperature decreases with height.
• Contains ¾ of the total atmospheric weight.
• Contains almost all weather activity.
The Structure of the
Atmosphere
The Tropopause:
• Definition: Marks the boundary between the
troposphere and the stratosphere.
• Temperature Behavior:
• The point where temperature stops decreasing with
height.
• Defined as the altitude where temperature decreases
less than 0.65°C per 100 meters (2°C per 1000 ft).
The Structure of the
Atmosphere
• Height Variations:
• Controlled by surface temperature.
• Higher tropopause = warmer surface temperature.
• Lower tropopause = colder surface temperature.
• Averages:
• Equator: 16-18 km, -75°C to -80°C.
• Poles: 8 km, -40°C to -50°C.
• At 50°N: 11 km (36,090 ft), -56.5°C.
• Folds: Sudden changes in the height of the
tropopause occur around 40° and 60° latitude.
The Mean Height of the
Tropopause
The Structure of the
Atmosphere
The Stratosphere:
• Definition: The layer above the troposphere.
• Temperature Behavior:
• Initially, temperature remains constant up to ~20 km.
• Then temperature increases, reaching -2.5°C at ~47 km.
• After ~51 km, temperature decreases again.
• Reason for Temperature Increase: Ultraviolet
radiation causes the formation of ozone, which leads
to the increase in temperature.
The Structure of the
Atmosphere
Stratopause:
• The boundary between the stratosphere and the
mesosphere.
• Located at an average height of 50 km in
temperate latitudes.
Tropopause Significance
• Marks the maximum height of significant cloud.
• Indicates the presence of jet streams.
• Signals the presence of Clear Air Turbulence
(CAT).
• Represents the maximum wind speed.
• Denotes the upper limit of most weather
phenomena.
The International Standard
Atmosphere (ISA)
Why ISA is Necessary:
• Provides a standard set of atmospheric
conditions for aviation.
• Used for calibrating aircraft pressure
instruments.
• Essential for aircraft design and testing.
The International Standard
Atmosphere (ISA)
Key ISA Conditions:
• MSL Temperature: +15°C
• MSL Pressure: 1013.25 hPa
• MSL Density: 1225 g/m³
• Lapse Rate: 0.65°C/100 m (1.98°C/1000 ft) up to 11
km (36,090 ft)
• Constant Temperature: -56.5°C from 11 km to 20 km
(65,617 ft)
• Temperature Increase: 0.1°C/100 m (0.3°C/1000 ft)
from 20 km to 32 km.
The International Standard
Atmosphere (ISA)
ISA Deviation
Why ISA Deviation is Important:
• Used to determine true altitude.
• Assists in assessing aircraft performance data.
What does meteorology study?
A) Ocean currents and tides.
B) The earth's crust and tectonic activities.
C) The earth’s atmosphere and the physical
processes occurring in it.
D) The solar system and planetary movements.
What does meteorology study?
A) Ocean currents and tides.
B) The earth's crust and tectonic activities.
C) The earth’s atmosphere and the physical
processes occurring in it.
D) The solar system and planetary movements.
Why is it important for aviators to study meteorology?
A) To control weather conditions.
B) To understand physical processes in the
atmosphere and manage meteorological hazards.
C) To change the forecasted weather.
D) To reduce the need for weather documentation.
Why is it important for aviators to study meteorology?
A) To control weather conditions.
B) To understand physical processes in the
atmosphere and manage meteorological hazards.
C) To change the forecasted weather.
D) To reduce the need for weather documentation.
Which of the following is NOT a reason for studying
meteorology?
A) To evaluate weather information before and during
flight.
B) To devise solutions for problems caused by
weather.
C) To understand the effect of meteorological hazards
on aircraft.
D) To change the weather to suit flight conditions.
Which of the following is NOT a reason for studying
meteorology?
A) To evaluate weather information before and during
flight.
B) To devise solutions for problems caused by
weather.
C) To understand the effect of meteorological hazards
on aircraft.
D) To change the weather to suit flight conditions.
What is the one factor in modern aviation over which
man has no control?
A) Weather
B) Aircraft design
C) Air traffic control
D) Fuel consumption
What is the one factor in modern aviation over which
man has no control?
A) Weather
B) Aircraft design
C) Air traffic control
D) Fuel consumption
What is the atmosphere?
A) The solid outer shell of a planet.
B) The spheroidal gaseous envelope surrounding the
earth.
C) The layer of water covering a planet.
D) The magnetic field surrounding a planet.
What is the atmosphere?
A) The solid outer shell of a planet.
B) The spheroidal gaseous envelope surrounding the
earth.
C) The layer of water covering a planet.
D) The magnetic field surrounding a planet.
What percentage of the Earth's atmosphere is
oxygen?
A) 78.09%
B) 0.93%
C) 20.95%
D) 0.03%
What percentage of the Earth's atmosphere is
oxygen?
A) 78.09%
B) 0.93%
C) 20.95%
D) 0.03%
What layer of the atmosphere contains almost all the
weather?
A) Stratosphere
B) Tropopause
C) Troposphere
D) Mesosphere
What layer of the atmosphere contains almost all the
weather?
A) Stratosphere
B) Tropopause
C) Troposphere
D) Mesosphere
What does the tropopause height typically mark?
A) Minimum wind speed
B) Lowest temperature
C) Highest pressure
D) Maximum wind speed
What does the tropopause height typically mark?
A) Minimum wind speed
B) Lowest temperature
C) Highest pressure
D) Maximum wind speed
Which weather phenomenon is often associated with
the tropopause?
A) Clear Air Turbulence (CAT)
B) Formation of tornadoes
C) High humidity
D) Hurricanes
Which weather phenomenon is often associated with
the tropopause?
A) Clear Air Turbulence (CAT)
B) Formation of tornadoes
C) High humidity
D) Hurricanes
What is the tropopause NOT associated with?
A) Maximum cloud height
B) Jet streams
C) Low wind speed
D) Clear Air Turbulence
What is the tropopause NOT associated with?
A) Maximum cloud height
B) Jet streams
C) Low wind speed
D) Clear Air Turbulence
What is the standard MSL temperature according to
ISA?
A) +10°C
B) +20°C
C) +15°C
D) +5°C
What is the standard MSL temperature according to
ISA?
A) +10°C
B) +20°C
C) +15°C
D) +5°C
What is the lapse rate according to ISA up to 11 km?
A) 0.65°C/100 m
B) 1.98°C/100 m
C) 0.3°C/1000 ft
D) 2.5°C/1000 ft
What is the lapse rate according to ISA up to 11 km?
A) 0.65°C/100 m
B) 1.98°C/100 m
C) 0.3°C/1000 ft
D) 2.5°C/1000 ft
What is the MSL pressure in the ICAO ISA?
A) 1012 hPa
B) 1000 hPa
C) 1025 hPa
D) 1013 hPa
What is the MSL pressure in the ICAO ISA?
A) 1012 hPa
B) 1000 hPa
C) 1025 hPa
D) 1013 hPa
Meteorology is the study of the physical processes in
the ocean.
A) True
B) False
Meteorology is the study of the physical processes in
the ocean.
A) True
B) False
Understanding meteorology can help aviators
anticipate difficulties caused by weather.
A) True
B) False
Understanding meteorology can help aviators
anticipate difficulties caused by weather.
A) True
B) False
Aviators study meteorology to control weather
conditions during flight.
A) True
B) False
Aviators study meteorology to control weather
conditions during flight.
A) True
B) False
The height of the tropopause is influenced by the
temperature near the Earth's surface.
A) True
B) False
The height of the tropopause is influenced by the
temperature near the Earth's surface.
A) True
B) False
The stratosphere contains almost all of the Earth's
weather.
A) True
B) False
The stratosphere contains almost all of the Earth's
weather.
A) True
B) False
The tropopause height marks the upper limit of most
weather phenomena.
A) True
B) False
The tropopause height marks the upper limit of most
weather phenomena.
A) True
B) False
Clear Air Turbulence (CAT) is commonly found near
the tropopause.
A) True
B) False
Clear Air Turbulence (CAT) is commonly found near
the tropopause.
A) True
B) False
ISA is used to calibrate aircraft pressure instruments.
A) True
B) False
ISA is used to calibrate aircraft pressure instruments.
A) True
B) False
Why is it important for aviators
to have a knowledge of
meteorology?
Why is it important for aviators
to have a knowledge of
meteorology?
A knowledge of meteorology is important for aviators to
anticipate weather-related difficulties, understand the
impact of meteorological hazards on aircraft, and devise
solutions to minimize risks.
How does meteorology assist
aviators in preparing for a
flight?
How does meteorology assist
aviators in preparing for a
flight?
Meteorology helps aviators by providing the necessary
weather information, enabling them to interpret weather
conditions, analyze weather information before and
during flight, and prepare solutions for potential weather-
related problems.
Explain why the tropopause
height is significant for weather
patterns.
Explain why the tropopause
height is significant for weather
patterns.
The tropopause height is significant because it marks the
boundary where significant weather phenomena occur,
including the maximum height of clouds, the presence of
jet streams, and the upper limit of most weather activities.
It also indicates areas of maximum wind speed and the
occurrence of Clear Air Turbulence (CAT), making it
important for flight safety.
Explain why the ICAO
International Standard
Atmosphere (ISA) is important
in aviation.
Explain why the ICAO
International Standard
Atmosphere (ISA) is important
in aviation.
The ICAO ISA is essential for aviation because it provides
a standardized set of atmospheric conditions used for
calibrating aircraft instruments and designing aircraft.
Since temperature, pressure, and density vary with
altitude, the ISA creates a reference that allows for
accurate measurement and safe operation of aircraft in
various environmental conditions.
