Research ArticleGEOLOGY

Heterogeneous retreat and ice melt of Thwaites Glacier, West Antarctica

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Science Advances  30 Jan 2019:
Vol. 5, no. 1, eaau3433
DOI: 10.1126/sciadv.aau3433
  • Fig. 1 Thwaites Glacier, West Antarctica.

    (A) Map of Antarctica with Thwaites Glacier (red box). (B) Shaded-relief bed topography (blue) with 50-m contour levels (white) (16), grounding lines color-coded from 1992 to 2017, and retreat rates for 1992–2011 (green circle) versus 2011–2017 (red circle) in kilometer per year. Thick yellow arrows indicate CDW pathways (32). White boxes indicate outline of figs. S1 and S2 (C) DInSAR data for 11 to 12 and 27 to 28 April 2016, with grounding lines in 2011, 2016, and 2017 showing vertical displacement, dz, in 17-mm increments color-coded from purple to green, yellow, red, and purple again. Points A to F are used in Fig. 2. (D) Height of the ice surface above flotation, hf, in meters. (E) Change in ice surface elevation, dh, between decimal years 2013.5 and 2016.66 color-coded from red (lowering) to blue (rising). (F) Ice surface speed in 2016–2017 color-coded from brown (low) to green, purple, and red (greater than 2.5 km/year), with contour levels of 200 m/year in dotted black.

  • Fig. 2 Changes in ice surface elevation, h, of Thwaites Glacier.

    (A to F) from TDX data (blue dots) for the time period 2011–2017 over grounded ice (red domain, dh/dt) at locations A to F, with height above floatation, hf (red lines), and 1σ uncertainty (dashed red lines), converted into change in ice thickness, H, over floating ice (blue domain, dH/dt) in meters per year. Black triangles are TDX dates in (G) to (J). (G and H) Main trunk. (I and J) TEIS. Grounding line position is thin black for 2016–2017 and white dashed blue for 2011.

  • Fig. 3 Ice thickness change of Thwaites Glacier.

    (A) Ice surface elevation from Airborne Topographic Mapper and ice bottom from MCoRDS radar depth sounder in 2011, 2014, and 2016, color-coded green, blue, and brown, respectively, along profiles T1-T2 and (B) T3-T4 with bed elevation (brown) from (16). Grounding line positions deduced from the MCoRDS data are marked with arrows, with the same color coding. (C) Change in TDX ice surface elevation, h, from June 2011 to 2017, with 50-m contour line in bed elevation and tick marks every 1 km.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/1/eaau3433/DC1

    Table S1. Tidal corrections used with the Lagrangian framework to calculate ice shelf melt rate, derived using the CATS tidal model at the time of passage of the TDX satellites.

    Fig. S1. CSK DInSAR data over the main trunk of Thwaites Glacier.

    Fig. S2. CSK DInSAR data of the TEIS.

    Fig. S3. Speed map over Thwaites Glacier.

    Fig. S4. TDX surface deformation accuracy analysis.

    Fig. S5.TDX inferred thickness change accuracy analysis.

    Fig. S6. Relationship between ice shelf melt rate and the ice shelf draft slope.

    Fig. S7. Annual ice shelf melt rates.

    Movie S1. TDX time series of surface elevation.

    Movie S2. TDX time series of changes in height above flotation.

  • Supplementary Materials

    The PDF file includes:

    • Table S1. Tidal corrections used with the Lagrangian framework to calculate ice shelf melt rate, derived using the CATS tidal model at the time of passage of the TDX satellites.
    • Fig. S1. CSK DInSAR data over the main trunk of Thwaites Glacier.
    • Fig. S2. CSK DInSAR data of the TEIS.
    • Fig. S3. Speed map over Thwaites Glacier.
    • Fig. S4. TDX surface deformation accuracy analysis.
    • Fig. S5.TDX inferred thickness change accuracy analysis.
    • Fig. S6. Relationship between ice shelf melt rate and the ice shelf draft slope.
    • Fig. S7. Annual ice shelf melt rates.
    • Legends for movies S1 and S2

    Download PDF

    Other Supplementary Material for this manuscript includes the following:

    • Movie S1 (.mov format). TDX time series of surface elevation.
    • Movie S2 (.mov format). TDX time series of changes in height above flotation.

    Files in this Data Supplement:

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