Bed topography of Jakobshavn Isbræ, Greenland, and Byrd Glacier, Antarctica

作者：S. Gogineni, J.-B. Yan, John Paden, C. Leuschen, J. Li, Fernando Rodríguez‐Morales, D. Braaten, K. Purdon, Zhen Wang, Weibo Liu, John M. Gauch · 发表于：Journal of Glaciology · 年份：2014 · DOI：10.3189/2014jog14j129 · 被引用次数：73 · 研究领域：Cryospheric studies and observations、Winter Sports Injuries and Performance、Arctic and Antarctic ice dynamics

Abstract This paper presents the bed topography of Jakobshavn Isbræ, Greenland, and Byrd Glacier, Antarctica, derived from sounding these glaciers with high-sensitivity radars. To understand the processes causing the speed-up and retreat of outlet glaciers, and to enable the development of next-generation ice-sheet models, we need information on bed topography and basal conditions. To this end, we performed measurements with the progressively improved Multichannel Coherent Radar Depth Sounder/Imager (MCoRDS/I). We processed the data from each antenna-array element using synthetic aperture radar algorithms to improve radar sensitivity and reduce along-track surface clutter. We then applied array and image-processing algorithms to extract the weak bed echoes buried in off-vertical scatter (cross-track surface clutter). At Jakobshavn Isbræ, we observed 2.7 km thick ice ~30 km upstream of the calving front and ~850 m thick ice at the calving front. We also observed echoes from multiple interfaces near the bed. We applied the MUSIC algorithm to the data to derive the direction of arrival of the signals. This analysis revealed that clutter is dominated by the ice surface at Jakobshavn Isbræ. At Byrd Glacier, we found ~3.62 km thick ice, as well as a subglacial trench ~3.05 km below sea level. We used ice thickness information derived from radar data in conjunction with surface elevation data to generate bed maps for these two critical glaciers. The performance of current radars mus...