Ice and Snow (E-Journal) / Лёд и Снег
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Изотопные характеристики атмосферных осадков в Приэльбрусье
Get PDFThe aim of the work was to study the isotopic characteristics of precipitation to establish the dependence of δ18O values on temperature at the time of precipitation and to get closer to understanding the processes that form the isotopic signature of the Elbrus snow cover and glacial ice. The sampling of precipitation was organized at Azau station, located at the foot of Elbrus at an altitude of 2300 m for the period from May 01.2019 to September 27.2021. The sampling was carried out once a day at 9:00 Moscow time. The air temperature was recorded at the meteorological station in the Terskol village (Roshydromet station No. 4334250). To study the main features of long-range air transport and possible sources of moisture, 5-day back trajectories were reconstructed using the NOAA HYSPLIT_4 trajectory model. The results showed that precipitation in the Elbrus region in winter was associated with the prevailing transfer from the Atlantic, in summer – with the predominance of transfer from the regions of Central Europe, the Mediterranean and Black Seas. The Mediterranean Sea in all seasons was the area from which the air and moisture were transferred to Elbrus. The values of δ18О and δ2 Н of precipitation varied from 0.52 to −28.22‰ and from 16.3 to −224.1‰, respectively, revealing regular seasonality with high values of δ18О and δ2 Н in summer and low in winter. The deuterium excess varied over a wide range from 24.8 to −14.6‰. All obtained values of δ18О and δ2 Н were approximated by the equation δ2 Н = 8δ18О + 7.06 (R2 = 0.98), which was close to the global meteoric water line. In general, for 2 years of observations, the relationship between the δ18О values of precipitation and the temperature of the surface air layer was expressed as 0.85‰/°С. Total mean absolute error in the reconstruction of air temperatures from the δ18О value of precipitation was 3.2°С due to objective reasons and also differences in meteorological conditions of two years of observations.Приведены результаты изучения изотопных характеристик осадков, выпадающих у подножия южного склона Эльбруса, Кавказ. Отбор осадков организован на станции Азау (абс. высота 2300 м) на ежедневной основе. Установлены основные источники осадков для Приэльбрусья с применением метода обратных траекторий движения воздушных масс. Значения δ18О осадков содержат выраженную связь с температурой приземного слоя воздуха: Δδ18О/ΔT = 0.85‰/°С
Изотопные исследования льда пещер Аскинская и Киндерлинская (Южный Урал)
Get PDFThe aim of this work was to determine mechanisms of formation of perennial ice in caves of the Southern Urals, as well as to find sources of water and processes responsible for the formation of isotopic parameters of the cave ice. Isotopes δ18О and δD were investigated. The caves Askinskaya and Kinderlinskaya are the most famous ones in the Southern Urals located at the lowest levels a.s.l. (260 and 208 m, respectively). In the summer of 2019, samples of perennial ice and infiltration water were taken in both caves. Ices of the Askinskaya and Kinderlinskaya caves are characterized by a narrow range of δ18О and δD values with very slight variations in depth: −11.42…−12.89‰ and −83.8…−95.7‰, respectively. Values the isotopes in the infiltration water sampled in the Kinderlinskaya cave are: δ18О = −13 and δD = −76‰. For both Askinskaya and Kinderlinskaya caves, the isotopic parameters of ice correspond to the calculated line of Rayleigh crystallization in a closed system when water with the isotopes freezes. The narrow range of values δ18О and δD suggests that aufeises (naleds) existing in caves for many years are the congelation (hydrogenic) ice formed by the growth of thin water layers freezing through at a high rates. Infiltration waters are formed mainly due to the precipitation of the winter seasons. The ratio between winter and summer precipitation is about 2:1. The infiltration type of the cave ice alimentation as well as evidence of long time of averaging of the isotopic signal in the atmospheric precipitation do not allow to use the cave ices as a climatic (paleo)archive.Оценены вариации изотопного (δ18О, δD) состава наледного льда в пещерах Аскинская и Киндерлинская (Южный Урал). Установлено, что источником льда были инфильтрационные воды длительного пребывания в порово-трещинном пространстве карбонатных пород, питание которых происходит преимущественно за счёт атмосферных осадков осенне-зимнего периода
Состояние взлётно-посадочной полосы станции Новолазаревская (Восточная Антарктида) и оценка безопасности её эксплуатации по данным исследований 2021 г.
Get PDFAirbase Novo Runway has the status of the largest transport hub in the northern part of Antarctica, which can land large airlifter on wheeled chassis. However, the unsteady flow of the glacier leads both to the formation of hazardous glacial crevasses and changes the configuration of the runway. The purpose of this study was to investigation the state of the Novo Runway and to identify the degree of uneven flow of the glacier in this area. The article shows the results of research carried out from late October to mid-December 2021. Field work included GPR profiling, tacheometric survey, mechanical drilling, and downhole thermometry. The tacheometric survey was carried out at the beginning and at the end of the field work (in 42 days) to determine the displacements of pickets fixed on the glacier and then to calculate the glacier deformation rates. The results of the studies showed that there are no open crevasses in this area, which pose a danger to aircraft. There are non-hazardous healed crevasses at the beginning and end of the runway. At the same time, GPR data indicate that in the central part of the runway (at the distances from 1720 meters to 2240 meters from its beginning), there is a zone of junction of glacial flows. This zone is traced on parallel profiles for more than one kilometer. Calculation results indicate that the strain rates in this area in the transverse direction (across the runway) reaches -0.183 year-1. This corresponds to deformations (compressions) of more than 1.4 meters over 42 days of observations in absolute terms. Although these values significantly exceed the threshold values, there were no open crevasses in the glacier. It can be assumed that relatively recently the glacier flowed more slowly than now. This research should be continued to draw broader conclusions about the dynamics of the glacier in the area of the Novo Runway.Рассмотрены результаты комплексных инженерных изысканий, выполненных на посадочной площадке станции Новолазаревская в сезон 2021/22 г. Установлено, что в центральной части взлётно-посадочной полосы наблюдается сочленение двух ледовых потоков. Абсолютные скорости деформаций ледника на этом участке достигают -0,183 год-1, что существенно превышает пороговые значения, однако открытых трещин в леднике не наблюдалось
Многолетняя динамика гигантской Анмангындинской наледи на Северо-Востоке России (1962–2021 гг.)
Get PDFThe huge Anmangynda aufeis is located in the valley of the river of the same name in the Magadan region in North-East of Russia. This is the only in the world aufeis site with a 30-years period of ground-based observations (1962–1991). The materials of these observations were supplemented with data obtained from the analysis of Landsat and Sentinel satellite images for the period 2000–2021, as well as the results of field investigations carried out in 2020–2021. The long-term variability of the maximum area, volume and average thickness of ice, the dynamics of formation and destruction of the aufeis ice in the cold and warm periods of the year were analyzed. It was found that the maximum values of the area and volume of ice on the dates before the start of ablation decreased by 25 and 33%, respectively. In 2000–2021, the average values of the aufeis characteristics are estimated as 4.7 km2 and 7.1 million m3, while in 1962–1991 – 5.5 km2 and 8.5 million m3. The analysis of the intra-annual dynamics revealed that the Anmangynda aufeis being earlier the perennial formation has transformed to the seasonal one. Further researches of the Anmangynda aufeis will make possible to assess the influence of various factors, including climatic ones, on the processes of an aufeis formation and to forecast their changes in the future for the cryolitic zone of the North-East of our country.Приводятся материалы о многолетней и сезонной изменчивости морфометрических характеристик гигантской наледи в долине реки Анмангында на Северо-Востоке России. Показано, что за последние 60 лет максимальная площадь тарына сократилась на 25%, а объём на 33%. Период абляции ледяного массива уменьшился на 34 дня, наледь из разряда перелетовывающей перешла в категорию сезонных образований
Химический состав гидрокриогенной системы: снег на льду–лёд–подлёдная вода озера Байкал
Get PDFThe results of studies of the chemical composition and the basic regularities of migration of macro- and microelements within the hydro-cryogenic system “snow on ice–ice–water under ice” obtained in the winter of 2016/17 in the waters of Lake Baikal are presented. Such investigation over the Lake area was carried out for the first time. It has been found that due to climatic conditions, dates of freeze-up (formation of the ice on the Lake) differ by 7–10 days from North to South, and the depth of snow on ice and its density change over the Lake area by 2 times, however there are some parts without snow. It was found that the changes in the pH indexes were identical across the whole Lake area – minimum pH values are present in the snow (from 5.59 to 7.39), average values – in the ice (6.01–7.50), and maximum values are noted in the water under ice (7.42–8.50). For the most part, increased quantities of suspended matter and an increase in the pH of snow were recorded near settlements, which is obviously a result of the anthropogenic influence. It was determined that the concentration of ions in the ice in relation to their content in the initial solutions decreases within the series: NO2–> Cl – >SO42– >HCO3– . Among the cations, K+, Na+ ions are involved into the ice intensively, while the Ca2+ and Mg2+ – weakly. The ice phase is enriched with ammonium ions outside the settlements. Near settlements and in shallow water, quantity of salts in the ice may be close to or equal to their concentration in the water under ice. The coefficient of migration in the water (Kx) divide the chemical elements into two groups – the mobile ones and slow-moving elements. The first group includes Ca, Cu, Sr, Mg, Co, Zn, and Cd (Kx >1), the second one contains Ba, Mn, Si, Fe, Al, Ti, Ni, Cr, P, and K.Представлены результаты исследований гидрокриогенной системы: снег на льду–лёд–подлёдная вода, полученные в зимний период 2016/17 г. на акватории озера Байкал. Показаны особенности химического состава, распределение водородного показателя, минерализации, ионный состав и основные закономерности миграции макро- и микроэлементов гидрокриогенной системы снег на льду–лёд–подлёдная вода
Оценка погрешности измерений средней высоты снежного покрова на леднике Альдегонда (Шпицберген)
Get PDFThis study introduces an empirical equation allowing to estimate an uncertainty of area-averaged snow depth on the Aldegondabreen Glacier, computed from standard snow surveys and made by an avalanche probe or by similar equipment. The two-decade history of the ongoing mass-balance monitoring program on this glacier shows that the methodology of field work on snow-measuring survey varies somewhat from year to year: the number and location of measurement points change. To identify and quantify long-term trends and variations in snow cover, it is crucial to assess the inter-comparability of the data in the obtained measurement series. The proposed equation was intended to solve this task basing on the collected data only, allowing to estimate the uncertainty even retrospectively. To build this equation, we applied a bootstrap statistical approach to the results of snow surveys carried out in Svalbard in 2015–2021. After interpolating the field measurements, obtained rasters were sampled sequentially with different numbers of points, simulating the real snow survey. The points were initially located in a form of a quasiregular grid and then randomly shifted between the iterations. After a thousand simulations for each number of points, the standard deviations were calculated relative to the “true” values, derived from corresponding rasters. These standard deviations, which we admit to be a random error of the area-averaged snow depth value, expectedly decrease with the number of sampling points and increase with the coefficient of variation ( ). The well-known index indirectly characterizes the irregularity of snow cover. After approximating the bootstrap results, the authors derived an equation that yields a relative error. The equation includes only two predictors which are the probing density per area unit and the , which potentially allows using it for the other glaciers. However, the universality of the empirically obtained coefficients is debatable, since they may vary due toa glacier size, its morphology and other parameters.Предложен метод оценки относительной погрешности средней высоты снежного покрова, получаемой на архипелаге Шпицберген по снегомерным съёмкам. Уравнение для оценки погрешности включает в качестве предикторов плотность промеров на единицу площади и коэффициент вариации высоты снега. Уравнение получено на основе результатов применения статистического метода бутстрэп к набору данных снегомерных съёмок 2015–2021 гг. на леднике Альдегонда
Механическое бурение ледников с очисткой забоя сжатым воздухом
Get PDFForecasting of the Earth's climate change is important for many spheres of human activity but this cannot be successful without reliable paleoclimatic information, an important source of which is the ice core material obtained during drilling of glaciers. The process of core sampling from the upper permeable snow-firn layers of glaciers is complicated by huge losses of the drilling fluid. One of the possible solutions to this problem is using of compressed air to clean the borehole and transport the slime up to the surface due to its easy replenishment. A review and analysis of international experience in mechanical ice drilling using compressed air as a cleaning agent has shown that the method under consideration has a number of disadvantages (loss of air in permeable glacier layers, accumulation of heavy rime and formation of ice sticking) that limit its use. However, the scheme of air reverse bottom-hole air circulation, first applied by scientists from the St. Petersburg Mining University on the dome of the Academy of Sciences Glacier (the Severnaya Zemlya archipelago) is free of the above disadvantages. To adapt this method to conditions of drilling in Antarctica, it is necessary to carry out a complex of researches, the implementation of which will allow creating a new cable-suspended electromechanical drill for efficient and environmentally friendly drilling of the upper layers of glaciers.Проведён обзор и анализ зарубежного и отечественного опыта бурения льда с применением сжатого воздуха в качестве очистного агента. На основании анализа обзора предложен способ, отличительная особенность которого – использование буровых снарядов на грузонесущем кабеле с обратной призабойной циркуляцией воздуха. Установлены достоинства и недостатки данного метода, а также распространённых на сегодняшний день технологий бурения снежно-фирновых горизонтов. Сформулирован комплекс научно-исследовательских работ, проведение которых позволит создать новый электромеханический снаряд для реализации предлагаемого способа
Баланс льда в Северном Ледовитом океане в 1979–2019 гг. (по данным моделирования)
Get PDFThe results of numerical experiments on the model of joint water and ice circulation for the period from September 1979 to December 2019, aimed at studying the interannual variability of the ice balance in the Arctic Ocean, are considered. The results obtained made it possible to analyze the geographical features of the processes of ice formation and melting in the Arctic Ocean and to identify key areas that determine the volume of ice in the ocean. It is established that the main quantity of ice is formed in waters of the Siberian seas, and the most intense melting occurs in the North European Basin, where the ice transported by the Transpolar Current through the Fram Strait enters the relatively warm water of the Greenland Sea, heated by the North Atlantic Current. The formation of the absolute minimum of ice coverage in 2012 was promoted by the anomalous position of the anticyclonic hydrological cycle – much closer to the Canadian coast. This resulted in the fact that only a small part of the ice formed in the Siberian seas was involved into a weakened circulation, while most of the ice in the stream of the Transpolar Current was transported through the Fram Strait to the Greenland Sea. Statistical analysis of the results of numerical experiments demonstrated that the trend towards a decrease in the volume of ice in the Arctic Ocean is primarily determined by the global warming, and dynamic forcing exerts significant effect on local extremes.Для исследования изменчивости баланса льда Северного Ледовитого океана использовалась модель совместной циркуляции вод и льдов. Результаты специальных численных экспериментов для периода с сентября 1979 г. по декабрь 2019 г. позволили установить некоторые географические особенности процессов образования и таяния льда. Статистический анализ результатов показал, что тренд на уменьшение объёма льда в Северном Ледовитом океане определяется в первую очередь глобальным потеплением, а на локальные экстремумы сильное влияние оказывает динамический форсинг
Катастрофические лавины на Сахалине и Курильских островах (1910–2020 гг.)
Get PDFSakhalin Island and the Kuril Islands are among the most dangerous regions in Russia in terms of the impact of avalanches on the population and economics. The orographic conditions of Sakhalin Island and the Kuril Islands impose limitations on the selection of areas for housing settlements and economic enterprises, that is why many of them are situated in avalanche-prone zones. Sixty-three settlements of the region are located in such zones. The article provides the most complete recent information about catastrophic avalanches on Sakhalin Island and the Kuril Islands for the period from 1910 to 2020. During this time, 256 events of releases of the catastrophic avalanches were recorded; as a result of which 1203 people were injured, and 783 died. Information on the conditions when catastrophic avalanches release and their characteristics are presented. It was found that during this period cases of people being caught or deceased in avalanches took place in 72% of winters, and in 12% of them there were five or more catastrophic avalanches per season. The largest number of catastrophic avalanches released on the western coast of Southern Sakhalin, which was conditioned by significant economic development and the high avalanche activity on this area. Despite the large number of avalanche victims, engineering avalanche protection still exists on Sakhalin and the Kuril Islands only on a very limited number of sites, and avalanche prevention services are few and cannot provide an adequate level of avalanche safety on these territories.Приведены сведения о катастрофических лавинах на острове Сахалин и Курильских островах за период с 1910 по 2020 г. За это время зафиксировано 256 случаев схода катастрофических лавин (пострадали 1203 человека, из них 783 – погибли). Рассмотрены условия схода катастрофических лавин и даны их характеристики. Установлено, что случаи попадания или гибели людей в лавинах отмечены в 72% зим этого периода, а в 12% зим происходило пять и более лавинных катастроф
Пространственно-временнáя изменчивость снегонакопления на Западном плато Эльбруса (Центральный Кавказ)
Get PDFCold glaciers in the middle latitudes are considered unique archives of environmental and climate change. However, alpine ice cores are difficult to interpret, since dynamic changes can occur over very short distances. Detailed radar survey can be used to assess the effect of ice inflow from areas with different conditions of snow accumulation on the surface compared to the drilling point on the isotopic and chemical record in the glacier core. The results of radar studies on the Western plateau of Elbrus (Central Caucasus), located at an altitude of 5100–5150 m above sea level, are presented. A high-frequency ground-based radar survey was carried out in the summer of 2017 to assess the spatial and temporal changes in snow accumulation in the upper (near the top area) part of Elbrus. The ZOND 12-e GPR (ground-penetrating radar, Radar Systems, Inc.) with 500 and 300 MHz shielded antennas was used. The receiving time window was set to 100 ns (500 MHz antenna) and 470 ns (300 MHz) to obtain reflection in the depth range of about 10 m and 50 m, respectively. The results of the GPR sounding are confirmed by data on the stratigraphy, density and chemical composition of the snow-firn thickness from a shallow (24 m) borehole. The density profile made it possible to identify peaks and corresponding ice crusts of 1–2 cm thick that formed during warm periods. The internal reflections, clearly visible on the radar profiles up to 50 m deep, are of isochronous origin and have been interpreted as the boundaries of annual and seasonal layers. Detailed maps of the distribution of snow accumulation covering the cold and warm seasons of 2015–2017 have been obtained. The average thickness of seasonal snow cover on the plateau during this period was equal to 2.07 m, with minimum and maximum values of 0.2 and 3.9 m, respectively. The average values of the water storage in seasonal horizons range from 754 to 1126 mm W.E., while the annual accumulation for the 2015/16 and 2016/17 balance years amounted to 2004 and 1874 mm W.E., respectively. The data obtained were used in 2018 to determine the optimal location for deep core drilling and will further serve as the basis for modeling the age of ice on the Western Plateau of Elbrus.По данным наземного высокочастотного радиозондирования летом 2017 г. на Западном ледниковом плато Эльбруса (Центральный Кавказ) установлено, что аккумуляция снега в привершинной области характеризуется значительной изменчивостью, а также имеет сезонные различия. Анализ полей аккумуляции показал, что в средней части плато снега накапливается меньше, чем в восточной и западной, но распределение снега по площади плато аналогично из года в год. В тёплый период снегонакопление в среднем больше, чем в холодный, и происходит оно более равномерно по площади плато