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Benjamin Smith

Principal Physicist

Affiliate Associate Professor, Earth and Space Sciences





Department Affiliation

Polar Science Center


B.S. Physics, University of Chicago, 1997

M.S. Geology & Geophysics, University of Wisconsin - Madison, 1999

Ph.D. Earth & Space Sciences/Geophysics, University of Washington - Seattle, 2005


2000-present and while at APL-UW

Ice-shelf retreat drives recent Pine Island Glacier speedup

Joughin, I., D. Shapero, B. Smith, P. Dutrieux, and M. Barham, "Ice-shelf retreat drives recent Pine Island Glacier speedup," Sci. Adv., 7, doi:10.1126/sciadv.abg3080, 2021.

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11 Jun 2021

Speedup of Pine Island Glacier over the past several decades has made it Antarctica's largest contributor to sea-level rise. The past speedup is largely due to grounding-line retreat in response to ocean-induced thinning that reduced ice-shelf buttressing. While speeds remained fairly steady from 2009 to late 2017, our Copernicus Sentinel 1A/B-derived velocity data show a >12% speedup over the past 3 years, coincident with a 19-km retreat of the ice shelf. We use an ice-flow model to simulate this loss, finding that accelerated calving can explain the recent speedup, independent of the grounding-line, melt-driven processes responsible for past speedups. If the ice shelf’s rapid retreat continues, it could further destabilize the glacier far sooner than would be expected due to surface- or ocean-melting processes.

Comparisons of satellite and airborne altimetry with ground-based data from the interior of the Antarctic ice sheet

Brunt, K.M., B.E. Smith, T.C. Sutterly, N.T. Kurtz, and T.A. Neumann, "Comparisons of satellite and airborne altimetry with ground-based data from the interior of the Antarctic ice sheet," Geophys. Res. Lett., 48, doi:10.1029/2020GL090572, 2021.

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28 Jan 2021

A series of traverses has been conducted for validation of the National Aeronautics and Space Administration Ice, Cloud, and land Elevation Satellite 2 (ICESat‐2) on the flat interior of the Antarctic ice sheet. Global Navigation Satellite System data collected on three separate 88S Traverses intersect 20% of the ICESat‐2 reference ground tracks and have precisions of better than ±7 cm and biases of less than ~4 cm. Data from these traverses were used to assess heights from ICESat‐2, CryoSat‐2, and Airborne Topographic Mapper (ATM). ICESat‐2 heights have better than ±3.3 cm bias and better than ±7.2 cm precision. ATM heights have better than 9.3 cm bias and better than ±9.6 cm precision. CryoSat‐2 heights have –38.9 cm of bias and ±47.3 cm precision. These best case results are from the flat ice‐sheet interior but provide a characterization of the quality of satellite and airborne altimetry.

Brief communication: Heterogenous thinning and subglacial lake activity on Thwaites Glacier, West Antarctica

Hoffman, A.O., K. Christianson, D. Shapero, B.E. Smith, and I. Joughin, "Brief communication: Heterogenous thinning and subglacial lake activity on Thwaites Glacier, West Antarctica," Cryosphere, 14, 4603-4609, doi:10.5194/tc-14-4603-2020, 2020.

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18 Dec 2020

A system of subglacial lakes drained on Thwaites Glacier from 2012-2014. To improve coverage for subsequent drainage events, we extended the elevation and icevelocity time series on Thwaites Glacier through austral winter 2019. These new observations document a second drainage cycle in 2017/18 and identified two new lake systems located in the western tributaries of Thwaites and Haynes glaciers. In situ and satellite velocity observations show temporary < 3% speed fluctuations associated with lake drainages. In agreement with previous studies, these observations suggest that active subglacial hydrology has little influence on thinning and retreat of Thwaites Glacier on decadal to centennial timescales.

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In The News

Edge of Pine Island Glacier’s ice shelf is ripping apart, causing key Antarctic glacier to gain speed

UW News, Hannah Hickey

For decades, the ice shelf helping to hold back one of the fastest-moving glaciers in Antarctica has gradually thinned. Analysis of satellite images reveals a more dramatic process in recent years: From 2017 to 2020, large icebergs at the ice shelf’s edge broke off, and the glacier sped up.

11 Jun 2021

Shrinking ice sheets lifted global sea level 14 millimeters

Eos (American Geophysical Union), Tim Hornyak

Researchers measure both grounded and floating ice sheets using satellite data spanning a 16-year period.

15 May 2020

NASA: 318 gigatons of ice are melting in Antarctica and Greenland each year

Tech Times, Giuliano J.

The results of a new study reveal that the ice sheet in Antarctica's interior is getting thicker because of increased snowfall. However, the warming of the ocean has also caused ice meltdowns in the Antarctic Peninsula and West Antarctica, which outweigh the gains in the interior.

3 May 2020

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