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Volume loss from Antarctic ice shelves is accelerating

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Science  17 Apr 2015:
Vol. 348, Issue 6232, pp. 327-331
DOI: 10.1126/science.aaa0940
  • Fig. 1 Eighteen years of change in thickness and volume of Antarctic ice shelves.

    Rates of thickness change (meters per decade) are color-coded from –25 (thinning) to +10 (thickening). Circles represent percentage of thickness lost (red) or gained (blue) in 18 years. Only significant values at the 95% confidence level are plotted (table S1). (Bottom left) Time series and polynomial fit of average volume change (cubic kilometers) from 1994 to 2012 for the West (in red) and East (in blue) Antarctic ice shelves. The black curve is the polynomial fit for All Antarctic ice shelves. We divided Antarctica into eight regions (Fig. 3), which are labeled and delimited by line segments in black. Ice-shelf perimeters are shown as a thin black line. The central circle demarcates the area not surveyed by the satellites (south of 81.5°S). Original data were interpolated for mapping purposes (percentage area surveyed of each ice shelf is provided in table S1). Background is the Landsat Image Mosaic of Antarctica (LIMA).

  • Fig. 2 Variability in the rate of Antarctic ice-shelf thickness change (meters per year).

    Maps for (columns from left to right) Filchner-Ronne, Amundsen, and Ross ice shelves (locations in the bottom right corner) showing average rate of thickness change for (rows) four consecutive 4.5-year intervals (1994–1998.5, 1998.5–2003, 2003–2007.5, and 2007.5–2012). Shorter-term rates can be higher than those from an 18-year interval. Ice-shelf perimeters are thin black lines, and the thick gray line demarcates the limit of satellite observations.

  • Fig. 3 Time series of cumulative thickness change relative to series mean for Antarctic ice-shelf regions (1994–2012).

    Time series correspond to averages for all ice-shelf data within the Antarctic regions defined in Fig. 1. Dots represent average thickness change every 3 months. Error bars are small (in many cases, smaller than the symbols themselves, thus omitted from the plots), making the interannual fluctuation shown by the dots significant. The blue curve is the long-term trend from polynomial regression with the 95% confidence band (18), and the red line shows the regression line to the segment of our data set that overlaps with the period used for a prior ICESat-based analysis (2003–2008) (5). Average rates (in meters per decade) are derived from the end points of the polynomial models.

  • Fig. 4 Evolution of the rate of thickness change in the Antarctic Peninsula.

    Instantaneous rate-of-thickness (meters per year) change for four specific times (1994, 1997, 2000, and 2008) is calculated as the derivative of the polynomial fit to the thickness-change time series. The rate increases spatially with time from north to south in the Larsen Ice Shelf (movie S1). The eastern (Weddell Sea) side of the Antarctic Peninsula (top) shows independent behavior from the western (Bellingshausen Sea) side (bottom).

Supplementary Materials

  • Volume loss from Antarctic ice shelves is accelerating

    Fernando S. Paolo, Helen A. Fricker, Laurie Padman

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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    • Materials and Methods
    • Figs. S1 to S4
    • Table S1 and S2
    • Full Reference List

    Images, Video, and Other Other Media

    Movie S1
    Animation of cumulative thinning for the West Antarctic ice shelves (1994 to 2012). Each time step corresponds to a three-month average thickness centered at the midpoint of the time interval. Each time step represents thickness loss with respect to 1994.

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