Meteorology: Air Pressure and Wind Patterns
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Questions and Answers

What is the main characteristic of high pressure air systems?

  • Unstable and dry
  • Unstable and moist
  • Dry and stable (correct)
  • Descending and moist

What vertical displacement is associated with severe turbulence?

  • 10-15 meters
  • Up to 1 meter
  • 3-6 meters
  • Up to 30 meters (correct)

What phenomenon is primarily caused by warm ascending air from valleys during the day?

  • Valley winds
  • Foehn winds
  • Land breezes
  • Anabatic winds (correct)

During which season are polar jet streams weaker in the northern hemisphere?

<p>Summer (B)</p> Signup and view all the answers

In the context of wind patterns, what is a sea breeze?

<p>Wind blowing from cool water to warm land (C)</p> Signup and view all the answers

What type of winds are characterized by turbulent eddies found downwind of a mountain range?

<p>Mountain waves (C)</p> Signup and view all the answers

What is the primary cause of jet streams?

<p>Breaks in the tropopause (B)</p> Signup and view all the answers

What characterizes the vertical movement during moderate turbulence?

<p>3-6 meters (D)</p> Signup and view all the answers

Which type of air is characterized by being warm and moist?

<p>Unstable Air (D)</p> Signup and view all the answers

What defines an inversion layer?

<p>Temperature increases with altitude (A)</p> Signup and view all the answers

What occurs when warm air mass overrides a cold air mass?

<p>Frontal inversion (C)</p> Signup and view all the answers

Which atmospheric condition is most likely to yield poor visibility?

<p>Stable air (A)</p> Signup and view all the answers

What type of precipitation is characterized by pellets or lumps exceeding 8mm in size?

<p>Hail (B)</p> Signup and view all the answers

Which phenomenon is caused by large-scale sinking air associated with high-pressure systems?

<p>Subsidence inversion (D)</p> Signup and view all the answers

What occurs during absolute instability?

<p>Air continues to rise despite cooling effects (B)</p> Signup and view all the answers

Which factor is NOT used to classify an air mass?

<p>Altitude (C)</p> Signup and view all the answers

Which of the following is NOT a method of adding moisture to the air?

<p>Radiation (C)</p> Signup and view all the answers

Which characteristic is associated with stratus-type clouds?

<p>Steady precipitation (A)</p> Signup and view all the answers

What occurs when a warm air mass catches up to a cold air mass?

<p>Warm front (C)</p> Signup and view all the answers

What happens when the air reaches its saturation point at a temperature of 100% relative humidity?

<p>Condensation begins to form (B)</p> Signup and view all the answers

What is the theoretical standard lapse rate?

<p>-1.8 C/1000 ft (B)</p> Signup and view all the answers

What term describes the process of a front dissipating?

<p>Frontolysis (D)</p> Signup and view all the answers

Which of the following methods can cause air to reach saturation due to temperature changes?

<p>Warm air moving over cold surfaces (D)</p> Signup and view all the answers

What is sleet primarily formed from?

<p>Raindrops that freeze during descent (B)</p> Signup and view all the answers

What type of precipitation is typically associated with unstable air?

<p>Showery (D)</p> Signup and view all the answers

What effect can temperature inversions have on visibility in certain weather conditions?

<p>Low visibility due to fog (C)</p> Signup and view all the answers

What is the dew point defined as?

<p>Temperature at which air is saturated with moisture (D)</p> Signup and view all the answers

What happens during nighttime or radiation inversion?

<p>Warm air cools faster than the layer above (A)</p> Signup and view all the answers

Which combination of conditions does NOT contribute to the formation of temperature inversions?

<p>High pressure with low humidity (C)</p> Signup and view all the answers

What is described as the greatest horizontal distance at which prominent objects can be seen?

<p>Visibility (B)</p> Signup and view all the answers

Which type of precipitation is characterized by drops smaller than 0.02 inches?

<p>Drizzle (A)</p> Signup and view all the answers

Which of the following statements accurately describes freezing rain?

<p>It creates a glaze when it contacts cold surfaces. (D)</p> Signup and view all the answers

How is the cloud ceiling calculated based on temperature and dew point?

<p>T - DP x 400 (B)</p> Signup and view all the answers

What characterizes the base of the lowest layer of broken or overcast clouds?

<p>Cloud ceiling (C)</p> Signup and view all the answers

Which of these statements is true regarding raindrop size during rainfall?

<p>Raindrops larger than 0.5mm are always termed as rain. (B)</p> Signup and view all the answers

What is the average density of snow as a form of precipitation?

<p>0.1 g/cc (A)</p> Signup and view all the answers

What is the term used to describe water that forms in the atmosphere and falls to the ground?

<p>Precipitation (C)</p> Signup and view all the answers

What is the primary characteristic of a thunderstorm during its mature stage?

<p>Onset of rain and simultaneous up/downdrafts (A)</p> Signup and view all the answers

What occurs during a cold front occlusion?

<p>Fast-moving cold front catches up with slow-moving warm front (B)</p> Signup and view all the answers

Which of the following best describes a stationary front?

<p>Forces of two air masses are relatively equal (B)</p> Signup and view all the answers

What atmospheric conditions are necessary for developing a thunderstorm?

<p>Moist, unstable air masses with lifting action (A)</p> Signup and view all the answers

During which stage of a thunderstorm is the anvil typically observed?

<p>Mature stage (B)</p> Signup and view all the answers

What happens when a warm front occlusion takes place?

<p>The warm air ahead is colder than the cold front's air (B)</p> Signup and view all the answers

What phenomenon is characteristic of thunderstorms?

<p>Strong winds along with lighting and thunder (D)</p> Signup and view all the answers

In terms of air density, how does a fast-moving cold front behave relative to warmer air?

<p>It slides underneath the warmer air due to higher density (C)</p> Signup and view all the answers

Flashcards

Wind

Air movement caused by differences in atmospheric pressure, where air flows from high pressure to low pressure areas.

Turbulence

A sudden and violent change in airflow caused by irregular atmospheric movement.

High Pressure System

A large-scale atmospheric circulation pattern characterized by descending air masses.

Low Pressure System

A large-scale atmospheric circulation pattern characterized by rising air masses.

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Jet Streams

Fast-moving air currents found at high altitudes, generally blowing eastward.

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Sea Breeze

A localized wind pattern that blows from cool water to warm land during the day.

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Land Breeze

A localized wind pattern that blows from cool land to warm water during the night.

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Valley Wind

A wind pattern that occurs in mountainous areas, where cool air descends from valleys and warm air rises from slopes.

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Ridge

An elongated area of high atmospheric pressure.

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Trough

An elongated area of low atmospheric pressure.

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Col

The intersection between a ridge and a trough, or an area of neutral pressure between two highs or two lows.

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Atmospheric Stability

The tendency of air to resist vertical movement.

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Absolute Instability

Air that continues to rise because the environmental lapse rate exceeds the dry adiabatic lapse rate.

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Inversion

A layer of air where temperature increases with altitude.

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Sleet

Frozen raindrops formed when rainfall passes through air at subfreezing temperatures.

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Hail

Showery precipitation in the form of pellets or lumps larger than 8 mm, occurring in violent thunderstorms.

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Air Mass

A large body of air with fairly uniform temperature and moisture content.

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Source Region

The area where an air mass acquires its temperature and moisture properties; determines its stability.

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Fronts

Boundaries between air masses, formed when different air masses with varying temperature and moisture characteristics meet.

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Temperature Inversion

A condition where the temperature increases with altitude, creating a stable atmospheric layer and inhibiting vertical air movement.

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Frontal Inversion

A type of temperature inversion that occurs when warm air moves over a cold air mass, creating a boundary layer with a temperature increase with altitude.

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Subsidence Inversion

A temperature inversion caused by large-scale descending air masses that compress and warm due to increased pressure.

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Humidity

The amount of moisture present in the air.

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Relative Humidity

The ratio of the actual amount of moisture in the air to the maximum amount of moisture the air can hold at a given temperature.

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Dew Point

The temperature at which air becomes saturated with water vapor and condensation begins to form.

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Evaporation

The process by which liquid water changes into water vapor.

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Condensation

The process by which water vapor changes into liquid water.

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Sky/Cloud Cover

A portion of the sky concealed by clouds, visually divided into eighths.

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Ceiling

The vertical distance between the ground and the lowest layer of broken or overcast clouds.

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Visibility

The furthest distance at which prominent objects can be seen.

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Precipitation

Any form of water that falls from the atmosphere to the ground, including drizzle, freezing rain, rain, hail, graupel, and snow.

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Drizzle

Rain with drops smaller than 0.02 inches in diameter.

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Freezing Rain

Rain or drizzle that freezes upon contact with a surface below 0 degrees Celsius, forming a layer of ice.

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Snow

Ice crystals in a flaky form, forming precipitation with a lower density than water.

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Stationary Front

A front where two air masses meet and the forces are relatively equal, resulting in a mixture of warm and cold front characteristics.

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Occluded Front

A front where a fast-moving cold front overtakes a slower-moving warm front, lifting the warm air and creating a mixture of weather conditions.

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Cold Front

A front where the warm air mass is pushed upward by a colder, advancing air mass.

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Warm Front

A front where a warm air mass advances over a colder air mass, leading to gradual changes in weather.

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Thunderstorm

A storm characterized by cumulonimbus clouds, lightning, thunder, and strong winds, often with hail and heavy rain.

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Cumulus Stage (Thunderstorm)

A storm characterized by a violent updraft, creating towering cumulus clouds that often produce heavy rain and lightning.

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Mature Stage (Thunderstorm)

A stage of a thunderstorm where downdrafts from precipitation begin to form, leading to heavy rain and sometimes hail.

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Dissipating Stage (Thunderstorm)

A stage of a thunderstorm where the updraft weakens and the downdraft dominates, causing the storm to dissipate.

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Study Notes

CPL Meteorology

  • Meteorology is a science that studies the physical properties of the atmosphere.
  • It is a key factor in influencing aircraft performance and safety.
  • CPL students need to understand weather theory to access and interpret available weather services.

Atmosphere Overview

  • The atmosphere is a blanket of gases surrounding Earth.
  • It contains nitrogen (78%), oxygen (21%), other gases (1%), and water vapor (0-5%).
  • It regulates temperature and protects from space vacuum.

Atmospheric Layers

  • Troposphere: Extends up to 20,000 feet, contains most weather.
  • Stratosphere: Similar composition to the troposphere, extends to 160,000 feet, with less turbulence and holds some weather phenomenon.
  • Mesosphere: Extends from 45 to 51 miles, meteors burn up here and has no weather phenomenon.
  • Thermosphere: Outermost layer of the atmosphere.

Atmospheric Circulation

  • Uneven heating of Earth is the root cause of atmospheric events.
  • This modifies air density and creates circulation patterns.
  • Air pressure varies due to altitude, temperature, and air density.

Convection and Advection

  • Convection: Vertical movement of air (warm air rises).
  • Advection: Horizontal movement of air.
  • Coriolis Force: Deflection of winds due to Earth's rotation. (right in the Northern Hemisphere, left in the Southern Hemisphere).

Global Atmospheric Circulation

  • Consists of three main cells: Hadley, Ferrel, and Polar cells.
  • Polar easterlies, westerlies, and trade winds are important global wind patterns.
  • Horse latitudes are a zone of calm between trade winds and westerlies, characterized by warm and dry climates.

Pressure Systems

  • High-pressure areas (HPA): Characterized by clockwise rotation in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.
  • Low-pressure areas (LPA): Characterized by counterclockwise rotation in the Northern Hemisphere and clockwise in the Southern Hemisphere.

Atmospheric Pressure and Temperature

  • Pressure measured using barometers; often aneroid barometers due to ease of transport.
  • Standard atmospheric pressure (ISA): 29.92 inches of mercury (Hg) or 1013.2 millibars (mb).
  • Standard air temperature (ISA): 15°C (or 59°F)

Standard Lapse Rate

  • Temperature decreases by approximately 1.8°C per 1000 feet of ascent.

Wind and Currents

  • Winds flow from high-pressure regions to low-pressure regions, influenced by the Coriolis effect.
  • Turbulences are sudden and violent shifts in airflow, classified as light, moderate, and severe based on vertical displacement.
  • Winds and currents are party responsible for weather events.

Jet Streams

  • Fast-moving air currents in the upper atmosphere, with polar jet streams and subtropical jet streams
  • Jet streams are located in the tropopause, influenced by convection and other weather systems

Local Wind Patterns

  • Sea breeze: Wind blows from cool water to warm land.
  • Land breeze: Wind blows from cool land to warm water.
  • Valley wind: Cooler air sinks in the valley, warmer air rises on mountains.
  • Katabatic wind: Cooling air flows down a slope.

Cloud Types

  • Clouds are made of condensed water vapor. Categorized into low, medium, and high cloud types.

Precipitation

  • Includes rain, snow, sleet, hail, freezing rain, and drizzle.

Atmospheric Stability

  • Stability of air dictates how it responds to vertical movement.
  • Stable air tends to resist significant vertical movement.

Icing

  • Icing can occur when the temperature of the aircraft is near freezing.
  • This can cause a reduction in lift and increase in drag and weight.

Fog

  • Fog is a cloud that touches the ground.
  • Several types of fog exist, distinguished by their formation processes.

Haze and Smog

  • Haze is the reduced visibility due to suspended particles.
  • Smog is a combination of smoke and fog.

Thunderstorms

  • Thunderstorms are characterized by their electrical activity. Develop through stages (cumulus, mature, and dissipating).
  • Need moisture-laden, unstable air with lift.

Fronts

  • Fronts are boundaries between different air masses, characterized by temperature and moisture differences.
  • Different types of fronts exist, with common types being warm, cold, stationary, and occluded fronts.

Tornadoes

  • Violent rotating vortex formed in thunderstorms on/or ahead of cold fronts.
  • Can produce significant damage.
  • Vortices can be over water.

Aviation Weather Services

  • Provide weather data or forecasts.
  • Information presented in various formats (e.g., METARs, TAFs).
  • Methods include observations, automated systems (AWOS, ASOS), radar, satellites, briefings and specific outlets like Flight Service Stations (FSS).

Sky/Cloud Cover

  • Covers the percentage of the sky obscured by clouds. Determined by assessing fraction of a section in 8 equal parts.

Ceiling

  • The vertical distance between ground level and the base of the lowest layer of broken or overcast clouds.

Visibility

  • The greatest horizontal distance at which prominent objects can be seen.

CPL Meteorology, Climatology

  • Studying climate and changes over time.
  • Climate information helps in predicting weather.

Other Topics

  • High-level weather, different phenomena (e.g. lightning, wind shear) and other critical information are covered in the notes.

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CPL Meteorology PDF

Description

Test your knowledge of meteorological concepts related to air pressure systems, wind patterns, and turbulence. This quiz covers various phenomena, including sea breezes, jet streams, and instability in atmospheric conditions. Perfect for students of meteorology or anyone interested in understanding weather dynamics.

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