Mass balance of four East Antarctic outlet glaciers

Abstract

The East Antarctic ice sheet (EAIS) is Earth's largest reservoir of fresh water and has the potential to raise sea level by 50 m. A significant amount of the ice sheet's mass is discharged by outlet glaciers draining through the Transantarctic Mountains, the balance characteristics of which are largely unknown. Here the mass balance is estimated for four glaciers draining ice from the EAIS through the Transantarctic Mountains into the Ross Sea embayment: David, Mulock, Byrd and Nimrod glaciers. Remote-sensing observations are used to map changes in ice flow and surface elevation, and ultimately to compute the mass balance of each glacier using the input–output method and three separate estimates for accumulation rate. Results computed using this method indicate small positive balances for David (2.41±1.31 Gt a–1), Mulock (1.91±0.84 Gt a–1) and Nimrod (0.88 0.39 Gt a–1) glaciers, and a large positive imbalance for Byrd Glacier (21.67±4.04 Gt a–1). This large imbalance for Byrd Glacier is inconsistent with other observations, and is likely due to an overestimation of accumulation rates across large regions of the interior catchment.