Fast Ice Thickness Distribution in the Western Ross Sea in Late Spring

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Langhorne, PJ, Haas, C, Price, D, Rack, W, Leonard, GH, Brett, GM, Urbini, S
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Geophysical Union (AGU) 2023
• Subjects: Adare; Cape Adare; Granite Harbor; Hells Gate; McMurdo Sound; Moubray Bay; New Harbor; Ross Sea; Silverfish Bay; Ice Shelf
• Online Access: https://epic.awi.de/id/eprint/58715/; https://epic.awi.de/id/eprint/58715/1/JGROceans2023%20Langhorne%20PUBLISHED.pdf; https://doi.org/10.1029/2022jc019459; https://hdl.handle.net/10013/epic.b7428542-26cc-4e54-8f84-1ce0b0530f6b

We present a 700 km airborne electromagnetic survey of late-spring fast ice and sub-ice platelet layer (SIPL) thickness distributions from McMurdo Sound to Cape Adare, providing a first-time inventory of fast ice thickness close to its annual maximum. The overall mode of the consolidated ice (including snow) thickness was 1.9 m, less than its mean of 2.6 ± 1.0 m. Our survey was partitioned into level and rough ice, and SIPL thickness was estimated under level ice. Although level ice, with a mode of 2.0 m and mean of 2.0 ± 0.6 m, was prevalent, rough ice occupied 41% of the transect by length, 50% by volume, and had a mode of 3.3 m and mean of 3.2 ± 1.2 m. The thickest 10% of rough ice was almost 6 m on average, inclusive of a 2 km segment thicker than 8 m in Moubray Bay. The thickest ice occurred predominantly along the northwestern Ross Sea, due to compaction against the coast. The adjacent pack ice was thinner (by ∼1 m) than the first-year fast ice. In Silverfish Bay, offshore Hells Gate Ice Shelf, New Harbor, and Granite Harbor, the SIPL transect volume was a significant fraction (0.30) of the consolidated ice volume. The thickest 10% of SIPLs averaged nearly 3 m thick, and near Hells Gate Ice Shelf the SIPL was almost 10 m thick, implying vigorous heat loss to the ocean (∼90 W m −2). We conclude that polynya-induced ice deformation and interaction with continental ice influence fast ice thickness in the western Ross Sea.