Platelet Ice Under Arctic Pack Ice in Winter
Christian Katlein, Volker Mohrholz, Igor Sheikin, Polona Itkin, Dmitry Divine, Julienne Strœve, Arttu Jutila, Daniela Krampe, Egor Shimanchuk, Ian Raphael, Benjamin Rabe, Ivan Kuznetsov, Maria Mallet, Hailong Liu, Mario Hoppmann, Ying‐Chih Fang, Adela Dumitrascu, Stefanie Arndt, Philipp Anhaus, Marcel Nicolaus, Ilkka Matero, Marc Oggier, Hajo Eicken, Christian Haas
Abstract
Abstract The 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.