Межгодовая изменчивость продолжительности безледного периода в юго-западной части Карского моря

In the coming years, exploration drilling in the geological structures in the Kara Sea is planned. It will be carried out during the ice-free period using floating drilling facilities of a different ice class. The aim of the work is analysis of the interannual variability of duration of the ice-free period in the area of the geological structures the results of which are necessary for planning operational activity of the drilling platforms and optimization of expenses for exploration drilling on the Arctic shelf. For an assessment of interannual variability of the ice-free period duration in the area of the geological structures there were used data on the dates of water area clearance from ice and beginning of ice formation in the southwestern part of the Kara Sea for the period of 30 years on the basis of the AARI weekly ice charts. An analysis of interannual variability of the ice-free period duration showed that a 20-year summer (1989–2008) and a 10-year (2009–2018) intervals could be identified. It is shown that in the last decade as a result of combination of favorable hydrometeorological conditions the ice-free period duration has increased by more than 1 month. An analysis of the main hydrometeorological factors determining the ice-free period duration indicated that it is possible to perform an assessment of duration of exploration drilling operations in the water area of the East-Prinovozemelsky license blocks with a period in advance of several months. Drilling with the use of ice-resistant drilling platform allows us to extend the operation period, as drilling could be started after disappearance of close ice and finished after the ice thickness growth up to 30 cm.Рассмотрена межгодовая изменчивость сроков очищения акватории ото льда, начала ледообразования и продолжительность безледного периода в районе геологических структур в юго-западной части Карского моря. Показано, что в последнее десятилетие в результате сочетания благоприятных гидрометеорологических условий продолжительность безледного периода увеличилась более чем на месяц. Анализ основных гидрометеорологических факторов, определяющих продолжительность безледного периода, показал, что возможно выполнять оценку продолжительности операционного периода поисково-разведочного бурения на акватории Восточно-Приновоземельских лицензионных участков с заблаговременностью в несколько месяцев

Комплексное исследование старых торосов в Северном Ледовитом океане

In May 2015, the old hummock located to the North of the Bennett island (the East Siberian Sea) was investigated using several methods, among which were water thermal drilling, tachometric and sonar surveys, underwater video recording, as well as techniques to determine the strength and physical properties of ice. It was found out that only a combination of different methods provides a way to correctly estimate the main morphometric characteristics of a large ice formation and to determine its volume and mass. Analysis of the internal structure of the hummock, obtained by the water thermal drilling with a record of the drilling rate on the logger, made it possible to reveal a composite character of the ice formation (the hummock consisted of two fragments – the large old one and the smaller first-year piece) and to estimate approximately its age (3–4 years). Comparison of the main morphometric characteristics of the old hummock with the average values of first-year hummocks, investigated in the same area and the time, showed that the old hummock had significantly greater geometric parameters: its volume and mass exceeded similar parameters of the average younger formation by factors 5.6 and 5.8, respectively. This significant difference allows suggestion that the reason is not the age but a composite structure of the old formation. The average thickness of the consolidated layer of the old hummock equal to 4.6 m is almost twice larger than similar parameter of a first-year hummock (2.33 m) while the average value of the thickness in the old part of the old hummock (5.22 m) is larger than that of a young one by the factor 2.2. Note also, that the old hummock is characterized by almost complete smoothness (impossible to separate individual blocks) and minimal porosity (1%) of its ice. The salinity and density of the ice composing the frontal part of the old hummock is much smaller than in first-year hummocks. The average density of ice in the old hummock, determined analytically from the buoyancy condition, was equal to 896 kg/m3, while the average density of ice in the first-year hummocks, determined from measurements, – 917 kg/m3.На основе исследования морфометрии, внутренней структуры и физико-механических свойств старого тороса на северо-западе Восточно-Сибирского моря сделан вывод, что он состоит из более крупного старого и меньшего однолетнего фрагментов. Средняя толщина консолидированного слоя в старой части тороса больше, чем в среднем у однолетних торосов, в 2,2 раза

Исследования ледового режима на акватории Хатангского залива в море Лаптевых

The study was carried out to reveal characteristics of the ice regime of poorly explored water area of the Khatanga Bay in the South-Western part of the Laptev Sea. Actuality of the research is due to the high potential of hydrocarbon reserves in the license area «Khatangsky» of the PAO «NK «Rosneft Currently available methods of monitoring ice cover and hydrometeorological conditions throughout the year were used. The main features of the hydrological regime of the region in the ice-free period, reflected in the spatial distribution of thermohaline characteristics and sea level fluctuations, are shown. The area under investigation has specific features of the conditions for the formation of ice cover: the entire area is covered with the fast ice; the winter fresh water infl w from Khatanga and Anabar rivers results in the desalination of sea water, and this promotes formation of ice cover, which differs in crystal structure and texture from both fresh and sea ices. These factors do influence on the mechanical properties of ice, including its strength. It was found that the average and maximum values of strength of the smooth and deformed ice of the Khatanga Gulf are approximately twice as high as the similar values of the sea ice strength in the southern part of the Laptev Sea. The basic features of the spatial distribution of different types of deformations of the ice cover such as lines of ice hummocks, zones of homogeneous ice hummocking, and stamukhas had been determined.Цель исследований – выявить особенности ледового режима малоизученной акватории Хатангского залива в море Лаптевых. На основе круглогодичных исследований на стационаре «Хастыр» и весенних исследований с использованием вертолёта обнаружены новые особенности формирования ледяного покрова, связанные с притоком пресных вод и большого количества примесей, которые приводят к повышенной прочности льда. Установлено пространственное распределение различных видов деформированного льда