Research ArticleGEOLOGY

Pan–ice-sheet glacier terminus change in East Antarctica reveals sensitivity of Wilkes Land to sea-ice changes

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Science Advances  06 May 2016:
Vol. 2, no. 5, e1501350
DOI: 10.1126/sciadv.1501350
  • Fig. 1 Median rate of East Antarctic outlet-glacier terminus position change in each drainage basin (red, retreat; blue, advance).

    (A to C) Data for (A) 1974–1990, (B) 1990–2000, and (C) 2000–2012. Note the anomalous retreat of outlet glaciers in Wilkes Land between 2000 and 2012. All glacier terminus position measurements are presented in database S1.

  • Fig. 2 Mean austral summer (December to February) air temperature from Casey station (red) and the entire Wilkes Land coastline (orange) (sourced from the ERA-Interim data set).
  • Fig. 3 EN4 subsurface ocean temperature.

    (A) Bed topography of Wilkes Land (from Bedmap2), with the spatial location of the EN4 data extraction on the continental shelf boundary. (B) EN4 subsurface objective analysis temperature depth profile for 1974–2012. Data were extracted from 31 grid cells between 100° and 130°E, 64°S (continental shelf boundary, Wilkes Land), with the black dashed line representing the median glacier terminus position change of outlet glaciers per epoch in Wilkes Land.

  • Fig. 4 Difference in the number of sea-ice days per year during the sea-ice season (April to October) compared to 1990–2000, with shaded drainage basins representing glacier terminus position trends (red, retreat; blue, advance).

    (A and B) Data for (A) 1974–1990 and (B) 2000–2012. Sea-ice data only extend back to 1979 (see Materials and Methods).

  • Fig. 5 Time series of winter air temperature and meridional wind flow.

    (A) Mean winter (April to October) air temperature from Casey station (red) and the entire Wilkes Land coast from the ERA-Interim data set (orange). (B) Mean monthly meridional flow on the Wilkes Land coast; positive values indicate southerly winds (south to north). (C) Mean monthly zonal flow on the Wilkes Land coast; positive values indicate westerly winds (west to east).

  • Table 1 Glacier terminus position change across the entire EAIS at each epoch.

    Results from DB16 to DB13 were obtained from a previous study (11).

    Sample1974–19901990–20002000–2012
    nMedian (m year−1)nMedian (m year−1)nMedian (m year−1)
    All glaciers254−17.833420.034217.9
    DB16187.5191.81610.9
    DB1569−3.57012.67120.6
    DB1424−43.53530.33719.4
    DB1315−49.43754.939−63.6
    DB1233−3.4408.94115.9
    DB8/DB9/DB1119−1.43414.23513.8
    DB743−38.06024.56229.1
    DB6/DB515−66.118158.72072.4
    DB418−23.62154.52149.9

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/2/5/e1501350/DC1

    fig. S1. A series of mapping figures, with digitized terminus positions (green, 1974; yellow, 1990; blue, 2000; red, 2012) and glacier ID numbers, overlain on the 2000 Landsat base image.

    fig. S2. Subsurface ocean change per meter in DB13 with uncertainty estimates (for example, Fig. 3).

    fig. S3. Mean winter (April to October) sea-ice days for 1990–2000 (for example, the reference period in Fig. 4).

    fig. S4. Schematic diagram of shelf water dynamics in Wilkes Land.

    table S1. Glacier terminus position change across each epoch.

    table S2. Wilcoxon tests for significant differences between glacier terminus position change between each epoch.

    database S1. Terminus position change measurements for all outlet glaciers in East Antarctica.

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. A series of mapping figures, with digitized terminus positions (green, 1974; yellow, 1990; blue, 2000; red, 2012) and glacier ID numbers, overlain on the 2000 Landsat base image.
    • fig. S2. Subsurface ocean change per meter in DB13 with uncertainty estimates (for example, Fig. 3).
    • fig. S3. Mean winter (April to October) sea-ice days for 1990–2000 (for example, the reference period in Fig. 4).
    • fig. S4. Schematic diagram of shelf water dynamics in Wilkes Land.
    • table S1. Glacier terminus position change across each epoch.
    • table S2. Wilcoxon tests for significant differences between glacier terminus position change between each epoch.
    • database S1. Terminus position change measurements for all outlet glaciers in East Antarctica.

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