Aviation Weather Surveillance Systems: Advanced radar and surface sensors for flight safety and air traffic management (Radar, Sonar and Navigation)

This book has been written to provide a comprehensive introduction to the science, sensors and systems that form modern aviation weather surveillance systems. Focusing on radar-based surveillance, it deals in logical, stepwise detail with the fundamentals of the various disciplines involved and with their complex interplay. This includes giving a background to aviation systems and control, atmospheric and meteorological aspects, weather issues in relation to aviation, and broad coverage of modern aviation weather surveillance and information systems, including detailed material on Doppler weather radar, plus new generation atmospheric sensors. Preface 4 Acknowledgments 5 Abbreviations 6 Symbols 9 Preface 17 Acknowledgments 18 Abbreviations 19 Symbols 22 Table of Contents 27 1. Introduction 37 1.1 Aviation and Electronics: a Symbiotic Relationship 37 1.2 Phases in Evolution of Aircraft Navigation 38 1.3 Modern Aviation Weather Surveillance 40 1.4 Scope and Organisation of the Book 41 1.5 References 45 2. Basic Background of Aviation 46 2.1 Goal of Aviation Systems 46 2.2 Phases of Aircraft Flight 46 2.2.1 Terminal Area Operations 47 2.2.2 En Route Operations 49 2.3 Mechanics of Aircraft Flight 49 2.4 Aircraft Navigation Systems 57 2.4.1 En Route Navigation: Dead-reckoning Systems 58 2.4.2 En Route Navigation: Position Fixing Systems 59 2.4.3 Aircraft Landing Guidance Systems 60 2.5 Air Traffic Control and Air Traffic Services 61 2.6 Radars in Aircraft Navigation and Air Traffic Control 64 2.7 Aeronautical Communication Systems 67 2.8 Summary 69 2.9 References 70 3. Atmospheric Effects on Aviation 72 3.1 Weather as a Factor in Aviation 72 3.2 Overall Effects of Weather on Aviation 72 3.2.1 Safety 72 3.2.2 Comfort 73 3.2.3 Schedule-keeping 74 3.2.4 Efficiency 75 3.2.5 Economy 75 3.2.6 Combination of Factors 76 3.3 Atmospheric Phenomena Involving Air Motion 77 3.3.1 Wind Shear 78 3.3.2 Turbulence 85 4. Origins of Harmful Atmospheric Effects on Aircraft 93 4.1 General 93 4.2 Structure of Atmosphere 93 4.3 Thunderstorms: Nature, Initiation and Evolution 95 4.4 Thunderstorm Parameters 99 4.5 Phenomena Associated with Thunderstorms 100 4.5.1 Divergence and Convergence 101 4.5.2 Turbulence 103 4.5.3 Downburst 105 4.5.4 Cyclonic Motion and Tornadoes 105 4.5.5 Rain 107 4.5.6 Hail 107 4.5.7 Lightning, Electric Fields and Atmospherics 109 4.5.8 Icing 111 4.5.9 Poor Visibility 111 4.5.10 Overall Thunderstorm Scenario 112 5. Requirements of Systems for Aviation Weather Surveillance 113 5.1 General 113 5.2 Types of Weather Surveillance Systems for Aviation 114 5.2.1 In Situ and Remote Sensing 114 5.2.2 Ground-based, Airborne and Spaceborne Sensors 116 5.3 Spatial Coverage 117 5.4 Data Update Rates 121 5.5 Spatial Resolution 122 5.6 Data Processing and Display Systems 124 5.6.1 Stages in Data Processing 124 5.6.2 Display of Aviation Weather Data 126 5.6.3 Requirements of Data Processing and Display Systems 127 5.7 Automated Operation 129 5.8 Selection of Primary Sensors 130 5.8.1 Atmospheric Parameters Monitored for Aviation 130 5.8.2 Primary Sensors for Modern Aviation Weather Surveillance 131 5.9 Summary 132 5.10 References 133 6. Doppler Weather Radar as a Primary Aviation Weather Sensor 135 6.1 General 135 6.2 Basic Aspects 136 6.2.1 Weather Radar Resolution 137 6.2.2 Mapping of Weather Fields 142 6.2.3 Scattering by Raindrops and Radar Reflectivity of Weather 146 6.2.4 Radar Echoes from Clear Air 149 6.2.5 Weather Attenuation of Radar Signals 150 6.2.6 Operating Frequencies of Weather Radars 154 6.3 Conventional Weather Radar 156 6.3.1 Reflectivity Measurement: Radar Range Equation 157 6.3.2 Estimation of Rain Rates 164 6.3.3 WSR-57 Radar 170 Colour Plates 173 Colour Plate 1 - Colour Plate 14 173 7. Modern Doppler Weather Radars for Aviation 188 7.1 General 188 7.2 WSR-88D System 189 7.2.1 Architecture 189 7.2.2 Parameters 190 7.2.3 System Features 190 7.2.4 Data Products 193 7.2.5 Performance 194 7.3 Range and Velocity Ambiguities 195 7.3.1 Nature of Problem 195 7.3.2 Minimisation of Range Overlays 200 7.3.2.1 Low Elevation Angles 200 7.3.2.2 Middle Elevation Angles 200 7.3.2.3 High Elevation Angles 201 7.3.3 Velocity Dealiasing 201 7.3.4 Advanced Ambiguity Resolution Methods 201 7.3.5 Potential and Futuristic Methods 203 7.3.5.1 Spectral Decomposition 203 7.3.5.2 Triple-PRF Radar Observation 204 7.3.5.3 Staggered PRT Scheme 205 7.3.5.4 Random Phase Transmission 206 7.3.5.5 Systematic Discrete Phase Coding 206 8. Other Sensors and Systems for Aviation Weather 208 8.1 General 208 8.2 Wind Profilers 209 8.2.1 Conventional Wind Profiling 209 8.2.2 Radar Wind Profilers 210 8.3 Radio-acoustic Sounding Systems RASS 221 8.3.1 Basic System 221 8.3.2 RASS Augmentation for Sensing Aircraft Icing Conditions 223 8.4 Low-level Wind Shear Alert System LLWAS 224 8.4.1 Concept and Basic Configuration 225 8.4.2 Enhanced System 226 9. Integrated System Approaches 229 9.1 General 229 9.2 Integrated Terminal Weather System 230 9.2.1 Data Integration 231 9.2.2 Automated Operation and Fully Processed Output 232 9.2.3 Performance Enhancement, Versatility and Adaptability 233 9.2.4 Predictive Capability 233 9.3 Aviation Gridded Forecast System 234 9.4 Aviation Weather Products Generator 235 9.5 Summary 240 9.6 References 241 10. Automatic Detection and Tracking of Hazardous Weather Features 243 10.1 General 243 10.2 Basis of Automated Weather Feature Detection 244 10.3 Thunderstorm Cells 245 10.4 Mesocyclones 248 10.5 Gust Fronts 255 10.6 Storm Outflows and Microbursts 261 10.7 Summary 264 10.8 References 265 Special Topics in Aviation Weather Surveillance 266 11. Atmospheric Turbulence and Its Detection by Radar 266 11.1 General 266 11.2 Wind Shear and Turbulence in Meteorological Events 267 11.2.1 Thunderstorms 268 11.2.2 Thermal Plumes 269 11.2.3 K-H Waves 270 11.3 Detection of Turbulence with Doppler Radar 271 11.4 Statistical Theory of Turbulence 275 11.4.1 Correlation and Spectral Functions in the Inertial Subrange 279 11.4.2 Filtering by the Radar's Weighting Function 282 11.4.3 Variance of Point and Average Velocities 286 11.5 Doppler Spectrum Width and Eddy Dissipation Rate 287 11.6 Eddy Dissipation Rates in Thunderstorms 289 11.7 Avoiding Turbulence 291 11.8 Summary 294 11.9 References 295 Special Topics in Aviation Weather Surveillance 297 11. Atmospheric Turbulence and Its Detection by Radar 297 11.1 General 297 11.2 Wind Shear and Turbulence in Meteorological Events 298 11.2.1 Thunderstorms 299 11.2.2 Thermal Plumes 300 11.2.3 K-H Waves 301 11.3 Detection of Turbulence with Doppler Radar 302 11.4 Statistical Theory of Turbulence 306 11.4.1 Correlation and Spectral Functions in the Inertial Subrange 310 11.4.2 Filtering by the Radar's Weighting Function 313 11.4.3 Variance of Point and Average Velocities 317 11.5 Doppler Spectrum Width and Eddy Dissipation Rate 318 11.6 Eddy Dissipation Rates in Thunderstorms 320 11.7 Avoiding Turbulence 322 11.8 Summary 325 11.9 References 326 12. Lightning and Aviation 328 12.1 General 328 12.2 Lightning, Electric Fields and Atmospherics 328 12.3 Lightning-aircraft Interaction 332 12.4 Weather Conditions and Lightning Strikes to Aircraft 339 12.5 Detection and Surveillance of Lightning Phenomena 344 12.6 Lightning Threats to Aircraft: What Else Do We Need to Know? 346 12.7 Summary 346 12.8 References 347 13. Polarisation Diversity Radars 349 13.1 General 349 13.2 Description 349 13.3 Basic Definitions 351 13.4 Propagation Effects 352 13.5 Rainfall Measurement 354 13.6 Hail Detection 358 13.7 Automatic Classification and Quantification of Precipitation 359 13.8 Status and Prospects for Aviation Use 361 13.9 Summary 361 13.10 References 362 Index 364 A 364 B 368 C 369 D 371 E 373 F 373 G 375 H 375 I 376 J 377 K 377 L 377 M 378 N 379 O 380 P 380 R 382 S 384 T 386 U 388 V 389 W 389 Z 391

The need to enhance the safety and efficiency of aviation systems has escalated with increasing aviation activity and competitiveness around the world. Weather, which is one of the principal factors affecting aviation performance, is acquiring ever more importance as aviation is poised to shift to futuristic paradigms such as free flight. Advanced systems and approaches to the surveillance of weather and the resultant generation of highly processed, detailed, accurate and reliable weather data, are becoming integral parts of support systems for navigation and air traffic management.

This accessible multidisciplinary book touches on all of the important scientific and technological aspects of the aviation weather surveillance problem. The emphasis is balanced between physical and system concepts, as well as description of state-of-the art and future devices and software.

Among the subjects covered are:

• wind shear and atmospheric turbulence
• surveillance system requirements
• Doppler weather radar
• polarimetric weather radars
• wind profilers
• radiometric satellite observation
• automated surveillance systems
• integrated aviation weather systems

Aviation weather surveillance systems should be of interest not only to personnel directly handling aviation meteorological functions, but also to pilots, air traffic controllers, airline managers, civil aviation system planners and regulators, accident investigators and indeed anyone with a serious interest in aviation.

The book has 13 chapters. The first chapter is introduction. The second chapter deals with basic background of aviation. The third chapter deals with atmospheric effects on aviation. The fourth chapter deals with origins of harmful atmospheric effects on aircraft. The fifth chapter deals with requirements of systems for aviation weather surveillance. The sixth chapter deals with Doppler weather radar as a primary aviation weather sensor. The seventh chapter deals with modern Doppler weather radars for aviation. The eight chapter deals with other sensors and systems for aviation weather. The ninth chapter deals with integrated system approaches. The tenth chapter deals with automatic detection and tracking of hazardous weather features. The eleventh chapter deals with atmospheric turbulence and its detection by radar. The twelfth chapter deals with lightning and aviation. The thirteenth chapter deals with polarisation diversity radars Content: • Front Matter Preface • Table of Contents 1. Introduction 2. Basic Background of Aviation 3. Atmospheric Effects on Aviation 4. Origins of Harmful Atmospheric Effects on Aircraft 5. Requirements of Systems for Aviation Weather Surveillance 6. Doppler Weather Radar as a Primary Aviation Weather Sensor Colour Plates 7. Modern Doppler Weather Radars for Aviation 8. Other Sensors and Systems for Aviation Weather 9. Integrated System Approaches 10. Automatic Detection and Tracking of Hazardous Weather Features •Special Topics in Aviation Weather Surveillance 11. Atmospheric Turbulence and Its Detection by Radar 12. Lightning and Aviation 13. Polarisation Diversity Radars • Index Focusing on radar-based surveillance techniques, this introduction deals with the fundamentals of the various disciplines involved and their complex interplay. Detailed coverage of modern surveillance and information systems includes material on Doppler weather radar and new atmospheric sensors. Focusing on radar-based surveillance, this book has been written to provide a comprehensive introduction to the science, sensors and systems that form modern aviation weather surveillance systems.