Identifying flowlines and limitations of flux analyses in the interior of Thwaites Glacier, Antarctica

T. J. Fudge, H. Conway, G. Catania, D. D. Blankenship, K. Christianson, I. Joughin, B. Smith, S. D. Kempf, D. A. Young, S. Anandakrishnan

Research output: Contribution to journalArticle

Abstract

Patterns in radar-detected internal layers in glaciers and ice streams can be tracked hundreds of kilometers downstream. We use distinctive patterns to delineate flowbands of Thwaites Glacier in the Amundsen Sea sector of West Antarctica. Flowbands contain information for the past century to millennium, the approximate time for ice to flow through the study region. GPS-detected flow directions (acquired in 2007/08) agree within uncertainty (̃48) with the radar-detected flowlines, indicating that the flow direction has not changed significantly in recent centuries. In contrast, InSARdetected directions (from 1996) differ from the radar- and GPS-detected flowlines in all but the middle tributary, indicating caution is needed when using InSAR velocities to define flow directions. There is agreement between all three datasets in the middle tributary. We use two radar-detected flowlines to define a 95km long flowband and perform a flux balance analysis using InSAR-derived velocities, radardetected ice thickness, and estimates of the accumulation rate. Inferred thinning of 0.49±0.34ma-1 is consistent with satellite altimetry measurements, but has higher uncertainty due mainly to the velocity uncertainty. The uncertainty is underestimated because InSAR velocities often differ from GPS velocities by more than the stated uncertainties.

Original languageEnglish (US)
Pages (from-to)107-114
Number of pages8
JournalAnnals of Glaciology
Volume55
Issue number67
DOIs
StatePublished - Jul 2014

All Science Journal Classification (ASJC) codes

  • Earth-Surface Processes

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    Fudge, T. J., Conway, H., Catania, G., Blankenship, D. D., Christianson, K., Joughin, I., Smith, B., Kempf, S. D., Young, D. A., & Anandakrishnan, S. (2014). Identifying flowlines and limitations of flux analyses in the interior of Thwaites Glacier, Antarctica. Annals of Glaciology, 55(67), 107-114. https://doi.org/10.3189/2014AoG67A033