Sustained increase in ice discharge from the Amundsen Sea Embayment, West Antarctica, from 1973 to 2013

J Mouginot,E Rignot,B Scheuchl

doi:10.1002/2013gl059069

J Mouginot, E Rignot + Show 1 more

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https://doi.org/10.1002/2013gl059069

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Abstract

We combine measurements of ice velocity from Landsat feature tracking and satellite radar interferometry, and ice thickness from existing compilations to document 41 years of mass flux from the Amundsen Sea Embayment (ASE) of West Antarctica. The total ice discharge has increased by 77% since 1973. Half of the increase occurred between 2003 and 2009. Grounding‐line ice speeds of Pine Island Glacier stabilized between 2009 and 2013, following a decade of rapid acceleration, but that acceleration reached far inland and occurred at a rate faster than predicted by advective processes. Flow speeds across Thwaites Glacier increased rapidly after 2006, following a decade of near‐stability, leading to a 33% increase in flux between 2006 and 2013. Haynes, Smith, Pope, and Kohler Glaciers all accelerated during the entire study period. The sustained increase in ice discharge is a possible indicator of the development of a marine ice sheet instability in this part of Antarctica.

Highlights

Pine Island, Thwaites, Haynes, Smith, Pope, and Kohler Glaciers are among the fastest-flowing glaciers in continental Antarctica [Rignot et al, 2011b]
Pine Island Glacier is 30 km wide at the grounding line, fed by nine tributaries, and developing a 55 km long floating section that flowed at 4 km/yr in 2006
Thwaites Glacier is 120 km wide, with a 60 km wide fast-moving section that develops into the Thwaites Glacier Tongue to the west and a 60 km wide slower-moving section that flows into an ice shelf buttressed by ice rumples to the east, the Thwaites Eastern Ice Shelf (TEIS), an unofficial name

Summary

Introduction

Pine Island, Thwaites, Haynes, Smith, Pope, and Kohler Glaciers are among the fastest-flowing glaciers in continental Antarctica [Rignot et al, 2011b]. Combined together, they drain one third of the West Antarctic Ice Sheet into the Amundsen Sea Embayment (ASE), or 393 million square kilometers. The ASE glaciers are major contributors to sea level rise from Antarctica with about 0.28 ± 0.05 mm/yr between 2005 and 2010 [Shepherd et al, 2012], which itself amounts to about 10% of the global sea level rise (3 mm/yr) [Church and White, 2011]. These glaciers and their catchment basins combined contain 1.2 m global sea level rise

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