Ice and Snow (E-Journal) / Лёд и Снег
Not a member yet
681 research outputs found
Sort by
Колебания ледников Авачинской группы вулканов (Камчатка) в позднем голоцене
Get PDFThe study of moraines at the Avacha volcano group revealed that glaciers changes at all volcanoes within the group happened almost synchronously. Glacial deposits could be grouped into three generations, corresponding to three periods of glacier fluctuations in Neoholocene. The largest glaciation within the group occurred ~2000 years ago. Fragments of moraine, corresponding to that period were found only in the moraine complex of the Ditmar Glacier which was 15% larger then today at that time. The most of moraines at the Avacha volcano group were formed during the Little Ice Age, which in the studied region continued up to the first decades of XX centuries. The maximal advance of glaciers probably happened in XVII century. The moraine corresponding to that period was found at the Kozelsky Glacier valley. At present time the total area of glaciers which moraines were described and dated approaches 21.46 km2. The area of reconstructed moraines corresponding to the Little Ice Age is estimated to be 2.79 km2, therefore at that period the total glaciation area reaches 24,25 км2 exceeding the present area by 13%. It could be claimed that in general during the time past the Little Ice Age the glaciation nature and glacier types did not change sufficiently. The rate of glacier degradation at various parts of the group is different and depends mainly on exposition. At the valleys of four glaciers we found moraines formed in the middle of XX century. They may appear in 1941–1952 when the unfavorable weather conditions leaded to stable negative anomalies in accumulation have happened.Представлена реконструкция колебаний ледников Авачинской группы вулканов в позднем голоцене по результатам изучения моренных комплексов. Выделены и описаны три генерации морен, формирование которых произо- шло около 2000 л.н., в эпоху малого ледникового периода – с середины XVII до начала XX в. и в середине XX в
Активность ледника Малый Актру (Центральный Алтай) и изменения границы леса в бассейне Актру за исторический период
Get PDFMajor problems of dating of the glaciers activity from the wood residues found in moraines are discussed by the example of Maly Aktru Glacier. First of all, these are the underestimation of the glacier development features, the age of the sample itself and its content as well as losses of some outer rings. The study proves that disagreements between dendrochronological and radiocarbon ages of the samples are caused by manifestation of the Suess effect and contents of the wood cells. The reconstruction of June–July temperatures in the Aktru valley for two thousand years was used to reconstruct the altitudinal variability of the tree line thermal potential. Existence of a climatic optimum (I–IV A.D.) had been revealed that brought to the higher position of the tree line in mid ages than its thermal potential could enable. On the basis of variability of growth indices for Siberian larch, it is shown that the medieval optimum stands out against a background of solely strong temperature depressions separating it from ancient and modern times, and the climate’s natural history is evidence that the current climate warming is an ordinary phenomenon.Рассматриваются проблемы датирования активности ледников по древесным остаткам, находящимся в морене, на примере ледника Малый Актру. Анализируются причины расхождения между дендрохронологическим и радиоуглеродным возрастом образцов. Реконструируется ход июньской и июльской температуры в долине р. Актру за две тысячи лет, и на базе этого восстанавливается картина высотной изменчивости термического потенциала границы леса. Основываясь на ходе естественной истории климата, показывается рядовой характер современного потепления
Динамика покровных ледников Антарктиды и Гренландии по результатам скважинных, радиолокационных и космических наблюдений
Get PDFBased on data of measurements in deep ice boreholes, as well as of radar and space geodetic observations in Antarctica and Greenland, a number of new features of the ice mass transport had been revealed. Note that these features do not correspond to the traditional but still hypothetical notions (ideas) of the monotonous and uniform spatial changes in the ice sheet dynamics. Using results of the long-term monitoring of the borehole coordinate axes at the Vostok station (down to 1920 m), east profile Vostok – Vostok 1 – Pionerskaya – Mirny (1409 km, down to the depth of 450 m), and analysis of radar sections, Russian specialists revealed the following: a) the Antarctic ice sheet has stratified changes in speed and a fan-like change in the flow direction along the depth; b) plastic firn layer has individual parameters of dynamics and actually flows down from more monolithic body of the ice sheet (the flow directions differ by 30–80°); c) in some places inside the sheet, the underlying ice masses flow faster than the upper ones. Researchers from the United States and Denmark registered on the radar sections of the lowest third of the ice domes in the central regions of the Antarctica (AGAP) and Greenland (NEEM) some folded structures, which were not typical of ice sheets (vertical amplitude of the folds is about 400 m, inclination of the wings is about 45 degrees or more). The tectonic analysis we have performed allows making a conclusion that a genesis of these ice structures is identical to the diapir folds and to diapirs which are formed at a displacement of lower plastic ice masses by the upper monolithic ones, or to echelon folds of crumpling of lower ice layers at their faster flow along original bed as compared with the overlying ice mass. This makes possible to suggest that a turbulent ice flow can occur in the spacious near-bottom and the most plastic area, and a model of the ice sheet dynamics is considered as extruding of underlying masses by the overlying ones. Specialists of the United States analyzed results of the radar interferometry obtained from satellites of Canada, the US, Europe, and Japan (RADARSAT-1, 2; Envisat ASAR; ERS-1/2; ALOS PALSAR) and determined a velocity of the flow of the day surface of the Antarctic ice sheet. They constructed a map of the 3D-structure of the ice flows and had revealed that the dominating ice diffluence from the central area down to the coastal zone is in a complicated way composed by many local streams. We conducted the morphological analysis and made the conclusion that these flows interact to one another under conditions of the strong differentiation of a surface inclination of the ice flow moving down along the mountain relief of original bedrock, and this process is similar to a merging of glaciers with individual characteristics due to different ice-catchments.На основании измерений в глубоких ледниковых скважинах, радиолокационных и космогеодезических наблюдений в Антарктиде и Гренландии зарегистрирован ряд явлений массопереноса льда, не укладывающихся в традиционные представления о монотонном единообразном изменении в пространстве динамики покровных ледников. Наличие новых экспериментальных данных диктует необходимость пересмотра сложившейся модели динамики ледниковых покровов с учётом следующих особенностей: 1) ледяной поток характеризуется субгоризонтальной расслоённостью по структуре, свойствам и скорости движения льда; 2) радиолокационные разрезы отражают не только «изохронные», но и «изореологические» поверхности; 3) верхний фирновый слой «стекает» с нижней толщи; 4) нижние массы льда в покрове местами перемещаются быстрее верхних, что сопровождается, в частности, образованием структур нагнетания; 5) в нижней трети разреза присутствуют структуры складчатого турбулентного течения льда; 6) общее растекание ледникового покрова представляет собой совокупность локальных ледниковых потоков
Современное оледенение хребта Чихачева (Юго-Восточный Алтай) и его динамика после максимума малого ледникового периода
Get PDFGlaciation of the Chikhachev ridge (South-Eastern Altai) remains poorly known: field observations were not performed since the mid-twentieth century, available schemes and estimates of the glaciation and its scale made on the basis of remote sensing cover only a part of the glaciers, reconstructions of the Little Ice Age (LIA) glaciations are absent. This research was based on interpretation of the satellite images: Landsat-4 (1989), Landsat-7 (2001), and Spot-5 (2011), as well as with the use of data of the field season of 2015. Characteristics of glaciations of the Chikhachev ridge as the whole and of its individual centers (Talduair massif, Mongun-Taiga-Minor massif, and southern part of the Chikhachev ridge) were determined for the first time. Recent glaciation is represented by 7 glaciers with their total area of 1.12 km2 in the Talduair massif, by 5 glaciers with total area of 0.75 km2 in the Mongun-Taiga-Minor massif, and by 85 glaciers with total area of 29 km2 in the southern part of the Chikhachev ridge. Since the LIA maximum, areas of glaciers decreased by 61% in the Talduair massif, by 74% in the Mongun-Taiga-Minor massif, by 56% in the southern part of the Chikhachev ridge with simultaneous lifting of the firn line by 50 m, 65 m, and 70 m, respectively.The largest rates of the glacier contractions were determined for the period 1989–2011. Different mechanisms of the glacier retreats were shown by the example of the glacier complexes Burgastyn-Gol (one-sided retreat and disintegration) and the Grigorjev glacier (gradual retreat of the tongue). Retreat of the Grigorjev glacier has been reconstructed for the period from the LIA maximum until 2015. Average rate of the retreat increased from 1,6 m/year in 1957–1989 up to 11,3 m/year in 2011–2015. The present-day scales of the glaciers and rates of their retreating do not significantly differ from estimations made by other researchers for the nearest centers of glaciation of the Altai arid part. Stabilization of the temperature against the background of increasing precipitation suggests that in future retreating of small glaciers will slow down.На основе дешифрирования космических снимков и полевых исследований составлены каталоги и карты современных ледников малоисследованных центров оледенения Юго-Восточного Алтая: массивов Талдуайр, Монгун-Тайга-малая и южной части хребта Чихачева. Реконструировано оледенение хребта в малую ледниковую эпоху по снимкам 1989, 2001, 2011 гг. и результатам полевых исследований 2015 г.; выявлена динамика оледенения в целом и конкретных ледниковых комплексов
Динамика кромки заприпайной полыньи в Обской губе и прогноз её широтного положения
Get PDFDynamics of the ice edge of (flaw lead) a large polynya in the River Ob Bay was investigated over the period 1997–2016 on the basis of satellite data. More than 800 satellite images were analyzed during the investigation. Relationship between the obtained time series of changing latitude of the ice edge and time series of air temperature, wind and indices of Wangenheim–Girs, the Arctic Oscillation (AO), and North Atlantic Oscillation (NAO) was studied by means of the correlation analysis. The statistical analysis made it possible to reveal that southern position of the ice edge in autumn indicated to warmer winter months. Boundaries of the polynya during every next decade were identically determined by its position during the preceding period, and therewith the pronounced trend of the ice edge shift to south was noticed in 1997–2012. In addition, periodic fluctuations with two different periods were found against the background of trend. During 1996– 2006 the fluctuations were quasi-biennial while after 2006 the period of fluctuations increased up to 4–5 years. Effort to predict the ice edge position aimed at determination of the polynya boundaries in January-February of 2016 was undertaken; data on the air temperature and latitude of the ice edge position for preceding period were used as the predictors. The difference between the prediction and actual data was equal to 0.01 ÷ −0.43 of latitude with the average value for six decades equal to 0.11°. Analysis of inter-annual variability of the edge position indicated that the most close relationship took place with the Vangenheim–Girs index E in May (coefficient of correlation r = −0.73). Maximal values of r exceeding ±0.7 were calculated for the Arctic Oscillation indices in February with a positive shift of one year. When investigating long-term large-scale changes of climatic parameters, analysis of anomalies of average latitude values of the polynya southern boundary had been performed. This allowed to reveal that period of 2005–2006 was a point of inflection. This substantiates the known thesis (conclusion) that a well developed polynya exerts the warming effect on adjacent territories.На основе спутниковых данных рассматривается динамика кромки заприпайной полыньи в Обской губе за период 1997–2016 гг. Граница полыньи в каждую последующую декаду почти однозначно определялась её положением в предшествующий период. Анализ межгодовой изменчивости положения кромки показал, что наибольшая связь прослеживается с индексом Вангенгейма–Гирса Е в мае. Максимальные значения r, превышающие ±0,7, получены для февральских индексов Арктической осцилляции со сдвигом на один год
Изотопно-геохимические исследования нивально-гляциальных систем горного массива Табын-Богдо-Ола (Западная Монголия)
Get PDFResults of investigation of glacio-nival systems made in the Tabyn-Bogdo-Ola mountains (Western Mongolia) are presented in the paper. Average content of δ18О in the Tsagan-Us river water amounts to 17.44‰ that is almost equal to the isotope content in the clear glacier runoff near the edge of the Kozlov Glacier (−17.43‰). It means that the isotope content in water doesn’t significantly change over a distance of 30 km along the Tsagan-Us river. Hence, it appears that for this distance the river has no additional non-glacial feed. The magnitude 17.4±0.1‰ can be considered as the average content of isotopes in the glacio-nival system in the Tabyn-Bogdo-Ola mountain massif. This value can also be the precipitation-weighted average isotope content in the solid precipitations which are accumulated in glaciers of this massif. Seasonal isotope fluctuations are partly preserved in the snow-firn mass in the accumulation area of the Kozlov Glacier. A rate of annual accumulation was estimated by multiplying the apparent thickness (160 cm) of an annual layer into the snow density. According to our observations, it is equal to 800 mm w.e./year during 2013–2014. Accumulation is increased due to the wind and avalanche transportation of snow. During the ablation season, summer and spring snowfalls over the Kozlov Glacier area melt. Thus, it is possible to suppose that the autumn snowfalls play the important role in the accumulation. We may also suppose that the main source of the moisture for the Tabyn-Bogdo-Ola massif is located somewhere in the Inner Asia.По результатам полевых работ 2013 и 2014 г. выполнен анализ изотопных характеристик образцов речной воды, снега и осадков. Оценена степень сохранности сезонного изотопного сигнала в снежно-фирновой толще, а также показана возможность использования изотопно-геохимического метода в гидрологических исследованиях. В области питания ледника Козлова получены оценки годовой аккумуляции в 800 мм. в.э. Показано, что основной источник осадков, питающих массив, – Внутренняя Азия
Пространственно‑временнóе изменение составляющих водного баланса на северном склоне Заилийского Алатау
Get PDFAnalysis of changes in WB components (precipitation, evaporation, glacier runoff, dynamical water resources) on the Northern slope of the Zailiisky Alatau was performed for the 1946–2005 time divided into two periods: 1946–1975 and 1976–2005. The territory under investigation included basins of the following rivers: Bolshaya Almatinka, Malaya Almatinka, Talgar, Turgen, Issyk, Chemolgan, Kaskelen, Kargalinka, Prohodnaya, and Uzunkargaly. Their total area down to the closing gauge points amounts to 2644 km2. Summarized glacier areas in these basins and annual runoff were equal, respectively, to: 306.6 km2 and 39.05 km3in 1946–1975, and 253.0 km2 and 38.35 km3 in 1975–2005. In 1946–2005, typical features of regional glaciation dynamics were increasing area of the moraine cover on glaciers and reducing area of bare ice that results in decreasing of the glacial runoff volume, all other factors being the same. The method to calculate the WB components consists of the following constituents: model of seasonal runoff from melted snow and ice in the areas of accumulation and ablation of glaciers; complex of formulas to calculate precipitation, air temperature and humidity, intensity of ice melting under the moraine, bare ice and evaporation within the height intervals corresponding to the main types of surfaces on the glaciers. On the basis of our method, we could reconstruct for the 1876–2015 period long‑term series of data on a runoff, separately annual values and sums for the vegetation periods. They can be used for regional scientific and applied analyses of the river stream discharges. The data on runoff in the Malaya Almatinka River basin and observational data on the meteorological station Almaty (Hydrometeorological Observatory) had been quantitatively substantiated as the representative information for modeling and calculation of water resources on the Northern slope of the Zailiisky Alatau Range.Анализ изменения составляющих водного баланса (осадки, испарение, ледниковый сток, динамические запасы воды) на северном склоне Заилийского Алатау выполнен для временнóго интервала 1946–2005 гг., разделённого на две части: 1946–1975 и 1976–2005 гг. Пространственные границы района исследования включают в себя бассейны следующих рек: Большая Алматинка, Малая Алматинка, Аксай, Талгар, Тургень, Иссык, Чемолган, Каскелен, Каргалинка, Проходная, Узункаргалы с обшей площадью до замыкающих гидропостов 2644 км2. Суммарные значения площади оледенения в этих бассейнах и годовой объём стока по данным гидрологических и гляциологических справочников 1946–1975 гг. были равны соответственно 306,6 км2 и 39,05 км3, а в 1976–2005 гг. – 253,0 км2 и 38,35 км3. Характерные свойства региональной динамики оледенения в 1946–2005 гг. – увеличение площади моренного покрова на ледниках и сокращение площади открытого льда, что, при прочих равных условиях, приводит к уменьшению объёма ледникового стока. Метод определения составляющих водного баланса включает в себя следующие компоненты: модель сезонного стока от таяния снега и льда в областях аккумуляции и абляции ледников; комплекс расчётных формул для определения осадков, температуры и влажности воздуха, интенсивности таяния льда под мореной, открытого льда и испарения в интервалах высоты для основных типов поверхности на ледниках. Реконструированы многолетние ряды годового и вегетационного стока за 1876–2015 гг., пригодные для региональных научно-прикладных исследований водоносности рек. Количественно обоснована репрезентативность стока в бассейне р. Малая Алматинка и данных наблюдений на метеостанции Алматы для моделирования и расчёта водных ресурсов на северном склоне Заилийского Алатау
Условия питания и изменчивость ледников архипелага Северная Земля по результатам наблюдений 2014–2015 гг.
Get PDFGlaciological investigations on the Severnaya Zemlya archipelago were resumed in 2013 when a new research station «Ice base Cape Baranova» had been organized by Arctic and Antarctic Research Institute in the North-West of the Island Bolshevik. In 2014–2015, the glaciological polygon named after Leonid Govorukha was established on glaciers Mushketov and Semenov-Tyan-Shanskiy. Two years of observations on the glaciers allowed us to estimate the mass balance of the Mushketov Glacier, which was positive in the 2013–2015. By the end of the melting periods, a superimposed ice was formed on the glacier with thickness of 4 cm in 2014 and 17 cm in 2015, on the average. A snow-firn mass with its vertical thickness exceeding 3 m had been found on the upper part of the Semenov-Tyan-Shansky Glacier. Based on analyses of summer air temperatures and precipitation at the meteorological station «The Golomyanny Island», we assumed that in 2013–2015 the mass balance was also positive on the other glaciers of the archipelago, located to the North of the studied glaciers on the Island of Bolshevik. Data of remote sensing of the catastrophic advancing of the outlet glacier from the Vavilov Ice Cap, obtained in 2013–2016, testify that for much longer period, i.e. during 25 years, conditions for the ice mass accumulation were favorable on the southern and eastern slopes of the Vavilov Ice Cap.Гляциологические исследования ААНИИ продолжены работами 2014–2015 гг. на ледниках о. Большевик (архипелаг Северная Земля): Мушкетова высотой 560 м и Семенова-Тян-Шанского высотой 725 м. Работы на полигоне показали положительный баланс массы ледника Мушкетова, питающегося наложенным льдом, и наличие мощной (более 3 м) снежно-фирновой толщи в вершинной части ледника Семенова-Тян-Шанского. Данные метеостанции «Ледовая база «Мыс Баранова» и автоматической метеостанции на леднике Мушкетова позволили определить условия накопления льда. Катастрофическая подвижка на запад выводного ледника из ледникового купола Вавилова обусловлена более чем 25-летним периодом преобладания накопления льда, подлёдным рельефом и всплыванием ледника на глубине моря около 40 м
Исследование разномасштабных взаимосвязей между изменениями приземной температуры воздуха и концентрации СО2 в атмосфере
Get PDFA concept of the anthropogenic origin of the current global climate warming assumes that growth of concentration of the atmospheric carbon dioxide and other greenhouse gases is of great concern in this process. However, all earlier performed analyses of the Antarctic ice cores, covering the time interval of several glacial cycles for about 1 000 000 years, have demonstrated that the carbon dioxide concentration changes had a certain lag relative to the air temperature changes by several hundred years during every beginning of the glacial terminations as well as at endings of interglacials. In contrast to these findings, a recently published careful analysis of Antarctic ice cores (Parrenin et al., 2013) had shown that both, the carbon dioxide concentration and global temperature, varied almost synchronously during the transition from the last glacial maximum to the Holocene. To resolve this dilemma, a special technique for analysis of the paleoclimatic time series, based on the wavelets, had been developed and applied to the same carbon dioxide concentration and temperature time series which were used in the above paper of Parrenin et al., 2013. Specifically, a stack of the Antarctic δ18O time series (designated as ATS) and the deuterium Dome C – EPICA ones (dD) were compared to one another in order to: firstly, to quantitatively estimate differences between time scales of these series; and, secondly, to clear up the lead–lag relationships between different scales variations within these time series. It was found that accuracy of the mutual ATS and dD time series dating lay within the range of 80–160 years. Perhaps, the mutual dating of the temperature and carbon dioxide concentration series was even worse due to the assumed displacement of air bubbles within the ice. It made us to limit our analysis by the time scales of approximately from 800 to 6000 years. But it should be taken into account that any air bubble movement changes the time scale of the carbon dioxide series as a whole. Therefore, if a difference between variations in any temperature and the carbon dioxide time series is found to be longer than 80–160 years, and if these variations are timescale‑dependent, it means that the bubble displacements are not essential, and so these advancing and delays are characteristic of the time series being compared. Our wavelet‑based comparative and different‑scale analysis confirms that the relationships between the carbon dioxide concentration and temperature variations were essentially timescale‑dependent during the transition from the last glacial maximum to the Holocene. The carbon dioxide concentration variations were ahead of the temperature ones during transition from the glacial maximum to the Boelling – Alleroud warming as well as from the Young Drias cooling to the Holocene optimum. However, the temperature variations were ahead during the transition from the Boelling – Alleroud warming to the Young Drias cooling and during the transition from the Holocene optimum to the present‑day climate.С целью выяснения причин современного изменения климата сопоставляются многомасштабные изменения средней глобальной приземной температуры воздуха и концентрации СО2 в атмосфере по данным антарктических ледниковых кернов. Рассматривается период перехода от максимума последнего оледенения к голоцену. Для этого разработана специальная техника кроссвейвлетного анализа временных рядов. Установлено, что соотношения лидирования – запаздывания между изменениями температуры и концентрации СО2 существенно зависели на рассматриваемом временнóм интервале от временных масштабов и фаз ускорения или замедления изменений сравниваемых характеристик
Температурный и радиационный режим ледников на склонах Эльбруса в период абляции за последние 65 лет
Get PDFThe temperature and radiation regimes of the Elbrus mountain area were reconstructed for summer seasons of 1948–2013 using observational data obtained by expeditions of the Institute of Geography of the Russian Academy of Sciences and the Faculty of Geography of the Lomonosov Moscow State University together with NCEP/NCAR reanalysis. This made possible to analyze in details the meteorological conditions and to calculate statistical characteristics of both the air temperature and the radiation components. The reanalysis data were compared with the observational ones for the purpose to estimate an applicability of the reanalysis techniques for reconstruction of the Elbrus temperature regime. Using the above data the temperature trends were analyzed for the last 65 years, and the hypothesis on possible physical mechanisms of intensive glacier melting of the Central Caucasus in the XXI century had been formulated.На основе материалов наблюдений, полученных в экспедициях Института географии РАН и географического факультета МГУ имени М.В. Ломоносова, в сочетании с данными реанализа NCEP/NCAR проведена реконструкция температурного и радиационного режима Эльбруса в летний сезон за период 1948–2013 гг. Проанализированы данные метеорологических измерений, оценены основные статистические характеристики рядов температуры и компонентов радиационного баланса. Выполнено сравнение данных реанализа с натурными исследованиями, сделаны предположения о применимости реанализа для реконструкции термического режима горы Эльбрус. На основе восстановленных данных анализируются тренды температуры за последние 65 лет, формулируется гипотеза о возможных физических механизмах интенсивного таяния ледников Центрального Кавказа в XXI в