Drill hole measurements of fast ice and sub-ice platelet layer thickness, and snow depth in McMurdo Sound - November 2017

• Main Authors: Langhorne, Patricia J, Leonard, Gregory, Brett, Gemma Marie, Rack, Wolfgang, Haas, Christian, Fraser, Eamon, Xie, Hongjie, Bault, Jennifer, Gao, Yongli
• Format: Dataset
• Language: English
• Published: PANGAEA 2021
• Subjects: Antarctica; Date/Time of event; Deep South National Science Challenge: Targeted observations and process-informed modeling of Antarctic sea ice; Event label; Fast ice; Freeboard; ICEDRILL; Ice drill; Identification; Latitude of event; Longitude of event; McMurdo-2017_1; McMurdo-2017_11; McMurdo-2017_2; McMurdo-2017_20; McMurdo-2017_21; McMurdo-2017_22; McMurdo-2017_23; McMurdo-2017_24; McMurdo-2017_3; McMurdo-2017_4; McMurdo-2017_5; McMurdo-2017_6; McMurdo-2017_7; McMurdo-2017_70; McMurdo-2017_71; McMurdo-2017_72; McMurdo-2017_73; McMurdo-2017_74; McMurdo-2017_75; McMurdo-2017_76; McMurdo-2017_77; McMurdo-2017_EM31_1; McMurdo-2017_EM31_2; McMurdo Sound; PIPERS; Polynyas; ice production; and seasonal evolution in the Ross Sea; Sea ice thickness; Snow layer; Snow thickness; Sub-ice platelet layer; Sub-ice platelet-layer thickness; TOPOMASI; Antarctic; Ross Sea; Annals of Glaciology; Antarc*; Sea ice; The Cryosphere; The Cryosphere Discussions
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.933076; https://doi.org/10.1594/PANGAEA.933076

The thicknesses of sea ice and sub-ice platelet layer were measured at regular intervals on fast ice in McMurdo Sound, Antarctica in November of 2017. 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 MagnaProbe. 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 10 km apart.