HANDBOOK ON RADIOMETEOROLOGY PREFACE
PREFACE
Contents
CHAPTER 1 - Introduction
1.1 Purpose of the Handbook on Radiometeorology
1.2 Applicable texts
1.3 Cross-reference table
CHAPTER 2 - Physical characteristics of the atmosphere
2.1 Variability of water vapour and oxygen density at ground level
2.2 Variability of the height profile of water vapour
2.3 Precipitation characteristics 2.3.1 Types of precipitation
2.3.1 Types of precipitation
2.3.2 Drop size distribution
2.3.3 Hydrometeor shape and orientation
2.3.4 Terminal velocity
2.3.5 Drop temperature
2.4 Statistical characteristics of point rainfall intensity 2.4.1 Cumulative distribution of rainfall intensity
2.4.1 Cumulative distribution of rainfall intensity
2.4.2 Yearly variability of the cumulative rainfall rate distribution
2.4.3 Conversion of rainfall rate distributions to equivalent one-minute statistics
2.4.4 Models for the rainfall rate distribution
2.4.5 Statistics of rainfall event duration
2.5 Horizontal structure of rainfall
2.5.1 Application to scattering by rain
2.5.2 Application to attenuation by rain
2.6 Vertical structure of precipitation
2.6.1 Vertical variation of reflectivity
2.6.2 Vertical variation of specific attenuation
2.6.3 The 0°C isotherm height and the rain height
2.7 Characteristics of fog and clouds
2.8 Sand and dust storms
REFERENCES
CHAPTER 3 - Atmospheric refraction
3.1 Influence of the atmosphere on radiowave propagation
3.2 Refractive index and refractivity
3.3 Models of the atmospheric refractive index
3.3.1 Linear models
3.3.2 Exponential models
3.3.3 Other models
3.4 Departures from the models
3.5 Refractivity at ground level
3.5.1 Monthly averages of ground refractivity
3.5.2 Seasonal and year-to-year variability of ground refractivity
3.6 Refractivity gradients
3.6.1 Models for refractivity gradient distribution
3.6.2 Statistical information on refractivity gradients
3.6.3 Correlation between ground refractivity and refractivity gradient
3.6.4 Equivalent refractivity gradient along a path
3.7 Refractivity structures at meso and macroscales
3.7.1 Ducting layers – definition and experimental observations
3.7.2 Sub-refractive conditions
3.8 Horizontal refractivity gradients
3.9 Techniques of refractive index measurements
3.9.1 Direct measurements – microwave refractometers
3.9.2 Indirect measurements - measurement of meteorological quantities
3.9.3 Measurement of vertical profiles
3.9.4 Measurement of vertical and horizontal structures
REFERENCES
CHAPTER 4 - Influence of refraction on propagation
4.1 Introduction
4.1.1 Ray approximation
4.1.2 Modified refractive index and effective Earth radius
4.2 Refractive effects in normal conditions 4.2.1 Sub-refraction and super-refraction
4.2.1 Sub-refraction and super-refraction
4.2.2 Apparent elevation angle
4.2.3 Radioelectric path length
4.2.4 Beam spreading on slant paths
4.2.5 Range rate error
4.3 Propagation during sub-refractive conditions
4.3.1 Effective Earth radius factor for the path, Ke
4.3.2 Prediction of the minimum value of
4.4 Propagation with super-refractive layers
4.4.1 Qualitative description by ray tracing
4.4.2 Ducting effects
4.4.3 Multipath propagation
4.4.4 Angle-of-arrival variations
4.5 Representation of the propagation channel during super-refractive conditions
4.5.1 Multi-ray model
4.5.2 Theoretical considerations on single-frequency statistics
4.5.3 Models for the multipath transfer function
4.6 Simplified representations of the propagation channel 4.6.1 Ray models 4.6.1.1 Two-ray and fixed-delay model
4.6.1 Ray models
4.6.2 Parametric representation of amplitude distortion
4.7 Signal scintillations due to atmospheric turbulence
4.7.1 Amplitude scintillation
4.7.2 Angle-of-arrival scintillations
4.8 Tropospheric scatter propagation
4.8.1 Modelling of long-term variations of field strength
4.8.2 Troposcatter transfer function
Annex 1 - Statistical prediction models of scintillation standard deviation and amplitude
A1.1 Introduction
A1.2 Prediction models of the scintillation standard deviation A1.2.1 Karasawa model
A1.3 Prediction models of the distribution of the scintillation amplitude A1.3.1 Karasawa and ITU-R models
REFERENCES OF ANNEX 1
CHAPTER 5 - Single-particle scattering
5.1 General considerations
5.1.1 Integral representation of the field
5.1.2 Scattering of a plane wave in the far field. The optical theorem 5.1.2.1 Scattering amplitude
5.2 Solution methods 5.2.1 Analytical methods
5.2.1 Analytical methods
5.2.2 Approximate numerical methods
5.3 Numerical implementation
REFERENCES
CHAPTER 6 - Attenuation and dispersion by atmospheric gases
6.1 Physical background of gaseous absorption
6.2 Calculation of gaseous attenuation through the Earth's atmosphere
6.3 Algorithms found in Annex 2 of Recommendation ITU-R P.676-9 for specificattenuation in the frequency range 1-350 GHz
6.4 Algorithms presented in Annex 2 for slant-path attenuation in the frequency range1-350 GHz
6.5 Effects of dispersion due to atmospheric gases
6.6 Comparison of predictions from various gaseous absorption models withmeasurements
6.6.1 Ground-based radiometric measurements
6.6.2 Ground-based Fourier transform spectrometers
6.6.3 Conclusion
6.7 Attenuation of infrared and visible radiation
REFERENCES
CHAPTER 7 - Attenuation by atmospheric particles
7.1 Prediction of specific attenuation from rain intensity data
7.2 Attenuation over propagation links of finite extent
7.2.1 Effects of spatial non-uniformity in rain
7.2.2 Earth-space links
7.3 Prediction of attenuation from radio propagation data
7.3.1 Single-frequency scaling: constant attenuation ratio
7.3.2 Single-frequency scaling: variable attenuation ratio
7.3.3 Multi-frequency scaling
7.3.4 Instantaneous scaling: single frequency
7.3.5 Path length scaling of rain attenuation statistics for line-of-sight links
7.4 Variability of rain attenuation statistics
7.5 Radiometer and radar measurements
7.6 Propagation delay due to precipitation
7.7 Attenuation by hydrometeors other than rain
7.7.1 Aerosols, fog, clouds, hail and snow
7.8 Attenuation by sand and dust storms
REFERENCES
CHAPTER 8 Radio emissivity of atmosphere and ground
8.1 Introduction
8.2 Radiative transfer 8.2.1 Fundamentals
8.2.2 Radiative transfer equation
8.2.3 Brightness temperature
8.3 Atmospheric emissivity
8.4 Ground emissivity
8.5 Radiometric estimation of attenuation and path length 8.5.1 General
8.5.2 Radiometric estimation of attenuation
8.5.3 Estimation of propagation path delay
8.6 Passive remote sensing of atmospheric composition 8.6.1 General
8.6.2 Atmospheric water content
8.6.3 Radiometric retrieval of atmospheric water content
8.6.4 Retrieval and scaling coefficients
REFERENCES
CHAPTER 9 - Cross-polarization and anisotropy
9.1 Mathematical background
9.1.1 Polarization state of a wave
9.1.2 Orthogonal polarizations
9.1.3 Dual-polarization transfer channel
9.1.4 Simplified medium models
9.2 Microphysics of the depolarizing medium
9.2.1 Existence of the Principal Planes
9.2.2 Equi-aligned raindrop-axes model
9.2.3 Raindrops with Gaussian distribution of orientations
9.2.4 Ice-needles in clouds
9.2.5 Ice depolarization during rainfall
9.3 Model parameters assessment
REFERENCES
CHAPTER 10 Statistical aspects of modelling
10.1 Variability of atmospheric processes
10.1.1 Definitions
10.1.2 Concepts and models
10.2 Worst-month statistics
10.2.1 The ITU-R definition
10.2.2 Calculation method using
10.2.3 Calculation method using
10.2.4 Variability aspects
10.3 Annual statistics
10.3.1 Crane model
10.3.2 Inter-annual variability of rainfall rate and rain attenuation statistics
10.4 Risk and reliability concepts
10.4.1 Risk analysis 10.4.1.1 First approach
10.4.2 Return period
10.4.3 Mean time to failure
10.4.4 Other considerations
10.4.5 Relation to services
10.4.6 Risk of occurrence of outages
10.5 Conclusions
Annex 10.A.1 - Rank-order statistics
ANNEX 10.A.2 - Determination of C0 and C1 from measured data
Annex 10.A.3 - Risk assessment Examples of outage and fade margin calculation associated with risk or confidence
a) Outage calculation
b) Fade margin calculation
REFERENCES