Remote Control of Filchner-Ronne Ice Shelf Melt Rates by the Antarctic Slope Current.
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| Title: | Remote Control of Filchner-Ronne Ice Shelf Melt Rates by the Antarctic Slope Current. |
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| Authors: | Bull, Christopher Y. S.1,2 christopher.bull@northumbria.ac.uk, Jenkins, Adrian1,2, Jourdain, Nicolas C.3, Vaňková, Irena1, Holland, Paul R.1, Mathiot, Pierre3,4, Hausmann, Ute5, Sallée, Jean-Baptiste5 |
| Source: | Journal of Geophysical Research. Oceans. Feb2021, Vol. 126 Issue 2, p1-22. 22p. |
| Subject Terms: | *Ocean currents, *Oceanography, Ice shelves |
| Geographic Terms: | Filchner Ice Shelf (Antarctica), Ronne Ice Shelf (Antarctica), Antarctica |
| Abstract: | Recent work on the Filchner-Ronne Ice Shelf (FRIS) system has shown that a redirection of the coastal current in the southeastern Weddell Sea could lead to a regime change in which an intrusion of warm Modified Circumpolar Deep Water results in large increases in the basal melt rate. Work to date has mostly focused on how increases in the Modified Circumpolar Deep Water crossing the continental shelf break leads directly to heat driven changes in melting in the ice-shelf cavity. In this study, we introduce a Weddell Sea regional ocean model configuration with static ice shelves. We evaluate a reference simulation against radar observations of melting, and find good agreement between the simulated and observed mean melt rates. We analyze 28 sensitivity experiments that simulate the influence of changes in remote water properties of the Antarctic Slope Current on basal melting in the FRIS. We find that remote changes in salinity quasi-linearly modulate the mean FRIS net melt rate. Changes in remote temperature quadratically vary the FRIS net melt rate. In both salinity and temperature perturbations, the response is rapid and transient, with a recovery time-scale of 5-15 years dependent on the size/type of perturbation. We show that the two types of perturbations lead to different changes on the continental shelf, and that ultimately different factors modulate the melt rates in the FRIS cavity. We discuss how these results, are relevant for ocean hindcast simulations, sea level, and melt rate projections of the FRIS. Plain Language Summary Ocean water temperature or the speed of ocean currents can directly influence the melt rate of the floating ice shelves at the edge of the Antarctic Ice Sheet. Ice sheet modelers use simple relationships between ocean temperature and ice-shelf melt rates to create projections of sea level rise, whereby changes in salinity are not directly considered. Here, using a model of the ocean and ice shelf for the Weddell Sea region, we re-visit these relationships in a simulated environment with realistic settings. We find that changes in far field salinity and temperature in the Antarctic Slope Current can cause changes in the Filchner-Ronne Ice Shelf melt rate; this is because both far field temperature and salinity variations have the capacity to change the strength of the ocean circulation in the ice shelf cavity. Our results suggest that future numerical simulations of this region may need to consider changes in both far field temperature and salinity. [ABSTRACT FROM AUTHOR] |
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| Database: | GreenFILE |
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