Проблемы Арктики и Антарктики
Not a member yet
266 research outputs found
Sort by
Актуальные проблемы гидрологических расчетов в арктической зоне Российской Федерации и сопредельных территориях распространения многолетней мерзлоты
Get PDFThe article reveals the main problems facing hydrologists in engineering design in the Arctic zone of Russia and adjacent territories of permafrost. Climate warming and degradation of permafrost cause a significant transformation of the hydrological cycle. The retrospective observations of runoff cannot be considered therefore in modern conditions. The density of the hydrological network in the permafrost zone of Russia has decreased by more than 1.5 times, and on small rivers – more than three times in recent decades. Thus, the use of standard calculation methods (SP 33-101-2003) to assess the runoff characteristics in the Arctic regions is practically impossible. It is shown that in the developed Arctic countries where the size of the territories and their inaccessibility could be compared with withRussia, the low density of the standard observation network is compensated by the organization of small scientific research stations for studying hydrological processes in various physical and geographical conditions and the development of mathematical modeling methods. It is shown that historicallyRussiawas the leader of hydrological research in cold regions. It is stated that there is an urgent need to create a state program aimed at restoring the previously operating in the cryolithоzone and organizing new research hydrological watersheds, improving the standard hydrological network, and developing complex modeling systems and methods for their parameterization.В статье раскрыты основные проблемы, стоящие перед гидрологами при инженерном проектировании в Арктической зоне России и прилегающих территориях распространения многолетней мерзлоты. Основной из них является практическая невозможность использования стандартных методов расчета (СП 33-101-2003) для оценки характеристик стока в регионах с крайне ограниченными данными наблюдений гидрометрической сети в современных условиях изменений климата. Констатируется срочная необходимость создания государственной программы, направленной на восстановление ранее действовавших в криолитозоне и организацию новых научно-исследовательских гидрологических стационаров, совершенствование стандартной гидрологической сети, а также развитие комплексных моделирующих систем и методов их параметризации
Сезонная и межгодовая изменчивость ледяных массивов Восточно-Сибирского моря
Get PDFThe paper considers the seasonal and interannual variability of the Novosibirsky and Ayonsky ice massifs of the East Siberian Sea, which represent the main difficulty for navigation during summer.Analysis of ice conditions showed the tendency towards the onset of a new climatic period - “relative warming”. This is consistent with the regional quasi-periodic 30-year alternations beetween the “relatively cold” and “relatively warm” climatic periods identified in the AARI.We have compared ice conditions of the “relatively cold” period of 1958–1987 and the “relatively warm” period of 1988–2017. Since the end of the 1980s the ice massifs began to decrease more intensively with the onset of break up some 10–20 days earlier.In general, the drift ice area during summer has decreased by 15–20 % in the western part of the sea and by 20–30 % in eastern one. The fast decrease of close floatingice in the East Siberian Sea observed in the last decades resulted in increase of the possibilities of autonomous navigation.The latest works containing the analysis of in conditions of the East Siberian Sea belong to the 90s of last century. In these works ice conditions of the period of the 40–80s of the 20th century were considered. During this period, the background of the ice cover extent was high. As a result, the usage of the average values of ice massifs areas calculated on all observations series (since 1946), is not informative for characterizing ice conditions during separately taken periods.В работе рассмотрены сезонная и межгодовая изменчивости площадей ледяных массивов Восточно-Сибирского моря. Представлены результаты расчетов изменения ледовитости и повторяемости типов развития ледяных массивов в период 60–80-х годов прошлого столетия и за последние десятилетия.Эти изменения хорошо согласуются с выявленными в ААНИИ квазипериодическими чередованиями «относительно» холодных и «относительно» теплых климатических периодов с продолжительностью около 30 лет.За последние десятилетия уменьшение ледяных массивов стало происходить более интенсивно. В целом площадь сплоченных льдов в летний сезон уменьшилась на 15–20 % в западной части моря и на 20–30 % в восточной, существенно расширив возможности самостоятельного плавания судов
«Атлантификация» как вероятная причина сокращения площади морского льда в бассейне Нансена в зимний сезон
Get PDFThe paper presents arguments in favor of an explanation of the reduction of the ice-covered area in the Nansen basin of the Arctic Ocean (AO) in winter by the so-called “atlantification “ — the strengthening of the influence of waters of Atlantic origin on the hydrological regime of the Arctic Ocean. We hypothesize that the main agent of “atlantification” in theWesternNansenBasinis winter thermal convection, which delivers heat from the deep to the upper mixed layer, thus melting sea ice and warming the near-surface air. To check up this hypothesis we used ocean reanalysis MERCATOR data for time interval 2007–2017. The quantitative criterion of thermal convection, based on the type of vertical thermohaline structure in the upper ocean layer, was applied to access the change of convection depth between climatic values in 1950–1990 and the present time. The main conclusion of the paper can be summarized as the following. Due to a gradual reduction of sea ice in the 1990s, the vertical stratification of waters in theWesternNansenBasinhas changed. As a result, the potential for penetration of vertical thermal convection into the warm and saline Atlantic layer and the consumption of heat and salt content of this layer for warming and salinification of the overlying waters increased, thus leading to additional loss of sea ice in winter
О некоторых инженерных оценках параметров нефтяного разлива в море
Get PDFEstimation of the oil spill size at continuous spills on the moving sea surface or on the drifting ice field is the actual practical problem. Engineering estimation means the reduction of the hydrodynamic equations system to the balance of only two main forces that cause movement and resistance of the oil flow. From the simplified problem statement some practical relations were obtained for estimating the size of spill, including continuous oil spill with surface water currents presence, for spill onto porous snow-ice cover and onto the drifting ice cover. The obtained estimations can be used in more complicated models of oil spill transformation in the marine environment, primarily in the Arctic zone, and give basis for development of adequate responses on oil spills. The comparison of the obtained estimates with the self-similar solutions of the corresponding equations of motion of the spreading substance shows a satisfactory fit.При решении многих практических задач часто бывает необходимо быстро оценить размеры нефтяного пятна, т.е. получить инженерную оценку. Инженерная оценка размеров нефтяного пятна получается при рассмотрении упрощенной постановки задачи, сведенной к балансу основных действующих сил. Из упрощенной постановки задачи в настоящей статье были получены практические соотношения для оценивания размеров разлива при продолжительном сбросе нефти на движущуюся морскую поверхность и на дрейфующий ледяной покров с учетом фильтрации в пористую среду. Полученные оценки могут быть использованы в более сложных моделях трансформации нефтяного разлива в морской среде, в первую очередь в Арктической зоне, и дают основания для разработки адекватных мер реагирования на разливы. Сравнение полученных оценок параметров разлива с автомодельными и численными решениями задач показало удовлетворительное соответствие
Широтные вариации структуры сообществ и продуктивности зоопланктона в Баренцевом море (лето 2013 г.)
Get PDFThe Barents Sea is regarded as one of the world’s most unique regions with its high summer productivity. However, there were a few studies dealing with estimation of daily secondary production in the Barents Sea. The aim of the present study was to conduct an investigation of the pelagic mesozooplankton assemblage in the Barents Sea, to calculate daily production levels of mesozooplankton and to analyze the relationship between the community structure and environmental drivers.Structure of zooplankton communities was investigated within the main water masses of the Barents Sea in the summer 2013 (June–July). Calanus finmarchicus presented as copepodites IV–V dominated in terms of the total zooplankton abundance and biomass in Murmansk Coastal Water and Atlantic Water. Spring phase of zooplankton succession cycle was found in Arctic Water where Copepoda nauplii were the most abundant and Calanus glacialis dominated by zooplankton biomass. Zooplankton of the Barents Sea Water had features of spring and summer phases of zooplankton succession cycle. Spatial variations in the zooplankton distribution were associated with hydrological conditions and phytoplankton density. Maximum of the mean zooplankton biomass was registered in Atlantic Water (30,7 mg dry mass/m3) while the minimum was found in Barents Sea Water (5,4 mg dry mass/m3). Calculated daily production of zooplankton ranged from 0,01 to 1,57 mg dry mass/m3 per day. Total zooplankton stock for the study area of 281 000 km2 was estimated to be > 740 000 t of dry mass. The obtained values of zooplankton biomass and stock were considerably lower than in previous years, which are probably connected with higher predator pressure — grazing of zooplankton by capelin and other predators as well as with possible climatic influence.Исследована структура зоопланктона в пределах основных водных масс Баренцева моря. В мурманской прибрежной и атлантической водной массах по численности и биомассе зоопланктона доминировал Calanus finmarchicus. В арктической водной массе преобладали науплии копепод, основу биомассы составлял Calanus glacialis. Пространственные вариации распределения зоопланктона были связаны с гидрологическими факторами и концентрацией фитопланктона. Наибольшая средняя биомасса отмечена в атлантических водах, наименьшая — в баренцевоморских. Общий запас зоопланктона для исследованной акватории площадью 281 тыс. км2 составил более 740 тыс. т сухой массы. Биомасса, продукция и запас зоопланктона были существенно ниже, чем в предшествующие годы, что, скорее всего, связано с более высоким прессом мойвы и других хищников, также возможным влиянием климатических факторов
Ртуть в компонентах экосистемы заливов Западного Шпицбергена в летний период 2017 года
Get PDFThe total content of mercury was studied in marine water, sediments and benthic organisms in Billefjord, Isfjord and Gronfjord (Western Spitsbergen) in 2017. The samples were collected between 21 and 24 of July 2017 on-board RV “Dalnie Zelentsy” of Murmansk Marine Biological Institute. Total mercury content was measured at chemical-analytical laboratory of the Russian Scientific Center on Spitsbergen in Barentsburg.Total mercury concentration in the water did not exceed 10 ng/l in all fjords. In the surface sediments the highest concentrations of total mercury were found in Isfjord (median 55 ng/g d.w.) while the Billefjord sediments were characterised by the lowest concentrations (median 10.4 ng/g d.w.). This fact might reflect the differences in water circulation and therefore sediment accumulation peculiarities.Total mercury data were obtained for benthic organisms of various feeding modes. Generally mercury levels were comparatively low (median 12.2 ng/g w.w.), however the highest concentrations were measured in the benthic fauna of Isfjord, specifically in polychaetes Maldania sarsi (max. 49.2 ng/g w.w.). Mercury accumulation in benthic organisms predominantly depended on their trophic level in the ecosystem and location in the fjord: benthic detritus feeders accumulate more mercury (median 25.0 ng/gw.w.).Выполнено исследование содержания ртути в воде, донных отложениях и бентосных организмах в заливах Билле-фьорд, Ис-фьорд и Грён-фьорд (арх. Шпицберген) в июле 2017 г. Содержание ртути во всех образцах (вода, донные отложения и биологические объекты) определяли в химикоаналитической лаборатории Российского научного центра в пос. Баренцбург на арх. Шпицберген. Концентрация ртути в водах заливов Билле-фьорд, Ис-фьорд и Грён-фьорд была менее 10 нг/л. В поверхностном слое донных отложений самые высокие валовые концентрации ртути были отмечены в Ис-фьорде, а наименьшие в Билле-фьорде. Аккумулирование ртути в гидробионтах было связано с их трофическим уровнем в экосистеме и локализацией во фьордах. Ртуть в большей степени аккумулировали бентосные организмы детритофаги-грунтоеды
О литорально-сублиторальном виде рыб из Западной Антарктики — Антарктическом гарпагифере harpagifer antarcticus nybelin, 1947 (harpagiferidae, notothenioidei, pisces). Сообщение 2. Биологические и экологические особенности, распространение, происхождение и вероятные пути расселения вида
Get PDFThis report is a continuation of the study of H. antarcticus by authors published in the previous issue of this magazine. On our and literary data on the most southern representative of the genus Harpagifer – H. antarcticus from the western coasts of the Antarctic Peninsula and the neighboring waters of the archipelagos of the Western Antarctic a descriptions of biological and ecological peculiarities are given as the only species of the genus inhabiting both littoral and upper sublittoral zones (up to 100 m depth). The base of our materials consists of fishes collected at the Russian Antarctic station Bellinsgausen in 2006–2011. Also distribution patterns and problems of the origin of the species from possible ancestor form inhabited in near coast waters of the pacific sector of the Antarctic and the south parts of the South America up to their division are considered and discussed. The problems of “advance” of harpagifer ancestor, its origin and speciation independent on far distant subantarctic islands and some causes of impossibility to occupy coast waters of the Continental seas of the Eastern Antarctic are discussed
Межгодовая изменчивость водных масс в области формирования донных вод в заливе Прюдс
Get PDFThe results of field studies of the processes of Antarctic Bottom Water formation conducted in the period from 2004 to 2016 in the Prydz Bay of the Commonwealth Sea is discussed. During this period the oceanographic observations along the 70° E section, crossing the shelf and the continental slope, were repeated nine times. In this area in the austral summer of 2004 during the AARI expedition on the r/v “Akademik Fedorov” the process of formation of bottom water has been recorded for the first time. A further study of the structure and characteristics of water masses on this section and in the adjacent area confirmed the regularity of these processes during the summer period. At the same time, a significant interannual variability of the structure, characteristics, and mechanisms of distribution of the main water masses in the section shelf, deep and bottom waters — was found. For the first time, detailed information on the bottom topography of the ocean in the vicinity of this section made it possible to show the determining role of bottom topography features in the distribution of newly formed bottom water along the continental slope. The tendency of increasing of the volume of bottom water formed in the Prydz Bay in recent years is revealed, which is associated with the intensification of the basal melting of the ice shelf leading to an increase in the volume of the formation of supercooled Shelf Water, the most important component in the formation of bottom water
Повторно-жильные льды в аномальном магнитном поле: численное моделирование
Get PDFIce wedges could be sources of negative magnetic anomalies due to their low magnetic susceptibility in comparison with surrounding frozen ground. This allows their mapping using highprecision magnetic survey. The work dedicated to analyze of typical models of polygonal-wedge structures in cryolithic zone. Total magnetic field anomalies are calculated at elevations of 1–5 m above the ice wedges upper boundary level. Ice wedge width varies from 1 to 3 m while polygon sizes vary from 6 to 15 m, respectively. Magnetic susceptibility of frozen ground assumed equal to 10–3 SI. Calculated anomalies magnitude amounts from several nT to several tens of nT. Provided estimations allows defining a necessary survey precision for ice wedge mapping. Ice wedges more than 3 m wide are observable in anomalous magnetic field even in the case of covering deposits thickness of up to 4 m on the condition that covering layers are laterally relatively uniform and magnetic susceptibility of frozen ground is about 10–3 SI
