Внутренняя дренажная сеть и характеристики подледникового стока ледника Альдегонда (о. Западный Шпицберген)

The polythermal Aldegondabreen is one of the most widely studied glaciers of the Nordenskjöld Land (Svalbard). However, the structure of its internal drainage network remains poorly understood. In order to determine the position and hydro-chemical characteristics of the surface and internal drainage channels of the glacier complex studies were carried out including ground penetrating radar (GPR) measurements and hydrological surveys. The GPR profiling performed in 2018–2020 identified four channels of internal drainage network, two of which are found along the northern side of the glacier in the area of cold ice and are subglacial. The other two are located in the area of temperate ice along the southern side of the glacier and are englacial, stretching at the cold-temperate surface. At the outlet grotto, the subglacial waters have a bicarbonate-calcium composition and low salinity (electrical conductivity 30–40 μS/cm), inherited from the surface meltwater streams that enter the moulins in the upper part of the glacier. No noticeable increase in mineralization occurs during the movement of the flow along the glacier bed. The englacial channels’ waters at the outlet grotto have the same bicarbonate-calcium composition but a higher salinity (electrical conductivity 100 μS/cm), which we attribute to the filtration through the rocks of the riegel near the Aldegonda terminus, or, alternatively, to the influx of the groundwater at the same spot. Measuring the hydrochemistry of the Aldegonda river tributaries both on the glacier’s surface, at the grottos and on the moraine in the valley made it possible to identify the zone of enrichment of the main volume of the low-mineralization glacial meltwater of bicarbonate-calcium composition by the high-mineralization (electrical conductivity up to 760 μS/cm) groundwater of sulphate-calcium composition coming from the springs on the riegel in front of the glacier’s terminus in the central part of the Aldegonda Valley. Presumably, the springs are fed by the deep filtration of melted glacial waters along the Aldegonda subglacial talik.С целью определения положения и гидрохимических характеристик поверхностных и внутренних дренажных каналов ледника были выполнены комплексные исследования, включавшие детальное георадиолокационное профилирование и гидрологическую съемку. Проанализированы материалы предшествующих работ по изучению дренажной сети и подледникового стока. По данным георадиолокации сделаны выводы о строении внутренней дренажной сети ледника, согласно которым выделены основные каналы движения талых вод: 2 подледниковых в области холодного льда и 2 внутриледниковых вблизи области теплого льда. Выдвинуты и обоснованы предположения об области питания внутриледниковых каналов в верховьях ледника и их дренировании в местах переуглублений. Показано изменение электропроводности и гидрохимического состава подледниковых выходов и реки Альдегонды на всем ее протяжении. Выявлена зона обогащения слабоминерализованных талых ледниковых вод гидрокарбонатно-кальциевого состава сильноминерализованными подземными водами сульфатно-кальциевого состава, поступающими из источников на ригеле перед фронтом ледника в центральной части долины реки Альдегонды

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

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

ФОРМИРОВАНИЕ ОБЪЕМНЫХ ВЫВОДОВ ПОЛУПРОВОДНИКОВЫХ ПРИБОРОВ МЕТОДОМ ЭЛЕКТРОХИМИЧЕСКОГО ОСАЖДЕНИЯ

Using nonstationary regimes electrolysis for electrodepositing silver solder bump semiconductor blocked has reduced lateral expansion of different height on the plate, to improve the qualitative characteristics of the product, increase the number of devices produced on a semiconductor wafer, and thereby improve process performance and achieve economies of precious metals.Исследовано влияние состава электролита и программируемых импульсно-реверсных режимов на скорость и равномерность формирования объемных серебряных выводов полупроводниковых приборов. Показано, что использование нестационарных режимов электролиза позволяет снизить их боковое разрастание и разновысотность по пластине, улучшить качественные характеристики изделий, увеличить количество приборов, получаемых на одной полупроводниковой пластине, и, тем самым, повысить производительность технологического процесса и обеспечить экономию драгметаллов

Лёд и снег озера Стемме (о. Западный Шпицберген) зимой 2019/20 г.

The results of observations and modeling of the formation of the snow-ice cover of Lake Stemme (West Svalbard Island) in winter 2019/20 are presented. The main information was obtained by two radar (GPR) survey, performed on the floating ice of the Lake on March 12 and April 22 of 2020. Authors believe that probably these observations were the first ones on the Lake. The use of the radar made it possible to obtain data on the dynamics of the thickness of the layers of snow and ice cover, the so-called “snow ice” which is formed when the boundary between snow and ice was submerged under water. During the time between records, the thickness of the last “snow ice” increased two to three times, i.e., from units to the first tens of cm, and it spread to the entire deep-water part of the Lake area. In addition, analysis of high-precision positioning of the radar records revealed a significant deflection in the ice surface in the central part of the Lake under the influence of snow load and the decreasing level of the reservoir. The calculations of the thermodynamics of the floating ice cover have shown that its thickening occurs as a result of the processes of congelation and isostatic ice formation, replacing each other at its lower and upper boundaries, respectively. At the same time, the formation of “snow ice” violates the characteristic feature of decreasing of ice thickness with growth of the snow thickness, which significantly influences on the thermal and mass balance of the Lake snow-ice cover. Results of calculations of the ice cover deformation did show that it takes place not only due to the elastic, but also to the viscous properties of ice, and it is concentrated in a narrow coastal zone. The maximum radial stress is reached at a distance of several meters from the shore, where a circular crack parallel to the shoreline is formed. Such a crack is formed at all ice thicknesses at about the same distance from the shore.Представлены и проанализированы результаты комплексных наблюдений снежно-ледяного покрова оз. Стемме (о. Западный Шпицберген) зимой 2019/20 г. Полевые данные дополнены результатами моделирования, описывающими особенности его нарастания и деформации

ELECTRODEPOSITION OF SOLDER BUMP TO SEMICONDUCTOR DEVICES

Using nonstationary regimes electrolysis for electrodepositing silver solder bump semiconductor blocked has reduced lateral expansion of different height on the plate, to improve the qualitative characteristics of the product, increase the number of devices produced on a semiconductor wafer, and thereby improve process performance and achieve economies of precious metals