Изотопный состав зимних атмосферных осадков и снежного покрова в предгорьях Алтая

Over the past three decades, several general circulation models of the atmosphere and ocean (atmospheric and oceanic general circulation models  – GCMs) have been improved by modeling the hydrological cycle with the use of isotopologues (isotopes of water) HDO and H2 18O. Input parameters for the GCM models taking into account changes in the isotope composition of atmospheric precipitation were, above all, the results obtained by the network GNIP – Global Network of Isotopes in Precipitation. At different times, on the vast territory of Russia there were only about 40 simultaneously functioning stations where the sampling of atmospheric precipitation was performed. In this study we present the results of the isotope composition of samples taken on the foothills of the Altai during two winter seasons of 2014/15 and 2015/16. Values of the isotope composition of precipitation changed in a wide range and their maximum fluctuations were 25, 202 and 18‰ for δ18О, dexc and δD, respectively. The weighted-mean values of δ18О and δD of the precipitation analyzed for the above two seasons were close to each other (−21.1 and −158.1‰ for the first season and −21.1 and −161.9‰ for the second one), while dexc values differed significantly. The comparison of the results of isotope analysis of the snow cover integral samples with the corresponding in the time interval the weighted-mean values of precipitation showed high consistency. However, despite the similarity of values of δ18О and δD, calculated for precipitation and snow cover, and the results, interpolated in IsoMAP (from data of the GNIP stations for 1960–2010), the dexc values were close to mean annual values of IsoMAP for only the second winter season. According to the trajectory analysis (the HYSPLIT model), the revealed differences between both, the seasons, and the long-term average values of IsoMAP, were associated with a change of main regions where the air masses carrying precipitation were formed, namely, the North Atlantic (the winter season of 2014/15) and the inland areas with open ice-free water bodies (the season of 2015/16). Thus, with the correct interpretation of the results, the data on the snow cover isotope composition on the Altai foothills can be used as an alternative data sources instead of the GNIP data.Приводятся результаты изотопного анализа состава атмосферных осадков и снежного покрова предгорий Алтая. Показано, что средневзвешенные значения осадков двух зимних сезонов (2014/15 и 2015/16 гг.) для δ18О составили −21,1‰, а для δD −158,1 и −161,9‰ соответственно и хорошо согласуются с изотопным составом интегральных проб снежного покрова. Проявившиеся отличия в dexc, очевидно, связаны со сменой основных регионов формирования воздушных масс, приносящих атмосферные осадки: сменой открытых ото льда акваторий Северной Атлантики на внутриконтинентальные водоёмы. При корректной интерпретации результатов данные изотопного состава атмосферных осадков и снежного покрова в предгорьях Алтая могут быть использованы в ряде моделей МОЦ

Изотопный состав и регионы-источники зимних осадков в Надымской низменности

According to the forecast of IPCC (Intergovernmental Panel of the Climate Change), an increase in precipitation is expected in this century in the Arctic. The main reason is intensification of evaporation from waters of the Arctic Ocean opening due to the intensive melting of sea ice. It is supposed that these changes will be most severe in winters in the Arctic regions, which are subject to significant anthropogenic load. In this respect, the intensively developed Nadym Lowland may be considered as a promising area for researches. The results of our study showed that the circulation conditions (primarily cyclones coming from the North Atlantic under the Eastern (E) circulation form of the G.Ya. Vangenheim–A.A. Girs classification) significantly influence on the isotopic composition of precipitation in this region. Thus, in the cold period of 2016–2017, the isotopic composition of precipitation changed for δ18О by 21 ‰, and for δD by 167 ‰ (weighted average values δ18О = −22.3 ‰, δD = −172.6 ‰, and dexc = 5.6 ‰). The use of the dew point temperature at the moment of precipitation in the calculations of the isotopic-temperature dependences allows obtaining the following coupling equation: δ18О = 0.67Tdp − 15.2 (R2 = 0.67). On the basis of the joint analysis of synoptic, trajectory and isotopic data, the main regions-sources of atmospheric moisture, precipitated in the Nadym Lowland during the cold period of 2016–2017, were determined. The major contributions were made by the Atlantic Ocean (35.7%), the North Atlantic Ocean and the Arctic Ocean (30.4%), and the Black Sea-Caspian region (20%). The last one is characterized by the most weighted isotopic composition. Inland source regions have contributed the least to precipitation (slightly larger 10%), and their lightweight isotopic composition is related to cryogenic fractionation.В результате совместного анализа синоптических, траекторных и изотопных данных определены основные регионы‑источники поступления атмосферной влаги, выпавшей в виде осадков в Надымской низменности. Наибольший вклад вносит Атлантический океан (35,7%), меньше – северная часть Атлантического океана и Северный Ледовитый океан (30,4%), а также Черноморско‑Каспийский регион (20%) и внутриконтинентальные регионы (немногим более 10%)

МИКРОЭЛЕМЕНТНЫЙ И ИЗОТОПНЫЙ СОСТАВ СНЕЖНОГО ПОКРОВА КАТУНСКОГО ПРИРОДНОГО БИОСФЕРНОГО ЗАПОВЕДНИКА (РЕСПУБЛИКА АЛТАЙ)

The present-day regional level of various trace elements contents together with characteristics of isotopic composition was for the first time estimated in seasonal snow cover of Altai. As a background territory, the State Nature Biosphere reserve «Katunsky» had been chosen. This reserve is included into the World network of biosphere reserves under the UNESCO Program «Man and biosphere». The route snow survey had been carried out at the end of February 2014 since this is a period of maximum snow accumulation. The snow survey involved evaluation of snow storages, stratigraphic analysis of the snow cover, and layer-by-layer snow sampling for analysis of its trace element and isotopic compositions. Isotopic and stratigraphic analysis of visually selected layers of the snow cover revealed substantial variation in the values of δ18O and δD (the maximum difference between layers was 120.1 and 15.3 ‰, respectively), whiledexc changed within the range from 5.6 to 16.6 ‰. The weighted-mean values of the snowpack isotopic composition are the following: δ18O = −24.9 and δD = −188.9 ‰, and the isotopic ratio of oxygen and deuterium is described by the equation δD = 8,3δ18О + 18.9. The analysis of microelement composition of the snow samples made with the use of the crustal enrichment factor (EFc) and correlation matrix allowed determination of elements (Ba, Be, V, Co, Li, Mn, Ni, Sr, Tl, Th, U и Cs) released into the atmosphere above the territory under investigation mainly with particles of fly ash, in which the ratio of elements corresponds to the regional natural sources – soils and underlying rocks. It was shown that the main part of elements Ag, As, Bi, Cu, Mo, Sb, Zn come preferably from anthropogenic sources which are non-ferrous metallurgy enterprises of East Kazakhstan and pits of operating and abandoned mines of Rudny Altai.По наблюдениям зимой 2013/14 г. оценён современный фоновый уровень содержания широкого спектра микроэлементов в сезонном снежном покрове Алтая и изучены особенности изменения его изотопного состава. С помощью расчётных коэффициентов «обогащения» определены элементы (Ba, Be, V, Co, Li, Mn, Ni, Sr, Tl, Th, U и Cs), поступающие в основном в составе золы уноса при сжигании углей и имеющие схожие с природными источниками соотношения данных металлов, тогда как основные источники поступления Ag, As, Bi, Cu, Mo, Sb и Zn – это предприятия цветной металлургии и шламоотвалы горнодобывающих карьеров Рудного Алтая

Изотопный состав и палиноспектры атмосферных осадков и краевых частей ледника Корумду (Северо-Чуйский хребет, Горный Алтай)

The article presents results of study of the isotope composition and pollen spectra of atmospheric precipitation and ice taken from marginal parts of Korumdu Glacier (North-Chu Ridge, the Altai Mountains). The study was aimed at identification of sources and ways of precipitation into the nival-glacial region of Altai. Investigation of the isotope composition of ice taken from the tongue of the Korumdu Glacier and summer precipitation in its basin has shown that here the isotope concentrations are much smaller than similar ones of the cold Belukha Glacier. The last one is located near the Korumdu Glacier. This difference can be explained by the fact that main source of moisture forming layers of relatively warm Korumdu Glacier is precipitation of the cold season while accumulation on the cold Belukha Glacier proceeds during the whole year mainly due to the most heavy precipitation of warm (from March to November) season. Analysis of the isotope composition and the air mass trajectories on the day of July 16, 2013 allowed conclusion that the air masses started their way in the Baltic Sea region and moved mainly along middle latitudes. On this way they underwent insignificant isotope fractionation. Synoptic analysis had shown that the main reason of precipitation on the area under investigation was a front of occlusion over the Altai. In addition, results of palynological analysis of precipitation allow identification sources of pollen in this region. With high probability we can assume that on that day the main sources of pollen in Altai precipitation are as follows: the Naryan-Mar area for Scots pine (Pinus sylvestris) pollen, tundra zones of the East European Plain for alder (Alnaster sp.) pollen and the steppe regions of Kazakhstan, and the West Altai for pollen grains – the dominant component of the pollen spectrum.Исследование изотопного состава льда языка ледника Корумду и летних осадков, выпадавших в его бассейне, показало, что изотопный состав льда изучаемого ледника значительно облегчён как относительно осадков, так и относительно ледовых слоёв расположенного недалеко от Корумду холодного ледника Белуха. Такое отличие, в первую очередь, можно объяснить тем, что основной источник влаги при формировании слоёв тёплого ледника Корумду – атмосферные осадки холодного периода года, в то время как аккумуляция на холодном леднике Белуха происходит весь год, в основном за счёт наиболее обильных осадков тёплого (с марта по ноябрь) периода года. Результаты изотопного и споровопыльцевого анализа атмосферных осадков конкретных единичных событий и данные об обратных траекториях движения воздушных масс (модель HYSPLIT) позволяют получать объективную информацию о генезисе приходящей в изучаемый регион атмосферной влаги, а также определять источники поступления и оценивать дальность переноса пыльцы тех или иных растений на исследуемую территорию. Так, по данным изотопного состава осадков, выпавших в горноледниковом бассейне ледника Корумду 16 июля 2013 г., и траектории движения воздушных масс, принёсших эти осадки на территорию Алтая, сделан вывод, что воздушные массы, начавшие свой путь в Балтике, продвигались преимущественно по умеренным широтам и подвергались незначительному изотопному фракционированию. Анализ синоптической ситуации позволяет утверждать, что основной причиной выпадения осадков на изучаемой территории стало формирование фронта окклюзии над Алтаем. Результаты спорово-пыльцевого анализа осадков дополнительно дают возможность идентифицировать источники поступления пыльцы в изучаемый регион. Например, с большой вероятностью можно предположить, что в это время район г. Нарьян-Мар служил основным источником поступления пыльцы сосны обыкновенной (Pinus sylvestris) в изучаемый ледниковый бассейн. При этом пыльца злаковых – доминирующего компонента пыльцевого спектра – может быть как местной, так и принесённой с севера степных районов Казахстана и запада Алтайского края, а пыльца ольховника (Alnaster sp.) в атмосферных осадках 16 июля 2013 г., вероятно, принесена из лесотундровой и тундровой зон Восточно-Европейской равнины

Стабильные изотопы 18O и D в ключевых компонентах водного стока и криолитозоны Центральной Якутии (Восточная Сибирь)

On the basis of about 430 analyses, the 18O and D compositions (%o) of atmospheric precipitation, ground ice, surface and inter-permafrost underground waters of cryogenic-aeolian landscapes of Central Yakutia (Eastern Siberia) are discussed. Precipitation compositions here demonstrate a large annual variation (from -6.12 to -45.0 % for δ18O, and from -72.1 to -350.1 % for δD), and they are described by the Local Meteoric Water Line according to the equation δD = 7.81518O - 1.57). In winter and in the process of spring melting, the snow storage is subjected to a significant evaporative fractionation, that is expressed by the equation δD = 6.85518O - 31.9. The heaviest and deuterium-depleted compositions (δ18O = -19.3 %, δD = -160.9, dexc = -6.7 %) are found in the last snow patches in early June. The lightest compositions similar to the present-day winter precipitation (snow) are characteristic of the polygonal wedge ices (PWI) of the Central Yakutia. The most lightweight (from -30 to -34 % for δ18O, and from 240 to 275% for δ D) were established to be typical for the ancient PWI, dated by the first half of the Late Pleistocene (MIS 3-4). Heavier compositions (δ18O = -27.2±1.4, δD = -215.8±8.5, dexc = 1.7±3.1 %) with obvious features of evaporative fractionation correspond to younger PWI (MIS 2-1). The heaviest compositions (δ18O = -12.2±0.7, δD = -99.2±4.7, dexc = -2.0±0.8 %) and high angular coefficients of approximating equations were determined in the investigated cave ices of sublimation origin, that implies the atmospheric origin of them. The current processes of evaporative fractionation are the most intensively reflected in the waters of aeolian lakes (δ18O = -11.8±3.5, δD = -120.2±18.4, dexc = -25.8±10.5 %), and the compositions are described by the regression equation 5D = 5.52 δ18O - 54.12 (R2 = 0.97). The phenomenal objects of the cryogenic-eolian landscapes of the Central Yakutia are high-debit underground sources. Among all other components of the water flows, composition of these sources is the most stable (δ18O = -21.6±0.8, δD = -172.6±5.1, dexc = 0.23±3.0 %). The regression of compositions of the largest underground source Bulus is approximated by the equation 5D = 6.31 δ18O - 36.7 (R2 = 0.78), that is indicative to significant evaporative fractionation and close relation with the aeolian lakes in the alimentation area.Особенности рельефа и строения криолитозоны Центральной Якутии связаны с широким распространением здесь позднечетвертичных супесчаных дюнных покровов. Они вмещают разветвлённые сети обводнённых межмерзлотных таликов, гидравлически связанных эоловых озёр, подземных источников, фрагменты едомных отложений с мощными ледяными жилами, а также наледи. На основе выборки более чем из 430 определений обсуждается разнообразие состава стабильных изотопов (18O и D) перечисленных компонентов водного стока

Link of volcanic activity and climate change in Altai studied in the ice core from Belukha Mountain

In the present research we discuss a role of volcanic activity in Altai thermal regime. Here we analyses the sulfate and temperature data reconstructed from the natural paleoarchive – ice core from the Belukha Mountain saddle. Sulfate ice-core reconstructions can serve as volcanic markers. The both – sulfate and temperature reconstructions – are for the last 750 years. As the characteristic of volcanic activity we consider Volcanic Explosivity Index (VEI), Dust Veil Index (DVI) and Ice core volcanic index (IVI). The analysis was done using wavelet analysis and analysis of wavelet cross coherence and phase. As the result, we conclude that observed increases in the values of the indexes VEI, DVI, IVI basically correspond to decreases of temperature and increases of sulfate concentrations. This confirms the dependence of changes in the thermal regime of the Altai from volcanic activity. But in the 1750–1850 years period there is a delay of the changes in temperature with respect to the changes in volcanic activity. We suggest that it can be due to the superposition of the influence of solar and volcanic activity on changes in the thermal regime of Altai

Forecast of temperature changes in the Altai in the next 50 years based on reconstructed ice core data from Belukha Mountain

Paleotemperature time series reconstructed from δ¹⁸O changes in Belukha ice core were expanded into several heteroperiodic sinusoidal functions with the help of the spectral Fourier analysis. The main harmonics selected from obtained periodogram have allowed to perform (without taking into account the contribution of changes in the existing anthropogenic load) scenario forecasts of average annual (from March to November) temperature changes in the Altai region in the nearest future (until 2050). Forecast shows that a cold phase came to Altai since 2008 reaches its maximum by 2020. Then after the 15-year period of temperature increase a cold phase will come back after 2035. Our forecast agrees very well with the forecast made from the natural climatic variability (for example, the change of global temperature for the last 150 years)

Isotope composition of macrocirculation processes responsible for precipitation in the Altai mountains

An estimation of changes in the precipitation over the Altai mountains in 1959-2016 was carried out using the Mann-Kendall-Sneyers test. It was found that the precipitation has a step change in 1980. The step change point of precipitation in the Altai mountains coincides with the beginning of «zonal epoch of elementary circulation mechanisms» for the Siberian sector according to Dzerdzeevskii’s classification. B.L. Dzerdzeevskii considered 41 subtypes of elementary circulation mechanisms (ECMs) based on analysis of maps of baric topography at the 500 hPa level. To reveal the role of various ECMs in the Altai precipitation, we calculated the contribution of the ECMs which correspond to the Siberian sector to the precipitation. It was found that the most significant contribution to the precipitation regime of the Altai mountains was provided by the «West zonal and southern meridional» circulation group. The maximal contribution to the precipitation of 2016 was given by the «West zonal and southern meridional» circulation group (26.8%). The precipitation of this ECM group is characterized by the heaviest isotope composition (δ18O -9.85‰ and δD -78.65 ‰) relatively to the values obtained for the other circulation groups. In the ECM of this group of circulations the precipitation is most often caused by southern cyclones coming from the Aral-Caspian region, the waters of which have the heaviest isotope composition

Isotope composition of winter precipitation and snow cover in the foothills of the Altai

Over the past three decades, several general circulation models of the atmosphere and ocean (atmospheric and oceanic general circulation models  – GCMs) have been improved by modeling the hydrological cycle with the use of isotopologues (isotopes of water) HDO and H2 18O. Input parameters for the GCM models taking into account changes in the isotope composition of atmospheric precipitation were, above all, the results obtained by the network GNIP – Global Network of Isotopes in Precipitation. At different times, on the vast territory of Russia there were only about 40 simultaneously functioning stations where the sampling of atmospheric precipitation was performed. In this study we present the results of the isotope composition of samples taken on the foothills of the Altai during two winter seasons of 2014/15 and 2015/16. Values of the isotope composition of precipitation changed in a wide range and their maximum fluctuations were 25, 202 and 18‰ for δ18О, dexc and δD, respectively. The weighted-mean values of δ18О and δD of the precipitation analyzed for the above two seasons were close to each other (−21.1 and −158.1‰ for the first season and −21.1 and −161.9‰ for the second one), while dexc values differed significantly. The comparison of the results of isotope analysis of the snow cover integral samples with the corresponding in the time interval the weighted-mean values of precipitation showed high consistency. However, despite the similarity of values of δ18О and δD, calculated for precipitation and snow cover, and the results, interpolated in IsoMAP (from data of the GNIP stations for 1960–2010), the dexc values were close to mean annual values of IsoMAP for only the second winter season. According to the trajectory analysis (the HYSPLIT model), the revealed differences between both, the seasons, and the long-term average values of IsoMAP, were associated with a change of main regions where the air masses carrying precipitation were formed, namely, the North Atlantic (the winter season of 2014/15) and the inland areas with open ice-free water bodies (the season of 2015/16). Thus, with the correct interpretation of the results, the data on the snow cover isotope composition on the Altai foothills can be used as an alternative data sources instead of the GNIP data