Browsing by Subject "Iceland"
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Item Polarimetric SAR decomposition of temperate Ice Cap Hofsjokull, central Iceland(2010-08) Minchew, Brent Morton; Buckley, Sean M.; Hensley, ScottFully-polarimetric UAVSAR data of Hofsjokull Ice Cap, central Iceland, taken in June 2009 was decomposed using Pauli-based coherent decomposition as well as Cloude and H/A/alpha eigenvector-based decomposition methods. The goals of this research were to evaluate the effect of the near-surface conditions of temperate glaciers on polarized SAR data and investigate the potential of creating a model of the radar scattering mechanisms based on the decomposed elements and local temperature. The results of this data analysis show a strong relationship between the Pauli and H/A/alpha decomposition elements and the near-surface conditions. Fitting curves to the normalized Pauli decomposition elements shows consistent trends across several spatially independent regions of the ice cap suggesting that the Pauli elements might be useful for modeling the scattering mechanisms of temperate ice with various surface conditions.Item Timeline reconstruction of Holocene jökulhlaups along the Jökulsá á Fjöllum channel, Iceland(2016-05) Wells, Greta Hoe; Luzzadder-Beach, Sheryl; Beach, Timothy P; McKinney, Daene CThe Jökulsá á Fjöllum is Iceland’s second longest river, draining from the Vatnajökull ice cap and winding for over 200 km through the eastern highlands before emptying into the Arctic Ocean. Hydrothermal activity and subglacial eruptions beneath Vatnajökull generate enormous quantities of meltwater, which can drain catastrophically in outburst floods, known as jökulhlaups. Jökulhlaups have flowed through the Jökulsá á Fjöllum channel throughout the Holocene, but intense debate exists over their timing and magnitude. While previous studies report a peak flood discharge of 0.9 x 106 m3 s-1, Howard et al. (2012) found evidence of a peak discharge of 2.2 x 107 m3 s-1, which would make this the largest known flood on Earth. This project seeks to test Howard et al.’s (2012) hypothesis and, more broadly, to reconstruct a timeline of Holocene jökulhlaups along the Jökulsá á Fjöllum. First, it reviews current literature and research on Icelandic geology and megafloods; second, it reviews and critiques previous research methods and evidence of Holocene jökulhlaups along the channel, while also presenting new geomorphologic and geochronological evidence from field work in August 2015; and finally, it sets up a framework for future research and explores unanswered questions regarding the history of Holocene jökulhlaups along the Jökulsá á Fjöllum.