Preprints
https://doi.org/10.5194/egusphere-2023-2724
https://doi.org/10.5194/egusphere-2023-2724
06 Dec 2023
 | 06 Dec 2023

Seasonal and diurnal variability of sub-ice platelet layer thickness in McMurdo Sound from electromagnetic induction sounding

Gemma Marie Brett, Gregory Howard Leonard, Wolfgang Rack, Christian Haas, Patricia Jean Langhorne, Natalie Robinson, and Anne Irvin

Abstract. Here, we present observations of temporal variability of sub-ice platelet layer over seasonal and diurnal timescales under Ice Shelf Water-influenced fast ice in McMurdo Sound. Electromagnetic induction (EM) sounding time-series measurements of the thicknesses of fast ice and sub-ice platelet layer were made in winter and late spring of 2018. Winter objectives were to measure the seasonal growth of fast ice and sub-ice platelet layer near the McMurdo Ice Shelf in the east, while in late spring we assessed the diurnal variability of sub-ice platelet layer with coincident EM time-series and oceanographic measurements collected in the main outflow path of supercooled Ice Shelf Water in the west. During winter, we observed when the sub-ice platelet layer formed beneath consolidated ice. Episodes of rapid sub-ice platelet layer growth (~0.5–1 m) coincided with strong southerly-wind-events and polynya activity, suggesting wind-enhanced Ice Shelf Water circulation from the McMurdo-Ross Ice Shelf cavity. In late spring, we investigated how the tides and ocean properties influenced the sub-ice platelet layer. Over a two-week neap-spring tidal cycle, changes in sub-ice platelet layer thickness were observed to correlate with the tides, increasing more during neap than spring tide cycles, and on diurnal timescales, more on ebb than flood tides. Neap and ebb tides correspond with stronger northward circulation out of the cavity, indicating that sub-ice platelet layer growth was driven by tidally-enhanced Ice Shelf Water outflow. The observed variability indicated that wind-driven circulation and the tides influence Ice Shelf Water outflow in McMurdo Sound, and consequently, sub-ice platelet layer evolution over a range of timescales.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Gemma Marie Brett, Gregory Howard Leonard, Wolfgang Rack, Christian Haas, Patricia Jean Langhorne, Natalie Robinson, and Anne Irvin

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-2724', Anonymous Referee #1, 14 Jan 2024
    • AC2: 'Reply on RC1', Gemma Marie Brett, 26 Feb 2024
  • RC2: 'Comment on egusphere-2023-2724', Anonymous Referee #2, 29 Jan 2024
    • AC3: 'Reply on RC2', Gemma Marie Brett, 26 Feb 2024
  • EC1: 'Comment on egusphere-2023-2724', Jean-Louis Tison, 30 Jan 2024
    • AC1: 'Reply on EC1', Gemma Marie Brett, 26 Feb 2024

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-2724', Anonymous Referee #1, 14 Jan 2024
    • AC2: 'Reply on RC1', Gemma Marie Brett, 26 Feb 2024
  • RC2: 'Comment on egusphere-2023-2724', Anonymous Referee #2, 29 Jan 2024
    • AC3: 'Reply on RC2', Gemma Marie Brett, 26 Feb 2024
  • EC1: 'Comment on egusphere-2023-2724', Jean-Louis Tison, 30 Jan 2024
    • AC1: 'Reply on EC1', Gemma Marie Brett, 26 Feb 2024
Gemma Marie Brett, Gregory Howard Leonard, Wolfgang Rack, Christian Haas, Patricia Jean Langhorne, Natalie Robinson, and Anne Irvin

Data sets

Drill hole measurements of fast ice and sub-ice platelet layer thickness, and snow depth in McMurdo Sound - November 2018 G. M. Brett, G. H. Leonard, F. Isaacs, and N. J. Robinson https://doi.org/10.1594/PANGAEA.933050

Gemma Marie Brett, Gregory Howard Leonard, Wolfgang Rack, Christian Haas, Patricia Jean Langhorne, Natalie Robinson, and Anne Irvin

Viewed

Total article views: 393 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
274 90 29 393 15 17
  • HTML: 274
  • PDF: 90
  • XML: 29
  • Total: 393
  • BibTeX: 15
  • EndNote: 17
Views and downloads (calculated since 06 Dec 2023)
Cumulative views and downloads (calculated since 06 Dec 2023)

Viewed (geographical distribution)

Total article views: 374 (including HTML, PDF, and XML) Thereof 374 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 11 Jun 2024
Download
Short summary
Glacial meltwater with ice crystals flows from beneath ice shelves, causing thicker sea ice with sub-ice platelet layers (SIPL) beneath. Thicker sea ice and SIPL reveal where and how much meltwater is outflowing. We collected continuous measurements of sea ice and SIPL. In winter, we observed rapid SIPL growth with strong winds. In spring, SIPL grew when tides caused offshore circulation. Wind-driven and tidal circulation influence glacial meltwater outflow from ice shelf cavities.