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SUMMARY:Hartmut Hellmer (Alfred Wegener Institute)
DTSTART:20210505T130000Z
DTEND:20210505T140000Z
DTSTAMP:20260423T021421Z
UID:BAS-PO/16
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/BAS-PO/16/">
 From Models to Observations: A Case Study for the Filchner-Ronne Ice Shelf
 </a>\nby Hartmut Hellmer (Alfred Wegener Institute) as part of BAS Polar O
 ceans Seminar\n\n\nAbstract\nWarm water of open ocean origin on the contin
 ental shelf of Amundsen and Bellingshausen Seas drives the highest basal m
 elt rates reported for Antarctic ice shelves. This has severe consequences
  for ice shelf/ice sheet dynamics and the mass balance of the Antarctic Ic
 e Sheet. Ice shelves fringing the broad continental shelf in Weddell and R
 oss Seas melt at rates orders of magnitude smaller. However\, simulations 
 using coupled ice–ocean models forced with the atmospheric output of the
  HadCM3 SRES-A1B scenario run indicate that the circulation in the souther
 n Weddell Sea might change during the 21st century. As elaborated by addit
 ional sensitivity studies\, certain environmental settings support the flo
 w of Circumpolar Deep Water derivatives southward underneath the Filchner
 –Ronne Ice Shelf\, warming the cavity and intensifying basal melting. Th
 e results also identify a tipping point in the southern Weddell Sea: a pos
 itive melt water feedback enhances the shelf circulation and the onshore t
 ransport of open ocean heat. Motivated by the model results\, the Alfred W
 egener Institute in collaboration with the British Antarctic Survey and No
 rwegian Research Centre participated in two projects (FISP and FISS) focus
 ed on the investigation of the Filchner-Ronne Ice Shelf (FRIS) cavity and 
 the southern Weddell Sea continental shelf. Here\, I combine the results f
 rom data of four moorings operating beneath FRIS with the most recent surv
 ey (PS111-2018) along the FRIS front and across the Filchner Trough\, comp
 lemented by mooring data recovered during the PS124-2021 COSMUS cruise. It
  turns out that wide-ranging atmospheric teleconnections influence sea ice
  and thus dense water formation in the southern Weddell Sea on interannual
  time scales. The shelf process (a) controls the cavity circulation\, (b) 
 causes mode shifts underneath the northern Filchner Ice Shelf\, and (c) de
 termines the strength of the density barrier at the continental shelf brea
 k\, thereby affecting the onshore flow of warmer waters. This suggests tha
 t keeping an eye on the large-scale atmospheric conditions in the Southern
  Ocean might be one (easy) way to infer changes in the northern Filchner T
 rough.\n
LOCATION:https://researchseminars.org/talk/BAS-PO/16/
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