ALBERT

Note: CONTENTS Preface Photo Credits Computer Codes 1 Introduction 1-1 Why Microwaves for Remote Sensing? 1-2 A Brief Overview of Microwave Sensors 1-3 A Short History of Microwave Remote Sensing 1-3.1 Radar 1-3.2 Radiometers 1-4 The Electromagnetic Spectrum 1-5 Basic Operation and Applications of Radar 1-5.1 Operation of Remote-Sensing Radars 1-5.2 Applications of Remote-Sensing Radars 1-6 Basic Operation and Applications of Radiometers 1-6.1 Radiometer Operation 1-6.2 Applications of Microwave Radiometry 1-7 Image Examples 2 Electromagnetic Wave Propagation 2-1 EM Plane Waves 2-1.1 Constitutive Parameters 2-1.2 Maxwell's Equations 2-1.3 Complex Permittivity 2-1.4 Wave Equations 2-2 Plane-Wave Propagation in Lossless Media 2-2.1 Uniform Plane Waves 2-2.2 General Relation between E and H 2-3 Wave Polarization in a Lossless Medium 2-3.1 Linear Polarization 2-3.2 Circular Polarization 2-3.3 Elliptical Polarization 2-4 Plane Wave Propagation in Lossy Media 2-4.1 Low Loss Dielectric 2-4.2 Good Conductor 2-5 Electromagnetic Power Density 2-5.1 Plane Wave in a Lossless Medium 2-5.2 Plane Wave in a Lossy Medium 2-5.3 Decibel Scale tor Power Ratios 2-6 Wave Reflection and Transmission at Normal Incidence 2-6.1 Boundary between Lossless Media 2-6.2 Boundary between Lossy Media 2-7 Wave Reflection and Transmission at Oblique Incidence 2-7.1 Horizontal Polarization—Lossless Media 2-7.2 Vertical Polarization 2-8 Reflectivity and Transmissivity 2-9 Oblique Incidence onto a Lossy Medium 2- 10 Oblique Incidence onto a Two-Layer Composite 2-10.1 Input Parameters 2-10.2 Propagation Matrix Method 2-10.3 Multiple Reflection Method 3 Remote-Sensing Antennas 3-1 The Hertzian Dipole 3-2 Antenna Radiation Characteristics 3-2.1 Antenna Pattern 3-2.2 Beam Dimensions 3-2.3 Antenna Directivity 3-2.4 Antenna Gain 3-2.5 Radiation Efficiency 3-2.6 Effective Area of a Receiving Antenna 3-3 Friis Transmission Formula 3-4 Radiation by Large-Aperture Antennas 3-5 Rectangular Aperture with Uniform Field Distribution 3-5.1 Antenna Pattern in x-y Plane 3-5.2 Beamwidth 3-5.3 Directivity and Effective Area 3-6 Circular Aperture with Uniform Field Illumination 3-7 Nonuniform-Amplitude Illumination 3-8 Beam Efficiency 3-9 Antenna Arrays 3-10 N-Element Array with Uniform Phase Distribution 3-10.1 Uniform Amplitude Distribution 3-10.2 Grating Lobes 3-10.3 Binomial Distribution 3-11 Electronic Scanning of Arrays 3-12 Antenna Types 3-12.1 Horn Antennas 3-12.2 Slot Antennas 3-12.3 Microstrip Antennas 3-13 Active Antennas 3-13.1 Advantages of Active Antennas 3-13.2 Digital Beamforming with Active Antennas 4 Microwave Dielectric Properties of Natural Earth Materials 4-1 Pure-Water Single-Debye Dielectric Model (f 〈 50 GHz) 4-2 Saline-Water Double-Debye Dielectric Model (f〈 1000 GHz) 4-3 Dielectric Constant of Pure Ice 4-4 Dielectric Mixing Models for Heterogeneous Materials 4-4.1 Randomly Oriented Ellipsoidal Inclusions 4-4.2 Polder-van Santen/de Loor Formulas 4-4.3 Tinga-Voss-Blossey (TVB) Formulas 4-4.4 Other Dielectric Mixing Formulas 4-5 Sea Ice 4-5.1 Dielectric Constant of Brine 4-5.2 Brine Volume Fraction 4-5.3 Dielectric Properties 4-6 Dielectric Constant of Snow 4-6.1 Dry Snow 4-6.2 Wet Snow 4-7 Dielectric Constant of Dry Rocks 4-7.1 Powdered Rocks 4-7.2 Solid Rocks 4-8 Dielectric Constant of Soils 4-8.1 Dry Soil 4-8.2 Wet Soil 4-8.3 εsoil in 0.3-1.5 GHz Band 4-9 Dielectric Constant of Vegetation 4-9.1 Dielectric Constant of Canopy Constituents 4-9.2 Dielectric Model 5 Radar Scattering 5-1 Wave Polarization in a Spherical Coordinate System 5-2 Scattering Coordinate Systems 5-2.1 Forward Scattering Alignment (FSA) Convention 5-2.2 Backscatter Alignment (BSA) Convention 5-3 Scattering Matrix 5-3.1 FSA Convention 5-3.2 BSA Convention 5-3.3 Stokes Parameters and Mueller Matrix 5-4 Radar Equation 5-5 Scattering from Distributed Targets 5-5.1 Narrow-Beam Scatterometer 5-5.2 Imaging Radar 5-5.3 Specific Intensities for Distributed Target 5-6 RCS Statistics 5-7 Rayleigh Fading Model 5-7.1 Underlying Assumptions 5-7.2 Linear Detection 5-7.3 Square-Law Detection 5-7.4 Interpretation 5-8 Multiple Independent Samples 5-8.1 N-Look Amplitude Image 5-8.2 N-Look Intensity Image 5-8.3 N-Look Square-Root Intensity Image 5-8.4 Spatial Resolution vs. Radiometric Resolution 5-8.5 Applicability of the Rayleigh Fading Model 5-9 Image Texture and Despeckle Filtering . 5-9.1 Image Texture 5-9.2 Despeckling Filters 5-10 Coherent and Noncoherent Scattering 5-10.1 Surface Roughness 5-10.2 Bistatic Scattering 5-10.3 Specular Reflectivity 5-10.4 Bistatic-Scattering Coefficient 5-10.5 Backscattering Response of a Smooth Surface 5-11 Polarization Synthesis 5-11.1 RCS Polarization Response 5-11.2 Distributed Targets 5-11.3 Mueller Matrix Approach 5-12 Polarimetric Scattering Statistics 5-13 Polarimetric Analysis Tools 5-13.1 Scattering Covariance Matrix 5-13.2 Eigenvector Decomposition 5-13.3 Useful Polarimetric Parameters 5-13.4 Image Examples 5-13.5 Freeman-Durden Decomposition 6 Microwave Radiometry and Radiative Transfer 6-1 Radiometric Quantities 6-2 Thermal Radiation 6-2.1 Quantum Theory of Radiation 6-2.2 Planck's Blackbody Radiation Law 6-2.3 The Rayleigh-Jeans Law 6-3 Power-Temperature Correspondence 6-4 Radiation by Natural Materials 6-4.1 Brightness Temperature 6-4.2 Brightness Temperature Distribution 6-4.3 Antenna Temperature 6-5 Antenna Efficiency Considerations 6-5.1 Beam Efficiency 6-5.2 Radiation Efficiency 6-5.3 Radiometer Measurement Ambiguity 6-6 Theory of Radiative Transfer 6-6.1 Equation of Radiative Transfer 6-6.2 Brightness-Temperature Equation 6-6.3 Brightness Temperature of a Stratified Medium 6-6.4 Brightness Temperature of a Scatter-Free Medium 6-6.5 Upwelling and Downwelling Atmospheric Brightness Temperatures 6-7 Terrain Brightness Temperature 6-7.1 Brightness Transmission Across a Specular Boundary 6-7.2 Emission by a Specular Surface 6-7.3 Emissivity of a Rough Surface 6-7.4 Extreme Surface Conditions 6-7.5 Emissivity of a Two-Layer Composite 6-8 Downward-Looking Satellite Radiometer 6-9 Polarimetric Radiometry 6-10 Stokes Parameters and Periodic Structures 7 Microwave Radiometric Systems 7-1 Equivalent Noise Temperature 7-2 Characterization of Noise 7-2.1 Noise Figure 7-2.2 Equivalent Input Noise Temperature 7-2.3 Noise Temperature of a Cascaded System 7-2.4 Noise Temperature of a Lossy Two-Port Device 7-3 Receiver and System Noise Temperatures 7-3.1 Receiver Alone 7-3.2 Total System Including Antenna 7-4 Radiometer Operation 7-4.1 Measurement Accuracy 7-4.2 Total-Power Radiometer 7-4.3 Radiometric Resolution 7-5 Effects of Receiver Gain Variations 7-6 Dicke Radiometer 7-7 Balancing Techniques 7-7.1 Reference-Channel Control Method 7-7.2 Antenna-Channel Noise-Injection Method 7-7.3 Pulsed Noise-Injection Method 7-7.4 Gain-Modulation Method 7-8 Automatic-Gain-Control (AGC) Techniques 7-9 Noise-Adding Radiometer 7-10 Summary of Radiometer Properties 7-11 Radiometer Calibration Techniques 7-11.1 Receiver Calibration 7-11.2 Calibration Sources 7-11.3 Effects of Impedance Mismatches 7-11.4 Antenna Calibration 7-11.5 Cryoload Technique 7-11.6 Bucket Technique 7-12 Imaging Considerations 7-12.1 Scanning Configurations 7-12.2 Radiometer Uncertainty Principle 7-13 Interferometric Aperture Synthesis 7-13.1 Image Reconstruction 7-13.2 MIR Radiometric Sensitivity 7-14 Polarimetric Radiometer 7-14.1 Coherent Detection 7-14.2 Incoherent Detection 7-15 Calibration of Polarimetric Radiometers 7-15.1 Forward Model for a Fully Polarimetric Radiometer 7-15.2 Forward Model for the Polarimetric Calibration Source 7-15.3 Calibration by Inversion of the Forward Models 7-16 Digital Radiometers 8 Microwave Interaction with Atmospheric Constituents 8-1 Standard Atmosphere 8-1.1 Atmospheric Composition 8-1.2 Temperature Profile 8-1.3 Density Profile 8-1.4 Pressure Profi