Three-dimensional reconstruction of glacier-derived freshwater in East Antarctica using an end-member-independent hydrographic parameterization.

Abstract

The melting of the Antarctic Ice Sheet contributes to global sea-level rise and widespread ocean freshening. A major driver of this process is the intrusion of warm deep water onto the continental shelf, which enhances basal melting of ice shelves and weakens their buttressing of inland ice. However, the three-dimensional distribution of glacier-derived freshwater remains poorly constrained in East Antarctica. Here we present a hybrid multiple linear regression-neural network (MLR-NN) framework that reconstructs glacier-derived freshwater from dissolved inorganic carbon (DIC) residuals without prescribing fixed freshwater end-member compositions. Applying this framework to hydrographic observations around the Totten and Moscow University Ice Shelves, we estimate freshwater discharge rates of 70 ± 7 and 53 ± 9 Gt yr⁻¹, respectively. The reconstructed freshwater signal extends across the continental shelf to approximately 64°S. We also identify differences in freshwater discharge between observations collected during the 2010s and the 2020 s, although sparse temporal sampling prevents these differences from being interpreted as a robust long-term trend. Our results provide a three-dimensional observational reconstruction of glacier-derived freshwater in this sector of East Antarctica and demonstrate the potential of an end-member-independent hydrographic parameterization for investigating glacier-ocean interactions in data-limited polar environments.