1 Introduction ................................................. 1
1.1 Ice Inhomogeneities and Methane Bubbles ................. 3
1.2 Subarctic Lakes ......................................... 4
1.3 Polarimetrie SAR: State of the Art ...................... 6
1.4 ALOS-PALSAR System ...................................... 7
1.5 Objectives and Scope of the Work ........................ 8
2 Polarimetrie SAR Principles ................................. 11
2.1 Polarimetrie Scattering Matrix ......................... 12
2.2 Pauli Scattering Vector ................................ 13
2.3 Radar Cross Section .................................... 14
2.3.1 Covariance Matrix ............................... 16
2.3.2 Coherency Matrix ................................ 16
2.4 Eigen Decomposition .................................... 17
2.4.1 Polarimetrie Entropy, Anisotropy and Mean
Alpha Angle ..................................... 19
2.4.2 Entropy-Alpha Histogram ......................... 20
2.5 Model-Based Decomposition .............................. 23
2.5.1 Surface Scattering Contribution ................. 23
2.5.2 Dihedral Scattering Contribution ................ 24
2.5.3 Volume Scattering Contribution .................. 26
3 Experimental Data ........................................... 29
3.1 Test Sites ............................................. 30
3.1.1 Churchill Site .................................. 30
3.1.2 Baker Lake Site ................................. 33
3.1.3 Inuvik Site ..................................... 33
3.1.4 Lena Delta Site ................................. 36
3.2 Data Processing ........................................ 38
3.3 Data Analysis ......................................... 40
3.3.1 Churchill Site .................................. 40
3.3.2 Baker Lake Site ................................. 44
3.3.3 Inuvik Site ..................................... 46
3.3.4 Lena Delta Site ................................. 48
4 Random Rough Surface Scattering ............................. 51
4.1 Surface Properties ..................................... 51
4.1.1 Physical Properties ............................. 52
4.1.2 Geometrical Properties .......................... 53
4.2 Surface Modelling ...................................... 55
4.2.1 Coherent Component (Specular Reflection and
Transmission) ................................... 56
4.2.2 Incoherently Scattered Component ................ 57
4.3 Small Perturbation Model (Bragg Surface Scattering) .... 58
4.4 X-Bragg Model .......................................... 60
5 Particle and Volume Scattering .............................. 63
5.1 Scattering of a Single Particle ........................ 63
5.2 Rayleigh Scattering .................................... 65
5.2.1 Sphere Shaped Particle .......................... 66
5.2.2 Dipole Shaped Particle .......................... 68
5.2.3 Ellipsoid Shaped Particle ....................... 70
5.3 Mie Scattering ......................................... 72
5.3.1 Sphere Shaped Particle .......................... 73
5.3.2 Dipole Shaped Particle .......................... 73
5.3.3 Ellipsoid Shaped Particle ....................... 74
5.4 Coherency Matrix for a Cloud of Particles .............. 75
6 Multiple Scattering (Dihedral Backscattering) ............... 79
6.1 Sphere Shaped Particles ................................ 80
6.2 Dipole Shaped Particles ................................ 82
6.2.1 Short Dipole .................................... 84
6.2.2 Long Dipole ..................................... 86
6.3 Ellipsoid Shaped Particles ............................. 88
6.4 Coherency Matrix for a Dihedral of a Cloud of
Particles and a Subsurface ............................. 91
7 Two-Layer Structure Ice-Subsurface .......................... 95
7.1 Model equation ......................................... 96
7.2 Scenario Simulation .................................... 97
7.2.1 Combination of Volume and Dihedral
Backscattering .................................. 98
7.2.2 Subsurface, Volume and Dihedral
Backscattering Combination ..................... 100
7.3 Data Interpretation ................................... 103
7.3.1 Churchill site ................................. 103
7.3.2 Baker Lake site ................................ 106
7.3.3 Inuvik site .................................... 111
7.3.4 Lena Delta site ................................ 115
7.4 Data Representation ................................... 118
7.4.1 Churchill site ................................. 120
7.4.2 Baker Lake site ................................ 126
7.4.3 Inuvik site .................................... 127
7.4.4 Lena Delta site ................................ 128
8 Conclusion ................................................. 131
Bibliography ............................................... 137
A Nomenclature ................................................ 149
В Derivation of the dipole scattering matrix .................. 153
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