Ice and Snow (E-Journal) / Лёд и Снег
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Изменения характеристик ледового режима рек водосбора Воткинского водохранилища за период с 1936 по 2018 г.
Get PDFThe paper is devoted to the study of long-term variability of the stable dates of ice formation and the duration of the freeze-up period at 12 gauges on the rivers of the Votkinskoe Reservoir catchment for 1936–2018. It turns out which of the statistical models is more consistent with the series of observations: the resampling model, the linear regression model, or the model of the change in the mean value starting from a certain point in time. The study was carried out in two stages. At the first stage the stable dates of ice formation and the duration of the freeze-up data were analyzed separately for each gauge. There were tested: the hypotheses of randomness, normality of the series of observations, hypotheses about the absence of a linear trend and autocorrelations in the data; hypotheses of homogeneity of series of observations. At the second stage the stable dates of ice formation and the duration of the freeze-up data were analyzed jointly using a two-dimensional normal distribution model for each gauge. There were tested: the hypotheses on two-dimensional normality and equality of data covariance matrices; the hypothesis of homogeneity of two-dimensional data. Using the methods of difference-integral curves and t-test revealed statistically significant changes in the behavior of the characteristics under consideration with the change point in 1997. Within each of the periods 1936–1997 and 1998–2017 for all gauges, the initial data allow describing the behavior of the characteristics under study using a resampling model, the elements of which have the same normal distribution law. There are no auto-correlations in the observation series. At the same time, statistically significant shifts in the dates of ice formation to the late side by 7–14 days and a reduction in the duration of the freeze-up period by 6–18 days were established. The transition from a separate analysis of the dates of ice formation and the duration of the freeze-up period to their joint analysis did not affect the nature of the results obtained. The results make it possible to improve the forecasting of the ice-thermal regime of rivers and improve the planning and organization of the work of water transport and hydraulic structures.Выявлены статистически значимые изменения сроков появления устойчивых ледяных образований и продолжительности периода ледостава на 12 гидрологических постах на реках водосбора Воткинского водохранилища за период 1936–2018 гг. Обнаружены статистически значимые смещения сроков появления ледяных образований в позднюю сторону на 7–14 дней и сокращение продолжительности периода ледостава на 6–18 дней
Экспериментальные исследования переноса ледяного шлама воздухом при бурении снежно-фирновой толщи
Get PDFThe snow-firn layer of the glaciers of Antarctica and Greenland contains data on the composition of the atmosphere in the past, volcanic eruptions, forest fires, anthropogenic pollution, and many other unique information. Nowadays, core drilling methods are widely used for sampling the snow-firn layer. Due to numerous complications (loss of air circulation, drill bit sticking, ice balling up, etc.), air ice drilling is not wide spread, yielding in productivity and reliability to thermal and auger drilling methods. However, core barrel drilling with reverse bottom-hole air circulation is a promising technology for drilling the glaciers of Antarctica and Greenland. However, core drilling with reverse bottom-hole air circulation is a promising technology for drilling Antarctic and Greenland glaciers. The authors suggest that this technology, if successfully implemented, will significantly exceed the currently used methods of drilling the upper layers of the glacier. Taking into account the failures of previous projects of core drilling with air, it was decided to conduct research in the conditions of Central Antarctica in order to substantiate the design parameters of the new drill. During 67th Russian Antarctic Expedition (RAE) experimental studies of ice cuttings air transportation while drilling of the snow-firn layer were conducted at Vostok station. In the course of the experimental studies, the VK-22 borehole was drilled to a depth of 30 m with full core and ice cuttings sampling. According to the selected probes, the dependences of the change in the density of the snow-firn layer, bulk density and fractional composition of ice cuttings on the depth of occurrence were established. By using the experimental facility, the suspension velocity (critical speed in drilling) of ice particles of various sizes and shapes was found for the first time. Directions for further research and ways to improve the experimental facility are proposed, which are planned to be implemented in the season of the 68th RAEВ целях разработки технологии бурения снежно-фирновой толщи с обратной призабойной циркуляцией воздуха на станции Восток проведены экспериментальные исследования. Установлена динамика изменения характеристик ледяного шлама, таких как: фракционный состав, насыпная плотность, форма и скорость витания в зависимости от параметров снежно-фирнового горизонта, в том числе от распределения плотности массива по глубине
Оценка содержания металлов и металлоидов в снежном покрове на участках нефтедобычи Среднего Приобья
Get PDFThis article presents results of investigation of dust load and content of metals and metalloids (MMs) in the snow samples taken at the Vatinskoye oil field (Khanty-Mansi Autonomous District - Yugra). Concentrations of dissolved and suspended forms of MMs in 20 samples collected in March 2021 were determined by the ICP-MS and ICP-AES methods. Eighteen elements (Ag, Ba, Bi, Cd, Cr, Cu, Fe, Hg, Li, Mn, Ni, Pb, Sb, Sn, Sr, Ti, W, and Zn) indicating various sources of emissions were selected for further analysis. Filters with a pore diameter of 0.45 μm were used to separate dissolved and suspended forms. Enrichment of the suspension with chalcophile elements (Ag, Cu, Zn, Sn, Sb, Pb) was noted in the background areas. Calculations of enrichment coefficients (CO) using Li as a reference element demonstrated that Cu, Mn and Ni come from natural sources (rocks and soils), while the others have a mixed natural-anthropogenic origin. It was noted also that the mass fraction of a number of metals (Cr, Cu, Ni, Zn) increases in solid-phase deposits. The metals Zn, Cu and Cr are mainly contained in snow in suspended form, and Ni - both in dissolved and suspended forms. As a result of calculations of the total Cr pollution index, most of the deposit is classified as "low, non-hazardous" pollution areas. The highest concentrations of MMs in the snow were found in the southern part of the deposit, where the main infrastructure facilities and the communications lines are concentrated, including roads, railways and pipelines. They were specified as "average, moderately dangerous" level of pollution. To determine sources of pollution, the factor analysis was applied, and as a result of which two main factors were identified: 1) the background pollution, which is indicative of deposition of Cu, Sn, Sb, Ag; 2) the anthropogenic one, corresponding to high levels of Cr, Ni, Zn. Spatial analysis of the MMs distribution showed that the deposition of Ni, Cr is associated with drilling operations, while Zn - with the presence of transport. The data obtained can be used to understand the processes of atmospheric deposition of potentially toxic metals and metalloids, as well as to assess the quality of the environment at oil and gas fields.Проведена оценка уровня загрязнения снежного покрова потенциально токсичными металлами и металлоидами на территории Ватинского нефтяного месторождения (Ханты-Мансийский автономный округ - Югра). В результате исследования фильтрата талого снега и твёрдофазных выпадений (частиц крупнее 0,45 мкм) отмечено увеличение концентрации Ni и Cr, связанное с ведением буровых работ, а также Zn за счёт работы транспорта. Уровень загрязнения возрастает на участках с повышенной концентрацией промышленных объектов
Расчёт преобладающей ориентации разрывов в ледяном покрове моря Лаптевых по данным дрейфа льда
Get PDFThe paper shows that in order to solve the problem of predicting the predominant orientation of cracks in ice covering the Laptev Sea, when the satellite information is absent, the orientation of cracks in ice cover can be calculated using data on the ice drift in the Sea. We have selected 200 satellite images made in both visible and infrared spectral bands allowing to obtain actual data on ice cracks in the Laptev Sea for seasons 2016–2021, and then calculated the predominant orientation of them using data on the OSI SAF ice drift for the date of each image as well as for several previous days. Results obtained were compared with actual modal orientations of the cracks and with characteristics of the atmospheric pressure fields in these days. It was found that selecting of initial ice drift data should be done with regard for the intensity of air flows, the invariability or constancy of the direction of air flows over the sea aquatory during several days, and the presence of a cyclone centered over the sea area. An algorithm has been developed for automatic selection of a date when the ice drift can be most likely accompanied by formation of cracks on the day under consideration, and calculation of predominant orientation of cracks should be made exactly on that day. The selected data on ice drift serve as a basis for calculating. It was revealed also that with the difference in the types of intensity of air flows in the northern and southern parts of the Laptev Sea, the developed algorithm for determining the date of ice drift should be applied to each part of the sea separately. The number of squares of the Laptev Sea grid in which the calculated orientation of cracks corresponded to its actual meaning with an established permissible error of 30° has been determined. The ratio of this number to the total quantity of grid squares (skill score) was equal to 69% on the average. The skill score exceeded 70% in 46 percent of the cases. The skill score falls below 60% in only 16 percent of the cases, with minimum value of 50%.Изложены основы алгоритма, позволяющего определить по последовательности полей приземного атмосферного давления за предшествующий период дату возникновения дрейфа льда, приведшего к деформациям в ледяном покрове и образованию существующей системы разрывов в море Лаптевых. Приведены результаты оправдываемости расчётной ориентации разрывов, полученной по данным фактического дрейфа льда на основе разработанного алгоритма
Решение одномерной задачи Стефана с двумя фазовыми границами на примере моделирования замерзания воды в ледниковой трещине
Get PDFThis article presents a numerical solution of the one-dimensional Stefan problem with two phase transitions, which is implemented on a non-uniform grid. The system of equations is written in a general form, i.e. it includes not only conductive, but also convective and dissipative terms. The problem is solved numerically by the front-fixing method on a non-uniform grid using an implicit finite-difference scheme, which is implemented by the sweep method. This algorithm can also be used to create more complex mathematical models of heat and mass transfer, as well as to describe glacial and subglacial processes. The mathematical apparatus proposed in the article was used to solve a specific problem of water freezing in a glacial crevasse. The presence and progression of crevasses, in turn, is a demonstrative factor indicating the dynamic activity of the glacier. Crevasses formed in one way or another can not only expand, but also decrease in size until they completely disappear. One of the reasons for their closure is the freezing of near-surface meltwater in the crevasse. Such a process was observed on glaciers near Mirny and Novolazarevskaya stations (East Antarctica). This process is modeled as an example of solving the Stefan problem. It is believed that all media are homogeneous and isotropic. The temperature of the water in the crevasse corresponds to the melting temperature of the ice. Modeling has shown that for the coastal part of the cold Antarctic glacier with an average temperature of –10°C and below, crevasses 5–10 cm of width freeze in less than a week. Wider ones freeze a little longer. 30 cm wide crevasses close in about two to three weeks, depending on the temperature of the glacier.Представлено численное решение одномерной задачи Стефана с двумя фазовыми границами в виде конечно-разностных схем, реализованных на неравномерной сетке. Уравнения записаны в наиболее общей форме, то есть включают в себя не только кондуктивный, но также конвективный и диссипативный члены. В качестве примера выполнено оценочное моделирование процесса замерзания трещины в леднике, заполненной водой. Получено, что для ледников с температурой ниже –5°C время замерзания 30-сантиметровой трещины составляет менее трёх месяцев
Геобиохимические характеристики снежного покрова побережья Белого моря в 2021 и 2022 гг.
Get PDFFor two years (2021 and 2022) snow sampling carried out in the coastal zone of the Onega and Dvina Bays of the White Sea during the period of maximum snow accumulation (March). The snow was analyzed for the content of the main ions (Cl–,SO42-, Na+, Ca2+, K+); biogenic elements (phosphorus, silicon, nitrogen), pH and mineralization were determined. The algological composition of the snow cover was also studied. The results showed that the snow was slightly acidic (average pH 5.4). Cl– and Na+ were the main ions in the coastal zone; SO42- and Ca2+ in the estuary zone. The high content of marine ions and mineralization were determined near the Paranikha Bay (Dvina Bay), where the release of sea water onto the ice is noted annually. Compared to previous studies, in which snow samples were taken in the costal zone, the content of marine ions in the territory under consideration is an order of magnitude higher. As a result of the influence of marine aerosols, the values of snow cover mineralization can reach 140–680 mg/L. The content of dissolved silicon in melt water is increased in the zone of influence of atmospheric emissions from urbanized territories (Arkhangelsk, Novodvinsk, Severodvinsk), as well as near the granite quarry on the coast of Onega Bay. During the study period, 14 taxa of microalgae (species and supraspecific taxa) belonging to the division Bacillariophyta were found in snow samples. The maximum value of the total number of microalgae (1.293 thousand cells/L.) in the snow cover was determined in 2022.Исследован снежный покров прибрежной зоны Онежского и Двинского заливов Белого моря на содержание главных ионов (Cl–,SO42- , Na+, Ca2+, K+), биогенных элементов (фосфор, кремний, азот), его альгологический состав. Показано, что морские аэрозоли даже в зимний период оказывают значительное влияние на окружающую среду прибрежных районов
Прорыв ледниково-подпрудного озера Спартаковское и изменения выводного ледника купола Семёнова–Тян-Шанского в 2021 г. (Северная Земля)
Get PDFIn the second half of August 2021, outburst flood from the Spartakovskoe Lake, one of the largest glacierdammed lakes in the Russian sector of the Arctic, occurred on the Bolshevik Island (the Severnaya Zemlya archipelago). The lake hollow was drained. The volume of water discharged from the lake into the Spartak fjord was about 376 ± 21 mln. m3 . Only 5 years have passed since the last outburst of the lake in August 2016. The lake hollow was filled with water faster than in the period 2006–2016. The volume of runoff into the lake increased significantly due to more intensive surface ablation on the glaciers of the drainage basin during the anomalously warm summers in 2018–2021. For the up-floating of the ice dam restraining the lake overflowing, the height of the water edge in the lake before the outburst should have been about 113 m. Compared to the state of 2016, the maximum possible water level in the lake has dropped by about 10 m. That was a result of lowering of the glacier surface and, accordingly, a decrease in the thickness of the dam ice. The cartographic method was used to find a location of the area of the greatest depression of the dam surface, the occurrence was conditioned by the development of the under-ice runoff channel in 2016. It can be assumed that during the lake outburst in the second half of August 2021, its location was approximately the same as in 2016. The water level in the lake will no longer be able to rise to the watershed with the Bazovaya River basin (123 m). The flow from the lake to the Bazovaya River is now impossible. The glacial-dammed Lake Spartakovskoe is now a part of only the Kara Sea basin. Under the present-day climatic conditions, the surface of the ice dam decreases and, accordingly, the volume of runoff into the lake increases. In the future, this will probably result in more frequent outburst of the lake, a decrease in its volume, and accordingly, a reduction of the water volume discharging into the lake.Во второй половине августа 2021 г. на острове Большевик (Северная Земля) произошел прорыв ледниково-подпрудного озера Спартаковское. Объём спущенной из озера во фьорд Спартак воды составил около 376 ± 21 млн м3 . Озёрная котловина наполнялась водой в 2016–2021 гг. существенно быстрее, чем в 2006–2016 гг. за счёт усиления поверхностной абляции на ледниках водосборного бассейна в условиях аномально теплого лета в 2018–2021 гг. Система “ледяная плотина–озеро” пришла к новому состоянию – сток в долину реки Базовая происходить более не может
Условия на ложе и поверхности ледникового купола Вавилова (Северная Земля) во время его подвижки по данным аэрорадиозондирования
Get PDFThe glacier surge at Vavilov Ice Cap, Severnaya Zemlya, Russia (79°18′ N, 94°40′ E) began as early as the mid-1960s with a slow advance of its margin in the western part. Since 2012, the advance switched to the phase of catastrophic movement, which reached its climax in 2016, when the glacier velocity reached 9.2 km a‒1. An ice fan with an area of about 140 km2 advanced into the Kara Sea water area 11 km from the shore, and a strongly crevassed ice stream was formed in the ice cap itself, which continues to move now with speeds of about 2 km a‒1. The dynamic instability of Vavilov Ice Cap can be triggered by changes in basal conditions, which are still poorly known. In this study, we used airborne radio-echo sounding data acquired in September 2014 over the ice cap to characterize its surface and bedrock conditions. Based on the delay time and reflection amplitudes, the power reflection coefficient (PRC) from glacier surface and bedrock was estimated. For its calibration, we used the amplitude of reflections from the sea surface registered from different altitudes. The bedrock PRC values were converted to dielectric permittivity and compared with the glacier surface velocities in 2014 obtained from Landsat-7 images. We found a high positive correlation between the bedrock PRCs and velocities in the area with glacier speed higher than 1000 m a-1. In this area, the PRC is 20 dB higher than in the neighboring slower moving areas. Such a difference may be because the ice stream advanced on marine loose sediments with higher dielectric permittivity and conductivity and a higher reflection coefficient. The range of estimated bedrock PRCs corresponds to bed materials with relative dielectric permittivity from 5 to 10 and electrical conductivity from 10–5 to 10–2 Sm m‒1.По данным измерений времени запаздывания и амплитуд радиоотражений от ложа ледникового купола Вавилова, полученным в период быстрой подвижки его западной части, определены значения коэффициента отражения от ложа по мощности, которые коррелируют с высокими скоростями (более 1000 м/год) движения ледника в области, наступившей на участок мелководья
Влияние климатических изменений на условия формирования селей в районах распространения многолетнемерзлых пород на примере Чукотки
Get PDFThe factors influencing the formation of mudflows in areas of the permafrost are considered. The data of studies performed in two regions of Chukotka – “Continental” (the Anyuysky ridge) and “Coastal” (the Iskaten ridge) were used for this research. The air temperature data series obtained in Chukotka in 2000–2020 demonstrate a steady growth of the average annual values. The air temperature rise estimated for the mudflow–dangerous period (June–August) amounted 1.4°C for the “Continental” area, and 1.0°C for the “Coastal”. This warming affects thickness of the seasonal melt layer of permafrost, mainly in the bottoms of valleys and on the slopes of mountains. This factor promotes the involvement of certain volumes of ground into mudflows. As a result of the research, it was found that the dynamics of the change in the thickness of the seasonal melt layer within the studied areas is positive, which is a consequence of warming and leads to additional moistening of grounds. The two periods of the mudflow formation were identified. During the first one (May–June), the mudflow formation is connected with the onset of intensive snowmelt that is favorable mainly for snow-water streams and loose mudflows. In the second period (July–August), mudflows are mostly caused by liquid precipitations, when the maximum thickness of seasonal melt layer is reached. It is the second period when a release of a large cohesive mud stream is the most probable. On the whole, the results obtained allow making a conclusion that in the near future the predominant type of mudflows in Chukotka will remain those of snow genesis. But, at the same time, under conditions of the climate change, occurrence of the snow-water mud streams will increase, especially in the “Coastal” area.Сели повсеместно наблюдаются в горах Чукотки, где их распространение и характеристики во многом определяются вечной мерзлотой. Мы использовали данные полевых исследований 2019 г. и ГИС-анализ ЦМР для оценки вероятности увеличения частоты формирования селей в континентальных и прибрежных районах Чукотки в связи с текущими изменениями климата