The relationship between sticky spots and radar reflectivity beneath an active West Antarctic ice stream

David W. Ashmore, Robert G. Bingham, R. C. A. Hindmarsh, Hugh F. J. Corr, Ian R. Joughin

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Isolated areas of high basal drag or "sticky spots" are important and poorly understood features in the force 10 balance and dynamics of West Antarctic ice streams. Characterising sticky spots formed by thin or drying subglacial till using ice-penetrating radar is theoretically possible, as high radar bed returned power (BRP) is commonly related to an abundance of free water at the ice-bed, provided losses from englacial attenuation can be reinstated. In this study we use airborne radar data collected over Evans Ice Stream, West Antarctica by the British Antarctic Survey during the 2006/07 austral summer to extract BRP profiles and test the sensitivity of BRP to the adopted englacial attenuation corrrection. We analyse 11 20 km proles in four fast-flow areas where sticky spots have been inferred to exist, on the basis of model and surface data inversions. In the majority of profiles we note that the increase in basal drag is accompanied by a decrease in BRP and suggest that this is evidence for both the presence of a sticky spot in this location and that local variations in subglacial hydrology are responsible for its existence. A comparison is made between empirical and numerical modelling approaches for deriving englacial attenuation and our findings generally support previous studies which advocate a modelling approach.
Original languageEnglish
Pages (from-to)29-38
JournalAnnals of Glaciology
Volume55
Issue number67
DOIs
Publication statusPublished - 2014

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