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The Bjerknes Centre is a collaboration on climate research, between the University of Bergen, Uni Research, the Institute of Marine Research, Nansen Environmental and Remote Sensing Centre.

Seminar: Influences of tides, heat, and circulation on the melting of Filchner-Ronne Ice Shelf, Weddell Sea, Antarctica

Rachael Mueller from Earth & Space Research, Aqvaplan-Niva will give a talk on Friday 16 June.

Rachael Mueller

Short biography:

Rachael Mueller has been with ESR since 2006. She received her Ph.D. from Oregon State University in 2014, advised by Drs. Laurie Padman (ESR) and Eric Skyllingstad. As a NASA Earth and Space Science Fellow, she advanced research on how tides and topography influence ice shelf basal melting using the Regional Ocean Modeling System (ROMS). Her primary research focus was the Larsen-C and Filchner-Ronne Ice Shelves. She is currently funded through Akvaplan-Niva and supervised by Drs. Tore Hattermann and Laurie Padman to investigate the basal melting of the Filchner-Ronne Ice Shelves. This research is important because it helps us to better understand how changing climate will affect Antarctica's contribution to sea level rise.

Abstract:

Recent modeling studies of ocean circulation in the southern Weddell Sea, Antarctica, show an increase over this century of ocean heat influx into the cavity beneath Filchner-Ronne Ice Shelf (FRIS). This increase in ocean heat would lead to more basal melting and a modification of the FRIS ice draft. The corresponding change in cavity shape will affect the spatial distribution of tidal current speeds, which play important roles in basal melting under FRIS. This feedback between heat flux, basal melting, and tides will affect the evolution of FRIS under the influence of a changing climate. We explore the impact of these feedbacks with a three-dimensional ocean model of the southern Weddell Sea that is forced by (1) thermodynamic exchange beneath the ice shelf and (2) tides along the open boundaries. Our results show regionally-dependent feedbacks that, in some areas, substantially modify the melt rates near the grounding lines of buttressed ice streams that flow into FRIS. These feedbacks are introduced by variations in meltwater production as well as the circulation of this meltwater within the cavity; they are influenced locally by sensitivity of tidal currents to water column thickness and non-locally by changes in circulation pathways that transport an integrated history of mixing and meltwater entrainment along flow paths. This presentation highlights the influence of tides on affecting the response of FRIS to a changing climate, with a special emphasis on regional variations and feedbacks.