Мониторинг физико-механического состояния морского льда и краткосрочное прогнозирование экстремальных ледовых явлений

The article presents the results of studies that complement each other. New methods of instrumental studies of the physical and mechanical characteristics of ice and ice cover are considered.There is briefly described the complex system to developed in the AARI (Arctic and Antarctic research Institute) to determine the strength characteristics of ice formations in natural conditions. The results of determining the ice strength in wells (local strength) at the research station of AARI “Ice Base Cape of Baranov” are presented. The coefficient of comparison of local strength and strength of samples under uniaxial compression is obtained. This allows to determine the ice strength without sampling and testing of samples. On a large experimental material, linear and quadratic approximations for local ice strength were obtained. The influence of the indenter penetration rate on the local ice strength is studied.There is considered the application of the contact remote method for monitoring the dynamic state of the ice cover in order to obtain new data for creating a method of predicting the phenomena of compression and destruction of sea ice in real time.To study the large-scale mechanics of ice during dynamic processes in the air — ice — water system, a modular-block system for ice cover monitoring was developed. The layout of the system was tested in Arctic expeditions.The developed complex system for determining the strength characteristics of ice formations in natural conditions and the modular-block system for monitoring the state of the ice cover complement each other, suggest their further development and improvement, provide wide opportunities for ice research.В статье дается обзор двух дополняющих друг друга направлений исследований морского льда, которые осуществляются Арктическим и антарктическим научно-исследовательским институтом (ААНИИ). Рассмотрены новые методы инструментального исследования физико-механических характеристик ледяного покрова. Приведены результаты определения локальной прочности льда на научно-исследовательском стационаре ААНИИ «Ледовая база Мыс Баранова». Рассмотрено применение контактного дистанционного метода мониторинга динамического состояния ледяного покрова с целью получения новых данных для создания метода прогнозирования явлений сжатия и разрушения морских льдов в режиме реального времени

Основные физические и механические характеристики льда по результатам экспедиции «Трансарктика-2019»

On the “Transarktika-2019” expedition, works were carried out for determining the physical and mechanical characteristics of frost field of the first-year sea ice and the field of second-year ice. The thickness of the ice cover was determined by contact and non-contact methods, the temperature, salinity and density of ice, the strength of the samples at central bending and uniaxial compression, as well as the local (borehole) strength of ice were measured. Studies have shown that most of the field is an ice formation formed in the process of dynamic metamorphism. At the beginning of the expedition, an ice floe passed through a section of warm surface waters. This led to the disappearance of the openwork layer on the lower boundary of the ice and stopping the growth of ice from below. During the observation period, the average temperature and salinity of the deformed ice increased, while the average density decreased. The values of mechanical characteristics decreased with increasing temperature and brine volume. The average borehole strength were close to the values obtained by the quadratic approximation for ice in the area of the Ice Station “Cape of Baranov”. The physical and mechanical properties of the level ice are generally similar to the properties of ice, composed mainly of fibrous structures. The ratios between the borehole strength and the strength under uniaxial compression of ice samples drilled parallel to the ice surface were 4.5 and 4.7, which corresponds to the literature data. The thickness of the second-year sea ice at the place of work was 166 — 169 cm, the snow height was 27 cm, the raft of the ice surface above the water surface was 15 cm. The average ice temperature was –4.0 °C. Second-year ice can be divided into three parts that differ in their physical properties. The upper part (0 — 10 cm) was formed in the autumn. The second part (10 — 85 cm) is ice that has undergone seasonal thermometamorphic changes. The lower part was formed during the natural growth of ice from below at the current season.В экспедиции «Трансарктика-2019» были выполнены работы по определению физико-механических характеристик однолетнего льда поля сморози и поля двухлетнего льда. Поле сморози является ледяным образованием, сформированным в процессе динамического метаморфизма. В работе представлены данные по температуре, солености, плотности, текстуре, прочности при центральном изгибе круглых пластин, локальной прочности и прочности при одноосном сжатии образцов льда, выбуренных параллельно и перпендикулярно поверхности льда. Средние значения локальной прочности были близки к значениям, получаемым по квадратичной аппроксимации для льдов в районе НИС «Ледовая база Мыс Баранова». В целом механические характеристики ровного льда аналогичны характеристикам прочности льда с преобладанием волокнистой структуры

Overview of the MOSAiC expedition: Snow and sea ice

Year-round observations of the physical snow and ice properties and processes that govern the ice pack evolution and its interaction with the atmosphere and the ocean were conducted during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition of the research vessel Polarstern in the Arctic Ocean from October 2019 to September 2020. This work was embedded into the interdisciplinary design of the 5 MOSAiC teams, studying the atmosphere, the sea ice, the ocean, the ecosystem, and biogeochemical processes.The overall aim of the snow and sea ice observations during MOSAiC was to characterize the physical properties of the snow and ice cover comprehensively in the central Arctic over an entire annual cycle. This objective was achieved by detailed observations of physical properties and of energy and mass balance of snow and ice. By studying snow and sea ice dynamics over nested spatial scales from centimeters to tens of kilometers, the variability across scales can be considered. On-ice observations of in situ and remote sensing properties of the different surface types over all seasons will help to improve numerical process and climate models and to establish and validate novel satellite remote sensing methods; the linkages to accompanying airborne measurements, satellite observations, and results of numerical models are discussed. We found large spatial variabilities of snow metamorphism and thermal regimes impacting sea ice growth. We conclude that the highly variable snow cover needs to be considered in more detail (in observations, remote sensing, and models) to better understand snow-related feedback processes.The ice pack revealed rapid transformations and motions along the drift in all seasons. The number of coupled ice–ocean interface processes observed in detail are expected to guide upcoming research with respect to the changing Arctic sea ice