Physical and mechanical properties of winter first-year ice in the Antarctic marginal ice zone along the Good Hope Line

• Main Authors: Skatulla, Sebastian, Audh, Riesna R., Cook, Andrea, Hepworth, Ehlke, Johnson, Siobhan, Lupascu, Doru C., MacHutchon, Keith, Marquart, Rutger, Mielke, Tommy, Omatuku, Emmanuel, Paul, Felix, Rampai, Tokoloho, Schröder, Jörg, Schwarz, Carina, Vichi, Marcello
• Format: Text
• Language: English
• Published: 2021
• Subjects: Antarctic; Pancake; Southern Ocean; The Antarctic; Antarc*
• Online Access: https://doi.org/10.5194/tc-2021-209; https://tc.copernicus.org/preprints/tc-2021-209/

As part of the 2019 Southern oCean seAsonal Experiment (SCALE) Winter Cruise of the South African icebreaker SA Agulhas II first-year ice was sampled at the advancing outer edge of the Antarctic marginal ice zone along a 150 km-Good Hope Line transect. Ice cores were extracted from four solitary pancake ice floes of 1.83–2.95 m diameter and 0.37–0.45 m thickness as well as a 12 × 4 m 2 pancake ice floe of 0.31–0.76 m thickness part of a larger consolidated pack ice domain. The ice cores were subsequently analyzed for temperature, salinity, texture, anisotropic elastic properties and compressive strength. All ice cores from both, solitary pancake ice floes and consolidated pack ice, exhibited predominantly granular textures. The vertical distributions of salinity, brine volume and mechanical properties were significantly different for the two ice types. High salinity values of 12.6 ± 4.9 PSU were found at the topmost layer of the solitary pancake ice floes but not for the consolidated pack ice. The uniaxial compressive strength for pancake ice and consolidated pack ice were determined as 2.3 ± 0.5 MPa and 4.1 ± 0.9 MPa, respectively. The Young’s and shear moduli in longitudinal core direction of solitary pancake ice were obtained as 3.7 ± 2.0 GPa and 1.3 ± 0.7 GPa, and for consolidated pack ice as 6.4 ± 1.6 GPa and 2.3 ± 0.6 GPa, respectively. Comparing Young’s and shear moduli measured in longitudinal and transverse core directions, a clear directional dependency was found, in particular for the consolidated pack ice.