Texture features of multi-year fresh ice in the Transcription bay, East Antarctica, in the period of summer melting

• Main Authors: V. Kharitonov V., V. Borodkin A., В. Харитонов В., В. Бородкин А.
• Other Authors: This work was carried out within the framework of 64 and 65 Russian Antarctic Expedition (RAE) The authors express their gratitude to the head of the RAE A V Klepikov for providing logistics and Sergey Kashin of the AARI for his assistance in field work., Работа выполнена в рамках 64-й и 65-й РАЭ. Авторы выражают благодарность руководству РАЭ в лице А. В. Клепикова за обеспечение логистики и сотруднику ААНИИ С В Кашину за помощь при проведении полевых работ.
• Format: Article in Journal/Newspaper
• Language: Russian
• Published: IGRAS 2022
• Subjects: perennial ice;Antarctica;ice core;density;air inclusions;congelation ice;infiltration ice;ice formation; многолетний лёд;Антарктида;керн;плотность;воздушные включения;конжеляционный и инфильтрационный лёд;формирование льда; Antarctic; East Antarctica; The Landing; Rae; Antarc*; Antarctic and Alpine Research; Antarctica; Arctic; ice core; Антарктида
• Online Access: https://ice-snow.igras.ru/jour/article/view/986; https://doi.org/10.31857/S2076673422020132

The paper presents new data on the texture and density of a unique natural object – perennial fresh landfast ice in the Gulf of Transcription (East Antarctica), obtained in January 2020. The main purpose of the work was a planned (scheduled) inspection of the landing site selected for the 63rd season of the Russian Antarctic Expedition (RAE), investigation of the ice core sampling and analysis of its texture, including measuring the ice density. The thickness of the ice cover at the core sampling site was 3.02 m. In the long-standing (perennial) fast ice, the new ice is formed mainly from below as a natural growing of the congelation ice. From above a new ice is formed in smaller volumes, and it is either the infiltration ice in spring or freezing of melt water on the surface in autumn. Infiltration ice does not contribute much to the old fast ice, remaining a seasonal phenomenon. The reasons for that are insufficient snow accumulation in winter and the lack of salt water in the subglacial layer. In the upper layer of ice, its density is minimal and amounts to 680–720 kg/m3, increasing with depth and approaching its maximum at the lower edge – 917 kg/m3. The average density of ice is 875 kg/m3. The effect of primary air inclusions (bubbles) on the density of ice which contains large crystals of tens of centimeters in size is approximately the same for the whole ice thickness. Significant changes in the density of ice are caused by secondary inclusions which are formed during the freezing of melt water in the runoff and riverbed flows. It is shown how a crack in the ice, probably thermal, is further transformed under the influence of temperature and melt water runoff into a sinusoidal channel. This is rather common phenomenon associated with the thermal physics of the ice cover, the melting–freezing processes, and surface tension. The period of the sinusoid increases linearly with depth (the coefficient of determination R2 = 0.99). Thus, the new data obtained allows expanding the present-day scientific notions on ...