Spectral Imaging of the Atmosphere (eBook)

Cover 1
Copyright Page 5
Contents 8
Preface 14
Chapter 1. Observing Atmospheric Radiation 16
1.1 Atmospheric Radiation 16
1.2 Measuring Atmospheric Radiation 23
1.3 The Scope of Spectral Imaging 27
1.4 One-Dimensional (Vertical) Spatial Information 28
1.5 Two-Dimensional (Horizontal–Vertical) Information 31
1.6 Three-Dimensional Information 33
1.7 Spectral Information 35
1.8 Temporal Information 41
1.9 Preview 43
1.10 Problems 44
Chapter 2. Spectral Concepts 45
2.1 Introduction 45
2.2 The Spectral Concept 46
2.3 Formal Statement of the Fourier Transform 48
2.4 Fundamental Properties of the Fourier Integral 50
2.5 Doing a Fourier Integral Without Integration 51
2.6 Building Up a Set of Fourier Transforms 52
2.7 Convolutions and Correlations 53
2.8 The Dirac Delta Function and the Dirac Comb 54
2.9 The Discrete Fourier Transform 56
2.10 The Autocorrelation Function and Power Spectral Density 59
2.11 Optical Devices as Linear Dynamical Systems 60
2.12 The Diffraction Grating as a Linear Dynamical System 62
2.13 The Fabry–Perot Etalon as a Linear Dynamical System 66
2.14 Problems 67
Chapter 3. Instrument Responsivity and Superiority 69
3.1 Responsivity of an Elementary Photometer 69
3.2 The Measurement of Irradiance 72
3.3 Responsivity for Line and Continuum Sources 72
3.4 Photometer Calibration 74
3.5 Generalized Definition of Responsivity 76
3.6 Jacquinot’s Definition of Étendue 77
3.7 Resolving Power and the Superiority of Spectral Imagers 78
3.8 Dispersion, Classification and Nomenclature 81
3.9 Problems 83
Chapter 4. Imaging Concepts 85
4.1 Elementary Detectors and Noise 85
4.2 Scanning Satellite Imager 87
4.3 Weather Satellite Imagers 91
4.4 Introduction to Array Detectors 95
4.5 The Charge Coupled Device (CCD) Detector 96
4.6 Spectral Response and Materials 102
4.7 Considerations Specific to Infrared Array Detectors 103
4.8 Other Types of Array Detectors 104
4.9 Early Array Detector Imagers 107
4.10 CCD Satellite Imagers 110
4.11 Summary 114
4.12 Problems 115
Chapter 5. The Fabry–Perot Spectrometer 117
5.1 Introduction 117
5.2 The Idealized Etalon 118
5.3 The Real Etalon 122
5.4 Elementary Fabry–Perot Spectrometer Configuration 123
5.5 The Spherical Fabry–Perot Spectrometer 124
5.6 Scanning Methods for Fabry–Perot Spectrometers 127
5.7 The Application of Fabry–Perot Spectrometers 129
5.8 Applications of the Fabry–Perot Imager 136
5.9 Problems 142
Chapter 6. The Michelson Interferometer 144
6.1 Historical Background 144
6.2 Basic Concept 145
6.3 Spectral Resolution 148
6.4 Field of View 149
6.5 The Real Michelson Interferometer 150
6.6 Sampling the Interferogram 150
6.7 Superiority of the Michelson Interferometer 151
6.8 Scanning Methods for the Ordinary Michelson Interferometer 152
6.9 Some Atmospheric Applications of the Michelson Interferometer 154
6.10 Field Widening 157
6.11 Problems 164
Chapter 7. Multiplexers and Modulators 166
7.1 Spectral Operating Modes 166
7.2 Multiplexers 167
7.3 Modulators 169
7.4 Problems 181
Chapter 8. Doppler Michelson Interferometry 183
8.1 The Measurement of Doppler Temperature 183
8.2 The Measurement of Doppler Wind 187
8.3 Phase Stepping Interferometry 188
8.4 The Wide-Angle Michelson Interferometer 190
8.5 Cube Corner Doppler Michelson Interferometer 191
8.6 Achromatizing a Field-Widened Michelson Interferometer 192
8.7 Thermally Stabilizing a Solid Michelson Interferometer 193
8.8 A Fully Compensated Solid Doppler Michelson Interferometer 194
8.9 Defocusing a Wide-Angle Michelson Interferometer 195
8.10 Polarizing Doppler Michelson Interferometers 196
8.11 The Phase Quadrature Michelson Interferometer 200
8.12 Optimized Reflective Wide-Angle Phase-Stepping MI 202
8.13 Problems 204
Chapter 9. Operational Atmospheric Spectral Imagers 206
9.1 Introduction 206
9.2 The Wind Imaging Interferometer (WINDII) 206
9.3 ERWIN: An E-Region Wind Interferometer 222
9.4 MICADO – Michelson Interferometer for Coordinated Auroral Doppler Observations 226
9.5 The High-Resolution Doppler Imager (HRDI) 228
9.6 CLAES: The Cryogenic Limb Array Etalon Spectrometer on UARS 235
9.7 MOPITT – Measurements Of Pollution In The Troposphere 238
9.8 Problems 242
Chapter 10. Future Atmospheric Spectral Imagers 245
10.1 The TIMED Doppler Imager (TIDI) 245
10.2 The Mesospheric Imaging Michelson Interferometer (MIMI) 250
10.3 The Stratospheric Wind Interferometer for Transport Studies (SWIFT) 255
10.4 The Atmospheric Chemistry Experiment (ACE) 263
10.5 The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) 266
10.6 Problems 269
Chapter 11. Grating Spectrometers as Spectral Imagers 270
11.1 Introduction 270
11.2 Fundamental Aspects of the Diffraction Grating Spectrometer 272
11.3 Selected Airglow Missions Accomplished 273
11.4 Selected Atmospheric Missions Accomplished 281
11.5 Future Atmospheric Missions using Grating Spectrographs 286
11.6 Spatial Heterodyne Spectroscopy (SHS) 289
11.7 Problems 292
Chapter 12. Postscript 294
References 296
List of Symbols 312
List of Acronyms and Abbreviations 315
Author Index 320
Subject Index 325