vi
Chapter 8. Global Circulations and Jet Streams8-1
8.1 Non-Rotating Earth Circulation System8-1
8.2 Rotating Earth Circulation System8-1
8.3 Jet Streams8-2
8.3.1 Introduction8-2
8.3.2 Direction of Wind Flow8-3
8.3.3 Location8-4
Chapter 9. Local Winds9-1
9.1 Description9-1
9.2 Hazards9-2
9.3 Sea Breeze9-2
9.3.1 Sea Breeze Front9-3
9.3.2 Effects of Coastline Shape9-3
9.4 Land Breeze9-4
9.5 Lake Breeze9-5
9.6 Valley Breeze9-7
9.7 Mountain-Plains Wind System9-8
9.8 Mountain Breeze9-9
Chapter 10. Air Masses, Fronts, and the Wave Cyclone Model10-1
10.1 Air Masses10-1
10.1.1 Air Mass Classification10-1
10.1.2 Air Mass Modification10-2
10.2 Fronts10-3
10.3 The Wave Cyclone Model10-7
10.4 Dryline10-9
Chapter 11. Vertical Motion and Cloud Formation11-1
11.1 Introduction11-1
11.2 Vertical Motion Effects on an Unsaturated Air Parcel11-1
11.3 Vertical Motion Effects on a Saturated Air Parcel11-2
11.4 Common Sources of Vertical Motion11-5
11.4.1 Orographic Effects11-5
11.4.2 Frictional Effects11-6
vii
11.4.3 Frontal Lift11-6
11.4.4 Buoyancy11-7
Chapter 12. Atmospheric Stability12-1
12.1 Introduction12-1
12.2 Using a Parcel as a Tool to Evaluate Stability12-1
12.3 Stability Types12-1
12.3.1 Absolute Stability12-1
12.3.2 Neutral Stability12-2
12.3.3 Absolute Instability12-3
12.3.4 Conditional Instability12-4
12.3.5 Summary of Stability Types12-6
12.4 Processes that Change Atmospheric Stability12-7
12.4.1 Wind Effects on Stability12-7
12.4.2 Vertical Air Motion Effects on Stability12-7
12.4.3 Diurnal Temperature Variation Effects on Stability12-8
12.5 Measurements of Stability12-9
12.5.1 Lifted Index12-9
12.5.2 Convective Available Potential Energy12-10
12.6 Summary12-11
Chapter 13. Clouds13-1
13.1 Introduction13-1
13.2 Cloud Forms13-1
13.3 Cloud Levels13-2
13.4 Cloud Types13-2
13.4.1 High Clouds13-2
13.4.2 Middle Clouds13-5
13.4.3 Low Clouds13-9
Chapter 14. Precipitation14-1
14.1 Introduction14-1
14.2 Necessary Ingredients for Formation14-1
14.3 Growth Process14-1
14.4 Precipitation Types14-3
viii
Chapter 15. Adverse Wind15-1
15.1 Introduction15-1
15.2 Crosswind15-1
15.3 Gust15-1
15.4 Tailwind15-2
15.5 Variable Wind/Sudden Wind Shift15-2
15.6 Wind Shear15-2
Chapter 16. Weather, Obstructions to Visibility, Low Ceiling, and Mountain Obscuration16-1
16.1 Weather and Obstructions to Visibility16-1
16.1.1 Fog16-1
16.1.2 Mist16-5
16.1.3 Haze16-5
16.1.4 Smoke16-5
16.1.5 Precipitation16-5
16.1.6 Blowing Snow16-6
16.1.7 Dust Storm16-6
16.1.8 Sandstorm16-6
16.1.9 Volcanic Ash16-7
16.2 Low Ceiling and Mountain Obscuration16-8
16.2.1 Low Ceiling16-8
16.2.2 Mountain Obscuration16-9
Chapter 17. Turbulence17-1
17.1 Introduction17-1
17.2 Causes of Turbulence17-1
17.2.1 Convective Turbulence17-1
17.2.2 Mechanical Turbulence17-3
17.2.3 Wind Shear Turbulence17-5
17.3 Turbulence Factors17-6
Chapter 18. Icing18-1
18.1 Introduction18-1
18.2 Supercooled Water18-1
ix
18.3 Structural Icing18-1
18.3.1 Rime Icing18-1
18.3.2 Clear Icing18-1
18.3.3 Mixed Icing18-2
18.3.4 Icing Factors18-2
18.3.5 Icing in Stratiform Clouds18-4
18.3.6 Icing in Cumuliform Clouds18-4
18.3.7 Icing with Fronts18-4
18.3.8 Icing with Mountains18-5
18.3.9 Icing Hazards18-6
18.4 Engine Icing18-7
18.4.1 Carburetor Icing18-7
18.4.2 High Ice Water Content (HIWC)18-7
Chapter 19. Thunderstorms19-1
19.1 Introduction19-1
19.2 Necessary Ingredients for Thunderstorm Cell Formation19-1
19.3 Thunderstorm Cell Life Cycle19-1
19.4 Thunderstorm Types19-2
19.5 Factors that Influence Thunderstorm Motion19-5
19.6 Hazards19-6
19.6.1 Lightning19-6
19.6.2 Adverse Wind19-6
19.6.3 Downburst19-6
19.6.4 Turbulence19-8
19.6.5 Icing19-8
19.6.6 Hail19-9
19.6.7 Rapid Altimeter Changes19-10
19.6.8 Static Electricity19-10
19.6.9 Tornado19-10
x
Chapter 20. Weather Radar20-1
20.1 Principles of Weather Radar20-1
20.1.1 Antenna20-1
20.1.2 Backscattered Energy20-1
20.1.3 Power Output20-2
20.1.4 Wavelengths20-2
20.1.5 Attenuation20-3
20.1.6 Resolution20-4
20.1.7 Wave Propagation20-7
20.1.8 Intensity of Precipitation20-9
Chapter 21. Tropical Weather21-1
21.1 Circulation21-1
21.1.1 Subtropical High Pressure Belts21-1
21.1.2 Trade Wind Belts21-3
21.1.3 The Intertropical Convergence Zone (ITCZ)21-5
21.1.4 Monsoon21-5
21.2 Transitory Systems21-7
21.2.1 Remnants of Polar Fronts and Shear Lines21-7
21.2.2 Tropical Upper Tropospheric Trough (TUTT)21-8
21.2.3 Tropical Wave21-9
21.2.4 West African Disturbance Line (WADL)21-10
21.2.5 Tropical Cyclones21-11
Chapter 22. Arctic Weather22-1
22.1 Introduction22-1
22.2 Climate, Air Masses, and Fronts22-1
22.2.1 Long Days and Nights22-2
22.2.2 Land and Water22-2
22.2.3 Temperature22-2
22.2.4 Clouds and Precipitation22-2
22.2.5 Wind22-3
22.2.6 Air Masses—Winter22-3
xi
22.2.7 Air Masses—Summer22-3
22.2.8 Fronts22-3
22.3 Arctic Peculiarities22-3
22.3.1 Effects of Temperature Inversion22-3
22.3.2 Light Reflection by Snow-Covered Surfaces22-3
22.3.3 Light from Celestial Bodies22-3
22.4 Weather Hazards22-4
22.4.1 Fog and Ice Fog22-4
22.4.2 Blowing and Drifting Snow22-4
22.4.3 Frost22-4
22.4.4 Whiteout22-4
Chapter 23. Space Weather23-1
23.1 The Sun—Prime Source of Space Weather23-1
23.2 The Sun’s Energy Output and Variability23-1
23.3 Sunspots and the Solar Cycle23-1
23.4 Solar Wind23-1
23.5 Solar Eruptive Activity23-2
23.6 Geospace23-2
23.7 Galactic Cosmic Radiation23-3
23.8 Geomagnetic Storms23-4
23.9 Solar Radiation Storms23-4
23.10 Ionospheric Storms23-5
23.11 Solar Flare Radio Blackouts23-5
23.12 Effects of Space Weather on Aircraft Operations23-6
23.12.1 Communications23-6
23.12.2 Navigation and Global Positioning System (GPS)23-6
23.12.3 Radiation Exposure to Flight Crews and Passengers23-6
23.12.4 Radiation Effects on Avionics23-6
xii List of Figures
Figure 1-1. Vertical Structure of the Atmosphere1-4
Figure 1-2. U.S. Standard Atmosphere within the Troposphere1-6
Figure 2-1. Comparison of Kelvin, Celsius, and Fahrenheit Temperature Scales2-3
Figure 2-2. Radiation Example2-4
Figure 2-3. Temperature’s Effect on Radiation Wavelength2-5
Figure 2-4. Solar Zenith Angle2-6
Figure 2-5. Heat Transfer Examples2-8
Figure 2-6. Specific Heat Capacity: Water Versus Sand2-10
Figure 2-7. Variation of Mean Daily Temperatures for San Francisco (Maritime)
and Kansas City (Continental)2-11
Figure 2-8. Sounding with an Isothermal Layer2-12
Figure 2-9. Sounding with a Temperature Inversion2-13
Figure 3-1. The Hydrologic Cycle3-1
Figure 3-2. Temperature Effects on Relative Humidity3-4
Figure 3-3. Temperature-Dewpoint Spread Effect on Relative Humidity3-5
Figure 3-4. Latent Heat Transactions when Water Undergoes Phase Transition3-6
Figure 4-1. Earth-Atmosphere Energy Balance4-1
Figure 4-2. Greenhouse Effect on Nighttime Radiational Cooling4-2
Figure 4-3. Development of a Thermal4-3
Figure 4-4. Example of Convection in the Atmosphere4-4
Figure 4-5. Solar Zenith Angle Variations with Latitude4-5
Figure 4-6. Solar Zenith Angle Variations with Northern Hemisphere Seasons4-6
Figure 4-7. Average Seasonal Temperature Variation in the Northern Hemisphere4-6
Figure 4-8. Clear Sky Diurnal Temperature and Radiation Variations Over Land4-7
Figure 5-1. Air Has Weight5-1
Figure 5-2. Aneroid Barometer5-2
Figure 5-3. Station Pressure5-3
Figure 5-4. Air Pressure in the Standard Atmosphere5-4
Figure 5-5. Temperature Effect on Pressure5-5
Figure 5-6. Reduction of Station Pressure to Sea Level5-5
Figure 5-7. Surface Chart Pressure Patterns5-7
Figure 5-8. Weather Balloon and Radiosonde5-8
xiii
Figure 5-9. 500 Millibar Constant Pressure Chart5-9
Figure 5-10. Density is Mass (Weight) per Volume5-10
Figure 5-11. Volume Effects on Density5-10
Figure 5-12. Pressure Effects on Density in the Atmosphere5-11
Figure 5-13. Temperature Effects on Density5-12
Figure 5-14. Water Vapor Effects on Density5-12
Figure 5-15. True Versus Indicated Altitude5-13
Figure 5-16. Pressure Change Effects on Altimeter Readings5-14
Figure 5-17. Temperature Change Effects on Altimeter Readings5-15
Figure 5-18. High Density Altitude Effects on Flight5-17
Figure 6-1. Weather Observation Sources6-1
Figure 6-2. Analysis Procedure Step 1: Determine the Optimal Contour Interval
and Values to be Analyzed6-3
Figure 6-3. Analysis Procedure Step 2: Draw the Isopleths and Extrema6-4
Figure 6-4. Analysis Procedure Step 3: Interpret Significant Weather Features6-6
Figure 6-5. Example of a Surface Chart6-7
Figure 6-6. Example of a 500 Millibar Constant Pressure Chart6-8
Figure 7-1. Direction of Pressure Gradient Force7-1
Figure 7-2. Magnitude of Pressure Gradient Force7-2
Figure 7-3. Illustration of Coriolis Force7-2
Figure 7-4. Coriolis Force Variations Across the Earth7-3
Figure 7-5. Coriolis Force Magnitude Variations with Wind Speed7-4
Figure 7-6. Friction Force Magnitude Variations with Terrain Roughness7-4
Figure 7-7. Friction Force Magnitude Variations with Wind Speed7-4
Figure 7-8. Geostrophic Wind7-5
Figure 7-9. Upper Air Wind Flow7-5
Figure 7-10. Surface Wind Forces7-6
Figure 7-11. Surface Wind Flow7-6
Figure 8-1. Non-Rotating, Non-Tilted, Waterless, Earth Circulation System8-1
Figure 8-2. Earth Circulation System8-2
Figure 8-3. Speed Relative to the Earth’s Axis Versus Latitude8-3
Figure 8-4. Three Cell Circulations and Jet Stream Location8-4
Figure 8-5. Polar and Subtropical Jet Streams8-4
xiv
Figure 8-6. Jet Stream Wind Speeds8-5
Figure 9-1. Local Wind Circulation9-1
Figure 9-2. Sea Breeze9-2
Figure 9-3. Sea Breeze Front9-3
Figure 9-4. Effects of Coastline Shape on a Sea Breeze9-4
Figure 9-5. Land Breeze9-5
Figure 9-6. Lake Breeze9-6
Figure 9-7. Sea Breeze/Lake Breeze Example9-7
Figure 9-8. Valley Breeze9-7
Figure 9-9. Mountain-Plains Wind System9-8
Figure 9-10. Mountain Breeze9-9
Figure 10-1. Air Mass Classification10-2
Figure 10-2. Air Mass Modification—Warm, Moist Air Mass Moving Over
a Cold Surface10-2
Figure 10-3. Lake Effect10-3
Figure 10-4. Fronts10-4
Figure 10-5. Cold Front10-5
Figure 10-6. Warm Front10-5
Figure 10-7. Stationary Front10-6
Figure 10-8. Occluded Front10-6
Figure 10-9. Wave Cyclone Model—Stage 110-7
Figure 10-10. Wave Cyclone Model—Stage 210-7
Figure 10-11. Wave Cyclone Model—Stage 310-8
Figure 10-12. Wave Cyclone Model—Stage 410-8
Figure 10-13. Wave Cyclone Model—Stage 510-8
Figure 10-14. Dryline Example10-9
Figure 11-1. Unsaturated Ascending/Descending Air Parcel Example11-2
Figure 11-2. Ascending Air Parcel that Becomes Saturated Example11-3
Figure 11-3. Descending Air Parcel Example11-4
Figure 11-4. Orographic Effects Example11-5
Figure 11-5. Frictional Effects11-6
Figure 11-6. Frontal Lift11-7
Figure 12-1. Absolute Stability Example12-2
xv
Figure 12-2. Neutral Stability Example12-3
Figure 12-3. Absolute Instability Example12-4
Figure 12-4. Conditional Instability Example12-5
Figure 12-5. Stability Types12-6
Figure 12-6. Temperature Lapse Rate Effects on Stability12-7
Figure 12-7. Vertical Motion Effects on Stability12-8
Figure 12-8. Diurnal Temperature Variation Effects on Stability12-9
Figure 12-9. Lifted Index Example12-10
Figure 13-1. Cirrus (Ci)13-3
Figure 13-2. Cirrocumulus (Cc)13-4
Figure 13-3. Cirrostratus (Cs)13-5
Figure 13-4. Altocumulus (Ac)13-6
Figure 13-5. Altocumulus Standing Lenticular (ACSL)13-7
Figure 13-6. Thin Altostratus (As)13-8
Figure 13-7. Thick Altostratus (As) or Nimbostratus (Ns)13-9
Figure 13-8. Cumulus (Cu) with Little Vertical Development13-10
Figure 13-9. Towering Cumulus (TCu)13-11
Figure 13-10. Stratocumulus (Sc)13-12
Figure 13-11. Stratus (St)13-13
Figure 13-12. Stratus Fractus (StFra) and/or Cumulus Fractus (CuFra) of Bad Weather13-14
Figure 13-13. Cumulonimbus (Cb) without Anvil13-15
Figure 13-14. Cumulonimbus (Cb) with Anvil13-16
Figure 14-1. The Collision-Coalescence or Warm Rain Process14-2
Figure 14-2. Snow Temperature Environment14-3
Figure 14-3. Ice Pellets Temperature Environment14-3
Figure 14-4. Freezing Rain Temperature Environment14-4
Figure 14-5. Rain Temperature Environment14-4
Figure 15-1. Crosswind15-1
Figure 16-1. Radiation Fog16-1
Figure 16-2. Advection Fog16-2
Figure 16-3. Advection Fog Formation16-3
Figure 16-4. Frontal Fog Formation16-4
Figure 16-5. Haboob16-7
xvi
Figure 16-6. Layer Aloft Ceiling Versus Indefinite Ceiling16-9
Figure 17-1. Convective Turbulence17-2
Figure 17-2. Thermals17-2
Figure 17-3. Mechanical Turbulence17-3
Figure 17-4. Mountain Waves17-4
Figure 17-5. Mountain Wave Clouds17-5
Figure 17-6. Wind Shear Turbulence17-5
Figure 17-7. Wind Shear Turbulence Associated with a Temperature Inversion17-6
Figure 18-1. Icing with Fronts18-5
Figure 18-2. Icing with Mountains18-6
Figure 19-1. Necessary Ingredients for Thunderstorm Cell Formation19-1
Figure 19-2. Thunderstorm Cell Life Cycle19-2
Figure 19-3. Multicell Cluster Thunderstorm19-3
Figure 19-4. Multicell Line Thunderstorm19-4
Figure 19-5. Supercell Thunderstorm19-5
Figure 19-6. Factors that Influence Thunderstorm Motion19-5
Figure 19-7. Downburst Life Cycle19-7
Figure 19-8. Landing in a Microburst19-7
Figure 19-9. Thunderstorm with Shelf Cloud19-8
Figure 19-10. Vivian, South Dakota Record Hailstone19-9
Figure 20-1. Radar Antenna20-1
Figure 20-2. Backscattered Energy20-2
Figure 20-3. Wavelengths20-3
Figure 20-4. Precipitation Attenuation20-3
Figure 20-5. Precipitation Attenuation Versus Wavelength20-4
Figure 20-6. Beam Resolution20-5
Figure 20-7. Beam Resolution Comparison Between WSR-88D and
Aircraft Weather Radar20-6
Figure 20-8. Normal Refraction20-7
Figure 20-9. Subrefraction20-8
Figure 20-10. Superrefraction20-8
Figure 20-11. Ducting20-9
Figure 20-12. Reflectivity Associated with Liquid Targets20-10
xvii Figure 21-1. Mean Worldwide Surface Pressure Distribution and Prevailing Winds
Throughout the World in July21-2
Figure 21-2. Mean Worldwide Surface Pressure Distribution and Prevailing Winds
Throughout the World in January21-2
Figure 21-3. A Shear Line and an Induced Trough Caused by a Polar High
Pushing into the Subtropics21-8
Figure 21-4. A TUTT Moves Eastward Across the Hawaiian Islands. Extensive
Cloudiness Develops East of the Trough21-9
Figure 21-5. A Northern Hemisphere Easterly Wave Progressing from A–B21-10
Figure 21-6. Vertical Cross Section along Line A–B in Figure 21-521-10
Figure 21-7. The Tracks of Nearly 150 Years of Tropical Cyclones and their
Strength Weave Across the Globe21-12
Figure 21-8. Radar Image of Hurricane Katrina Observed at New Orleans, Louisiana,
on August 29, 200521-14
Figure 21-9. Hurricane Andrew Observed by Satellite in 199221-14
Figure 22-1. The Arctic Circle22-1
List of Tables
Table 1-1. Composition of a Dry Earth’s Atmosphere1-1
Table 1-2. Selected Properties of the Standard Atmosphere1-6
Table 2-1. Celsius Temperature Conversion Formulae2-2
Table 2-2. Fahrenheit Temperature Conversion Formulae2-2
Table 2-3. Heat (Thermal) Conductivity of Various Substances2-7
Table 2-4. Specific Heat Capacity of Various Substances2-9
Table 3-1. Latent Heat of Water at 0 °C3-7
Table 5-1. Units of Pressure5-3
Table 5-2. Pressure System Symbols5-6
Table 5-3. Common Constant Pressure Charts5-9
Table 6-1. Common Isopleths6-2
Table 6-2. Common Weather Chart Symbols6-5
Table 11-1. Air Parcel Vertical Motion Characteristics11-4
Table 13-1. Cloud Forms13-1
Table 13-2. Approximate Height of Cloud Bases above the Surface13-2
Table 19-1. Enhanced Fujita Scale (Enhanced F Scale) for Tornado Damage19-11
Table 21-1. Wind Speed and Characteristic House Damage for the
Saffir-Simpson Hurricane Wind Scale21-15