О разрабатываемом методе анализа ледяных кернов с высоким разрешением

A continuous flow analysis (CFA) is a relatively new ice core analysis method deployed worldwide nowadays. This method allows measuring geochemical and gas concentrations in the ice core samples with ultra-high resolution in depth (age) domain. Different modifications of the CFA experimental setups were built in many research centers dealing with the ice cores and paleoclimate studies. Here we provide a brief history of the method, a description of a typical CFA setup. We analyze the advantages and disadvantages of a setup and propose some ways to solve current technical issues. We show the main principle of the first Russian CFA setup, which is to be built at the Climate and Environmental Research Laboratory, AARI, in order to measure a concentration of atmospheric dust particles and methane in the old atmospheric Vostok ice core.В статье приведена краткая история метода анализа непрерывного потока (Continuous Flow Analysis — CFA), дано описание типичной многофункциональной установки CFA, проанализированы ее преимущества и недостатки, а также намечены пути решения существующих технических проблем. Описаны основные параметры первой в России экспериментальной установки CFA, которую планируется создать в Лаборатории изменений климата и окружающей среды (ЛИКОС) ААНИИ для измерения концентрации частиц атмосферной пыли и метана в керне древнего льда со станции Восток

Variations of snow accumulation rate in Central Antarctica over the last 250 years

The present-day global climate changes, very likely caused by anthropogenic activity, may potentially present a serious threat to the whole human civilization in a near future. In order to develop a plan of measures aimed at elimination of these threats and adaptation to these undesirable changes, one should deeply understand the mechanism of past and present (and thus, future) climatic changes of our planet. In this study we compare the present-day data of instrumental observations of the air temperature and snow accumulation rate performed in Central Antarctica (the Vostok station) with the reconstructed paleogeographic data on a variability of these parameters in the past. First of all, the Vostok station is shown to be differing from other East Antarctic stations due to relatively higher rate of warming (1.6 °C per 100 years) since 1958. At the same time, according to paleogeographic data, from the late eighteenth century to early twenty-first one the total warming amounted to about 1 °C, which is consistent with data from other Antarctic regions. So, we can make a conclusion with high probability that the 30-year period of 1985–2015 was the warmest over the last 2.5 centuries. As for the snow accumulation rate, the paleogeographic data on this contain a certain part of noise that does not allow reliable concluding. However, we found a statistically significant relationship between the rate of snow accumulation and air temperature. This means that with further rise of temperature in Central Antarctica, the rate of solid precipitation accumulation will increase there, thus partially compensating increasing of the sea level

Capturing the Fire: Flame Energetics and Neutronizaton for Type Ia Supernova Simulations

We develop and calibrate a realistic model flame for hydrodynamical simulations of deflagrations in white dwarf (Type Ia) supernovae. Our flame model builds on the advection-diffusion-reaction model of Khokhlov and includes electron screening and Coulomb corrections to the equation of state in a self-consistent way. We calibrate this model flame--its energetics and timescales for energy release and neutronization--with self-heating reaction network calculations that include both these Coulomb effects and up-to-date weak interactions. The burned material evolves post-flame due to both weak interactions and hydrodynamic changes in density and temperature. We develop a scheme to follow the evolution, including neutronization, of the NSE state subsequent to the passage of the flame front. As a result, our model flame is suitable for deflagration simulations over a wide range of initial central densities and can track the temperature and electron fraction of the burned material through the explosion and into the expansion of the ejecta.Comment: 21 pages, 24 figures, to appear in Ap

Дослідження стійкості геміклональних популяційних систем гібридогенного комплексу зелених жаб за допомогою імітаційного моделювання

The concept of stability used in ecology and mathematics is analyzed. Stability is interpreted as the ability of the system to remain in a restricted zone of a phase space that corresponds to a certain type of systems. This approach is applied to describe changes in the structure of hemiclonal population systems of hybridogenous complex of water frogs (Pelophylax esculentus complex). Simulation model of these population systems built on a recursive difference equations in MS Excel is used. The dynamics of transitions in the part of phase space of the hemiclonal populationsystems of water frogs is described. Typology of stabile states of biosystems is analyzed.Проанализировано понятие устойчивости в экологии и математике. Обосновывается трак­товка устойчивости как способности системы оставаться в ограниченной зоне фазового пространства, соответствующей определенному типу рассматриваемых систем. Этот подход применен для описания изменений состава гемиклональных популяционных систем гибридогенного комплекса зеленых лягушек (Pelophylax esculentus complex). Использована имитационная модель, построенная на рекур­рентных разностных уравнениях в MS Excel. Описана динамика переходов в части фазового пространства гемиклональных популяционных систем зеленых лягушек. Проанализирована типология состояний устойчивости биосистем. Проаналізовано поняття стійкості в екології та математиці. Обґрунтовується трактування стійкості як здатності системи залишатися в обмеженій зоні фазового простору, що відповідає певному типу систем, які розглядаються. Цей підхід застосований для опису змін складу геміклональних популяційних систем гібридогенного комплексу зелених жаб (Pelophylax esculentus complex). Використано імітаційну модель, побудовану на рекурентних різницевих рівняннях в MS Excel. Описано динаміку переходів у частині фазового простору геміклональних популяційних систем зелених жаб. Проаналізовано типологію станів стійкості біосистем.

Decadal Scale Variability of Larsen Ice Shelf Melt Captured by Antarctic Peninsula Ice Core

In this study, we used the stable water isotope record (δ18O) from an ice core drilled in Palmer Land, southern Antarctic Peninsula (AP). Utilizing δ18O we identified two climate regimes during the satellite era. During the 1979–1998 positive interdecadal Pacific oscillation (IPO) phase, a low-pressure system north of the Weddell Sea drove southeasterly winds that are associated with an increase in warm air mass intrusion onto the Larsen shelves, which melted and a decreased sea ice concentration in the Weddell Sea/increase in the Bellingshausen Sea. This climate setting is associated with anomaly low δ18O values (compared with the latter IPO period). There is significantly more melt along the northern AP ice shelf margins and on the Larsen D and southern Larsen C during the 1979–1998 IPO positive phase. The IPO positive climatic setting was coincidental with the Larsen A ice shelf collapse. In contrast, during the IPO negative phase (1999–2011), northerly winds caused a reduction in sea ice in the Bellingshausen Sea/Drake Passage region. Moreover, a Southern Ocean north of the Weddell Sea high-pressure system caused low-latitude warm humid air over the tip and east of the AP, a setting that is associated with increased northern AP snowfall, a high δ18O anomaly, and less prone to Larsen ice shelf melt

Ice Core Chronologies from the Antarctic Peninsula: The Palmer, Jurassic, and Rendezvous Age-Scales

In this study, we present the age scales for three Antarctic Peninsula (AP) ice cores: Palmer, Rendezvous, and Jurassic. The three cores are all intermediate-depth cores, in the 133–141 m depth range. Non-sea-salt sulfate ([nssSO42−]) and hydrogen peroxide (H2O2) display marked seasonal variability suitable for annual-layer counting. The Palmer ice core covers 390 years, 1621–2011 C.E., and is one of the oldest AP cores. Rendezvous and Jurassic are lower elevation high-snow accumulation sites and therefore cover shorter intervals, 1843–2011 C.E. and 1874–2011 C.E., respectively. The age scales show good agreement with known volcanic age horizons. The three chronologies’ start and end dates of volcanic events are compared to the volcanic events in the published WAIS Divide core. The age difference for the Palmer age scale is ±6 months, Rendezvous ±9 months, and Jurassic ±7 months. Our results demonstrate the advantage of dating several cores from the same region at the same time. Additional confidence can be gained in the age scales by evaluating and finding synchronicity of [nssSO42−] peaks amongst the sites.</jats:p

Solution combustion synthesis of α-Al2O3 using urea

The processes involved in the solution combustion synthesis of α-Al2O3 using urea as an organic fuel were investigated. The data describing the influence of the relative urea content on the characteristic features of the combustion process, the crystalline structure and the morphology of the aluminium oxide are presented herein. Our data demonstrate that the combustion of stable aluminium nitrate and urea complexes leads to the formation of α-alumina at temperatures of approximately 600-800 °C. Our results, obtained using differential thermal analysis and IR spectroscopy methods, reveal that the low-temperature formation of α-alumina is associated with the thermal decomposition of an α-AlO(OH) intermediate, which was crystallised in the crystal structure of the diaspore. © 2012 Elsevier Ltd and Techna Group S.r.l

Climatic variability in the era of MIS-11 (370-440 ka BP) according to isotope composition (delta D, delta O-18, delta O-17) of ice from the Vostok station cores

The results of detailed isotopic studies of ice core samples from the Vostok station (East Antarctica) related to the MIS-11  era (the 11th sea isotope stage, i.e. 370–440 thousand years ago) are presented. Reconstruction of paleoclimatic conditions in this period of time was performed using the method of interpretation of the results of isotopic studies of ice, developed by the authors of the article, which is based on the joint analysis of three independent parameters: δD, d-excess, 17O-excess. The isotopic composition (δD) and the deuterium  excess depend on the following  three meteorological  parameters – the condensation temperature near the Vostok station, relative humidity,  and the sea surface temperature at the source of moisture, whereas 17O-excess depends only on the first two parameters. Accordingly,  the proposed method of interpretation allows reconstructing the paleoclimatic conditions (the condensation temperature and surface air temperature at the Vostok station; sea surface temperature and relative humidity  above the ocean) in two different regions in past epochs. For the first time, data on minor fluctuations in the relative humidity of the air in themoisture source throughout the MIS-11  era were obtained. The data resulted from the interpretation demonstrated that the relative humidity fluctuated within the measurement error of ±5%. Reconstructed climatic conditions in the era of MIS-11  were compared with published data for stations Vostok and Concordia, aswell as with the marine core data from 94-607 DSDP and ODP 177-1090. The results obtained on the basis of isotopic analysis of ice cores from stations Vostok and Concordia indicated that in the optimum MIS-11the air temperature was4 °C higher, and in the Termination V –8 °C lower than the present-day values. Thesimilarity of data between the marine columns DSDP  94-607 (North Atlantic), ODP 177-1090 (South Ocean)and our results points to the global nature of changes in the sea surface temperature during the MIS-11  era. The coordination  of the above results proves the high quality of the methods developed by the authors for measuring and interpreting the isotope composition of ice

Вариации скорости снегонакопления в Центральной Антарктиде за последние 250 лет

The present-day global climate changes, very likely caused by anthropogenic activity, may potentially present a serious threat to the whole human civilization in a near future. In order to develop a plan of measures aimed at elimination of these threats and adaptation to these undesirable changes, one should deeply understand the mechanism of past and present (and thus, future) climatic changes of our planet. In this study we compare the present-day data of instrumental observations of the air temperature and snow accumulation rate performed in Central Antarctica (the Vostok station) with the reconstructed paleogeographic data on a variability of these parameters in the past. First of all, the Vostok station is shown to be differing from other East Antarctic stations due to relatively higher rate of warming (1.6 °C per 100 years) since 1958. At the same time, according to paleogeographic data, from the late eighteenth century to early twenty-first one the total warming amounted to about 1 °C, which is consistent with data from other Antarctic regions. So, we can make a conclusion with high probability that the 30-year period of 1985–2015 was the warmest over the last 2.5 centuries. As for the snow accumulation rate, the paleogeographic data on this contain a certain part of noise that does not allow reliable concluding. However, we found a statistically significant relationship between the rate of snow accumulation and air temperature. This means that with further rise of temperature in Central Antarctica, the rate of solid precipitation accumulation will increase there, thus partially compensating increasing of the sea level.Современные изменения температуры воздуха и скорости накопления снега, полученные инструментальным путём на антарктической станции Восток, сопоставлены с палеоклиматическими реконструкциями за последние 250 лет. Показано, что период 1985–2015 гг., вероятно, был самым тёплым 30-летием за последние 2,5  века. Скорость снегонакопления положительно коррелирует с изменчивостью температуры воздуха – это показывает, что повышение температуры в будущем будет сопровождаться ростом количества снега, накапливаемого в Антарктиде, что частично скомпенсирует рост уровня Мирового океана. Вместе с ростом температуры воздуха на протяжении последних 50  лет имело место и увеличение количества осадков, однако являются ли современные значения скорости снегонакопления аномальными для последних 250 лет на основании имеющихся данных сказать трудно

Изменения климата в индоокеанском секторе Восточной Антарктиды за последние 350 лет

The temperature and snow accumulation rate anomaly over the past 350 years have been reconstructed based on isotopic composition of shallow ice cores and snow pits samples as well as glaciological observations in pits and at stake farms located in Indian Ocean sector of East Antarctica. The relationship of temporal variability of isotopic composition of precipitation and surface air temperature in ensemble with sea surface temperature has been analyzed. The fingerprints of Little Ice Age and climatic shift 1970s have been defined. We have also figured out the influence of non-climatic drivers on the formation of signal in stable water isotopic series.По данным об изотопном составе ледяных кернов, полученных из скважин, пробуренных в индоокеанском секторе Восточной Антарктиды между трассами Мирный – Восток и Прогресс – Восток, восстановлено изменение температуры воздуха и скорости снегонакопления за последние 350 лет. Проанализирована связь временнóй изменчивости изотопного состава осадков с местной приземной температурой воздуха и температурой в источнике влаги. Обнаружено проявление малого ледникового периода, а также так называемого климатического сдвига 1970‑х годов в исследуемом секторе Антарктиды. Обсуждается роль неклиматических факторов, влияющих на формирование долгопериодных трендов в рядах изотопного состава осадков, получаемых по ледяным кернам