Ice and Snow (E-Journal) / Лёд и Снег
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МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ ТЕЧЕНИЯ ЛЬДА НА ЗЕМЛЕ КОРОЛЕВЫ МОД В АНТАРКТИДЕ И ЕГО ПРИЛОЖЕНИЕ В ПАЛЕОРЕКОНСТРУКЦИЯХ ПОЗДНЕЧЕТВЕРТИЧНОГО КЛИМАТА
No full textOne of the main sources of our knowledge about past air temperature variations is the isotopic composition of the ice cores obtained during deep drilling of the ice sheets. During 2001–2006 deep drilling was carried out at Kohnen station in Dronning Maud Land, Antarcticawithin the frameworks of the European Project for Ice Coring in Antarctica (EPICA). As a result, an ice core of 2774 mlength was obtained. Variations of air temperature are linearly dependent on isotopic composition of an ice core, but the reconstructed temperature series contains besides the climatic signal, a topographic bias. Appearance of this bias is explained by the upstream advection from the elevated sites where the ice particles were originally deposited, and by the local vertical movements of the surface of the ice sheet through time. In order to calculate this non-climatic (topographic) bias in the isotopic and reconstructed air temperature record, we applied a methodology based on mathematical ice-flow modeling. In the lower part of the ice sheet ice chronology and non-climatic biases are strongly affected by unknown value of the geothermal heat flux (G). Melt water, which was found close to the bedrock suggests that that assumed G = 54.6 mWm-2 (the average value for Antarctica) was very likely underestimated in the surroundings of Kohnen. In order to estimate the range of possible values of ice age and of non-climatic bias in the lower part of the core we carried out a series of numerical experiment with G increased by 5–30%
О книге А.Н. Рудого и Г.Г. Русанова «Последнее оледенение Северо-Западного Алтая. Бассейн реки Коксы»
No full textAbout the book of A. N. Rudoy and G. G. Rusanov «The last glaciation of North-Western Altai. Koksy River Basin», Tomsk: NTL, 2010. 240 pages with ill. Number of copies 1000. ISBN 978-5-89503-474-3О книге А.Н. Рудого и Г.Г. Русанова «Последнее оледенение Северо-Западного Алтая. Бассейн реки Коксы». Томск: Изд-во НТЛ, 2010. 240 с., ил. Тираж 1000. ISBN 978-5-89503-474-
Изотопный состав (δ18O и δD) погребённого фирна на Лено-Амгинской равнине
No full textLayers of firn related to Karga (MIS 3) and Zyryan (MIS 4) horizons of Late Pleistocene were recovered in the permafrost stratum of Central Yakutia. Imaging points of δ¹⁸O and δD values characterizing the firn horizons are grouping near the line of meteoric water (Craig line). The firn was probably formed from permanent snow patches. The formation of permanent snow patches doesn’t occur at the present time due to climatic reasons – exceeding of evaporation over precipitation as well as high summer temperatures. We suppose that formation of the firn occurred in conditions different from the modern ones, under lower mean annual temperatures and higher humidity.В Центральной Якутии в толще многолетнемёрзлых отложений вскрыты слои фирна, которые отнесены к каргинскому и зырянскому горизонтам позднего неоплейстоцена. Фигуративные точки величин δ18O и δD этих горизонтов фирна группируются вблизи линии метеорных вод (линии Крейга). Вероятно, фирн образовался из снежников-перелетков. В настоящее время в рассматриваемом районе снежников-перелетков нет, что объясняется климатическими особенностями – превышением испарения над осадками и высокими летними температурами. Предполагается, что фирн вскрытых горизонтов формировался в иных по сравнению с современными климатических условиях: при более низких среднегодовых температурах и более высокой влажности воздуха
Моделирование деформаций русел, сложенных мёрзлыми породами, при повышении температуры окружающей среды
Get PDFThis paper is devoted to investigation of the influence of river flow and of the temperature rise on the deformation of the coastal slopes composed of permafrost with the inclusion of ice layer. The method of investigation is the laboratory and mathematical modeling. The laboratory experiments have shown that an increase in water and air temperature changes in a laboratory analogue of permafrost causes deformation of the channel even without wave action, i.e. at steady-state flow and non-erosive water flow velocity. The previously developed model of the bed deformation was improved to account for long-term changes of soil structure with increasing temperature. The three-dimensional mathematical model of coastal slopes thermoerosion of the rivers flowing in permafrost regions, and its verification was based on the results of laboratory experiments conducted in the hydraulic tray. Analysis of the results of mathematical and laboratory modeling showed that bed deformation of the rivers flowing in the permafrost zone, significantly different from the deformation of channels composed of soils not susceptible to the influence of the phase transition «water-ice», and can occur even under the non-erosive velocity of the water flow
К голоценовой истории ледника Уллукам
No full textUsing instrumental archives, aerial photographs, satellite images, old maps, descriptions of early explorers and old photographs we identified and mapped nine front positions of the Ullukam Glacier (SW slope of Elbrus) for the period from the end of XIX to the early XXI centuries. In 1884–2009 glacier retreated by 775 m. It advanced from 1971 to 1987 (36 m). The glacier fluctuations in the previous period were reconstructed using geomorphologic data, lichenometry, modern and buried soil description and radiorarbon analyses. We identified three Little Ice Age moraines of almost equal magnitude when the Ullukam Glacier was 889 m longer than in 2009. Two later advances occurred in the first third to middle of XIX century and in 1870s The recent fluctuations of the Ullukam Glacier closely correspond to the retreat two other glaciers in Elbus area. The location of the buried soil in the valley of Ullukam glacier brings evidence that the glacier have not advanced lower than 2813 m a.s.l. at least during the last four thousand years.Представлена реконструкция колебаний ледника Уллукам во второй половине голоцена. На основе сравнения аэрофото- и космических снимков, старых фотографий и карт реконструировано девять положений языка ледника за последние 125 лет. С 1884 по 2009 г. ледник сократился в горизонтальной проекции на 775 м, а высота его фронта повысилась на 190 м. На основе датирования лихенометрическим методом установлено, что две молодые морены возникли в первой трети – середине XIX в. и в 1870-х годах. На расстоянии 1,5 км от современного конца ледника найдена погребённая почва, возраст которой, согласно радиоуглеродному датированию, составляет 3580±80 л.н. Ненарушенность почвенного профиля показывает, что ледник не спускался до высоты 2813 м, по крайней мере, в последние четыре тысячелетия, а возможно и с начала голоцена
ЭВОЛЮЦИОННАЯ КОНЦЕПЦИЯ МЕТАМОРФИЗМА СНЕГА НА ОСНОВЕ КРИСТАЛЛОМОРФОЛОГИИ И ТЕОРИИ СИММЕТРИИ
No full textThe paper presents a novel approach to the study of development of microstructures in snowpack based on the crystal-morphology and on the fundamental laws of natural symmetry. An empirical deterministic model describing the sublimation-metamorphic cycle in seasonal snow cover and the polymorphic variants of this cycle is suggested. Staging in the formation of crystal shapes and self-development of snow microstructure in snow layers is revealed. The crystal shapes are the result of successive process of superposition of ice crystal-chemical symmetry and dissymmetry of the soil – snow cover – atmosphere system, according to the known P. Curie principle. Morphological classification of snow crystals in seasonal snow cover is developed on the base of evolutionary model. Evolution of snow microstructure is conditioned by a marked degree by probabilistic conformity to natural laws, manifesting itself in the processes of auto-regulation of metamorphism. These processes include two types of regulation: the self-regulation of snow layers, on the one hand, and the regulation related to external conditions – under the influence of atmospheric perturbations, on the other hand. The accounting the processes of auto-regulation of snow metamorphism for allows development of new methods in short- and long-term avalanche forecast
КАМЕННЫЕ ГЛЕТЧЕРЫ КОЛЫМСКОГО НАГОРЬЯ
No full textBased on remote mapping and field studies inGrand Rapids, Tumansky,Hasynsky,Del-Urechen Ridges as well as Dukchinsky and Kilgansky Mountain Massifs there were identified about 1160 landforms which morphologically are similar to the rock glaciers or they develop in close association with them. Besides tongue-shaped cirque rock glaciers originated due to ablation, a large number of lobate-shaped slope-associated rock glaciers were recognized. Significant quantity of such forms are developing within the active neotectonic areas, in zones of seismic-tectonic badland and in association with active earthquakes-controlling faults. Multiplication of regional data on volcanic-ash-chronology, lichenometry, Schmidt Hammer Test, pollen spectra and single radiocarbon data, most of the active rock glaciers were preliminary attributed to the Late Holocene.На основе дистанционного картографирования и полевых исследований в хребтах Больших Порогов, Туманском, Хасынском, Дел-Урэчэн, а также в Дукчинском и Килганском горных массивах установлено около 1160 образований, морфологически сходных с каменными глетчерами или развивающихся в тесной ассоциации с ними. Кроме каровых каменных глетчеров абляционного происхождения обнаружено большое число присклоновых лопастевидных образований, формирующихся в пределах контрастного неотектонического рельефа в зонах тектонического бедленда и в ассоциации с сейсмогенерирующими разломами. Использование комплекса региональных данных по тефрахронологии, лихенометрии, пыльцевым спектрам и радиоуглеродным датировкам позволяет предварительно отнести большинство активных каменных глетчеров к позднему голоцену
Влияние притока тёплых атлантических вод на аномалии климата в атлантическом секторе Арктики
Get PDFSignificant climatic changes of oceanic and atmospheric elements and a relation of them to the ocean surface winter anomalies in North Atlantic are analyzed in the paper. Periods of «warm» ocean (2002–2012) and «cold» ocean (1960–1970) were determined. Positive anomalies of the ocean surface temperature increase the ice-free water area and, correspondingly, decrease the ice-field area. As a result of such changes in a state of the ocean surface (open water and ice), surface air temperature rises, and, consequently, atmospheric pressure in central part of a given Arctic sector drops.Исследованы значимые климатические изменения океанических и атмосферных переменных в атлантическом секторе Арктике, определяемые аномалиями температуры поверхности океана зимой. Определены периоды «тёплого» (2002–2012 гг.) и «холодного» (1960–70‑е годы) океана.Положительная аномалия температуры поверхности океана вызывает увеличение площади свободной ото льда воды и сокращение площади сплошных льдов. В результате такого изменения свойств подстилающей поверхности (открытая вода и лёд) растёт приземная температура воздуха и, как следствие, понижается давление в центральной области заданного сектора Арктики
Роль угольного загрязнения в интенсификации таяния припайного льда в бухте Свеабукта (залив Ван-Майен-фьорд, о. Западный Шпицберген)
No full textThe processes of heat- and mass transfer in Sveabukta Bay sea ice cover during Spring 2010 the particularity of which is conditioned by pollution from open coal storages situated on shore have been studied. Typical features of land fast ice radiation and thermodynamic properties were described and estimates for vertical distribution of coal particles concentration within ice body were obtained. The coal particles were shown to serve as tracers of transfer processes in the sea ice thickness. It was revealed that the integral value of the absorbed solar radiation (shortwave radiation balance) is virtually independent of the features of the incoming solar radiation spectrum and the spectral dependence of the reflectivity of the ice cover of various contaminations. For computation of fast ice evolution characteristics the conceptual thermodynamic model which describes melting processes in the obvious form was used. According to calculations the melt pond forming on dirty ice under typical meteorological conditions begins one – three weeks earlier than that of clear ice depending on degree of contamination characterized by reflective ability of underlying surface. With decreasing of albedo the temperature of melt rises despite the fact that due to time difference the melting of clear ice occurs at higher temperatures.Анализируются результаты исследований таяния загрязнённого углём припая бухты Свеабукта залива Ван-Майен-фьорд (о. Западный Шпицберген), выполненных весной 2010 г. Приведены радиационные и термодинамические характеристики припайного льда, обусловленные осаждением частиц угля на его поверхность. Установлено, что интегральная величина поглощённой солнечной радиации (коротковолновый радиационный баланс) практически не зависит от особенностей спектра приходящей солнечной радиации. С помощью концептуальной термодинамической модели рассчитаны характеристики эволюции чистого и загрязнённого ледяного покрова. Показано, что при наблюдавшихся атмосферных условиях в зависимости от степени загрязнения льда сроки начала таяния верхних слоёв ледяного покрова могут отличаться между собой почти на три недели
