The role of ice streams in a coupled ice flow-ocean modeling approach at the Filchner-Ronne Ice Shelf, Antarctica

• Main Authors: Goeller, Sebastian, Determann, Jürgen, Timmermann, Ralph, Thoma, Malte
• Format: Conference Object
• Language: unknown
• Published: 2014
• Subjects: Antarc*; Antarctic; Antarctica; Filchner Ronne Ice Shelf; Filchner-Ronne Ice Shelf; Ice Sheet; Ice Shelf; Ice Shelves; Ronne Ice Shelf; Southern Ocean
• Online Access: https://epic.awi.de/id/eprint/35848/; https://epic.awi.de/id/eprint/35848/1/TitlePage_Talk_FRISP_Workshop_2014_Cologne.pdf; https://hdl.handle.net/10013/epic.43781; https://hdl.handle.net/10013/epic.43781.d001

The ice flow at the margins of the Antarctic Ice Sheet (AIS) is moderated by large ice shelves. Their buttressing effect substantially controls the mass balance of the AIS and thus its contribution to sea level rise. Recent results of ocean circulation models indicate that warm circumpolar water of the Southern Ocean may override the continental slope front and boost basal ice shelf melting. In particular, simulations demonstrate the redirection of a warm coastal current into the Filchner Trough and underneath the Filchner-Ronne Ice Shelf (FRIS) within the next decades. The increase of water temperature in the sub-shelf cavity is estimated to dramatically raise the basal shelf melting. Coupled simulations with a finite elements ocean model and a three-dimensional thermomechanical ice flow model reveal that the consequent thinning of the FRIS would lead to an extensive grounding line retreat associated with a vast mass loss of the AIS. In this subsequent study, we aim for an enhanced understanding of the complex feedbacks between ocean circulation and ice dynamics of the grounded AIS. Therefor, we focus on the ice streams which are draining into the FRIS and dominating the mass transport from grounded to floating ice. For a better representation of these fast-flowing ice streams we expand the above ice flow model by the incorporation of local processes at the ice base. There, sediment deformation and lubrication by subglacial hydrology locally allow high basal sliding rates and thus create the precondition for the development of ice streams. Based on satellite-observed ice surface velocity patterns we identify such areas with low basal drag and parametrize the ice flow model accordingly. As a result, the modeled ice flow patterns will depict velocity and locations of observed ice streams in the catchment of the FRIS more realistically. We present first results of this advanced ice-flow modeling approach, anticipating an even larger response of the AIS on increased sub-shelf melting rates in future coupled ...