6.2. An analysis of VHF field strength variations and refractive index 

 profiles 247 



6.2.1. Introduction 247 



6.2.2. Radio and meteorological data 247 



6.2.3. Classification of radio field strengths by profile types. 248 



6.2.4. Prediction of field strength for unstratified conditions. 250 



6.2.5. The effect of elevated layers on the Illinois paths 251 



6.2.6. Elevated layers at temperature inversions 252 



6.2.7. The influence of small layers 255 



6.2.7. Conclusions 257 



6.3. A new turbulence parameter 258 



6.3.1. Introduction 258 



6.3.2. The concept of thermal stability 258 



6.3.3. The adiabatic lapses of TV 261 



6.3.4. The turbulence parameter, II 262 



6.3.5. Comparison of radio-meteorological parameters 263 



6.3.6. Conclusion 266 



6.4. References 266 



Chapter 7. Attenuation of radio waves 269 



7.1. Introduction 269 



7.2. Background 269 



7.3. Attenuation by atmospheric gases 270 



7.4. Estimates of the range of total gaseous absorption 280 



7.5. Total radio path absorption 283 



7.6. Derivation of absorption estimate for other areas 286 



7.7. Attenuation in clouds 291 



7.8. Attenuation by rain 292 



7.9. Rainfall attenuation climatology 297 



7.10. Rain attenuation effects on radio systems engineering 298 



7.11. Attenuation by hail 302 



7.12. Attenuation by fog 303 



7.13. Thermal noise emitted by the atmosphere 304 



7.14. References 308 



Chapter 8. Applications of tropospheric refraction and refractive index 



models 311 



8.1. Concerning the bi-exponential nature of the tropospheric radio 

 refractive index 311 



8.1.1. Introduction and background 311 



8.1.2. TV structure in the I.e. A. O. atmosphere 312 



8.1.3. Properties of the dry and wet term scale heights 314 



8.1.4. Refraction in the bi-exponential model 32 1 



8.1.5. Extension to other regions 321 



8.2. Effect of atmospheric horizontal inhomogeneity upon ray tracing. _ 322 



8.2.1. Introduction and background 322 



8.2.2. Canterbury 323 



8.2.3. Cape Kennedy 324 



8.2.4. Ray bending 326 



8.2.5. Comparisons 328 



8.2.6. Extension to other regions 331 



8.2.7. Conclusions 333 



