LIST OF FIGURES
PAGE
Figures follow at the end of each chapter.
Figure 1.1: Site maps ..................................................................................... 7
Figure 3.1: The electromagnetic spectrum ..................................................... 13
Figure 3.2: Operating principle of a SAR ...................................................... 15
Figure 3.3: Real antenna positions forming a synthetic aperture ................... 17
Figure 3.4: Effect of pulse length ..................................................................19
Figure 3.5: Slant and ground range ................................................................ 22
Figure 3.6: SAR geometric distortions .......................................................... 22
Figure 3.7: Diffuse, specular, corner, and volume reflection ........................ 24
Figure 3.8: Benson's generalized cross-section of glacier facies ................... 34
Figure 4.1: ERS-2 and Radarsat look angles ................................................. 38
Figure 4.2: Optical depth vs. actual depth ..................................................... 38
Figure 4.3: Snow stakes on Commonwealth and Howard Glaciers............... 39
Figure 4.4: Digital Elevation Model (DEM) of Southern Victoria Land .......43
Figure 4.5: Ray diagrams of the reflections in a dihedral and a triangular
trihedral corner reflector ........................................................ 45
Figure 4.6: Inclination angle .......................................................................... 45
Figure 4.7: A trihedral corner reflector .......................................................... 47
Figure 4.8: Ice surface roughness measured from a 2 m bar to the ice
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surface .................................................................................... 51
Figure 5.1: ERS-2 uncorrected SAR .............................................................. 54
Figure 5.2: Radarsat uncorrected SAR .......................................................... 55
Figure 5.3: The portion of Taylor Valley that was imaged by ERS-2 ........... 57
Figure 5.4: Surface characteristics along the transect on Commonwealth
Glacier .................................................................................... 59
Figure 5.5: Photographs of Commonwealth and Howard Glaciers ............... 60
Figure 5.6: Cryoconite hole ........................................................................... 61
Figure 5.7: Snow depths along the transect on Commonwealth Glacier .......63
Figure 5.8: Sky and Water I ........................................................................... 63
Figure 5.9: Snow stakes, radar reflectors, transect route, and sample
sites on Commonwealth Glacier ............................................ 63
Figure 5.10: Snow layers graph .....................................................................64
Figure 5.11: Averaged snow depths along the transect on Howard Glacier ..66
Figure 6.1: Effect of a SAR beam scattering off specular surfaces of
different incidence angles ...................................................... 70
Figure 6.2: Intermediate Terrcorr images of Commonwealth Glacier ........... 73
Figure 6.3: Auto and un-corrected ERS-2 SAR of Commonwealth Glacier .74
Figure 6.4: Terrain and un-terrain corrected Radarsat ScanSAR .................. 76
Figure 6.5: ERS-2 terrain corrected SAR ...................................................... 77
Figure 6.6: Radarsat terrain corrected SAR ................................................... 79
Figure 6.7: Auto- and manual-correlation terrain correction of
Commonwealth Glacier and surrounding area ...................... 82
Figure 6.8: ERS-2 SAR of Commonwealth Glacier and surrounding area ...86
Figure 6.9: Slope and elevations (from DEM) of Commonwealth Glacier ...87
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Figure 6.10: ERS-2 SAR of Commonwealth Glacier with elevation
contours .................................................................................. 88
Figure 6.11: Manually-correlated and uncorrected ERS-2 SAR of
Commonwealth Glacier ......................................................... 90
Figure 6.12: Terrain and un-corrected Radarsat ScanSAR of Howard
Glacier .................................................................................... 94
Figure 6.13: SAR local incidence angles ....................................................... 95
Figure 7.1: Corrected SAR brightness and surface measurements along
the transect ............................................................................. 98
Figure 7.2: SAR image brightness relative to surface elevation .................... 99
Figure 7.3: Commonwealth Glacier ERS-2 SAR 1/15/1999 snow
measurement locations ........................................................... 99
Figure 7.4: ERS-2 brightness to snow depth graph .......................................100
Figure 7.5: Commonwealth Glacier ERS-2 SAR snowline classification
maps ....................................................................................... 102
Figure 7.6: Comparison of Commonwealth Glacier ......................................105
Figure 7.7: Detail of snowline on Commonwealth Glacier ERS-2 SAR .......108
Figure 7.8: Enhanced volume backscatter ..................................................... 111
Figure 7.9: Commonwealth Glacier snow stratigraphy .................................112
Figure 7.10: Reflections and primary refractions of the SAR beam at
stake 12 .................................................................................. 115
Figure 7.11: Uncorrected brightness comparison (along the transect)
between Radarsat and ERS-2 ................................................. 118
Figure 7.12: Terrain corrected SAR image transect locations ....................... 119
Figure 7.13: Comparison of corrected and uncorrected brightness values
x
along the transect ...................................................................120
Figure 7.14: Corrected brightness comparison (along the transect)
between Radarsat and ERS-2 ................................................. 122
Figure 7.15: Howard Glacier snow layers graph ........................................... 125
Figure 7.16: Landsat and Radarsat comparison of Howard Glacier
snowline ................................................................................. 127
Figure 7.17: Six SAR views of Commonwealth Glacier ............................... 129
Figure 7.18: The terminus of Canada Glacier as represented by six
SAR images ........................................................................... 131
Figure 7.19: Aerial photo of Canada Glacier taken November 1993 ............ 132
Figure 7.20: Images of Taylor Glacier ........................................................... 134
Figure 7.21: Ripples on the upper Taylor Glacier as represented by four
SAR images and one Landsat ................................................ 135
Figure 7.22: Lower Taylor Glacier as represented by five SAR images........ 136
Figure 7.23: Radarsat ScanSAR image transect of the centerline of
Taylor Glacier ........................................................................ 137
Figure 7.24: Comparison of backscatter of lake surfaces by season.............. 139