Sea ice thickness and sub-ice platelet layer thickness under fast ice were measured at regular intervals at two North-South oriented profiles and four east-west oriented profiles in McMurdo Sound, Antarctica in November 2013. Holes were drilled at regular intervals into sea ice at measurement sites about 10 km apart. The thickness was measured using measurement tapes. Snow depth on sea ice was also measured at all sites

Data of apparent ice thickness from airborne electromagnetic (AEM) surveys of fast ice in McMurdo Sound, Antarctica, carried out in Nov/Dec 2009, 2011, 2013, 2016, and 2017. Values are given for apparent thicknesses derived from both, in-phase and quadrature signals. The difference between both thicknesses is a scaled measure of sub-ice platelet layer thickness. Data are from east-west transects across McMurdo Sound, at fixed latitudes. Data were smoothed and interpolated onto a regular longitude grid (0.001 degree increments). More information can be found in: Haas, C., Langhorne, P. J., Rack, W., Leonard, G. H., Brett, G. M., Price, D., Beckers, J. F., and Gough, A. J.: Airborne mapping of the sub-ice platelet layer under fast ice in McMurdo Sound, Antarctica, The Cryosphere, 15, 247–264, https://doi.org/10.5194/tc-15-247-2021, 2021

Data of apparent ice thickness from airborne electromagnetic (AEM) surveys of fast ice in McMurdo Sound, Antarctica, carried out in Nov/Dec 2009, 2011, 2013, 2016, and 2017. Values are given for apparent thicknesses derived from both, in-phase and quadrature signals. The difference between both thicknesses is a scaled measure of sub-ice platelet layer thickness. Data are from east-west transects across McMurdo Sound, at fixed latitudes. Data were smoothed and interpolated onto a regular longitude grid (0.001 degree increments). More information can be found in Haas et al. (2021). Related Publication: Haas, C., Langhorne, P. J., Rack, W., Leonard, G. H., Brett, G. M., Price, D., Beckers, J. F., and Gough, A. J.: Airborne mapping of the sub-ice platelet layer under fast ice in McMurdo Sound, Antarctica, The Cryosphere, 15, 247–264, https://doi.org/10.5194/tc-15-247-2021, 2021

The thicknesses of sea ice and sub-ice platelet layer were measured at regular intervals on fast ice in McMurdo Sound, Antarctica in November and December of 2011. Thirty-metre cross-profiles were established at each site, and snow depths were measured at 0.5 m intervals along the transect lines with a metal ruler. A mean snow depth for each site was derived from these 120 measurements. Freeboard, sea ice thickness and sub-ice platelet layer thickness were recorded at five locations at each site - at the central crossing point and at the end points of each transect. The mean of these was then calculated and taken as representative of the site. Ice thicknesses were measured by using a tape measure with a brass T-anchor attached at the zero mark. This was deployed vertically through the drill-hole and allowed to rotate to a horizontal alignment when exiting the bottom of the drill-hole at the ice-ocean interface. From this position the anchor is slowly pulled upwards until some resistance is met and the first measurement is taken. This resistance is taken to mark the sub-ice platelet layer/ocean interface. The tape measure is then pulled harder, forcing the bar to pass through the sub-ice platelet layer until it sits flush against the sea ice/sub-ice platelet layer interface where a second measurement is taken. Measurement sites were about 5 km apart.

Here, we present drill hole measurements carried out at 14 field sites distributed over a ~1500 km^2 area of fast ice in the south of McMurdo Sound, Antarctica between 1 and 19 November 2018. At each site, five holes were drilled in the fast ice at the centre and end points of two cross‐profile lines, each 30 metre long. Sea ice and SIPL thicknesses were measured with a suspended thickness probe and metal bar using the procedure described in Price et al. (2014). Snow depth measurements at centimetre accuracy were made at half‐metre intervals along the cross‐profiles using a metal ruler or a GPS‐equipped Magnaprobe. Sea ice freeboard (i.e., the height of the sea ice surface above sea level) was measured in each of the drill holes. The average value for each parameter was calculated at each field site to provide a representative measurement over the 30 metre cross-profile fast ice area. The drill hole measurements were used to underpin spatial distribution surveys of the aforementioned parameters, to inform electromagnetic induction forward and inverse models, and to ground-validate satellite altimetry assessments of fast ice freeboard and derived ice thickness in McMurdo Sound.

Data from a measurement campaign examining the oceanic connection between an ice shelf cavity and sea ice. Here we present data from the ocean boundary-layer in an Ice Shelf Water outflow region from the Ross/McMurdo Ice Shelves. From a fast ice field camp during the Spring of 2015, we captured the kinematics of free-floating relatively large (in some cases 10s of mm in scale) ice crystals that were advecting and then settling upwards in a depositional layer on the sea ice underside (SIPL, sub-ice platelet layer). Simultaneously, we measured the background oceanic temperature, salinity, currents and turbulence structure. At the camp location the total water depth was 536 m, with the uppermost 50 m of the water column being in-situ super-cooled. Tidal flow speeds had an amplitude of around 0.1 m s-1 with dissipation rates in the under-ice boundary layer measured to be up to e=10-6 W kg-1. Acoustic sampling (200 kHz) identified backscatter from large, individually identifiable suspended crystals associated with crystal sizes larger than normally described as frazil. Crystal sizes in the SIPL were also measured. RELATED PUBLICATION: https://doi.org/10.3389/fmars.2023.1103740 GET DATA: https://doi.org/10.17882/90432