Изменчивость поверхностной абляции горных ледников Западного Шпицбергена

Measurements of surface ablation in 2016–2018 on the neighboring glaciers Aldegondabreen, Austre and Vestre Grønfjordbreen (West Spitsbergen) revealed significant differences in its magnitude both within the same altitude zones for one year, and on an interannual scale. Comparison of the region’s common variations in climatic conditions (air temperature, rainfall) and ablation data showed a significant contribution of the following additional factors of melting: aspect, size, altitude range, surface slope, the rocky bordering of glaciers. The maximum ablation were measured on the Aldegondabreen (with the smallest area and altitude range), which has a northeastern aspect; the average value over three years of observations was 1947 mm w.e. Austre Grønfjordbreen and Vestre Grønfjordbreen had in 2016–2018 average ablation values 1512 and 1385 mm w.e., respectively. The largest Vestre Grønfjordbreen has the lowest values of average ablation also because it lies higher then neighboring glaciers. Interannual variations of mean ablation in the same altitudinal zones show: the minimum scatter of values for the Aldegondabreen (130–370 mm w.e.); higher scatter of values for the Austre Grønfjordbreen (200–450 mm w.e.); the maximum scatter of values for the Vestre Grønfjordbreen (from 400–600 mm w.e. in most altitude zones to 1000 mm w.e. at altitudes of 250–350 m). Due to the influence of additional factors, the maximum average ablation was observed on the Aldegondabreen in 2016, on the Vestre Grønfjordbreen in 2017, and on the Austre Grønfjordbreen in 2017 and 2018. The results of the study indicate the need to take into account the contribution of these factors to the ablation parameters of the region’s glaciers in model calculations, as well as the relevance of a detailed study of the distribution of solar radiation on glaciers.Измерения значений абляции на соседних ледниках Альдегонда, Восточный и Западный Грёнфьорд (Западный Шпицберген) в 2016–2018 гг. показали наличие заметных вариаций в па­раметрах таяния, которые, помимо общих для района межгодовых изменений климатических условий (температура воздуха, осадки), обусловлены характеристиками экспозиции, размеров, высотных диапазонов, уклонов поверхности, скального обрамления ледников. Результаты ис­следования указывают на необходимость учета вклада этих характеристик в оценку абляции ледников района при модельных расчетах, а также на актуальность детального изучения рас­пределения солнечной радиации на рассматриваемых ледниках

Послеледниковые изменения относительного уровня моря на полуострове Файлдс, остров Кинг Джордж (Западная Антарктика)

Analysis and integration of data obtained in our field and laboratory investigations of 2008–2012 together with results of previous paleogeographic studies were conducted to reveal parameters and factors of the post-glacial changes in the relative sea-level on the Fildes Peninsula and the King George Island. Results of dating of organic material taken from cross-sections of Quaternary deposits, data on morphology of marine landforms as well as on bottom sediments in lakes were used to construct a curve of changes in the relative sea-level.Our research has shown that the rapid rise of relative sea level in the area (since the beginning of the Holocene) decelerated about 8000 years BP, achieving its maximum about 7000 years BP. This was followed by the fall of relative sea-level (the land elevation) by 18–20  m in total, and it was characterized by relatively high rate of fall during periods of 6000– 5000 years BP, 4000–2500 years BP, and during the last 1500 years; the rate decreased in 5000–4000 years BP and 2500– 1600 years BP. The changes in relative sea level in this region were determined by the following factors: the eustatic component of the global changes in sea-level and, possibly, oscillations in the global sea level of another nature; local parameters of the Last glacial maximum; a course of the Peninsula deglaciation; regional physical characteristics of the Earth's crust and the mantle substances; local tectonic processes, including the isostatic rebound. Since the beginning of the Holocene up to about 7000 years BP, the main contribution to changes of the relative sea-level in this area was made by the global eustatic factor. The subsequent fall of the relative sea-level (elevation of the Peninsula surface) proceeded under condition of reduced role of the eustatic factor and predominance of other factors.Послеледниковые изменения относительного уровня моря на п-ове Файлдс (о. Кинг Джордж) установлены на основе анализа и интеграции результатов собственных и предшествующих палеогеографических исследований. Быстрый подъём относительного уровня моря (с начала голоцена) замедлился около 8000 лет назад (л.н.) с достижением около 7000 л.н. своего максимума. Скорости последовавшего затем падения уровня моря (поднятия суши) на 18–20 м уменьшались в периоды около 5000–4000 и 2500–1600  л.н. Выявленные изменения зависели преимущественно от эвстатического фактора примерно до 7000  л.н.; дальнейшие изменения в большей степени были обусловлены региональными параметрами оледенения последнего ледникового максимума, ходом дегляциации, региональными особенностями земной коры и мантийного вещества, локальными тектоническими процессами (включая гляциоизостазию)

Первые результаты мерзлотных наблюдений на криосферном полигоне Российского научного центра на архипелаге Шпицберген (РНЦШ)

The system of long-term permafrost observations was organised on the cryospheric site of Russian Scientifi c Center on Spitsbergen in summer 2016. The monitoring site is established in the vicinity of mining settlement Barentsburg on a sequence of Holocene marine terraces. The core drilling showed that the thickness of gravel sands and clays with massive and schlieren cryostructure forming the accumulative terraces is of 2–7 m. Cretaceous and Neocene fractured sandstones and mudstones underlie them. Automated thermistor cables were installed in two boreholes to monitor the temperature on the depth of zero annual amplitude and seasonal distribution of zero-degree isotherm. The temperature –2,37 °C was measured at 15 m depth. The thickness of active layer measured at ten meter net on the observational site of 100100 m varied from 1,15 to 2,60 m with average of 1,56 m. Chemical analysis of aqueous extract revealed a geochemical barrier at 0,8–1,6 m below permafrost upper boundary in the period of maximum thawing, which apparently marks maximum seasonal thaw depth during the Holocene climatic optimum. In this paper recommendations on continuing and extending of pilot permafrost dynamic observations on Spitsbergen are given.В 2016 г. на криосферном полигоне РНЦШ (о. Западный Шпицберген) впервые начаты долговременные наблюдения за состоянием мерзлых пород. Полигон расположен в окрестностях пос. Баренцбург на типичной для побережья Шпицбергена лестнице голоценовых морских террас. Согласно результатам проведенного колонкового бурения мощность гравелистых песков и суглинков с массивной и шлировой криотекстурой, слагающих аккумулятивные террасы, варьирует от 2 до 7 м; ниже залегают меловые и неогеновые трещиноватые песчаники и сланцы. Две скважины оборудованы автоматическими термометрическими косами для мониторинга температуры на глубине нулевых амплитуд и сезонного проникновения в грунт нулевой изотермы. Температура на глубине 15 м составила –2,37 °С. Измерения мощности сезонно-талого слоя, проведенные в сентябре по регулярной сетке с шагом в 10 м на площадке размером 100100 м, показали значения от 1,15 до 2,60 м при среднем значении 1,56 м. Выявленный по результатам анализа водной вытяжки геохимический барьер, находящийся на 0,8–1,6 м ниже верхней границы мерзлоты в момент максимального оттаивания, вероятно, маркирует глубину оттаивания во время голоценового оптимума. Сделаны предложения по продолжению и расширению начатых на криосферном полигоне долговременных наблюдений за динамикой мерзлоты Шпицбергена

Изменения объема и геометрии ледника Восточный Дальфонна (Шпицберген) в 2008–2019 гг.

Previously published geodetic mass balance data indicate glacier shrinkage in the Barentsburg area of Svalbard since the beginning of the 20th century on the decadal time scale. However, observations for shorter time spans allowing one to compute the inter-annual variability of the mass balance are scarce. The study presents results of ground-based GNSS and the GPR surveys of the Austre Dahlfonna glacier (2 sq km) located on Spitsbergen island, south of the town of Barentsburg. According to the GPR survey of spring 2019 at 50 MHz frequency, the area-averaged ice thickness was equal to 82 m, while the maximum was 170 m. The results confirm the polythermal structure of the glacier, with a layer of underlying temperate ice. Since the end of the Little Ice Age, the area of Austre Dahlfonna has halved. By comparing the GNSS survey results (the end of the melt season of 2019) with the co-registered archived remote sensing data (ArcticDEM strip of 2013 and S0 Terrengmodell of 2008), it was computed that, within the last 12 years (2008–2019), Austre Dahlfonna lost 16 % of its volume, which corresponds to a geodetic mass balance of –12.05 ± 0.85 m w. e. The mass loss in 2008–2013 (5.22 ± 0.37 m w. e.) was lower than in 2013–2019 (6.83 ± 0.48 m w. e.), which is in agreement with the ongoing direct measurements on the neighboring Austre Grønfjordbreen glacier and with the archipelago-wide mass-balance patterns. We demonstrate that the less intensive glacier mass loss, which occurred in 2005–2012 and was detected previously for the whole archipelago, definitely took place in the Barentsburg area as well. This time interval is characterized by the prevalence of a negative NAO phase (65 % of recurrence), which may indicate more frequent intrusions of colder Arctic air masses. This fact proves that the mass-balance variability of the Barentsburg area glaciers is governed in time spans of 5–10 years by regional-scale factors, presumably by shifts in the atmospheric circulation regimes.В работе представлены результаты топографической и геофизической съемок на леднике Восточный Дальфонна площадью около 2 км2, расположенном на архипелаге Шпицберген к югу от поселка Баренцбург. Средняя толщина льда по состоянию на 2019 г. составляет 82 м, максимальная — 170 м. На основе сравнения с архивными данными дистанционного зондирования показано, что за 12 балансовых лет ледник потерял 16 % своего объема, что эквивалентно потере массы в 12,05 ± 0,85 м в. э. Сравнением двух шестилетних периодов установлено, что в 2008–2013 гг. потеря массы замедлялась по отношению к последующему интервалу 2013–2019 гг., что согласуется как с наблюдениями на соседнем леднике Восточный Грёнфьорд, так и с общей масс-балансовой изменчивостью на архипелаге. Это приводит к выводу, что на временных интервалах порядка 5–10 лет изменчивость баланса массы ледников в районе Баренцбурга определяется факторами регионального масштаба, а именно сменами режимов атмосферной циркуляции на Шпицбергене, которые могут быть охарактеризованы преобладанием положительной либо отрицательной фазы индекса Северо-Атлантического колебания (NAO) летом

Строение и динамика ледника Альдегонда (Западный Шпицберген) по данным повторных георадиолокационных исследований 1999, 2018 и 2019 годов

Over the last decades, glaciers on Svalbard were shrinking in response to the current climate change. Most of them decreased in size, area, and surface height with a stable negative or even accelerated changes in the mass balance. Many of them belong to the polythermal type, and as they shrink, their thermal regime can also change significantly depending on the climate and local parameters such as the ice facies distribution, the firn thickness, and others that affect the hydrology and movement of glaciers. Data from repeated GPR surveys in 1999 and 2018–2019 were used to identify changes in the thermal regime of the polythermal Aldegondabreen, Svalbard. The glacier has undergone a significant reduction of its temperate ice core, as a consequence of steadily negative mass balance, decreasing thickness, and the tongue retreat. The results show that over a 19‑year period, the total area of the glacier has decreased by 23.1% (from 6.94 to 5.34 km2), and the total volume of ice – by 36.4% (from 0.437 to 0.278 km3). At the same time, the area of its temperate core has decreased by 32.7% (from 1.196 to 0.804 km2), and the core volume – by 42.5% (from 0.035 to 0.02 km3). In this way, the relative rates of internal glacier changes associated with the warm core exceeded the external changes of the entire glacier. The share of temperate ice in the total volume of the glacier ice decreased from 8% to 7%. The glacier shrinking in response to rise of the air temperature was accompanied by its gradual internal «cooling». In the near future, this can result in a rapid transition of the glacier from a polythermal type into a cold one. Regular repeated geophysical surveys of the internal structure of the Svalbard polythermal glaciers can become an important element in the system of long-term monitoring of changes in climate and the natural environment of the archipelago, along with already existing observations of other sensitive natural indicators such as the size and mass balance.Сравнение данных наземных радиолокационных съёмок 1999 и 2018–2019 гг. политермического ледника Альдегонда на Шпицбергене показывает, что площадь ледника за эти годы сократилась на 23,1%, а объём – на 36,4%. При этом площадь его тёплого ледяного ядра уменьшилась на 32,7%, а его объём – на 42,5%. Сокращение ледника сопровождается его постепенным выхолаживанием, что, вероятно, со временем приведёт к тому, что он превратится из политермического в ледник холодного типа

Внутрисезонная изменчивость абляции ледника Альдегонда (Шпицберген)

The intra-annual variability of the surface ice ablation on the 5.5 km2 Aldegondabreen glacier (Spitsbergen Island, Barentsburg area) is presented. The ice ablation was measured during five seasons (2018–2022) at the two stakes, installed in the lower part of the glacier and at the index site, where the amount of ablation numerically coincides with the glacier-averaged value with the r = 0.99 agreement. The temporal resolution of the ice ablation data is uneven and varies from 3 to 45 days. To carry out the correlation analysis, meteorological data from the automated weather station located near the glacier terminus are used. The ice ablation rates, obtained after normalization for the number of days between stake readings, have a tight correlation with both the air temperature and the downwelling shortwave radiation flux for most of the seasons, in 2018– 2021 (r = 0.71–0.99). Surface air temperature and short-wave radiation are closely related; the above estimates indicate the leading role of short-wave radiation in the summer ablation of the glacier in the period 2018–2021. The year 2022 became anomalous, as the correlation with the shortwave radiation significantly decreased (r = 0.21–0.34). The European heat wave of 2022, which also affected the Svalbard archipelago, interrupted the ordinary intra-annual variability of the air temperature, causing the unprecedented ice melt on Aldegondabreen in September. The predicted increase in frequency and intensity of the future heat waves will result in an increased role of turbulent fluxes in the surface energy balance of the low-elevated Svalbard glaciers. The article demonstrates how the empirically identified dependencies can change from season to season in a non-stationary climate.Рассмотрена зависимость внутрисезонной изменчивости абляции льда на леднике Альдегонда (Шпицберген) от приземной температуры воздуха и потока коротковолновой радиации. В 2018– 2021 гг. абляция льда хорошо согласуется с обоими факторами (r = 0.80–0.98 и 0.71–0.99 соответственно). 2022 год – аномальный с точки зрения нарушения связей абляции и радиации, что объясняется продолжительной волной тепла в Европе

Оценка баланса массы ледника Альдегонда (Западный Шпицберген) в 2015–2018 гг. на основе модели ArcticDEM, геодезических и гляциологических данных

The Aldegonda (Aldegondabreen) Glacier, located on the Nordenskjold Land, West Spitsbergen, covers the area of about 6  km2 (in 2018) and does constantly retreat since the very first observations of 1936. In August 2018, a topographic survey of the glacier was carried out. By comparing the results with the ArcticDEM model, built from space images of 2015, the difference in heights of the surface over three years had been calculated. Comparison of this difference with in situ data of glaciological measurements by the ablation stakes, made during the same period 2015–2018, demonstrated a high correlation between them. Considering the almost complete absence of snow cover on the glacier at the end of the summer season, the difference was recalculated into the spatial distribution of the specific mass balance by multiplying the ice density (0.88 g cm−3). Using the empirical dependence of the specific mass balance on the altitude above sea level, the obtained values were extrapolated to that part of the glacier which was not surveyed in 2018. The total loss of the Aldegonda Clacier mass for 2015–2018, calculated on the basis of topographic survey and the ArcticDEM, was estimated as 30.3 million tons (about 10.1 million tons per year). This magnitude gives the value of mean annual specific balance of approximately −1.76 m w.e, which is almost 2.5 times larger modulo than the previously published mean for the period 1936–1990, but close to the values of the early 2000s. Despite the small difference in the values obtained by geodetic and glaciological methods, the measurements does not show a systematic shift relative to each other and demonstrate approximately the same intervals of specific balance from the glacier tongue to its upper reaches (−1.08 ÷ −3.01 m w.e). This makes possible to conclude that the ArcticDEM model has the satisfactory vertical accuracy (both relative and absolute) to study on its basis changes in the surface height of an individual glacier.Путём сравнения результатов топографической съёмки с моделью местности ArcticDEM изучено снижение поверхности ледника Альдегонда за 2015–2018 гг. Потеря массы ледником за три года составила 30,3 млн т, или −1,76 м в.э. Исследование показало возможность применения ArcticDEM для масс-балансовых оценок отдельных ледников

Изотопный состав атмосферных осадков и природных вод в районе Баренцбурга (Шпицберген)

In 2016–2017, during Russian Arctic Expedition on Svalbard (RAE‑S) we have collected the samples of atmospheric precipitation, terrestrial waters, snow and ice on Spitsbergen island in the vicinity of Grønfjorden. The measurements of stable water isotope content (δ18O and δD) in the atmospheric precipitation has allowed to draw the Local Meteoric Water Line (δD = 6,93δ18O − 0,35) and to analyze the relationship between the isotopic content and condensation temperature. Aside from this, the d-excess values in precipitation (dexc= δD − 8δ18O) was interpreted as a marker of the moisture source. It has been demonstrated that the isotopic content of the surface waters (lakes and rivers) clearly points to the dominating type of feeding (atmospheric, ground) of these hydrological objects. We have discovered the interannual variability of the isotopic composition of Lake Kongress water during 2 years and defined the sources of water in its tributes: 13 of them have atmospheric source and 9 – ground source. In general, isotopic content of water in the vicinity of Grønfjorden (mean values are: δ18O = −10,3 ‰, δD = −72,5 ‰) is higher than in other regions of Svalbard.Ключевые слова: атмосферные осадки, изотопный состав, природные воды, Шпицберген. Приведена интерпретация изотопных исследований проб воды, снега и льда, отобранных на ледниках Альдегонда, Западный и Восточный Грёнфьорд и в их долинах (озёра, снежники, реки), а также в долине оз. Конгресс. На основании анализа изотопного состава атмосферных осадков в посёлке Баренцбург в 2016–2017 гг. обсуждается использование изотопного состава как индикатора источника влаги для атмосферных осадков