New paper finds E. Antarctic ice shelf gaining more ice mass than previously believed

A paper published today in the Journal of Geophysical Research - Atmospheres finds the East Antarctica Fimbul ice shelf has accumulated significantly more ice mass over the past 26 years than previously believed. According to the authors, "the 26-year mean [surface ice mass balance] on the Fimbul ice shelf varies between 170 and 620 [kilograms per meter squared per year] giving a regional average value of 310 ±70 kg  [per meter squared per year]. Our measurements indicate higher long-term accumulation over large parts of the ice shelf compared to the [prior] large-scale studies."


Surface mass balance on Fimbul ice shelf, East Antarctica: comparison of field measurements and large-scale studies

Abstract:

Many challenges remain for estimating the Antarctic ice sheet surface mass balance (SMB), which represents a major uncertainty in predictions of future sea-level rise. Validating continental scale studies is hampered by the sparse distribution of in-situ data. Here we present a 26-year mean SMB of the Fimbul ice shelf in East Antarctica between 1983–2009, and recent interannual variability since 2010. We compare these data to results of large-scale SMB studies for similar time periods, obtained from regional atmospheric modeling and remote sensing. Our in-situ data include ground penetrating radar, firn cores and mass balance stakes, and provide information on both temporal and spatial scales. The 26-year mean SMB on the Fimbul ice shelf varies between 170 and 620 kg m^-2 a^-1 giving a regional average value of 310 ±70 kg m^-2 a^-1. Our measurements indicate higher long-term accumulation over large parts of the ice shelf compared to the large-scale studies. We also show that the variability of the mean annual SMB, which can be up to 90 %, can be a dominant factor in short-term estimates. The results emphasize the importance of using a combination of ground based validation data, regional climate models and remote sensing over a relevant time period in order to achieve a reliable SMB for Antarctica.

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ICESAT Data Shows Mass Gains of the Antarctic Ice Sheet Exceed Losses