Borehole indentation strength of first- and second-year sea-ice during GoNorth 2022 leg 1

Borehole indentation strength measurements were carried out on first- and second-year sea ice during two ice stations on 24 October 2022 and 30 October 2022, during leg 1 of the GoNorth 2022 expedition. The first station was termed station 6, located at 82°13.56' N, 26°41.43' E, while the second station was termed super station 14, located at 82°31.05' N, 17°30.04' E. The measurements were carried out using the NTNU borehole jack (Kallelid et al., 2019; Rødtang et al., 2023). At each station, a 77 mm borehole was augered and the borehole jack was inserted. The indentation was carried out at mainly 0.50 m and 0.16 m from the top of the ice on the second-year ice and first-year ice respectively, in the approximate middle of each ice sheet. Two indentations were carried out per borehole, in positive and negative y-direction. The indentation resistance was measured with two load cells and converted to pressure via a calibration factor. The borehole strength was recorded as the maximum measured pressure during indentation.