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

Abstract

Abstract. 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 pancake ice floe of 0.31–0.76 m thickness that was part of a larger consolidated pack ice domain. The ice cores were subsequently analysed 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 strengths for pancake ice and consolidated pack ice were determined as 2.3±0.5 and 4.1±0.9 MPa, respectively. Young's and shear moduli in the longitudinal core direction of solitary pancake ice were obtained as 3.7±2.0 and 1.3±0.7 GPa, respectively, and of consolidated pack ice as 6.4±1.6 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.

Physical and morphological properties of first-year Antarctic sea ice in the spring marginal ice zone of the Atlantic-Indian sector

“…Samples were kept horizontal as much as possible during transport and processing to minimise brine loss. No brine loss from samples was observed (Skatulla and others, 2022). Each core was cut every 5 cm from the bottom with a band saw and melted in the dark at room temperature in sealed, airtight containers.…”

Rafting of Growing Antarctic Sea Ice Enhances In‐Ice Biogeochemical Activity in Winter

“…It is difficult to differentiate between the two by means of visual inspection; the δ 18 O of the ice is therefore used to make the distinction, with negative δ 18 O values indicative of snow ice and positive δ 18 O values indicating frazil ice (Lange et al., 1990). The YI was characterized by a granular layer at the top and a transitional layer at the bottom (Figure S4 in Supporting Information ; with all YI cores showing the same stratigraphy; Skatulla et al., 2022). Surface δ 18 O was −0.08‰ and 0.59‰ for YI‐BGC‐01 and YI‐BGC‐02, respectively, increasing with depth to 1.56‰ and 1.77‰.…”

“…Stations were selected according to floe size, ice thickness, and topography. The physical data analyzed here are a subset of the data included in Skatulla et al (2022); here, we present the data from the FYI station and only one pancake floe (pancake D; Skatulla et al, 2022) from the YI station, augmenting the physical data with new biogeochemical data from both the FYI and YI. We refer to the sea ice from station M01 (sampled on 28 July 2019; snow depth of 3.5 cm), which was characterized by open drift conditions and a combination of pancakes and frazil ice (Figure 1b), as YI and the sea ice from station M03 (sampled on 29 July 2019; snow depth of 2 cm), located on a ∼200-m-diameter cemented floe (Figure 1c), as FYI.…”

Direct Observations of Wave‐Sea Ice Interactions in the Antarctic Marginal Ice Zone

“…Initial local conditions varied between the two seasons, both in sea ice type and atmospheric variability. During the winter deployment, the sea ice field was largely composed of unconsolidated pancake ice floes, generally of 1–5 m diameter and around 40 cm thickness (Skatulla et al., 2022). Open water regions between the floes was often occupied by grease or frazil ice.…”