1 / 15

Cadet Phase I & II Aerospace Dimensions Air Environment (Module 3)

Cadet Phase I & II Aerospace Dimensions Air Environment (Module 3). Session 1: Chapter 1 ‘Air Circulation’ Chapter 2 ‘Weather Elements’ Session 2: Chapter 3 ‘Moisture and Clouds’ Chapter 4 ‘Weather Systems and Changes’

alma
Download Presentation

Cadet Phase I & II Aerospace Dimensions Air Environment (Module 3)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Cadet Phase I & IIAerospace DimensionsAir Environment (Module 3) Session 1: Chapter 1 ‘Air Circulation’ Chapter 2 ‘Weather Elements’ Session 2: Chapter 3 ‘Moisture and Clouds’ Chapter 4 ‘Weather Systems and Changes’ (ONLY for all Cadets that have not yet passed corresponding AE test, and Cadet Mentors) Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing

  2. Air Circulation • Radiation - a method of Heat Transfer • This is the ONLY way heat can travel in a vacuum, and is therefore how the Sun heats the Earth • About 65% of the sun’s energy gets past the clouds • 15% is absorbed by the atmosphere, the remaining 50% is absorbed at the Earth’s surface • Heat and Pressure differences in the atmosphere, caused by Solar Heating are what causes weather • Heating and Cooling of the atmosphere also evaporates/condenses water vapor, causing clouds, rain, snow, and hail • Temperature and Pressure Changes also affect air density, which directly affects LIFT (remember Module 1?) Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing

  3. Air Circulation • Rotation and Revolution • The Earth Revolves around the sun once every 365 days (approx.) • The Earth also Rotates, tilted at an angle of 23.5° • Revolution and Rotation together cause the seasons, and different weather patterns at different latitudes • Tilted towards the sun = long day • Tilted away from the sun = short day • Sun tracking along equator = day/night of equal length • Autumnal Equinox: Equal length Day/Night (Fall - Sept 22/23) • Vernal Equinox: Equal length Day/Night (Spring - Mar 21/22) • Summer Solstice: Longest Day (June 21/22) • Winter Solstice: Shortest Day (Dec 21/22) Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing

  4. Air Circulation • Coriolis effect: Since the Earth is rotating Counter-Clockwise, anything travelling from North to South will be deflected WEST of the intended destination, if the fact that the earth is moving under them, is not accounted for • Circulation • Uneven heating (e.g. equator and poles) causes pressure differences, which result in movement of air • Air is heated at the equator, rises, then heads north or south, eventually cooling, and then much of it returns to the equator • This creates the ‘Trade Winds’, between 0° and 30° Lat. and an area of calm (rising) wind at the equator, called the ‘Doldrums’ Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing

  5. Air Circulation • Other predictable Wind patterns include: • Prevailing Westerlies, are cooling air moving towards the poles between 30° and 60° latitude • Above 60° latitude cooling and descending polar air forms Polar Easterlies • VERY large Temperature and Pressure differences, high up (in the Troposphere) cause special high speed winds called Jet Streams • These travel in a band around the earth at between 100 and 300 MPH • There are 4 jet streams, one of which is over the United States • Ours is at 30,000 to 35,000 ft, and travels West to East, dipping South over the Mid West (but it moves!) Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing

  6. Air Circulation • Important Terms (Quiz): • Autumnal Equinox • Equal length Day/Night (Fall - Sept 22/23) • Vernal Equinox • Equal length Day/Night (Spring - March 21/22) • Summer Solstice • Longest Day (June 21/22) • Winter Solstice • Shortest Day (Dec 21/22) • Coriolis Effect • Jet Stream • Radiation • Revolution (of Earth around Sun) • How long does it take? • Rotation (of Earth) • What angle is the earth’s axis tilted at? Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing

  7. Weather Elements • Wind • ‘A body of air in motion’ • Wind is defined by its Direction and Speed • e.g. Easterly (FROM the East) at 20 knots • 1 knot = 1.1 MPH • The Beaufort Scale (0 to 12) defined different wind strengths, by describing visible effects for different Wind Speeds • Wind can make the air feel colder than it is - this effect is called Wind Chill • The wind is removing the warm air from around your body, and speeding heat loss • A chart can be used to determine the wind chill • Flying into wind increases lift, flying with the wind increases speed, flying cross-wind pushes you off course. Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing

  8. Weather Elements • Microburst • A very strong, very fast moving downdraft, often from a thunderstorm, resulting in extreme turbulence • Temperature • Temperature is the result of Heating, and is measured in degrees Fahrenheit (°F) or Celsius/Centigrade (°C) • Conversion: F = (1.8xC)+32 C=(F/1.8)-32 • no need to memorize these equations • Water Boils at 212°F and Freezes at 32°F (100 & 0 °C) • Heat is defined as ‘the total Energy of all Molecules (illustrated by their motion) within a substance’ • Temperature is therefore defined as ‘a measure of molecular motion, using a man-made scale’ • Heat, and therefore Temperature affects air Pressure and Density, and is therefore VERY important information for Pilots • e.g. high temperature = lower density = LESS LIFT Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing

  9. Weather Elements • Pressure • A gas pressing on another, or a surface results in Pressure • Atmospheric Pressure is the effect of air pushing down on the Earth’s surface • As molecules collide, movement results • Measurement of Atmospheric Pressure: • Mercury Barometer - Accurate, Reliable and Stable, used by Scientists • Aneroid Barometer - Fast and Easy to Read, but not particularly accurate • Aneroid Barograph - Provides a permanent record of pressure changes, using a pen and a revolving drum of paper • Atmospheric Pressure affects air density, and differences causes bodies of air to move, thus creating wind. Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing

  10. Moisture and Clouds • Moisture • Moisture is Water in Solid (Ice), Liquid (Water), or Gaseous (Vapor) form • The air can only hold a limited amount of water vapor, when is contains the maximum amount, it is Saturated • Saturation depends on temperature, the temperature at which the air WILL become saturated is called the Dew Point • Add more moisture, or decrease the temperature BELOW the Dew Point, and Condensation (conversion to liquid) occurs • Clouds and Fog are both forms of Condensation • Humidity describes the amount of moisture in the air • The normal measure is Relative Humidity, which is the % of saturation which has been reached, e.g. 70% • Fog - mass of water droplets in suspension (Ground Level Cloud) • Occurs when Temp & Dew Point are within 5° and wind is low Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing

  11. Moisture and Clouds • Clouds • Like Fog, Clouds are a mass of water droplets in suspension, but they can also contain ice crystals, or water / ice mixed • There are 3 basic Cloud Forms: • Cumulus - White, Billowy, Puffy (Cotton Balls), Low Level • Normally seen in good weather, but also associated with turbulence • Stratus - Thin, Sheet like, Grey, Low Level • Cirrus - White, Thin, Wispy, High Level • Precipitation • When the temperature fall too far below the Dew Point, and the Cloud can no-longer hold the moisture in suspension, Precipitation Results • Either Rain, Snow or Ice (hail) depending on temperature • Precipitation is measured with a Rain Gauge • Precipitation reduces Visibility, and makes runways slippery • Ice increases Aircraft weight, and can block inlets Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing

  12. Weather Systems and Changes • Air Masses - A HUGE mass of air • Normally at least 1000 miles across • Essentially the same Temperature and Moisture characteristics throughout • Air masses are classified by where they came from, i.e. their Source Region • The 6 Source Regions are: • cA - continental Arctic • cP - continental Polar • cT - continental Tropical • mT - maritime Tropical • mP - maritime Polar • mE - maritime Equatorial • Maritime masses are wetter • Farther away from the equator = a colder mass Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing

  13. Weather Systems and Changes • Fronts - the boundary between 2 air masses: • WARM Fronts ride up over Cold Air • Normally COLD Fronts are heavy and low, and push Warm Fronts up, and away • When similar air masses meet, there may not be enough difference to cause movement, and a STATIONARY Front occurs • An OCCLUDED Front (3 air masses) the Warm air is still pushed up, but relatively cool air is pushed up also by colder air • ColdOccluded - Old Cool Air pushed up, basically like a Cold Air snowplough, pushing everything Upwards • WarmOccluded- New Cool Air pushed up behind Warm Air, by local colder air Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing

  14. Weather Systems and Changes • Severe Weather • Cumulonimbus clouds are a sign of Severe Weather, which could be a Thunderstorm, Tornado or Hurricane • Thunderstorms • Heavy Winds, Strong Rain, Sometimes Hail • Lightning - Electric Discharge, which can heat the air to 60,000°F! • About 200 are killed and 600 injured by lightning in the US annually! • 3 stages: Building (Updrafts), Mature (Up/Down air cycles), Dissipating (Downdrafts) • Do’s and Don’ts: • Don’t use electric appliances, telephones, or take a shower • DO Stay away from Windows and Doors • If Outdoors, DO go Inside • If in a car, DO stay there • If in a boat, DO get ashore • DO Move away from Water and Metal objects • Don’t stand in open space, or under a tree • DO Stay Low, and Don’t huddle in a group Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing

  15. Weather Systems and Changes • Tornadoes • Fujita Wind Damage Scale - F0 to F5, with wind speed range and expected scale of damage for each • F5 is over 261 MPH, with ‘Incredible’ Damage resulting • Do’s and Don’ts: • DO Get to a Basement (or lie down in low ground) • DO, If above ground, move at 90° to the Tornado • DO, if indoors, stay away from windows, got to the interior, or into a closet or bathroom • Hurricanes • Saffir-Simpson Hurricane Damage Potential Scale - Cat 1 (75-95 MPH), to Cat 5 (155+ MPH!), with Pressure Range, Wind Speeds, and Storm Surge (Sea Level increase) • Do’s and Don’ts: • same as Thunderstorms & Tornadoes, since they can produce BOTH • Worse, they can be HUGE, and can continue for more than a week! • But, Hurricanes have a ‘Eye’ at the center which is calm Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing

More Related