Higher Antarctic ice sheet accumulation and surface melt rates revealed at 2 km resolution

• Published in: Nature Communications
• Main Authors: Brice Noël, J. Melchior van Wessem, Bert Wouters, Luke Trusel, Stef Lhermitte, Michiel R. van den Broeke
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Portfolio 2023
• Subjects: Science; Q; Antarctic; Antarc*; Ice Sheet; Ice Shelf
• Online Access: https://doi.org/10.1038/s41467-023-43584-6; https://doaj.org/article/fb381f15ae3946148b8b22bebeafe5e3

Abstract Antarctic ice sheet (AIS) mass loss is predominantly driven by increased solid ice discharge, but its variability is governed by surface processes. Snowfall fluctuations control the surface mass balance (SMB) of the grounded AIS, while meltwater ponding can trigger ice shelf collapse potentially accelerating discharge. Surface processes are essential to quantify AIS mass change, but remain poorly represented in climate models typically running at 25-100 km resolution. Here we present SMB and surface melt products statistically downscaled to 2 km resolution for the contemporary climate (1979-2021) and low, moderate and high-end warming scenarios until 2100. We show that statistical downscaling modestly enhances contemporary SMB (3%), which is sufficient to reconcile modelled and satellite mass change. Furthermore, melt strongly increases (46%), notably near the grounding line, in better agreement with in-situ and satellite records. The melt increase persists by 2100 in all warming scenarios, revealing higher surface melt rates than previously estimated.