Desert dust deposition on Mt. Elbrus, Caucasus Mountains, Russia in 2009-2012 as recorded in snow and shallow ice core: high-resolution "provenancing", transport patterns, physical properties and soluble ionic composition

A record of dust deposition events between 2009 and 2012 on Mt. Elbrus, Caucasus Mountains derived from a snow pit and a shallow ice core is presented for the first time for this region. A combination of isotopic analysis, SEVIRI red-green-blue composite imagery, MODIS atmospheric optical depth fields derived using the Deep Blue algorithm, air mass trajectories derived using the HYSPLIT model and analysis of meteorological data enabled identification of dust source regions with high temporal (hours) and spatial (cf. 20–100 km) resolution. Seventeen dust deposition events were detected; fourteen occurred in March–June, one in February and two in October. Four events originated in the Sahara, predominantly in north-eastern Libya and eastern Algeria. Thirteen events originated in the Middle East, in the Syrian Desert and northern Mesopotamia, from a mixture of natural and anthropogenic sources. Dust transportation from Sahara was associated with vigorous Saharan depressions, strong surface winds in the source region and mid-tropospheric south-westerly flow with daily winds speeds of 20–30 m s−1 at 700 hPa level and, although these events were less frequent, they resulted in higher dust concentrations in snow. Dust transportation from the Middle East was associated with weaker depressions forming over the source region, high pressure centered over or extending towards the Caspian Sea and a weaker southerly or south-easterly flow towards the Caucasus Mountains with daily wind speeds of 12–18 m s−1 at 700 hPa level. Higher concentrations of nitrates and ammonium characterise dust from the Middle East deposited on Mt. Elbrus in 2009 indicating contribution of anthropogenic sources. The modal values of particle size distributions ranged between 1.98 μm and 4.16 μm. Most samples were characterised by modal values of 2.0–2.8 μm with an average of 2.6 μm and there was no significant difference between dust from the Sahara and the Middle East

High-resolution provenance of desert dust deposited on Mt. Elbrus, Caucasus in 2009–2012 using snow pit and firn core records

The first record of dust deposition events on Mt. Elbrus, Caucasus Mountains derived from a snow pit and a shallow firn core is presented for the 2009–2012 period. A combination of isotopic analysis, SEVIRI red-greenblue composite imagery, MODIS atmospheric optical depth fields derived using the Deep Blue algorithm, air mass trajectories derived using the HYSPLIT model and analyses of meteorological data enabled identification of dust source regions with high temporal (hours) and spatial (ca. 20–100 km) resolution. Seventeen dust deposition events were detected; fourteen occurred in March–June, one in February and two in October. Four events originated in the Sahara, predominantly in northeastern Libya and eastern Algeria. Thirteen events originated in the Middle East, in the Syrian Desert and northern Mesopotamia, from a mixture of natural and anthropogenic sources. Dust transportation from Sahara was associated with vigorous Saharan depressions, strong surface winds in the source region and mid-tropospheric southwesterly flow with daily winds speeds of 20–30 m s−1 at 700 hPa level. Although these events were less frequent than those originating in the Middle East, they resulted in higher dust concentrations in snow. Dust transportation from the Middle East was associated with weaker depressions forming over the source region, high pressure centred over or extending towards the Caspian Sea and a weaker southerly or southeasterly flow towards the Caucasus Mountains with daily wind speeds of 12–18 m s−1 at 700 hPa level. Higher concentrations of nitrates and ammonium characterised dust from the Middle East deposited on Mt. Elbrus in 2009 indicating contribution of anthropogenic sources. The modal values of particle size distributions ranged between 1.98 µm and 4.16 µm. Most samples were characterised by modal values of 2.0– 2.8 µm with an average of 2.6 µm and there was no signifi- cant difference between dust from the Sahara and the Middle East

Use of artificial neural networks for differentiated diagnostics of ischemic and hemorrhagic perinatal affections of central neural system in newborns of different terms of gestation

The article describes neonatal and pediatric neurology researching. Among the causes of childhood disability first place belongs to diseases of the nervous system. Among perinatal brain damage leading place is occupied by cerebrovascular pathology. One of the main causes of hemorrhagic and ischemic brain damage is impaired cerebral hemodynamics. However there is no single point of view on the processes underlying the development of ischemic brain lesions and intracranial hemorrhage in premature infants. It reveals necessity of immunobiochemical neurospecific proteins defining during neonatal period. Proteins, namely neurospecific enolase, a neurotrophicfactor of nerve growth, vascularendothelial growth factor, allow early finding of pathological disorder. What is a profitable advantage compared to the widely used clinical and instrumental examination and laboratory methods to assist in determining location and extent of the brain. Articleshows importance for a multifunction-oriented model of studying peculiarities of the child, starting with finding patterns in complex processes, due to the influence of internal and external factors on the functional state of the organism based on its individual characteristics, and ending with the solution of problems of differential diagnosis. Thus enabling to seek for hidden dependencies in complex processes conditioned by internal and external factors, leading us to performing differential diagnosis. As for mathematical models and data processing algorithms, the authors used an artificial neural network. These algorithms are used when there is no a precise decision-makingsystem. The medical diagnosis of ischemic and hemorrhagic perinatal central nervous system lesions of newborns maybe added in the list problems to be solved by artificial neural networks. The paper gives valuable information aboutinvestigating child's body properties with neural networks algorithms. Results of applying these algorithms are aimed to increase accuracy of differential diagnosis of ischemic or hemorrhagic perinatal damage to the central nervous system in newborns of different gestational ages are presented

КЛИНИКО-БИОХИМИЧЕСКАЯ ХАРАКТЕРИСТИКА НЕДОНОШЕННЫХ НОВОРОЖДЕННЫХ С ЭКСТРЕМАЛЬНО НИЗКОЙ И ОЧЕНЬ НИЗКОЙ МАССОЙ ТЕЛА ПРИ РОЖДЕНИИ

The purpose of this work was to study the levels of neurotrophic factor nerve growth of the brain, the levels of vascular endothelial growth factor, the levels of neurospecific enolase and the activity of endothelin-1 in the serum of blood in preterm infants with extremely low birth weight in association with the state of the cerebral circulation, and morphologic changes in the brain. We examined 60 preterm infants, which were divided into two groups depending on weight at birth. In neonates with extremely low birth weight the dysfunction of mechanism of autoregulation in cerebral blood flow was characterized by a decrease in blood flow velocities in the anterior cerebral and in the basilar arteries, in association with low levels of trophic factors in serum to month of life and the developments of degenerative changes in the brain. In neonates with very low birth weight infants in the early neonatal period the vasospasm of cerebral vessels with the activity of neurotrophic factors to month of life gave way to the stabilization of the cerebral hemodynamics.Целью работы стало изучение сывороточного содержания нейротрофического фактора роста нервов головного мозга, васкулоэндотелиального фактора роста, сывороточной концентрации нейроспецифической енолазы и сывороточной активности эндотелина-1 у недоношенных новорожденных с экстремально низкой массой тела в ассоциации с состоянием мозгового кровообращения и морфоструктурными изменениями головного мозга. Обследовано 60 недоношенных новорожденных, которые были разделены на две группы в зависимости от массы тела при рождении. У новорожденных с экстремально низкой массой тела дисфункция механизма ауторегуляции мозгового кровотока в раннем неонатальном периоде характеризовалась снижением показателей скоростей кровотока в передней мозговой и базилярной артериях в ассоциации с низким сывороточным содержанием трофических факторов роста, что к 1 мес жизни обусловливало развитие дистрофических изменений головного мозга. У новорожденных с очень низкой массой тела в раннем неонатальном периоде вазоспазм церебральных сосудов в сочетании с активностью нейротрофических факторов роста к 1 мес жизни сменялся стабилизацией мозговой гемодинамики

Пространственно-временнáя изменчивость снегонакопления на Западном плато Эльбруса (Центральный Кавказ)

Cold 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

Изменения ледника Чалаати (Грузинский Кавказ) с малого ледникового периода по данным космогенных изотопов (10Be) и дендрохронологии

Glacier variations over the past centuries are still poorly documented on the southern slope of the Greater Caucasus. In this paper, the change of Chalaati Glacier in the Georgian Caucasus from its maximum extent during the Little Ice Age has been studied. For the first time in the history of glaciological studies of the Georgian Caucasus, 10Be in situ Cosmic Ray Exposure (CRE) dating was applied. The age of moraines was determined by tree-ring analysis. Lichenometry was also used as a supplementary tool to determine the relative ages of glacial landforms. In addition, the large-scale topographical maps (1887, 1960) were used along with the satellite imagery – Corona, Landsat 5 TM, and Sentinel 2B. Repeated photographs were used to identify the glacier extent in the late XIX and early XX centuries. 10Be CRE ages from the oldest lateral moraine of the Chalaati Glacier suggest that the onset of the Little Ice Age occurred ~0.73±0.04 kyr ago (CE ~1250–1330), while the dendrochronology and lichenometry measurements show that the Chalaati Glacier reached its secondary maximum extent again about CE ~1810. From that time through 2018 the glacier area decreased from 14.9±1.5 km2 to 9.9±0.5 km2 (33.8±7.4% or ~0.16% yr−1), while its length retreated by ~2280 m. The retreat rate was uneven: it peaked between 1940 and 1971 (~22.9 m yr−1), while the rate was slowest in 1910– 1930 (~4.0 m yr−1). The terminus elevation rose from ~1620 m to ~1980 m above sea level in ~1810–2018.Для реконструкции колебаний ледника Чалаати в Грузии использовались космические снимки, старые карты, повторные фотографии, дендрохронология, лихенометрия и анализ космогенных изотопов. Максимальное наступание ледника в начале малого ледникового периода произошло в ~1250–1330 гг., второй максимум, когда ледник достиг почти такой же длины, датируется примерно 1810 г. С этого времени до 2018 г. площадь ледника уменьшилась с 14,9±1,5 до 9,9±0,5 км2 (33,8±7,4%, или ~0,16% год−1), а его длина сократилась на ~2280 м

Причины неопределённости в палеоклиматических реконструкциях по изотопному составу кислорода ледникового льда Эльбруса (Западное плато)

A study of the isotope signature of glacial ice in the Western Elbrus Plateau (the Caucasus) was made on the basis of five ice cores obtained in different years with high resolution. It was shown that the isotopic characteristics of ice are associated with the processes of accumulation and wind scouring of snow. Three ice cores were obtained in 2013 (C–1, C–2 and C–3), one in 2017 (C–4) and one more in 2018 (C–5). Core sampling was performed with a resolution of 5 cm. Isotopic analysis was done at the CERL laboratory (AARI) using a Picarro L2130-i isotope analyzer, the accuracy was 0.06‰ for δ18O and 0.30‰ for δ2Н. The values of d18О and δ2Н of the ice of the Western Plateau generally vary from –5 to –30‰ and from –18.7 to –225.8‰, respectively, with well-defined seasonality. Comparison of the isotope record for all cores showed that the differences in accumulation for individual seasons reach 0.3 m w. eq., differences in accumulation for individual seasons averaged over 5 years is approximately 0.2 m w.eq. The absolute differences in the average seasonal values of d associated with wind scouring and spatial redistribution of snow (deposition noise), averaged over 5 years, reached 1.38‰. The irregularity of precipitation amount within the season and errors in core dating are an additional contribution to non-climate variance (noise of definition). The absolute difference in the average seasonal values of δ18O associated with this type of noise averaged over 5 years is 1.7‰. Thus, the total uncertainty for two different types of noise can be estimated at 2.2‰, which is about 20% of the annual seasonal amplitude of δ18O values of the glacier ice in the Western Plateau (the average difference between the δ18O values of warm and cold seasons is ~10–11‰). One of the problems of linking the isotope record to the annual temperature record at the weather station was solved by using ammonium concentrations for dating the C-1 ice core and calculating the “ide+al” annual variation of δ18O values by a cosine function of the annual amplitude. Using ammonium ion (NH4) concentration each annual layer in C-1 ice core was divided into two parts associated to snow deposition in winter and in summer. It also showed δ18O values associated to change of seasons. The calculation of the cosine function showed the simplified δ18O values for each month of a particular year, due to which the δ18O values of the season boundaries in the ice core were linked to calendar months. This assimilation allowed us to compare the obtained average seasonal values of δ18O from the core with instrumental observations at the Klukhorskiy Pass meteorological station. The δ18O values of winter seasons have a weak relationship with surface temperatures, not only due to wind erosion, but also due to the high interannual variability of snow accumulation. At the same time, the average δ18O values of the warm seasons are significantly positive correlated with surface temperature (r = 0.7, p = 0.1), so ice core δ18O records can be used as a temperature proxy of the warm period.Выполнены измерения изотопного состава кислорода в неглубоких кернах, полученных в разные годы на Западном плато Эльбруса. Совмещение изотопной записи (δ18O) по глубине для трёх кернов показало, что в пределах локального участка Западного плато до 330 мм вод. экв. в слое годовой аккумуляции, т.е. около 20% средней годовой аккумуляции может быть сформировано за счёт перераспределения выпавшего снега. Неточности в реконструкции температур по среднесезонным значениям δ18O связаны с изменением сезонных пропорций в накоплении снега и с неравномерностью выпадения осадков внутри сезонов.

Гляциологические исследования института географии РАН на Эльбрусе в 2017 г.

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