Estimation of erosion, deposition, and net volumetric change caused by the 1996 Skeidararsandur joekulhlaup, Iceland, from synthetic aperture radar interferometry

• Published in: Water resources research 2000-06, Vol.36 (6), p.1583-1594
• Main Authors: Smith, L C, Alsdorf, DE, Magilligan, F J, Gomez, B, Mertes, LAK, Smith, N D, Garvin, J B
• Format: Article
• Language: English
• Subjects: Iceland
• ISSN: 0043-1397

Using repeat-pass satellite synthetic aperture radar interferometry, we develop a methodology to measure flood-induced erosion and deposition and apply it to a record 1996 glacier outburst flood (joekulhlaup) on Skeidararsandur, Iceland. The procedures include (1) coregistration of backscatter intensity images to observe morphological differences; (2) mapping of interferometric phase correlation to identify preserved and modified surfaces; and (3) construction, correction, and differencing of pre-joekulhlaup and post-joekulhlaup topography. Procedures 1 and 2 are robust and should be widely applicable to other fluvial environments, while procedure 3 is complicated by uncertainties in phase measurement, baseline estimate, and atmospheric effects. After a correction procedure involving interpolation of digital elevation model elevation differences across low-correlation areas, we find similar to 4 m of elevation change are required to calculate volumes of erosion or deposition. This condition was satisfied for the 40 km super(2) proglacial zone of Skeidararsandur, where we estimate +38 x 10 super(6) m super(3) of net sediment deposition along the ice margin, -25 x 10 super(6) m super(3) of net erosion in channels downstream, and a total net balance of +13 x 10 super(6). These estimates are supported by field observations and survey data collected in 1997.