Проблемы Арктики и Антарктики
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Arctic polar vortex dynamics during winters 2014/2015 and 2020/2021
Get PDFThe dynamic barrier of the polar vortex contributes to lowering the temperature inside the vortex in the lower stratosphere and prevents the penetration of air masses into the vortex. The presence of a dynamic barrier during winter is one of the criteria determining the possibility of ozone depletion from late winter to spring. We considered the dynamics of the Arctic polar vortex in the winters of 2014/2015 and 2020/2021 at the 50, 30 and 10 hPa levels by the vortex delineation method using the geopotential. In early January 2015 and 2021, sudden stratospheric warmings were recorded as a result of the splitting (4 January 2015) and the significant displacement (5 January 2021) of the polar vortex. In both cases, the weakening of the dynamic barrier of the polar vortex was observed. The polar vortex is characterized by the presence of a dynamic barrier, when the wind speed along the entire edge of the vortex is more than 20, 24 and 30 m/s at the 50, 30 and 10 hPa levels, respectively. A decrease in the average wind speed along the vortex edge below 30, 36 and 45 m/s, at the 50, 30 and 10 hPa levels, respectively, usually indicates a local decrease in the wind speed below 20, 24 and 30 m/s at these levels, i.e., indirectly indicates a weakening of the dynamic barrier.The dynamic barrier of the polar vortex contributes to lowering the temperature inside the vortex in the lower stratosphere and prevents the penetration of air masses into the vortex. The presence of a dynamic barrier during winter is one of the criteria determining the possibility of ozone depletion from late winter to spring. We considered the dynamics of the Arctic polar vortex in the winters of 2014/2015 and 2020/2021 at the 50, 30 and 10 hPa levels by the vortex delineation method using the geopotential. In early January 2015 and 2021, sudden stratospheric warmings were recorded as a result of the splitting (4 January 2015) and the significant displacement (5 January 2021) of the polar vortex. In both cases, the weakening of the dynamic barrier of the polar vortex was observed. The polar vortex is characterized by the presence of a dynamic barrier, when the wind speed along the entire edge of the vortex is more than 20, 24 and 30 m/s at the 50, 30 and 10 hPa levels, respectively. A decrease in the average wind speed along the vortex edge below 30, 36 and 45 m/s, at the 50, 30 and 10 hPa levels, respectively, usually indicates a local decrease in the wind speed below 20, 24 and 30 m/s at these levels, i.e., indirectly indicates a weakening of the dynamic barrier
Изучение взаимосвязей агрохимических показателей почв с видовым составом растений некоторых участков дельты реки Лены, Северная Якутия
Get PDFIn connection with climate change and the development of natural resources in the Arctic, increasingly relevant is the problem of revealing the response of tundra vegetation to various natural and anthropogenic impacts, as well as the search for indicators for developing a system of monitoring the state of ecosystems in the Far North. The aim of this work was to describe the floristic composition and structure of plant communities, as well as to search for relationships between agrochemical indicators of soils and the species composition of plants in certain key sites of the Lena River Delta. A total of ten key sites of the Lena delta were studied. Agrochemical analysis of the soil samples was performed using standard methods. The content of biogenic and abiogenic elements was measured using an emission spectrometer. The relationship between the soil parameters and floristic composition was studied using cluster analysis. It was shown that the clustering of sites by standard agrochemical indicators was weakly expressed, while in terms of the content of elements in the mineralized samples and in water extracts the sites were grouped into two clusters at the level of 40 %÷60 % of the differences. The clustering of sites by plant species composition was very weak, and it was not possible to identify clusters with high or medium level of similarity, nor was it possible to detect similarity between cluster diagrams constructed by soil parameters and by plant species composition. As a result of the study, it is shown that the species composition of vascular plants weakly correlates with the properties of the soils of the key sites. The individual features identified manifest themselves in the form of trends and no clear patterns of interrelation of vegetation and soil parameters are discerned.В связи с изменением климата и освоением природных ресурсов Арктики все более актуальной становится проблема выявления ответной реакции тундровой растительности на различные природные и антропогенные воздействия, а также поиск индикаторов для разработки системы мониторинга состояния экосистем Крайнего Севера. Целью данной работы было описание флористического состава и строения растительных сообществ, а также поиск взаимосвязей между агрохимическими показателями почв и видовым составом растений на отдельных ключевых участках дельты реки Лены. Всего было изучено десять ключевых участков дельты Лены. Агрохимический анализ образцов почв был изучен стандартными методами. Содержание биогенных и абиогенных элементов измеряли с помощью эмиссионного спектрометра. Взаимосвязь между показателями почв и флористическим составом выявляли с помощью кластерного анализа. Было показано, что кластеризация участков по стандартным агрохимическим показателям была выражена слабо, тогда как по содержанию элементов в минерализованных образцах и в водных вытяжках участки группировались в два кластера на уровне 40÷60 % различий. Кластеризация участков по видовому составу растений была выражена очень слабо, и выявить кластеры с высоким или средним уровнем сходства не удалось, так же как не удалось обнаружить сходства кластерных диаграмм, построенных по почвенным параметрам и по видовому составу растений. В результате проведенного исследования показано, что видовой состав сосудистых растений слабо коррелировал со свойствами почв ключевых участков. Выявленные отдельные особенности проявлялись в виде тенденций, и четких закономерностей взаимосвязи растительного покрова и показателей почв не прослеживалось
Изучение физических свойств льда в России и СССР (конец XIX в. — 1940 г.). Плотность и пористость льда
Get PDFThe paper deals with studies conducted in Russia and USSR of ice density, a most important characteristic of ice, and spans a period from the late XIXth century to 1940. It is shown that Russian scientists started their investigations of ice density only around the end of the XIX century, and those studies were often performed with specific applications in mind, e. g. works by B.P. Veinberg and his disciples in Tomsk in 1911–1914. In the USSR, there was a revival of interest in this kind of studies in the late 1920s in connection with explorations of the polar seas. Density measurements were mainly performed by hydrostatic weighing. At the request of N.N. Zubov and I.I. Mesyatsev in 1927 V.V. Shuleikin invented a simple instrument to measure ice density without weighing samples. In the early 1930s, ice porosity became an important field of research aimed at finding the causes of variance of experimental data on ice density. Ice porosity and density were studied using innovative devices developed by V.V. Shuleikin and V.I. Arnold-Alyabiev, which allowed studying ice properties in expedition conditions. The device developed by Arnold-Alyabiev found widespread use in field studies. Ice density and porosity are closely related physical quantities, therefore measuring the porosity of ice allowed researchers to estimate its density. By the end of the 1930s the ice density measurements had developed into a standard procedure of ice studies, which was due in large measure to the plans devised at the All-Union Arctic Institute headed by B.P. Veinberg to investigate ice at polar stations, which also included ice density and porosity studies.В работе рассматривается развитие изучения в России и СССР (конец XIX в. – 1940 г.) важнейшей характеристики льда — его плотности. Показано, что российские ученые занялись изучением плотности льда лишь в самом конце XIX в., причем эти исследования часто проводились с прикладными целями, например работы Б.П. Вейнберга и его учеников в Томске в 1911–1914 гг. В СССР интерес к исследованиям возродился в конце 1920-х гг. и был связан с развитием исследований в полярных морях. Измерения плотности в основном осуществлялись методом гидростатического взвешивания. По просьбе Н.Н. Зубова и И.И. Месяцева в 1927 г. В.В. Шулейкин создал простой прибор, позволяющий выполнять процедуру определения плотности льда без взвешивания образца. В начале 1930-х гг. важным направлением исследований становится изучение пористости льда, целью которого было выяснение причин изменчивости экспериментальных данных о плотности льда. Для проведения исследований пористости В.В. Шулейкиным и В.И. Арнольдом-Алябьевым были разработаны оригинальные приборы, которые обеспечили возможность изучения этих характеристик льда в экспедиционных условиях. Наибольшее распространение в практике полевых исследований получил прибор Арнольда-Алябьева. Плотность и пористость льда тесно связанные друг с другом физические величины, поэтому измерения пористости льда позволяли по полученным результатам вычислять его плотность. К концу 1930-х гг. измерение плотности льда становится стандартной процедурой при осуществлении ледовых исследований. Этому способствовала разработка во Всесоюзном арктическом институте под руководством Б.П. Вейнберга планов исследования льда на полярных станциях, которые включали изучение пористости и плотности
Сравнение характеристик явлений в F-области высокоширотной ионосферы при излучении мощных КВ радиоволн антеннами с узкой и широкой диаграммой направленности
Get PDFPhysical experiments in natural free plasma (ionosphere) using controlled injection of powerful HF radio waves (HF pump waves) into the high latitude upper (F-region) ionosphere allow the investigation of various nonlinear phenomena. HF pump waves with ordinary (O-mode) polarization are commonly used for the modification of the upper ionosphere (F-region). This is due to the fact that extraordinary (X-mode) polarized HF pump waves are reflected from altitudes significantly below the reflection altitude of the O-polarized HF pump wave and the altitude of electrostatic plasma waves. Because of that they are not able to generate such waves or, as a consequence, cause artificial plasma turbulence and accompanying phenomena. However, the results of experiments carried out by AARI researchers at the EISCAT/Heating facility (Tromsø, Norway) have clearly demonstrated for the first time that X-polarized HF pump waves are able to produce artificial ionosphere disturbances which may be much stronger compared with O-mode disturbances. This opens up new possibilities for the investigation of nonlinear phenomena and ionospheric disturbances in the upper ionosphere, leading to the development of technologies allowing one to observe the processes in the Arctic zone ionosphere. In contrast to the traditional investigations of artificial ionospheric disturbances induced by O-mode HF pump waves, X-mode disturbances in the upper ionosphere are poorly investigated, the mechanisms of their generation are not understood. Therefore, such investigations require serious experimental and theoretical development. We present investigation results of the influence of the HF Phased Array beam width at the EISCAT/Heating facility (Tromsø, Norway) on the features of artificial disturbances in the high latitude upper (F-region) ionosphere induced by powerful HF radio waves. The paper analyzes the features, behavior, and spatial structure of electron density and temperature (Ne and Te), Langmuir and ion-acoustic plasma waves, artificial field-aligned irregularities (AFAIs), and narrowband (±1кHz relative to heating frequency) stimulated electromagnetic emission (NSEE) induced by X-mode HF pumping by phased Arrays with a narrow beam width of 5–6° (A1) and a wide beam width of 10–12° (at — 3 dB level) (A3). It is shown that the spatial size in the north-south direction of the Neducts and HF-enhanced plasma and ion lines (HFPL and HFIL) depends on the width of the HF Heating facility antenna beam. It corresponds to the angle width of 7° for the A3 antenna and 4° for A1, which is approximately two times less than the width of th pattern of A3 and A1. The relationship between the Ne duct transverse size and the size of the region occupied by the X-mode artificial irregularities is found. It has been established that the intensities of all the discrete components in the NSEE spectra are 10–20 dB higher when a powerful X-wave is emitted to the antenna A1, providing ERP = 820 MW, compared to radiation to the antenna A3, providing ERP = 230 MW. A comparison is made of the influence of the radiation pattern width of the antennas A1 and A3 on the characteristics of disturbances during O- and X-mode HF pumping. It is shown that Ne ducts and narrow band stimulated electromagnetic emission during O-mode heating, at frequencies below the critical frequency of the F2 layer, are not excited at all when the pump wave is emitted by both antennas A1 and A3. However, perturbations in the electron temperature, AFAI intensity, and the size of the region occupied by AFAIs are greater during O-mode heating than during X-mode heating.Выполнено сравнение характеристик искусственных ионосферных возмущений в F-области высокоширотной ионосферы при излучении мощных коротких радиоволн нагревного стенда EISCAT/ Heating (г. Тромсё, Норвегия) фазированными антенными решетками (ФАР) с узкой (5–6°) и широкой (10–12°) диаграммами направленности (антенны А1 и А3 соответственно). Рассмотрены характеристики, поведение и пространственная структура электронной концентрации и температуры, продольных плазменных волн (ленгмюровских и ионно-акустических), мелкомасштабных искусственных магнито-ориентированных неоднородностей и искусственного узкополосного (в полосе ±1 кГц относительно частоты нагрева) радиоизлучения ионосферы, вызванных воздействием мощных КВ радиоволн необыкновенной (Х-мода) и обыкновенной (О-мода) поляризаций при их излучении антеннами А1 и А3 в направлении магнитного зенита
Классификация криогенно-оползневых форм рельефа для целей картографирования и прогноза
Get PDFA classification of cryogenic-landslide landforms is developed for mapping their distribution and dynamics. It is based on the previously suggested classification subdividing cryogenic landsliding into two main types: cryogenic translational landslides (or active-layer detachment slides), and cryogenic earth flows (or retrogressive thaw slumps). The increased proportion of retrogressive thaw slumps compared to active layer detachments in the North of West Siberia in the last decade creates the need for an expanded classification of cryogenic earth flows. One of the important issues is separating the process of landsliding and resulting landforms, which in English are covered by one term ‘retrogressive thaw slump’. In dealing with the landforms, we distinguish (1) open and (2) closed ones. Open cryogenic-landslide landforms are those formed by the retreating of the coast bluff due to the thaw of ice or ice-rich deposits with an additional impact from wave or stream action. Closed cryogenic-landslide landforms are those initiated on a slope landward, and thawed material is delivered to the coast or stream through an erosional channel. Morphologically we distinguish thermocirques and thermoterraces depending on the shape of the retreating headwall, crescent or linear, respectively. An important issue is the type of ground ice subjected to thaw: tabular, ice-wedge or constitutional ground ice are distinguished. Landforms can be active, stabilized or ancient. One can find both single landforms and their combination. The classification is based on a significant amount of field studies and interpretation of remote sensing data. Mapping of the cryogenic-landslide landforms is suggested using the proposed classification and indication features. The classification is based on the experience obtained mainly in the north of West Siberia. Applying it to other regions may require additional studies.Разработана классификация криогенно-оползневых форм рельефа, сформированных криогенными оползнями течения (КОТФР), для картографирования их распространения и динамики. В основе лежит значительный объем полевых исследований и интерпретации данных дистанционного зондирования Земли. Классификация включает генетические, морфологические и криолитологические особенности пород, определяющие морфологию и динамику КОТФР, их положение в рельефе, степень их активности, сочетание и комплексирование единичных КОТФР. Предложенная классификация и индикационные признаки используются для картографирования КОТФР на севере Западной Сибири
Водный, тепловой и солевой баланс юго-восточной части Баренцева моря
Get PDFThe south-eastern part of the Barents Sea is located away from the main currents, with a combination of climatic, hydrological and oceanological processes creating conditions that make the region different from the rest of the Barents Sea such that it is seen as a separate region and called sometimes the Pechora Sea. Despite the intensive economic activity in the south-eastern part of the Barents Sea, it is not yet clear to what extent the general Atlantic water transport in the Barents Sea and, consequently, the transport of heat and salt, affects this region. Therefore, the aim of this study was to assess advective flows at open boundaries, as well as other components of the water, heat and salt balances of the south-eastern part of the Barents Sea. Based on monthly average data from the MERCATOR GLORYS12V1 reanalysis for the period 1993–2018, we calculated water transport, heat and salt flows at the boundaries of the south-eastern part of the Barents Sea (at 50° E in the west, at 71° N in the north and in the Kara Gate Strait); to close the balances, an assessment was made of sea-atmosphere interaction characteristics on the sea surface based on ECMWF ERA5 reanalysis data. Water, heat and salt balances were combined with a residual not exceeding 1.6 %. Linear trends for the characteristics obtained were calculated. It is revealed that the average long-term resulting water transport in the south-eastern part of the Barents Sea is directed from the north-west of the region to the Kara Gate Strait (0.40 Sv). This current is associated with the Atlantic waters and also carries heat and salt. The resulting heat input (5.92 TW) creates a heat excess in the water area, which is compensated for by interaction with the atmosphere (1.86 TW). The salt flow through the region is estimated at 13.98 t/s. During the study period, all the main flows have a statistically significant positive trend in the incoming and outgoing parts of the balances: water transport — 0.005 Sv per year; salt flow — 0.18 t/s per year. This indicates an increase in the transit of Atlantic waters through the south-eastern part of the Barents Sea. An increase in the advective heat flux (0.15 TW per year) across the western border is accompanied by an increase in its release into the atmosphere (0.07 TW per year) and an increase in evaporation of 6.9 mm per year. Sea levels are also rising at a rate of 0.27 cm per year. Thus, the increasing dynamics of the processes in the region is a factor to take into account in conducting economic activities.В статье представлены оценки адвективных потоков на открытых границах, а также других компонентов водного, теплового и солевого балансов юго-восточной части Баренцева моря (иногда называемой Печорским морем). По среднемесячным данным реанализов MERCATOR GLORYS12V1 и ECMWF ERA5 за период 1993–2018 гг. рассчитаны объемный расход воды, потоки тепла и соли на границах юго-восточной части Баренцева моря (западная граница по 50° в. д., северная граница по 71° с. ш. и разрез в проливе Карские Ворота); потоки тепла и влаги на поверхности моря. Балансы воды, тепла и соли собраны с невязкой, не превышающей 1,6 %. Выявлено, что адвекция через границы акватории играет главную роль в формировании всех балансов. Основной поток вод направлен с северо-запада акватории транзитом через пролив Карские Ворота в Карское море. На основании анализа линейных трендов показано, что все основные потоки имеют значимый положительный тренд. Это указывает на рост транзита атлантических вод через юго-восточную часть Баренцева моря. Также отмечен рост испарения и теплоотдачи с поверхности моря, связанный с ростом температуры воды
Приливные и непериодические колебания уровня воды в средней части Обской губы
Get PDFNew estimates are suggested of harmonic constants of the tide for the summer (August) and winter (April) periods at the Sabetta, Utrenny posts, at the Tadibeyakha and Seyakha posts, as well as at the points of Cape Kharse, Cape Yaptik-Sale, Cape Kotelnikova and Cape Hampul-Yakha. The harmonic analysis of the tide was carried out using the least squares method according to the AARI version. According to AARI expedition observations in Sabetta for the period 2012–2016, and in Salman for the period 2016–2019, average vector estimates for each month of the year have been obtained. The observations were made using the ADCP device installed at autonomous buoy stations. Hourly level observations at the Seyakha and Tadibeyakha posts for the entire observation period from 1968 to 1992 were brought to a homogeneous form using the calibration method. The historical observations of the level at the points of Cape Kharse, Cape Yaptik-Sale, Cape Kotelnikova and Cape Khampul-Yakha, carried out in different years, are of scientific interest. Since the results of their processing and analysis in the original sources contained errors and did not include shallow water constituents, our analysis results are presented. Our tests show a significant contribution of shallow water constituents in the Ob’ Bay to the description of the tide curve and the calculation of the heights and times of high and low waters. Inter-annual and intra-annual estimation is given of the dispersions of the total and tidal level fluctuations in Seyakha and Tadibeyakha for the entire observation period. Comparison of the average seasonal course of the tide in the annual cycle based on the results of tide analysis in Seyakha and Tadibeyakha (XX century) and Sabetta and Utrenny (XXI century) shows significant differences. The study of surges of level is based on uniform series, as well as residual ones (observations minus predictions). Предложены новые оценки гармонических постоянных прилива на летний (август) и зимний (апрель) периоды на постах Сабетта, Утренний, на постах Тадибеяха и Сеяха, а также в пунктах м. Харсе, м. Яптик-Сале, м. Котельникова и м. Хампуль-Яха. Исследование непериодических колебаний уровня на постах Тадибеяха и Сеяха основано на однородных рядах, а также остаточных (наблюдения минус предвычисления).
Особенности совместного использования спутниковых данных видимого диапазона и радиолокационных данных для мониторинга арктических айсбергов на примере района Земли Франца-Иосифа
Get PDFGiven the availability of data, in order to monitor icebergs in the vast Arctic region, it is necessary to ensure an optimal ratio of the satellite radar data cost (with a wide swath and high spatial resolution) and the reliability of the results obtained. The aim of the study was to evaluate the effectiveness of using only non-commercial satellite information for monitoring icebergs. To achieve this goal, an iceberg detection technique was applied based on statistical criteria of searching for gradient zones in analyzing two-dimensional fields of satellite images. As a source of information, we used high spatial resolution satellite data obtained from non – commercial satellites Sentinel-1 (radar data) and Landsat-8 (visible spectral range data) with a pixel size of 40 × 20 and 15 m, respectively.Through comparison with the data of the visible spectral range of ultra-high resolution, the error was estimated of measuring the size of icebergs using the visible range equipment of the Landsat-8 satellite and the radar of the Sentinel-1 satellite. Based on the analysis of satellite data of the visible spectral range and radar data, the spatial dimensions of icebergs formed by the outlet glaciers of Franz Josef Land n 2020–2022 were estimated. The materials were collected for the period August-September, corresponding to the conditions of minimum ice extent in the Franz Josef Land area and sufficient natural illumination for using the data of the visible spectral range in the Arctic. In total, about 100 satellite images were analyzed. The sources of error in the satellite measurements are discussed, as well as the reasons for the impossibility in some cases to identify Franz Josef Land icebergs on radar images. It is shown that the largest contribution to the iceberg runoff of Franz Josef Land is made by outflow glaciers located on Georg Land, Wilczek Land, Gall, Salisbury and Champa islands. According to the results of the study, it is concluded that radar data with a pixel size of 40 m allow one to obtain essentially reliable information on the spatial distribution of icebergs in the water area. However, it is not possible to obtain a reliable function of the distribution of icebergs by size since most of the icebergs in the Franz Josef Land water area have small and medium sizes and are rarely identified in images of such spatial resolution.Обсуждается эффективность использования некоммерческих спутниковых данных, видимого спектрального диапазона и радиолокационных, для мониторинга айсбергов в районе архипелага Земля Франца-Иосифа. Путем сравнения с данными видимого диапазона сверхвысокого разрешения оценена погрешность измерения размеров айсбергов по данным видимого диапазона ИСЗ Landsat-8 и спутникового радиолокатора Sentinel-1. Установлена зависимость способности спутникового радиолокатора обнаруживать айсберги в прибрежной зоне от угла наклона луча. Сделан вывод, что радиолокационные данные с размером пикселя 40 м позволяют получить представление о закономерностях пространственного распределения айсбергов по акватории, но построить достоверную функцию распределения айсбергов по размерам не удается
Характеристики аэрозоля на научно-исследовательском стационаре «Ледовая база Мыс Баранова» в 2018–2023 гг.
Get PDFAtmospheric aerosol plays an important role in the processes of radiative transfers and mass exchange by different substances in the “continent–atmosphere–ocean” system. In this paper we discuss the results of a five-year measurement cycle of the atmospheric aerosol characteristics at the polar station “Ice base Cape Baranov”, located on the Bolshevik Island (the Severnaya Zemlya Archipelago). The set of the characteristics analyzed includes: the aerosol optical depth (AOD) of the atmosphere; the ground concentration of aerosol particles in the radius range of 0.15–5 microns; the content of the absorbing substance (soot) in the aerosol in the equivalent of elemental black carbon. The average values of the aerosol characteristics for the general measurement period (from April 2018 to May 2023) were: volumes of submicron and coarse aerosol particles 0.43 and 0.46 μm3/cm3, respectively; mass concentration of black carbon — 45.8 ng/m3; AOT of the atmosphere at a wavelength of 0.5 µm — 0.08; Angstrom selectivity exponent — 1.67. The average annual variation of aerosol and black carbon concentrations is characterized by a maximum in winter (January–March) and a minimum in summer (June–August). A comparison is made against the data from analogous measurements of aerosol characteristics at the polar station in Barentsburg (the Spitsbergen Archipelago) and against the data from model calculations, i. e., MERRA-2 reanalysis. A distinctive feature of the data in the Cape Baranov area is the low content of coarse aerosol — 1.7 less than in Barentsburg. There is agreement with the annual variation of black carbon concentrations at other polar stations, but the opposite nature of the seasonal variability of model (MERRA-2) concentrations: low values in winter and high values in summer. It is shown that the average spectral AODs of the atmosphere at the “Cape Baranov” are intermediate values between the data from polar stations in NyÅlesund and Barentsburg.Представлено обобщение результатов пятилетнего (апрель 2018 г. — май 2023 г.) цикла измерений характеристик атмосферного аэрозоля на полярной станции «Ледовая база Мыс Баранова» (архипелаг Северная Земля). Средние значения характеристик аэрозоля за общий период наблюдений составили: объемы частиц субмикронного и грубодисперсного аэрозоля 0,43 и 0,46 мкм3/см3 соответственно; концентрация поглощающего вещества (черного углерода) — 45,8 нг/м3; аэрозольная оптическая толщина атмосферы на длине волны 0,5 мкм — 0,08. Обсуждаются особенности среднего (многолетнего) годового хода приземных концентраций аэрозоля и черного углерода в сравнении с аналогичными данными на полярной станции в Баренцбурге (архипелаг Шпицберген, 2011–2022 гг.) и модельных расчетов — реанализа MERRA-2
Изменение температуры в Центральной Антарктиде после крупных вулканических извержений во втором тысячелетии нашей эры
Get PDFVolcanic forcing is one of the major drivers of climatic variability on Earth during the last millennium before the beginning of the industrial era, combined with solar activity, Milanković orbital forcing and greenhouse gas concentration. Large volcanic eruptions (with Volcanic Explosivity Index of 6 or more) eject a huge amount of sulfur dioxide into stratosphere thus reducing the amount of incoming solar radiation. The corresponding cooling may exceed 1 °C and lasts about 5 years. The identification of the volcanic events is carried out with the use of firn and ice core data drilled in the polar ice sheets, while the climatic response to the eruptions is studied with the use of dendrochronology and other terrestrial data, mainly in the Northern Hemisphere. Thus, the reaction of the Southern Hemisphere’s climate to the volcanic forcing is understood to a lesser extent. Here we use stable water isotope data (δ18O and dxs parameter, dxs = δD – 8 · δ18O) from 4 firn cores in order to study the temperature change in central Antarctica (in the vicinity of Vostok Station) after 5 major eruptions of the 2nd millennium of the Common Era: Samalas (1257), Unknown Event 1459 CE, Huaynaputina (1600), Parker (1641) and Tambora (1815). The isotopic composition of the cores was measured in the Climate and Environmental Research Laboratory of the Arctic and Antarctic Research Institute (St. Petersburg) with the use of Picarro L2130-i and L2140-i laser analyzers. We show that a post-eruption cooling in central East Antarctica is about 0.52 °C and lasts for about 5 years. At the same time, the temperature in the moisture source decreases to a lesser extent (0.46 °C), but the cooling lasts longer. We need to emphasize that only through using 4 parallel cores was it possible to significantly reduce the amount of the “deposition noise” in the isotopic records and detect the post-volcanic cooling in central East Antarctica.Вулканическая активность является одним из важнейших факторов естественной климатической изменчивости позднего голоцена до начала индустриальной эпохи. Влияние вулканов на климат изучается в основном по дендрохронологическим записям Северного полушария, тогда как о влиянии крупных извержений на температуру воздуха в полярных широтах Южного полушария известно существенно меньше. В настоящей работе использованы данные по изотопному составу (δ18O и δD) из 4 фирновых кернов для изучения изменения температуры в Центральной Антарктиде (окрестностях станции Восток) после 5 крупных извержений второго тысячелетия нашей эры: Самалас (1257 г.), Неизвестное Событие (1459 г.), Уайнапутина (1600 г.), Паркер (1641 г.) и Тамбора (1815 г.). Показано, что похолодание после извержения составляет около 0,52 °C и длится около 5 лет, при этом температура в источнике влаги снижается в меньшей степени (0,46 °С), но холодный период длится дольше