Ice and Snow (E-Journal) / Лёд и Снег
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Стабильные изотопы 18O и D в ключевых компонентах водного стока и криолитозоны Центральной Якутии (Восточная Сибирь)
Get PDFOn the basis of about 430 analyses, the 18O and D compositions (%o) of atmospheric precipitation, ground ice, surface and inter-permafrost underground waters of cryogenic-aeolian landscapes of Central Yakutia (Eastern Siberia) are discussed. Precipitation compositions here demonstrate a large annual variation (from -6.12 to -45.0 % for δ18O, and from -72.1 to -350.1 % for δD), and they are described by the Local Meteoric Water Line according to the equation δD = 7.81518O - 1.57). In winter and in the process of spring melting, the snow storage is subjected to a significant evaporative fractionation, that is expressed by the equation δD = 6.85518O - 31.9. The heaviest and deuterium-depleted compositions (δ18O = -19.3 %, δD = -160.9, dexc = -6.7 %) are found in the last snow patches in early June. The lightest compositions similar to the present-day winter precipitation (snow) are characteristic of the polygonal wedge ices (PWI) of the Central Yakutia. The most lightweight (from -30 to -34 % for δ18O, and from 240 to 275% for δ D) were established to be typical for the ancient PWI, dated by the first half of the Late Pleistocene (MIS 3-4). Heavier compositions (δ18O = -27.2±1.4, δD = -215.8±8.5, dexc = 1.7±3.1 %) with obvious features of evaporative fractionation correspond to younger PWI (MIS 2-1). The heaviest compositions (δ18O = -12.2±0.7, δD = -99.2±4.7, dexc = -2.0±0.8 %) and high angular coefficients of approximating equations were determined in the investigated cave ices of sublimation origin, that implies the atmospheric origin of them. The current processes of evaporative fractionation are the most intensively reflected in the waters of aeolian lakes (δ18O = -11.8±3.5, δD = -120.2±18.4, dexc = -25.8±10.5 %), and the compositions are described by the regression equation 5D = 5.52 δ18O - 54.12 (R2 = 0.97). The phenomenal objects of the cryogenic-eolian landscapes of the Central Yakutia are high-debit underground sources. Among all other components of the water flows, composition of these sources is the most stable (δ18O = -21.6±0.8, δD = -172.6±5.1, dexc = 0.23±3.0 %). The regression of compositions of the largest underground source Bulus is approximated by the equation 5D = 6.31 δ18O - 36.7 (R2 = 0.78), that is indicative to significant evaporative fractionation and close relation with the aeolian lakes in the alimentation area.Особенности рельефа и строения криолитозоны Центральной Якутии связаны с широким распространением здесь позднечетвертичных супесчаных дюнных покровов. Они вмещают разветвлённые сети обводнённых межмерзлотных таликов, гидравлически связанных эоловых озёр, подземных источников, фрагменты едомных отложений с мощными ледяными жилами, а также наледи. На основе выборки более чем из 430 определений обсуждается разнообразие состава стабильных изотопов (18O и D) перечисленных компонентов водного стока
Запасы льда в ледниках на Земле Норденшельда (Шпицберген) и их изменения за последние десятилетия
Get PDFData on thickness and area of 16 glaciers on the Nordenskiöld Land (Svalbard) were obtained in 1999 and 2010–2013. These data were used to determine volume of the glaciers and to establish statistical local relationship between the volume V and the area A (V–A scaling) in the form of the power function V = cAγ, and then to calculate the total ice volume of all 202 glaciers in this area and its changes during the period since 1936 to 2002–2008. The total area of 16 glaciers was 129.9±0.35 km2, 14 of which had areas from 0.2 to 8.1 km2. The two largest ones, the Fridtjof and the West Grenfjord, had the areas 17.5 and 47.3 km2, respectively, and thus occupied about 50% (64.8 km2) of the total area of 16 glaciers. These two glaciers account for 67% of the total measured volume (10,034 km3) of the 16 glaciers. A nonlinear least-squares method was used to estimate ice reserves in all 202 glaciers from data on the volume and area of 16 glaciers. The relation between volume V and area A of the glaciers (V–A scaling) was obtained as the ratio V = 0.03637A1,283 with 95%‑th confidence intervals of the coefficients с and γ, (0.02303–0,4971) and (1.184–1.381), respectively. This made possible to calculate total volume of 202 glaciers as of 2002-2008 state using data from RGI v.6.0, and that prove to be equal to 32.89 (16.75–56.63) km3. To verify this estimation, we applied the bootstrapping method for chosen 43 glaciers and calculated the volume by means of sequential use of data for large and smaller glaciers. According to this estimate, the total volume of 202 glaciers amounted to 30.34 km3 with a 95% confidence interval of 15.42–44.27 km3, that turned out to be slightly smaller than the volume calculated by nonlinear least squares method basing on measurements on 16 glaciers. Despite the large error (on the average, from −49% to +84%) in estimating the total volume of 202 glaciers in the Nordenskiöld Land, the data obtained were used for assessment of relative changes in the total volume of glaciers in this area over different time intervals. During the period from 1936 to1990 (54 years), the total area of all glaciers reduced from 738.1 to 546.7 km2, and the total volume decreased from 49,205 to 34,857 km3. Similar results for the period 1990–2002–2008 (~15 years) are the total area changes from 546.7 to 507.9 km2 and their total volume - from 34.857 to 32.890 km3. The rate of decrease of the volume for the period 1936–1990 was equal to −0.266 km3/year, for the period 1990–2002–2008 – minus 0.131 km3/year, and as a whole for the studied period (since 1936 to 2002–2008) – minus 0.236 km3/year. The average mass balance in the first period was equal to −0.372 m w.e./year, in the second one −0.224 m w.e./year, and for the whole time −0.342 m w.e./year. Приведены результаты наземных радиолокационных измерений в 1999 и 2010–2013 гг. толщины и объёма 16 ледников на Земле Норденшельда (Шпицберген) с применением статистической связи между объёмом и площадью ледников. Оценены запасы льда во всех 202 ледниках этого района и их изменения за последние десятилетия с использованием данных о площади ледников по состоянию на 1936, 1990, 2002–2008 гг. и на годы радиолокационных измерений
Мониторинг ледника Колка в 2014–2017 гг. методом наземной стереофотосъёмки
Get PDFThe Kolka Glacier, which rushed down the Genaldon valley on September 20, 2002 (North Ossetia), is now recovering after this catastrophe. One of the most important ways to predict a new disaster is to determine the rate of ice accumulation of the new glacier and to monitor the glacier volume regularly, since its trigger mechanisms have not yet been fully studied. Recent changes of the Kolka Glacier were investigated by means of ground stereoscopic photography. The field works were carried out in 2014, 2016 and 2017. Shooting was made manually with a digital camera Canon 5D Mark II (without using a tripod) at arbitrary points, the distance between which did not exceed 100 m. The reference points were placed on the elevated relief forms on the glacier surface and coordinated by a differential GNSS receiver in the "fast static" mode. Laboratory processing of the photos was performed using Agisoft Photoscan software in automatic mode, except for the procedure of identification of reference points on stereo images. The processing made possible to obtain digital models of the glacier surface in Geo-TIFF format, the vertical error of which amounted to 0.7 m, while the horizontal one – 2.3 m. In 2014–2017, the maximal increase in height of the surface (up to 30 m) was recorded in the low part of the glacier tongue that was the result of advancing of the Kolka front along the ice-free surface. Mean annual increase in the surface elevation was equal to 2.2 m/year. Lowering of the surface in some areas may be explained by the slowing-down of the glacier flow rate, which led to the appearance of thermokarst. The glacier volume increased by 7.4±0.7 million m3. As a result, the glacier tongue advanced by 50–70 m. Average over 2014–2017 increasing in the surface elevation (2.2 m/year) was slightly smaller than in 2004–2014 (3 m/year). Quick growth of the Kolka Gacier contrasts sharply with decreasing of volume of the representative Caucasus, Djankuat and Garabashi, over the same period. По данным наземной стереоскопической съёмки в 2014, 2016 и 2017 гг. оценены изменения объёма ледника Колка, восстанавливающегося после гляциальной катастрофы 2002 г. Ледник продолжает расти несмотря на неблагоприятные для ледников Кавказа климатические условия. Высоты поверхности ледника увеличивалась в среднем на 2,2 м/год, что резко контрастирует с негативным состоянием большинства ледников Кавказа
Влияние температуры поверхности океана в тропиках на антарктический морской лёд в период глобального потепления
Get PDFSea ice fields in the Antarctic, in contrast to the Arctic ones, did not show a reduction in observed global warming, whereas the global climate models indicate its certain decrease. The purpose of the study is to explain this climatic phenomenon on the basis of the idea of joint dynamics of oceanic structures in the Southern Ocean – the Antarctic polar front and the margin of the maximum distribution of sea ice. We used data from the ERA/Interim and HadISST as well as the database on the sea ice for 1979–2017. Relationship between the SST-anomalies in low latitudes of the Northern hemisphere and positions of the Antarctic polar front and maximum sea-ice extent was investigated. It was found that locations of these structures changed under the influence of the SST anomalies in low latitudes. The results obtained confirm existence of the opposite trends in changes in the sea ice extent in the Arctic and Antarctic under the influence of the SST anomalies in the central North Atlantic Ocean. When positive, the anomalies cause a shift of the Intertropical Convergence Zone (ITCZ) and the Hadley circulation to the North, while, on the contrary, the negative anomaly promotes the corresponding shift of the Antarctic polar front, followed by the boundary of sea ice.При наблюдаемом глобальном потеплении морской ледяной покров в Антарктике не проявлял тенденций к сокращению, в то время как глобальные климатические модели показывают его уменьшение. Цель исследования – объяснить этот климатический феномен на основе идеи о совместной динамике океанических структур Южного океана – Антарктического полярного фронта и границы максимального распространения морского льда, положение которых меняется под влиянием аномалий температуры на поверхности океана в низких широтах
Влияние свежевыпавшего снега на нарастание и таяние морского льда
Get PDFNumerical experiments were carried out using the thermodynamic model with the aim to optimize choice of parameterization of the density of fresh snow, its albedo, and thermal conductivity coefficient in order to reproduce the seasonal evolution of ice thickness in the North-Eastern part of the Sea of Azov. The simulation results were compared with each other as well as with the observations obtained at the costal station of the Southern Scientific Center of the Russian Academy of Sciences in the Taganrog Bay. It is shown that small differences in the schemes of parameterization of physical and thermal properties of snow and ice cover may result in significant scatter in the simulation results. To assess the quality of the forecasting of the seasonal course of the ice thickness, the standard deviation of the calculated ice thickness from the average value for the period of measuring ice thickness, the standard deviation, the correlation coefficient, and the verification of the forecast were determined. Based on the analysis of these parameters, the optimal configuration of the snow layer parameters is proposed, which allows adequate reproducing of the seasonal thermal dynamics of the sea ice thickness. For the conditions of winter 2010/2011 the most close values of calculated ice thickness to results of the measurements in the North-Eastern part of the Taganrog Bay were obtained by determining the dependence of the density of fresh snow on the temperature in the near-surface layer of the atmosphere by the algorithm CLASS, albedo of the snow surface - by the scheme EHAM5, and the coefficient of thermal conductivity of snow – by the formulas of N.I. Osokin or M. Janson. На основе термодинамической модели выполнены численные эксперименты с целью оптимального выбора параметризации плотности свежевыпавшего снега, его альбедо и коэффициента теплопроводности для воспроизведения сезонной эволюции толщины льда в северо-восточной части Азовского моря. Результаты моделирования сравнивались между собой и с данными наблюдений, полученными зимой 2010/11 г. на береговой базе Южного научного центра РАН в Таганрогском заливе
Влияние океанического притока тепла в Баренцево море на региональные изменения ледовитости и статической устойчивости атмосферы
Get PDFThe influence of the oceanic heat inflow into the Barents Sea on the sea ice concentration and atmospheric characteristics, including the atmospheric static stability during winter months, is investigated on the basis of the results of ensemble simulations with the regional climate model HIRHAM/NAOSIM for the Arctic. The static stability of the atmosphere is the important indicator of the spatial and temporal variability of polar mesocyclones in the Arctic region. The results of the HIRHAM/NAOSIM regional climate model ensemble simulations (RCM) for the period from 1979 to 2016 were used for the analysis. The initial and lateral boundary conditions for RCM in the atmosphere were set in accordance with the ERA-Interim reanalysis data. An analysis of 10 ensemble simulations with identical boundary conditions and the same radiation forcing for the Arctic was performed. Various realizations of ensemble simulations with RCM were obtained by changing the initial conditions for integrating the oceanic block of the model. Different realizations of ensemble simulations with RCM are obtained by changing the initial conditions of the model oceanic block integration. The composites method was used for the analysis, i.e. the difference between the mean values for years with the maximum and minimum inflow of oceanic water into the Barents Sea. The statistical significance of the results (at a significance level of p < 0.05) was estimated using Student's t-test. In general, the regional climate model reproduces the seasonal changes in the inflow of the oceanic water and heat into the Barents Sea reasonably well. There is a strong relationship between the changes in the oceanic water and ocean heat inflow, sea ice concentration, and surface air temperature in the Barents Sea. Herewith, the increase in the oceanic water inflow into the Barents Sea in winter leads to a decrease in static stability, which contributes to changes in regional cyclonic activity. The decrease of the static stability is most pronounced in the southern part of the Barents Sea and also to the west of Svalbard.На основе результатов ансамблевых расчётов с использованием региональной климатической модели HIRHAM/NAOSIM для Арктики исследовано влияние притока океанических вод в Баренцево море на концентрацию морских льдов и характеристики атмосферы в зимние месяцы. Показана определяющая роль вариаций притока океанических вод в Баренцево море на режим морских льдов и приповерхностной температуры воздуха, а также статическую устойчивость атмосферы в зимний период
Моделирование снегонакопления и снеготаяния в бассейне р. Кама с применением данных глобальных моделей прогноза погоды
Get PDFCurrently, the improvement of numerical models of weather forecasting allows using them for hydrological problems, including calculations of snow water equivalent (SWE) or snow storage. In this paper, we discuss the applicability of daily precipitation forecasts for three global atmospheric models: GFS (USA), GEM (Canada) and PL-AV (Russia) for calculating snow storage (SWE) in the Kama river basin for the cold season of 2017–2018. As the main components of the balance of snow storages the following parameters were taken into account: precipitation (with regard for the phase); snow melting during thaws; evaporation from the surface of the snow cover; interception of solid precipitation by forest vegetation. The calculation of snow accumulation and melting was based on empirical methods and performed with the GIS technologies. The degree-day factor was used to calculate snowmelt intensity, and snow sublimation was estimated by P.P. Kuz’min formula. The accuracy of numerical precipitation forecasts was estimated by comparing the results with the data of 101 weather stations. Materials of 40 field and 27 forest snow-measuring routes were taken into account to assess the reliability of the calculation of snow storages (SWE). During the snowmelt period, the part of the snow-covered area of the basin was also calculated using satellite images of Terra/Aqua MODIS on the basis of the NDFSI index. The most important result is that under conditions of 2017/18 the mean square error of calculating the maximum snow storage by the GFS, GEM and PL-AB models was less than 25% of its measured values. It is difficult to determine which model provides the maximum accuracy of the snow storage calculation since each one has individual limitations. According to the PL-AV model, the mean square error of snow storage calculation was minimal, but there was a significant underestimation of snow accumulation in the mountainous part of the basin. According to the GEM model, snow storages were overestimated by 10–25%. When calculating with use of the GFS model data, a lot of local maximums and minimums are detected in the field of snow storages, which are not confirmed by the data of weather stations. The main sources of uncertainty in the calculation are possible systematic errors in the numerical forecasts of precipitation, as well as the empirical coefficients used in the calculation of the intensity of snowmelt and evaporation from the snow cover surface.На примере холодного периода 2017/18 г. выполнено моделирование формирования и таяния снежного покрова в бассейне р. Кама с применением выходных данных глобальных моделей прогноза погоды GFS (США), GEM (Канада) и ПЛ-АВ (Россия). Валидация результатов проведена по данным 40 полевых и 27 лесных снегомерных маршрутов, а в весенний период – и по спутниковым снимкам MODIS. Ошибка расчёта снегозапасов по данным всех трёх моделей не превысила 25% фактических значений
Особенности промерзания болот при климатических изменениях на севере и северо-западе Европейской территории России
Get PDFLong-term complex observations covering the period of 1949–2018 made possible to determine the average annual characteristics of the depth of freezing of wetlands in the North and Northwest of the European territory of Russia together with main factors of its formation, and spatial and temporal variability. The main factors that determine the depth of freezing of wetlands are ambient temperature, snow cover thickness, and a degree of watering of the micro landscape (water reserves of the micro landscape). At the initial stage of freezing, the major factor is the ambient temperature, when intensity of the freezing reaches 0.5–0.8 cm/day. As snow falls, the freezing rate becomes smaller, and when the snow cover thickness reaches 25–30 cm the depth amounts to 0.2–0.3 cm/day and smaller. It was found that the spatial variability of the freezing depth decreases from large values of the coefficient of variation (0.3–0.4) at the depth of 20–30 cm to less than 0.1 when the depth exceeds 60 cm. The largest values of the depth are recorded in the North of the Kola Peninsula, where sometimes they reach from 84 to 97 cm with the average values of 48–66. In large hummocky bogs, when the seasonal freezing comes down to 63–65 cm it links with the permafrost layer. On average, swamps of these bogs freeze down to a depth of 68 cm. The average climatic depth of freezing of oligotrophic bogs of the NorthWest is 21–24 cm; in some years, freezing of them reaches 32–40 cm. It has been shown that the relative warming of the climate resulted in decreasing in the depth of freezing of wetlands in the North and North-West of the European territory of Russia. Relative to the previous climatic period, the depth of frost penetration in the northern Ilasskoye bog decreased by 32%, and in north-western Lammin-Suo bog – by 31%.Приведены данные об основных факторах, определяющих глубину промерзания болот: температуре воздуха, толщине снежного покрова и степени увлажнения микроландшафта. Относительное потепление климата привело к уменьшению глубины промерзания болот рассмотренной территории на 31–32% по отношению к предшествующему климатическому периоду.
Зонды для исследования ледяных и подлёдных сред планет
Get PDFThe article proposes a technology for increasing the thermic ice drilling rate under the influence of hydraulic force generated by the probe (or cryobot), which increases the coefficient of conversion of thermal energy into the energy of ice melting and allows increasing the power of thermal head of the probe. A single-wire Tesla system is proposed to use for the probe power supply, which makes it possible to reduce the volume of the cable and losses of transmitted energy. The method of the probe self-lifting to the ice surface without using the hydraulic force (traction), i.e. without a load on the cable, is proposed. To study thick (up to 5 km) ice sheets and subglacial water environments on the Earth, as well as the ice cover (up to 30 km thick) and the subglacial ocean of the Europe (the Jupiter’s satellite), conceptual principal designs of the probe (or cryobot) have been developed on the basis of thermic-hydraulic drilling (THD). Implementation of the THD‑cryobot designs will allow organizing systemic studies of glaciers and subglacial water environments on the Earth and other planets, not disturbing their ice isolation with multiple savings of financial and technical means, energy and time. Для исследования ледяных массивных щитов (до 5 км) и подледниковых водных сред на Земле, а также ледяного покрова толщиной до 30 км и подлёдного океана Европы (спутника Юпитера) разработан концептуальный проект термогидравлического бура-зонда (TГБ‑зонда и ТГБ‑криобота) и представлены ключевые конструкторские решения. Реализация идеи такого зонда (криобота) позволит организовать системные исследования ледников и подледниковых водных сред на Земле и других планетах без нарушения ледяной изоляции при многократной экономии финансовых и технических средств, энергии и времени
Методика оценки лавинного питания (на примере трёх ледников Тянь-Шаня)
Get PDFThe contribution of snow avalanches to the seasonal snow accumulation on a glacier is among the least studied components of the glacier’s mass balance. The methods for the numerical assessment of avalanche accumulation are still under development, which is related to poor avalanche data availability and difficulties in obtaining such data on most of mountain glaciers. We propose a possible methodology for the numerical assessment of snow avalanche contribution to snow accumulation at mountain glaciers based on DEM and weather data analysis using GIS and numerical modeling of snow avalanches. The developed methodology consists of the following steps: terrain analysis; weather data analysis; snow avalanche volume assessment during an analyzed balance year; numerical simulation of snow avalanches using RAMMS; evaluation of snow avalanches contribution into a glacier accumulation. The proposed methodology was tested on three glaciers located in the Inner Tien Shan: Batysh Sook, № 354 and Karabatkak during the 2015/16 balance year. To evaluate snow avalanche contribution to the seasonal accumulation, we reconstructed avalanche release zones that were most probably active during the 2015/16 balance year and corresponding snow fracture height in each of these zones. The numerical simulations of most probable released snow avalanches during the winter period 2015/16 using avalanche dynamics software RAMMS were performed and compared with the field observations and UAV orthophoto image from July 2016. The outlines of avalanches deposits were realistically reproduced by RAMMS according to the results of field observation. The estimated share of snow avalanche contribution to the accumulation on the research glaciers during the 2015/16 balance year turned out to be: Batysh Sook – 7,4±2,5%; № 354 – 2,2±0,7%; Karabatkak – 10,8±3,6% of the total accumulation. The next step would be to test the proposed methodology based on the data and regional dependences from the Inner Tien Shan in other mountainous regions. This methodology is applicable in the regions where DEMs, regular meteorological observations as well as data on the regional avalanche formation factors are available.Предложена новая методика количественной оценки лавинного питания ледников, основанная на анализе рельефа и данных метеорологических наблюдений с использованием методов геоинформационного картографирования и математического моделирования. Рассмотрены результаты её применения на трёх ледниках Тянь-Шаня: Западный Суёк, № 354, Карабаткак