Abstract
AbstractThe formation of platelet ice is well known to occur under Antarctic sea ice, where subice platelet layers form from supercooled ice shelf water. In the Arctic, however, platelet ice formation has not been extensively observed, and its formation and morphology currently remain enigmatic. Here, we present the first comprehensive, long‐term in situ observations of a decimeter thick subice platelet layer under free‐drifting pack ice of the Central Arctic in winter. Observations carried out with a remotely operated underwater vehicle (ROV) during the midwinter leg of the MOSAiC drift expedition provide clear evidence of the growth of platelet ice layers from supercooled water present in the ocean mixed layer. This platelet formation takes place under all ice types present during the surveys. Oceanographic data from autonomous observing platforms lead us to the conclusion that platelet ice formation is a widespread but yet overlooked feature of Arctic winter sea ice growth.
Highlights
The formation of platelet ice is well known to occur under Antarctic sea ice, where subice platelet layers form from supercooled ice shelf water
Platelet ice is a characteristic feature of Antarctic landfast sea ice, where supercooled ice shelf waters lead to the advection and growth of subice platelet layers (Hoppmann et al, 2020)
During the polar night of the international drift expedition MOSAiC in 2019–2020, we observed a widespread coverage of the ice underside with a subice platelet layer
Summary
Platelet ice is a characteristic feature of Antarctic landfast sea ice, where supercooled ice shelf waters lead to the advection and growth of subice platelet layers (Hoppmann et al, 2020) They consist of loosely attached decimeter sized plate‐shaped ice crystals (Hoppmann et al, 2017; Langhorne et al, 2015; Smith et al, 2001) and can be up to several meters thick. These ice platelets form by nucleation in supercooled layers of seawater either at depth (Dieckmann et al, 1986) or directly at the ice underside (Leonard et al, 2006; Mahoney et al, 2011) in the vicinity of large ice shelves, which provide supercooled water due to basal ice shelf melt in the water circulation of ice shelf cavities.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
