NSFGEO-NERC: Understanding the Response to Ocean Melting for Two of East Antarctica's Most Vulnerable Glaciers: Totten, and Denman

This project focuses on Totten and Denman glaciers, East Antarctica, which are influenced by ice-shelf melting. In situ observations constraining the ocean heat content causing the melt, however, are limited. To fill this gap, the project will use Air-Launched Autonomous Micro Observer (ALAMO profilers) to telemeter back repeated hydrographic profiles near the ice-shelf fronts to complement other planned ship-based efforts in these areas. Remote sensing data will be used to provide updated and improved estimates of the melt rate for each shelf. The combined melt and oceanographic data will be used to constrain parameterized transfer functions for cavity melting in response to ocean temperature, improving on current parametrizations based on limited data. These melt functions will be used with ocean temperatures from climate models to force a basin-scale, open-source ice-flow model to determine the century-scale response for a variety of scenarios, helping to reduce uncertainty in sea level contributions from this part of Antarctica. Processes other than melt that might further alter the response will also be examined. For example, as flow speed increases, damage to ice-shelf shear margins increases, potentially introducing a positive feedback. Another potential factor is reductions in ice-shelf extent that decrease buttressing and increase ice loss. To investigate these processes, numerical experiments using varying degrees of damage and ice-shelf loss will help determine the extent to which these factors might further increase sea level. Through the air-deployment of float profilers from a sonobuoy launch tube in polar settings, a long-term impact of the project will be to raise the technology readiness of operational in-situ monitoring of the rapidly changing polar shelf seas, paving the way for a transformative expansion of observations of ocean hydrographic properties from remote areas that currently are understood poorly.