Assessing Uncertainties in Mass Balance Estimation Using the Input-Output Method: A Case Study Around the Wilkes Land

Abstract. Accurate assessment of Antarctic mass balance is essential for understanding and projecting sea-level rise. In this study, we assess the uncertainties in mass balance estimates using the input–output method in Wilkes Land, East Antarctica, with a focus on Basin 13. We developed a new flux gate product based on enhanced radar echo sounding (RES) coverage from Bedmap1, Bedmap2, and Bedmap3, enabling placement closer to the grounding line and reducing spatial bias. Using five different ice thickness datasets (Bedmap2, Bedmap3, BedMachineV2, BedMachineV3, and RES-derived thickness) along with velocity maps from 1995 to 2022, we calculate ice discharge and quantified the associated uncertainties. The results show that the improved flux gate and high-accuracy thickness data reduced discharge uncertainty from 53% to 4%. Approximately 42% of this reduction was due to improved thickness data, while about 7% resulted from the use of higher-quality velocity datasets. These findings highlight the essential role of accurate flux gate placement and reliable thickness data in reducing uncertainties in input–output-based Antarctic mass balance estimates.