 | Sharma J. Estimation of glacier ice extinction coefficients using long-wavelength polarimetric interferometric synthetic aperture radar: Diss. … Dr.-Ing. / Deutsches Zentrum für Luft- und Raumfahrt, Institut für Hochfrequenztechnik und Radarsysteme, Oberpfaffenhofen. - Köln: DLR, Bibliotheks- und Informationswesen, 2010. - xvi, 214 p.: ill. - Bibliogr.: p.195-215. - (Forschungsbericht; 10-24). - ISSN 1434-8454
|
Abstract ....................................................... ii
Zusammenfassung ............................................... iii
List of Tables ................................................. xi
List of Figures .............................................. xiii
List of Symbols and Acronyms ................................. xvii
1. Introduction ................................................. 1
1.1. Motivation .............................................. 1
1.2. State-of-the-art ........................................ 3
1.2.1. SAR remote sensing of glaciers and ice sheets .... 3
1.2.2. Extinction ....................................... 6
1.3. Research objectives ..................................... 6
1.4. Synopsis ................................................ 7
2. Electromagnetic properties of ice and snow ................... 9
2.1. Electromagnetic wave propagation ........................ 9
2.1.1. Plane waves ..................................... 11
2.1.2. Wave polarisation ............................... 12
2.1.3. Scattering ...................................... 13
2.2. Complex dielectric constant of ice and snow ............ 17
2.2.1. Real dielectric constant ........................ 18
2.2.2. Imaginary dielectric constant ................... 19
2.2.3. Birefringence ................................... 20
2.3. Extinction coefficient ................................. 22
2.3.1. Absorption coefficient ......................... 23
2.3.2. Scattering coefficient .......................... 23
2.3.3. Summary of extinction coefficients in the
literature ...................................... 25
3. Glaciological concepts ...................................... 29
3.1. Glacier mass balance ................................... 29
3.1.1. Proxies for mass balance ........................ 30
3.2. Glacier Facies ......................................... 31
3.2.1. Firn zone ....................................... 33
3.2.2. Superimposed ice zone ........................... 33
3.3. Structure of the near-surface .......................... 34
3.3.1. Glacier surface roughness ....................... 34
3.3.2. Sastrugi ........................................ 36
3.3.3. Thermal regime .................................. 38
3.3.4. Vertical density profiles ....................... 38
4. SAR Polarimetry and Interferometry .......................... 41
4.1. Synthetic Aperture Radar ............................... 41
4.1.1. SAR measurement principle ....................... 41
4.1.2. Backscattering coefficient ...................... 46
4.2. Polarimetric SAR ....................................... 48
4.2.1. Polarimetric description of scatterers .......... 48
4.2.2. Scattering symmetries ........................... 51
4.2.3. Propagating eigenpolarisations .................. 52
4.2.4. Polarimetric basis transformations .............. 53
4.3. Interferometric SAR .................................... 53
4.3.1. Interferometric measurement principle ........... 54
4.3.2. Interferometric coherence ....................... 56
4.4. Polarimetric Interferometric SAR ....................... 60
4.4.1. Pol-InSAR measurement principle ................. 60
4.4.2. Pol-InSAR coherence ............................. 61
5. Modelling ice extinction using Pol-InSAR .................... 63
5.1. Review of ice scattering models ........................ 63
5.1.1. Introduction to scattering models ............... 63
5.1.2. Backscatter models .............................. 64
5.1.3. Interferometric models .......................... 65
5.1.4. Polarimetric Interferometric models ............. 66
5.1.5. Summary of existing models ...................... 67
5.2. Pol-InSAR model for glacier ice extinctions ............ 67
5.2.1. Interferometric coherence model ................. 68
5.2.2. Estimation accuracy ............................. 74
5.2.3. Summary ......................................... 82
6. Data sources ................................................ 83
6.1. Study area ............................................. 83
6.1.1. Austfonna general description and motivation .... 83
6.1.2. Data campaigns .................................. 84
6.1.3. Test sites ...................................... 85
6.2. Field measurements ..................................... 86
6.2.1. Snow and upper ice stratigraphy ................. 86
6.2.2. Ground penetrating radar ........................ 88
6.2.3. Meteorological data ............................. 94
6.3. SAR data description ................................... 96
6.3.1. E-SAR sensor and campaign description ........... 96
6.3.2. Pol-InSAR ice signatures ........................ 98
6.3.3. P-band sounder ................................. 113
7. Polarimetric decomposition ................................. 115
7.1. Review of scattering decompositions ................... 115
7.1.1. Freeman-Durden decomposition ................... 116
7.1.2. Oriented volume models ......................... 118
7.2. Polarimetric decomposition for glacier ice ............ 119
7.2.1. Ground scattering .............................. 119
7.2.2. Ice volume scattering .......................... 121
7.2.3. Oriented sastrugi field ........................ 128
7.2.4. Decomposition approach ......................... 129
7.2.5. Simulations .................................... 132
7.3. Polarimetric decomposition with experimental data ..... 136
7.3.1. Experimental decomposition results ............. 137
7.3.2. Temporal variations ............................ 141
7.3.3. Validation ..................................... 146
7.4. Polarimetric decomposition summary .................... 147
8. Extinction inversion with experimental data ................ 149
8.1. Overview and workflow ................................. 149
8.2. Surface-to-volume scattering ratios ................... 150
8.2.1. Validation of surface-to-volume scattering
ratios ......................................... 152
8.3. Extinction inversion .................................. 154
8.3.1. Extinction interpretation ...................... 158
8.3.2. Temporal variations ............................ 162
8.4. Extinction validation ................................. 168
8.4.1. Comparison of extinctions to published
values ......................................... 168
8.4.2. Ground penetrating radar ....................... 169
8.4.3. P-band sounder ................................. 171
8.5. Extinction inversion summary .......................... 174
9. Conclusions ................................................ 177
9.1. Summary ............................................... 177
9.2. Contributions ......................................... 180
9.3. Future work ........................................... 181
A. Derivation of interferometric coherence for
an ice scenario ............................................ 183
A.1. SAR backscatter model ................................. 183
A.1.1. SAR impulse response in a volume ............... 183
A.1.2. SAR backscattered signal ....................... 185
A.2. Interferometric coherence model ....................... 187
В. Derivation of surface-to-volume scattering ratio bias ...... 191
С. Monte Carlo simulation of Polarimetric SAR data ............ 193
References .................................................... 195
|
|
