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Microwave Propagation and Remote Sensing

Book Description

Because prevailing atmospheric/troposcopic conditions greatly influence radio wave propagation above 10 GHz, the unguided propagation of microwaves in the neutral atmosphere can directly impact many vital applications in science and engineering. These include transmission of intelligence, and radar and radiometric applications used to probe the atmosphere, among others.

Where most books address either one or the other, Microwave Propagation and Remote Sensing: Atmospheric Influences with Models and Applications melds coverage of these two subjects to help readers develop solutions to the problems they present. This reference offers a brief, elementary account of microwave propagation through the atmosphere and discusses radiometric applications in the microwave band used to characterize and model atmospheric constituents, which is also known as remote sensing.

Summarizing the latest research results in the field, as well as radiometric models and measurement methods, this book covers topics including:

  • Free space propagation
  • Reflection, interference, polarization, and other key aspects of electromagnetic wave propagation
  • Radio refraction and its effects on propagation delay
  • Methodology of estimating water vapor attenuation using radiosonde data
  • Knowledge of rain structures and use of climatological patterns to estimate/measure attenuation of rain, snow, fog, and other prevalent atmospheric particles and human-made substances
  • Dual/multifrequency methodology to deal with the influence of clouds on radiometric attenuation
  • Deployment of microwaves to ascertain various tropospheric conditions
  • Composition and characteristics of the troposphere, to help readers fully understand microwave propagation
  • Derived parameters of water, free space propagation, and conditions and variable constituents such as water vapor and vapor pressure, density, and ray bending

Table of Contents

  1. Cover Page
  2. Title Page
  3. Copyright Page
  4. Dedication
  5. Contents
  6. Preface
  7. Author
  8. 1 Outlines of Radio Waves and Troposphere
    1. 1.1 General Perspective
    2. 1.2 Troposphere
      1. 1.2.1 Composition and Characteristics
      2. 1.2.2 Relationships for Determination of Vapor Pressure
    3. 1.3 The Effective Earth’s Radius
    4. 1.4 Radio Link
    5. 1.5 Classification of Radio Waves According to Propagation Mechanism
      1. 1.5.1 Direct Wave
      2. 1.5.2 ground Wave or Surface Wave
      3. 1.5.3 Tropospheric Wave
    6. 1.6 Radio Refractivity and Delay through the Atmosphere
      1. 1.6.1 Forms of Refraction
      2. 1.6.2 Normal Refraction (0 > ∆ N > –100)
      3. 1.6.3 Subrefraction (∆N > 0)
      4. 1.6.4 Superrefraction (–100 ≥ ∆N > –157)
      5. 1.6.5 Ducting (∆N ≤ –157)
    7. 1.7 Tropospheric Aerosols
    8. 1.8 Rain Characteristics
      1. 1.8.1 Raindrop Size Distribution Model
        1. 1.8.1.1 LP Distribution
        2. 1.8.1.2 Negative Exponential Distribution
        3. 1.8.1.3 Gamma Distribution
        4. 1.8.1.4 Lognormal Distribution
      2. 1.8.2 Raindrop Terminal Velocity
    9. References
  9. 2 Propagation of Radio Waves: An Outline
    1. 2.1 Introduction
    2. 2.2 Power Gain of Directional Aerial
    3. 2.3 Free Space Field Due to Directional Transmitting Aerial
    4. 2.4 Power at the Receiving Directional Aerial
    5. 2.5 Free Space Transmission Loss
    6. 2.6 Radio Waves in Neutral Atmosphere
    7. 2.7 When Is a Medium a Conductor or Dielectric?
    8. 2.8 Wave Polarization
      1. 2.8.1 linear Polarization
      2. 2.8.2 Circular Polarization
    9. References
  10. 3 Reflection and Interference of Radio Waves
    1. 3.1 Introduction
    2. 3.2 Reflection of Radio Waves
    3. 3.3 Plane Wave at Dielectric Interface
    4. 3.4 Reflection Coefficient for Flat Smooth Earth
    5. 3.5 Field Strength Due to Reflection from Flat Earth
    6. 3.6 Effect of the Earth’s Curvature: Spherical Earth
    7. 3.7 Mechanism of Ground Wave Propagation
    8. References
  11. 4 Radio Refraction and Path Delay
    1. 4.1 Introduction
    2. 4.2 Radius of Curvature of the Ray Path
    3. 4.3 Refractivity is Complex and Frequency Dependent
      1. 4.3.1 Continuum for Dry air
      2. 4.3.2 Continuum for Water Vapor
      3. 4.3.3 Hydrosol Continuum
    4. 4.4 Turbulence-Induced Scintillation
      1. 4.4.1 Theoretical Model of Cn2
      2. 4.4.2 estimation of Cn2
    5. 4.5 Microwave Propagation through Tropospheric Turbulence
    6. 4.6 Propagation over Inhomogeneous Surface
    7. 4.7 Tropospheric Ducting
    8. 4.8 Propagation Delay through the Atmosphere
      1. 4.8.1 estimation of Refractivity
      2. 4.8.2 estimation of Delay (cm)
    9. References
  12. 5 Absorption of Microwaves
    1. 5.1 Introduction
    2. 5.2 Absorption Coefficient
    3. 5.3 Microwave and Millimeter Wave Absorption in the Atmosphere
      1. 5.3.1 absorption by atmospheric Constituents
      2. 5.3.2 absorption intensity
    4. 5.4 Centrifugal Distortion
    5. 5.5 Water Vapor Absorption at 22.235 GHz
    6. 5.6 Water Vapor Absorption at 183.311 GHz
    7. 5.7 Water Vapor and Microwave Attenuation
      1. 5.7.1 Modeling of Meteorological Parameters and attenuation Coefficients
      2. 5.7.2 Significant Heights for Water Vapor
        1. 5.7.2.1 Time-Scale Dependence of Vertical Distribution of Water Vapor
      3. 5.7.3 Frequency Dependence of Water Vapor Distribution
    8. 5.8 Choice of Frequency
    9. 5.9 Attenuation Studies in 50–70 GHz Band
      1. 5.9.1 Possible application in 50–70 gHz band
    10. 5.10 Attenuation Studies at 94 GHz
      1. 5.10.1 Theoretical Consideration
      2. 5.10.2 Computation of 94 gHz attenuation from Radiosonde Data
    11. References
  13. 6 Rain Attenuation and Its Application at Microwaves
    1. 6.1 Introduction
    2. 6.2 Radiometric Estimation of Rain Attenuation
      1. 6.2.1 Rain Height
      2. 6.2.2 Structure of Rain
      3. 6.2.3 Estimation of Rain Height
      4. 6.2.4 Variability of Rain Height
    3. 6.3 ITU-R Rain Attenuation Model and its Applicability
      1. 6.3.1 Procedure for Calculating attenuation based on the ITU-R Model
      2. 6.3.2 Procedure for Modifying the ITU-R Model applicable for Tropics
    4. 6.4 Raindrop Size Distribution in the Tropics
      1. 6.4.1 Case Study over Southern Part of India
        1. 6.4.1.1 Case 1
        2. 6.4.1.2 Case 2
        3. 6.4.1.3 Case 3
      2. 6.4.2 Case Study over Northern Part of india
    5. References
  14. Attenuation by Hydrometeors Other than Rain
    1. 7.1 Snow
    2. 7.2 Hail
    3. 7.3 Fog
    4. 7.4 Aerosols
    5. 7.5 Clouds: Nonprecipitable Liquid Water
      1. 7.5.1 a general idea of Maximum Water Content in Clouds
    6. 7.6 Microwave Radiometric Estimation of Water Vapor and Cloud Liquid
      1. 7.6.1 Single Frequency algorithm for Water Vapor estimation
      2. 7.6.2 Water Vapor Scale Height
      3. 7.6.3 Dual Frequency Algorithm for Water Vapor and Cloud Liquid Estimation
        1. 7.6.3.1 Use of Radiosonde Data
        2. 7.6.3.2 Use of Radiometric Data and Some Results over South America
    7. 7.7 Effect of Water Vapor and Liquid Water on Microwave Spectra
    8. 7.8 Cloud Radar
    9. References
  15. Appendix: Mean Atmospheric Temperature at Microwaves and Millimeter Waves in Clear Air Environment
  16. Index