Bathymetric and subglacial hydrological context for the basal melting of Antarctic ice shelves

Date

2021-12-02

Authors

Wei, Wei, Ph. D.

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Abstract

Today, Antarctica holds a 58 m (190 ft) sea level potential locked in its grounded ice. Ice shelves serve as a gatekeeper to this grounded ice. However, sea level is currently rising at an alarming rate, ultimately endangering lives and economies all over the world. To accurately project the future sea level in an ever-changing climate requires a deeper understanding of how ice shelves respond to environmental changes. Hence, this dissertation seeks to further our understanding of the ice-ocean-interaction process by investigating the mechanisms causing ice shelf changes and the sensitivity of ice shelves to changes in their oceanic environment. To achieve this, a combination of observation and modeling approaches are deployed. We provide the bathymetric and subglacial discharge context for two significant ice shelves, Getz Ice Shelf in West Antarctica and West Ice Shelf in East Antarctica. Getz Ice Shelf is the largest meltwater source from Antarctica to the Southern Ocean, highlighting a need to understand what factors control its melt rate. West Ice Shelf was the least-sampled ice shelf in East Antarctica and potentially sensitive to subglacial discharge forcing. For both regions, we show in this work that subglacial discharge plays a significant role in controlling the basal melt rate. In particular, the melt rate of West Ice Shelf is primarily controlled by sub-glacial discharges. We also infer the bathymetry beneath the two ice shelves from airborne geophysical data, from which we gain first insights on the potential pathways of the Circumpolar Deep Water, which is believed to intrude into the cavity beneath the ice shelf and drive the high basal melt rates at depth. Moreover, we demonstrate the importance of accurate and high-resolution ocean bathymetry for determining modified Circumpolar Deep Water pathways and ice shelf melt rates

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