HANDBOOK ON RADIOMETEOROLOGY – 1996
PREFACE
CONTENTS
CHAPTER 1 –PREFACE
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 Drop size distribution
2.3.2 Hydrometeor shape and orientation
2.3.3 Terminal velocity
2.3.4 Drop temperature
2.4 Statistical characteristics of rainfall intensity at a point
2.4.1 Cumulative distribution of rainfall intensity
2.4.2 Conversion of rainfall rate distributions to equivalent one-minute statistics
2.4.3 Models for the rainfall rate distribution
2.4.4 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
ANNEX 1 –Types of precipitation
ANNEX 2 –Rain climatology models
REFERENCES
CHAPTER 3– Atmospheric refraction
3.1 General
3.1.1 Influence of the atmosphere on radiowave propagation
3.1.2 Refractive index and refractivity
3.1.3 Models of the atmospheric refractive index
3.1.4 Departures from the models
3.2 Refractivity at ground level
3.2.1 Introduction
3.2.2 Monthly averages of ground refractivity
3.3 Refractivity gradients
3.3.1 Generalities
3.3.2 Models for refractivity gradient distribution
3.3.3 Statistical information on refractivity gradients
3.3.4 Correlation between ground refractivity and refractivity gradient
3.3.5 Equivalent refractivity gradient along a path
3.4 Refractive structures at mid and large scales
3.4.1 Ducting layers - definition and experimental observations
3.4.2 Duct modelling
3.4.3 Ducts statistics
3.4.4 Sub-refractive conditions
3.4.5 Statistics of sub-refractive conditions
3.4.6 Horizontal refractivity gradients
3.5 Techniques of refractive index measurements
3.5.1 General
3.5.2 Direct measurements - microwave refractometers
3.5.3 Indirect measurements
3.5.4 Humidity measurements
3.5.5 Measurement of vertical profiles
3.5.6 Measurements of vertical and horizontal structures
REFERENCES
CHAPTER 4 –INFLUENCE OF REFRACTION ON PROPAGATION
4 Influence of refraction on propagation
4.1 General
4.1.1 Introduction
4.1.2 Ray approximation
4.1.3 Modified refractive index and effective Earth radius
4.2 Refractive effects in normal conditions
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 ke
4.4 Propagation with super-refractive layers
4.4.1 General
4.4.2 Qualitative description by ray tracing
4.4.3 Ducting effects
4.4.4 Multipath propagation
4.4.5 Angle-of-arrival variations
4.5 Representation of the propagation channel during super-refractive conditions
4.5.1 General
4.5.2 Multi-ray model
4.5.3 Theoretical considerations on single-frequency statistics
4.5.4 Models for the multipath transfer function
4.5.5 Simplified representations of the propagation channel
4.6 Signal scintillations due to atmospheric turbulence
4.6.1 Amplitude scintillation
4.6.2 Angle-of-arrival scintillations
4.7 Tropospheric scatter propagation
4.7.1 General
4.7.2 Modelling of long-term variations of field strength
4.7.3 Troposcatter transfer function
REFERENCES
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
5.2 Solution 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 Introduction
6.2 Calculation of specific attenuation using simple algorithms
6.3 Calculation of attenuation along Earth-space paths
6.4 Dispersion due to atmospheric gases
6.5 Attenuation of infrared and visible radiation
CHAPTER 7 –Attenuation by atmospheric particles
7.1 Attenuation due to hydrometeors
7.1.1 Introduction
7.1.2 Prediction of specific attenuation from rainfall intensity data
7.1.3 Attenuation over propagation links of finite extent
7.1.4 Prediction of attenuation from radio propagation data
7.1.5 Variability of rain attenuation statistics
7.1.6 Radiometer and radar measurements
7.2 Propagation delay due to precipitation
7.3 Attenuation by hydrometeors other than rain
7.3.1 Aerosols, fog, clouds, hail and snow
7.4 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 Introduction
9.2 Mathematical background
9.2.1 Polarization state of a wave
9.2.2 Dual-polarization transfer channel
9.2.3 Simplified medium models
CHAPTER 10 –Statistical aspects of modelling
10.1 Variability of atmospheric processes
10.1.1 Introduction
10.1.2 Definitions
10.1.3 Concepts and models
10.2 Worst-month statistics
10.2.1 The ITU-R definition
10.2.2 Calculation method using Q
10.2.3 Calculation method using C0
10.2.4 Variability aspects
10.3 Annual statistics
10.3.1 Variability aspects
10.3.2 Accuracy and model testing
10.4 Risk and return period
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
REFERENCES