Ground-based electromagnetic induction (EM) measurements of land-fast sea ice and sub-ice platelet layer (SIPL) thickness distributions were carried out in McMurdo Sound, Antarctica in late spring (November 1-19) of 2018. Repeated west to east EM transects were carried out across McMurdo Sound along latitude 77.767°S. The EM data was acquired using a frequency-domain Geonics Ltd EM31-MK2 instrument mounted on a sledge and towed by skidoo. The thicknesses of consolidated ice (sea ice plus the snow layer) and the sub-ice platelet layer were simultaneously retrieved from the EM31 measured response using forward modelling and inversion methods of Irvin (2018). Variability in EM thicknesses detected significant growth of sub-ice platelet layer over the 18-day survey period (Brett et al., 2024).

All data are in NZST to correspond to Figure 7b of Brett et al., (2024).