bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient Acceleration of Electrons by Moderate-Power Femtosecond Laser Pulses
Authors: Vays O. E. , Lobok M. G. , Solov'ev A. A. , Mironov S. Yu. , Khazanov E. A. , Bychenkov V. Yu.
Published: April 2024

The relativistic self-trapping of a laser pulse is an efficient mechanism for the acceleration of electrons, whichallows one to achieve an extreme charge of a high-energy particle beam and the corresponding conversioncoefficient of laser energy. It has been shown that the compression of the femtosecond laser pulse in thisregime using the innovative compression after compressor approach (CafCA) [E.A. Khazanov,S.Yu. Mironov, and G. Mourou, Phys. Usp. 62, 1096 (2019)] to extremely short durations keeping the energyof the laser beam significantly increases the efficiency of particle acceleration. This effect has been illustratedon the example of the Multitera laser facility for the project implemented at the Russian National Center forPhysics and Mathematics.
Interlayer Conductivity of Quasi-Two-Dimensional Layered Conductors in a Magnetic Field at Yamaji Angles
Authors: Mogilyuk T. I. , Gudin S. A. , Grigor'ev P. D.
Published: April 2024

The behavior of the interlayer magnetoresistance Rzz is analyzed in quasi-two-dimensional layered metals ina magnetic field tilted at Yamaji angles at which the minimum of the interlayer conductivity is observed. Thecases of the Lorentzian line shape of Landau levels and of the shape corresponding to the self-consistent Bornapproximation are studied. At high fields, the behavior Rzz B3/2 is theoretically predicted, which agrees wellwith experimental data.
Interplay Between Electron Correlations, Magnetic State, and Structural Confinement in LaNiO3 Ultrathin Films
Authors: Vambol'd N. O. , Sazhaev G. A. , Leonov I. V.
Published: April 2024

We report a theoretical study of the effects of electron correlations and structural confinement on the electronic properties and magnetic state of LaNiO3(LNO) thin films epitaxially deposited on the(001)LaAlO3(LAO) substrate. Using the DFT + U method we compute the electronic band structure, magnetic properties, and phase stability of the 1.5 unit-cell-thick NiO2-terminated LNO thin films. Our results reveal complex diversity of the electronic states caused by the effects of structural confinement, interfacial charge transfer and electronic correlations. Our calculations suggest the appearance of in-plane (110) charge disproportionation of the Ni ions in the interface NiO2layer of the antiferromagnetically ordered LNO thin films. Moreover, the electronic states of both the antiferromagnetic and ferromagnetic LNO/LAO show a large orbital polarization of the Ni ions in the surface NiO2layers. Our results suggest the crucial importance of oxygen defects to explain the metal-to-insulator phase transition experimentally observed in a few-unit-cell-thick LNO/LAO thin films.
Magnetoresistance of a HgTe/CdHgTe Double Quantum Well in an In-Plane Magnetic Field
Authors: Yakunin M. V. , Aleshkin V. Ya. , Neverov V. N. , Popov M. R. , Mikhaylov N. N. , Dvoretskiy S. A.
Published: April 2024

A magnetic field parallel to the layers of a double quantum well with conventional semiconductor constituentsleads to a relative shift of the conduction band spectra of the constituent layers along the wave vector perpendicularto the field. If the states of the layers are tunnel-coupled, a tunneling gap is formed at the intersectionof the single-layer spectra and is shifted upward with increasing field. This leads to striking features in themagnetoresistance caused by intersections of the Fermi level with the edges of the tunneling gap. Similarstudies of transformations of the spectrum of the double quantum well in a HgTe/CdHgTe heterosystem,which has a p-type conductivity and HgTe layers with a gapless inverse energy spectrum, are reported in thiswork. Our experiments and corresponding calculations in the eight-band kp approach indicate that the evolutionof the magnetoresistance with the variation of the in-plane field here has a much more complex anddiverse character depending qualitatively on the thickness of the layers.
Solution of the One-Dimensional Stefan Problem with Two Transitions for Modelling of the Water Freezing in a Glacial Crevasse
Authors: Popov S. V.
Published: April 2024

This article presents a numerical solution of the one-dimensional Stefan problem with two phase transitions, which is implemented on a non-uniform grid. The system of equations is written in a general form, i.e. it includes not only conductive, but also convective and dissipative terms. The problem is solved numerically by the front-fixing method on a non-uniform grid using an implicit finite-difference scheme, which is implemented by the sweep method. This algorithm can also be used to create more complex mathematical models of heat and mass transfer, as well as to describe glacial and subglacial processes. The mathematical apparatus proposed in the article was used to solve a specific problem of water freezing in a glacial crevasse. The presence and progression of crevasses, in turn, is a demonstrative factor indicating the dynamic activity of the glacier. Crevasses formed in one way or another can not only expand, but also decrease in size until they completely disappear. One of the reasons for their closure is the freezing of near-surface meltwater in the crevasse. Such a process was observed on glaciers near Mirny and Novolazarevskaya stations (East Antarctica). This process is modeled as an example of solving the Stefan problem. It is believed that all media are homogeneous and isotropic. The temperature of the water in the crevasse corresponds to the melting temperature of the ice. Modeling has shown that for the coastal part of the cold Antarctic glacier with an average temperature of –10°C and below, crevasses 5–10 cm of width freeze in less than a week. Wider ones freeze a little longer. 30 cm wide crevasses close in about two to three weeks, depending on the temperature of the glacier.
Ice and Snow on Lake Stemmevatnet, Spitsbergen, in Winter 2019/20
Authors: Bogorodskiy P. V. , Filchuk K. V. , Sidorova O. R. , Ryzhov I. V. , Romashova K. V. , Novikov A. L. , Movchan V. V. , Marchenko A. V. , Kustov V. Yu. , Borisik A. L. , Khaustov V. A.
Published: April 2024

Received January 19, 2023 ;revised March 22, 2023; accepted June 27, 2023The 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.
Snow Cover as a Factor of Growth of Annual Tree Rings under Contrasting Environmental Conditions of the West Siberian Plain
Authors: Bykov N. I. , Shigimaga A. A. , Rygalova N. V.
Published: April 2024

The results of the analysis of the relationship between the width of annual tree rings of various woody plants and snow cover characteristics are presented: the dates of setting-up and destruction (loss) of stable snow cover, the duration of its existence, the thickness and water content of snow cover for the period of maximum snow accumulation. The studied areas are the forest-tundra zone, the northern taiga subzone, the southern forest-steppe subzone, and the dry steppe subzone within boundaries of the West Siberian Plain. Data from observations of snow cover on routes and meteorological sites of Roshydromet for 1966–2020 (for forest tundra and northern taiga) and 1966–2018 (for forest-steppe and dry steppe) together with dendrochronological samples obtained by the authors in these natural zones and subzones were used for this study. It was found that the thickness and water content of the snow cover play greater role for the radial growth of trees in the forest-tundra and dry steppe as compared to the northern taiga and southern forest-steppe. In the dry steppe, the trees of the upper parts of the low ridges and flat interfluves (plakors) are more sensitive to these snow cover characteristics, while in the forest-tundra this is important for the lower parts of the slopes. The dates of destruction of stable snow cover are more significant in the southern regions than in the northern ones. In the southern forest-steppe, the early loss of the snow cover increases the rate of growth of tree rings, while in the dry steppe it weakens it. The dates of setting-up of the stable snow cover are more important for the growth of trees compared to the dates of its loss, especially in the forest-tundra and southern forest-steppe since the later it starts, the greater the growth of trees. Importance of the duration of the period with stable snow cover for tree growth is higher in the southern regions. Its increasing in the southern forest-steppe reduces the growth of trees but increases in the dry steppe.
Thermal Regime of Snow Cover in Winter in The High-Mountainous Part of Elbrus According To Observational Data and Modeling Results
Authors: Drozdov E. D. , Turkov D. V. , Toropov P. A. , Artamonov A. Yu.
Published: April 2024

Based on the analysis of the results of two measurement episodes in February 2021/22 and calculations using the LSM SPONSOR model, we obtained estimates of the variability of the snow surface thermal balance components and the thermal regime of the snowpack in the ablation zone of the Garabashi glacier on the southern slope of Mount Elbrus at 3850 m above sea level. A quantitative assessment of the sensitivity of the heat balance components to variations in key physical parameters has been performed. It is shown that the optimal value of the emissivity coefficient of snow cover in mountainous areas is 0.98: the absolute error in calculating the radiation temperature of the snow surface at this value does not exceed 1°С, in addition, the model adequately reproduces the thermal regime of deep layers of snow cover. It is also shown that a change in snow density by ±100 kg/m3 can lead to deviations in the temperature of the snow mass by several degrees. This indicates an urgent need to solve the methodological problem of measurements with thermocouples, in which the integrity of the snow mass is inevitably violated. A good agreement between the results of calculations of turbulent sensible heat fluxes in the SPONSOR model with direct measurements (correlation coefficient 0.9) is demonstrated. Based on the measurement data, the fact of a fairly high frequency of high values of turbulent fluxes under conditions of intense radiative heating in combination with high wind speeds was revealed, which apparently turns out to be typical for high-mountain regions in winter (unlike the plains). For cases of strongly stable stratification in the surface layer, the model systematically overestimates the absolute values of heat fluxes. This may be due to the well-known problem of implementing the calculation scheme based on the Monin-Obukhov theory under conditions of temperature inversions. The inaccuracy in determining the snow surface roughness parameter, which in high mountain conditions is characterized by significant temporal variability, can contribute to the error.
On the Dependence of the ice Formation in the Lake Ladoga on the Air Temperature
Authors: Karetnikov S. G.
Published: April 2024

The purpose of the work was to establish regularities of the ice formation in the largest European Lake Ladoga depending on the air temperature. The average daily air temperatures obtained at the Sortavala weather station for thirty years were used for the analysis. The main task was to determine the sums of accumulated average daily air temperatures necessary for the appearance of primary ice phenomena in areas with different depths of the Lake. To solve this problem digitized remote sensing data of the spatial distribution of ice in the fixed cells with known average depth and data on average daily air temperatures were used. For thirty last winters, the dates of the first ice appearance in each of 180 cells were selected, which were related to the accumulated to this date sum of mean daily air temperatures after its steady transition through 0°С towards the negative values. The resulting scheme of the accumulated sums of air temperatures needed for the ice appearance indicates their regular growth with increasing depth. It is assumed that this dependence will make it possible to assess dynamics of ice formation on other lakes.
Calculation and Forecast of Glacial Feeding in River Basins
Authors: Konovalov V. G.
Published: April 2024

A two-stage method has been developed for calculating and forecasting the annual volumes of glacial runoff feeding mountainous rivers. At the first stage, the series of morphological characteristics of glaciers are reconstructed using limited data from regional glaciation monitoring. An example of a numerical description and analysis of the annual reconstructed dynamics of glaciation parameters in the upper Rhone River (Switzerland) is presented. Similar results of reconstruction of annual values of the morphological characteristics were obtained for the basins of tributaries of the Terek River (North Caucasus) and the Western Kyzylsu River (Pamir). At the second stage, the calculation and forecast of the time series of the average summer air temperature Ts(Zmean) at the height of Zmean is performed, which is used as an argument for determining the ablation layer by the formula Ab = f(Ts) on the glaciation area Fgl. The annual vertical profiles of mean air temperature of April T4 = T4(Z), summer ones Ts = Ts(Z), and formulas for calculating Ts as a function of T4 are constructed and used for the calculations. Thus, on a regional scale, it was established for the first time that the April air temperature T4 allows calculating a thickness of the annual ablation layer Ab = f(Ts) with a month earliness the forecast at the average height Zmean of the glacier. The reconstructed Fgl(t) series is used to obtain annual volumes of glacial alimentation. A regional study of variability of the index of glacial alimentation δ (Schultz, 1965) with time t was carried out using long-period measurements of runoff in the river basins of Eurasia, North America, Central Europe, and Central Asia. The index δ is equal to the ratio between the volumes W of flow or the average water discharges Q for the periods July-September (Q7–9) and March-June (Q3–6). As a result of the analysis of the expression δ = δ(t), it was found that the gradient of the linear trend equation for the δ index in all the above river basins is negative, which is indicative of a reduction in glacial-snow alimentation, or more precisely – in only its glacial component. Notwithstanding this, the annual runoff Qyear decreased only in three basins, and in the others Qyear, increased due to the growth of Q3–6, which overlapped decreasing of Q7–9. Index δ for the upper reaches of the Rhone River turned out to be not only a representative characteristic of changes in the vegetation period and annual runoff of the river, but also an efficient argument for the super-long-range prediction of these variables for 2025–2054 years.
Glaciers in the Russian Mountains (Caucasus, Altai, Kamchatka) in the First Quarter of the 21st Century
Authors: Kotlyakov V. M. , Khromova T. Y. , Nosenko G. A. , Muraviev A. Y. , Nikitin S. A.
Published: April 2024

The conducted studies allowed us to obtain a detailed picture of glaciation changes in the mountain regions of Russia, most provided with information about glaciers in the twentieth century. For the Caucasus glaciation, the data were obtained for the time periods 1911, 1952, 2000, 2014, 2018 and 2020; for Altai – for 1850, 1952, 2003 and 2018. For large glaciation nodes of the Central Altai – Katun, South and North Chuya Ridges additionally for 1968, 2008, and 2017. In both areas, a decrease in the area of glaciers since the beginning of the twentieth century and acceleration of the rate of reduction in the early twenty-first century have been revealed. The glaciers of the Caucasus and Altai reduced their size during this time by 46% and 48%, respectively. On average, in the twentieth century the glaciers of the Caucasus lost about 0.2% of the area per year, in the Altai – 0.15%, and in the early twentieth century 1.15 and 1.7% respectively. To study Kamchatka glaciers, we used data from the Glacier Inventory of the USSR (1950/1957) and images from different satellites in the period 2007–2019. The glaciers that were not previously registered in the Glacier Inventory of the USSR were identified. The greatest number of such glaciers is in the northern part of the Midnight Ridge, where out of 465 glaciers identified on modern satellite images, 216 were not included in the Glacier Inventory of the USSR. The area of glaciation in different regions of Kamchatka has changed extremely unevenly since the first cataloguing, which is associated with significant differences in glacier morphology. Glaciers of volcanic areas increased their size or remained stationary; here there is no tendency for glaciers to decrease due to the thick surface moraine consisting of volcanogenic material. Comparison of data from the Glacier Inventory of the USSR (as of the 1950s–70s) and the Glacier Inventory of Russia (2017–2019) shows a decrease in glaciation area from the mid-20th century to the end of the second decade of the 21st century in all mountainous regions of Russia except only the volcanic regions of Kamchatka. The area reduction ranges from 63% (Ural) to 13% (Kodar). The largest glacial systems of the Caucasus, Kamchatka and Altai have reduced their areas by 25, 22 and 39%, respectively
Estimation of Snow Water Equivalent in Semiarid Zone from Data of Global Numerical Models ICON and GFS/NCEP (Case Study of the Selenga River Basin)
Authors: Shikhov A. N. , Chernykh V. N. , Aurzhanaev A. A. , Pyankov S. V. , Abdullin R. K.
Published: April 2024

The possibility to use the global numerical (NWP) models ICON and GFS/NCEP for We consider the applicability of ICON and GFS/NCEP global numerical atmospheric model data for calculating the snow water equivalent (SWE) in the Selenga River basin located the semiarid zone. SWE was calculated for the cold periods of 2020–2022 based on the empirical methodology previously developed for the Kama River basin and adapted to the semiarid conditions. The main components of the SWE balance that are taken into account in the calculation are atmospheric precipitation (liquid or solid phase), snowmelt, sublimation from the snow surface and precipitation interception by vegetation with subsequent sublimation. The validation of the results was performed for the Russian part of the basin using the data of snow surveys carried out in the second half of the winter of 2021/22. In general, reasonable estimates of the SWE spatial distribution were obtained. While in 2021, both overestimation and underestimation by 1–15 mm (20–50%) of the calculated SWE was observed at different sites compared to the measurements, in 2022, its systematic underestimation was observed, especially significant in calculations using the ICON model data. In the steppe zone, SWE is significantly underestimated, which may be due to overestimation of the intensity of sublimation from the snow surface. The comparison of these results with the ERA5-Land reanalysis data and MODIS satellite images showed that the ERA5-Land reanalysis significantly overestimates the SWE and the snow cover area. The simulation results based on the GFS/NCEP and ICON models underestimated the snow cover area in 2022 and reproduced well in 2021, which correlates with the results of the SWE calculation.
Quality of Snow Cover Characteristics Derived from ERA 5-Land Reanalysis for the Territory of Perm Krai
Authors: Kryuchkov A. D. , Kalinin N. A. , Sidorov I. A.
Published: April 2024

Received March 31, 2023; revised June 6, 2023; accepted June 27, 2023Agreement between values of the mean monthly snow depth provided by the ERA 5-Land reanalysis and similar characteristics of snow cover calculated on the basis of the extended hydrometeorological monitoring performed in the Perm Region for 1990–2020 is analyzed. It was found that ERA 5-Land in 73% of cases reproduces the presence/absence of snow during the onset period, and in 53% – during the period of snow loss. The conclusions made in the authors' previous studies based on more limited material were generally confirmed. It is shown that the reanalysis values of the snow depth are overestimated in relation to instrumental measurements for most of the hydrometeorological stations of the Perm Region. In space, the magnitude of the reanalysis error increases from the southwest to the northeast of the region, with the exception of its central part, where the influence of the Kama water reservoir is perceptible. But the interannual variability of the average snow depth in the Perm Region was reproduced by the ERA 5-Land reanalysis adequately. For 30 years, the magnitude of the reanalysis error decreased as it was compared with 61% observation points. The analysis of seasonal variability showed that in ERA 5-Land time of the maximum snow depth was shifted to earlier onset. The complete coincidence of the seasonal course was recorded only in 5% of hydrometeorological monitoring sites. The value of the average monthly discrepancies between the data of the reanalysis and the information of the posts as a whole exceeds the similar characteristic for the stations, which is especially evident during the period of active snowmelt.
The Periglacial Lake Bretjorna (Ledovoe), Western Svalbard: History of Formation and Recent Sedimentation
Authors: Meshcheriakov N. I. , Kokin O. V. , Usyagina I. S. , Kasatkina N. E.
Published: April 2024

Received May 15, 2023; revised June 10, 2023; accepted June 27, 2023This paper presents the results of geomorphological, geochronological and lithological investigation of a young sedimentation basin – the periglacial Lake Bretjorna (Ledovoe). Formation of the lake began at the end of the first half of the 20th century in the west of Nordenskiöld Land (Western Svalbard) within the marginal zone of the Grönfjord glacier, after significant degradation of this glacial massif. The present-day look of the lake was formed at the end of the 20th century however its geomorphological development went on until the beginning of the 21st. The filling of the sedimentation basin with limnoglacial sediments began approximately from the 1930s and proceeded with spatial and temporal irregularity. Bottom sediments of the lake presented mainly by silty-pelitic material, but in places with an admixture of gravel and pebbles, were formed as the front of the Grenfjord glacier retreated in the direction from north-east to south-west. At the first stage, sediment-genesis was mainly accomplished by the intra- and subglacial sediments, which entered the lake as a result of thermal erosion at the contact of the lake and ice since the late 1940s until the end of the last century, as the present-day lake basin became ice-free. Sediments formed at this stage are composed by coarser and poorly sorted material, which is typical for glacial deposits. At the second stage, the sediments became less coarse and more sorted. After the loss of contact between the lake and the glacier, the role of intra- and subglacial sediments decreased. At this time, sedimentation in the lake goes on by the runoff of melted glacial waters and atmospheric precipitation falling on the catchment area of the lake. The value of the average sedimentation rate in the lake was determined by means of radioisotope dating according to 210Pb and 137Cs and amounted 5.4 mm/year in the north, 12.4 mm/year in the central part, and 16.4 mm/year in the south of the lake, which is comparable with the data obtained by gravity method using sedimentological traps (12–15 mm/year).
Remote and Radar Investigation of the Left Irbistu Glacier (South Chuisky Mountain Range, Altai Republic)
Authors: Ostanin O. V. , Kobylin S. A. , Dyakova G. S. , Burym R. D. , Patrusheva A. D. , Ramazanova N. E.
Published: April 2024

Received December 26, 2022; revised June 6, 2023; accepted June 27, 2023To determine changes of glacier No. 31 (SU5A15106031), happened in the beginning of the XXI century, satellite images, obtained from the Landsat-7, 8, 9 and Sentinel-2 satellites in different years, were analyzed. As a result, data on the glacier changes were obtained for the period from 2000 to 2022. During this time, the length of the main stream of the glacier decreased by 144 m (6.8%), and the total area of the entire glacier – by 0.089 km2 (9.7%). The rate of retreat of the glacier front varied from 2 to 15 m/year, on average – 6.5 m/year, and the glacier area decreased by on average of 0.004 km2/year. In 2022, the glacier consisted of two separate ice streams, with a total area of 0.823 km2 and a maximum length of 1.955 km. Aerial photography was carried out using a DJI Phantom 4 quadcopter. A high-resolution orthophotoplan (±5 cm), a digital terrain model, a three-dimensional model of the surface of the glacier tongue and adjacent territories, with a total area of 0.25 km2, were made. Radar sounding was performed by the Python-3 georadar in two configurations: at frequencies 50 and 100 MHz. Two cross-sections of the glacier were constructed from the radar data: one was taken at a frequency of 100 MHz, and the second at both – 50 MHz and 100 MHz. The analysis of the radiogram of these profiles made possible to reveal that the larger thickness of the glacier in the study area was measured along the left side of the glacier tongue, the maximum recorded thickness was equal to 66 m.
Changes in Climate and Snow Cover in View of Functioning of Ski Resorts in Russia in the Early 21th Century
Authors: Vinogradova V. V. , Titkova T. B.
Published: April 2024

Received December 14, 2023; revised April 21, 2023; accepted June 27, 2023The development of winter ski tourism and characteristics of ski resorts in various regions of Russia are closely related to climatic conditions, the most important of which are the presence and duration of snow cover. For the period 2000–2021, a study of snow cover, availability of “optimal ski days” and climatic indicators necessary for artificial snowmaking at ski resorts located in different regions of Russia was performed, using data of the reanalysis ERA5-Land. The characteristics of snow cover and temperature from the reanalysis data were compared with data of the meteorological network. The ERA5-Land data for temperature, precipitation, and snow cover thickness are well synchronized with the observational data, and estimates of the error of trends in air temperature and snow cover depth according to the reanalysis data relative to the station data give satisfactory results. In the conditions of the current climate, the average and maximum thickness of snow cover in all resorts is sufficient for their functioning, but in 2000–2021, a decrease in both the maximum and average values of snow cover is noted in most resorts. The study shows that in terms of snow and weather conditions, the highest mountain resorts of the North Caucasus and Kirovsk (Murmansk region) are the most prosperous, where thickness of the snow cover and duration of its occurrence as well as a significant number of “optimal ski days” sustains stability of the resorts and creates favorable conditions for their further development.
Large Periglacial Lakes on the Spitsbergen (Svalbard): State in 2008–2012 and Dynamics in 1991–2022
Authors: Chernov R. A. , Romashova K. V.
Published: April 2024

Received June 1, 2023; revised July 23, 2023; accepted October 2, 2023Approximately 3,790 lakes of various genesis existed in the Svalbard archipelago in 2008–2012, the total area of which reached 395 km2. Among them, periglacial lakes were new objects which had been formed since the beginning of the 20th century due to the deglaciation of the archipelago. We found 554 glacial lakes which areas exceeded 0.01 km2. The total area of these lakes amounted to about a half of the area of all the lakes in the archipelago – 185 km2, and two thirds of this value were large glacial lakes. The paper presents the spatial distribution of large periglacial lakes and variability of them caused by the climate warming in the archipelago. At present, there are 35 periglacial lakes (over 1 km2 in size); all of them are in contact with glaciers and the greater part of them are dammed by the terminal moraines or by a glacier itself. According to the cartographic data of the Norwegian Polar Institute and satellite images, the areas of large lakes were determined successively in 1991, 2002, 2012, and 2022. For the period from 1991 to 2012, there was a twofold increase in their area from 24.4 to 53.7 km2, but in 2012–2022 this process slowed down. On the east of the archipelago, where the inland ice is widespread, the process of the lake formation is much slower. It had been noted that on the west all large glacial lakes were formed after 1936 due to active retreat of the glaciers. At the same time, both on the north and east, most of the large glacial lakes existed prior to 1936. During the periods under consideration, changes in the areas of individual objects reached multiple values. The most large-scale changes in the lake areas were associated with the ablation of glacial fronts in contact with the lake, a glacier surge, and outbursts of a few dammed lakes. Six lakes were identified, where the water level drop reached tens of meters. Despite the slowdown in the formation of lakes in the last decade, the enlargement of lakes continues. Relative increase in the total area of the large periglacial lakes over the past 30 years on the west and east of the archipelago is in direct proportion to decreasing in glaciation of these regions. Thus, the process of formation of large periglacial lakes may be used as an indicator of climate change in the archipelago.
Glaciological Studies of the Institute of Geography, RAS, on the Elbrus Mount in 2023
Authors: Lavrentiev I. I. , Smirnov A. M. , Toropov P. A. , Elagina N. E. , Kiseleva T. D. , Drozdov E. D. , Degtyarev A. I.
Published: April 2024

Received August 29, 2023; revised 4, September 2023; accepted October 2, 2023In June 2023, mass-balance and meteorological observations on Elbrus were expanded: monitoring of the Mikelchiran glacier on the northern slope of the volcano was added to the permanent observations on the southern slope (Garabashi glacier). Such synchronized observations on the opposite macro-slopes of Elbrus have not been carried out before.
Variability of the Pechora Sea Ice Area and Its Correlation With the Barents Sea Surface Temperature According to Satellite Observations and Reanalysis
Authors: Lvova E. V. , Zabolotskikh E. V.
Published: April 2024

Received June 28, 2023; revised September 6, 2023; accepted October 2, 2023Variability of the Pechora Sea ice cover and the Barents Sea surface temperature during the season from October to June in 2002–2022 (except the season of 2011/2012) was studied on the basis of satellite observations and reanalysis ERA5. Influence of the sea surface temperature on the ice cover was also analyzed but without considering the other hydrometeorological parameters. Areas of the sea ice cover characteristics were calculated using data on the sea ice closeness obtained from the Advanced Microwave Scanning Radiometer 2 measurements. To analyze the variability of sea surface temperature, we used the average daily data of the European Centre for Medium-Range Weather Forecasts ERA5 reanalysis obtained by averaging hourly data. To study the spatial and temporal variability of sea ice cover and sea surface temperature, fields of daily averaged parameters were mapped. These maps and values of areas of the sea ice cover were analyzed. This made possible to reveal regularities of development of the sea ice processes in the Pechora Sea, to calculate the general trend of the sea ice area change over the considered period of time, and to divide the Barents Sea into four sectors with significantly different average values of the sea surface temperature: southwestern, northwestern, southeastern, northeastern ones. The seasonal and interannual variabilities of the Pechora Sea ice cover and the Barents Sea surface temperature were analyzed. To study the effect of sea surface temperature in different sectors of the Barents Sea on the sea ice area, the method of statistical analysis (Pearson’s linear correlation) was used for the monthly average data and the data, averaged over the sea ice season (from October to June) with different time lags. Significant correlation coefficients were obtained only for a two-month lag. With such a lag, high values of the inverse correlation coefficients were revealed between the sea surface temperature in the southwestern (up to –0.8) and northwestern (up to –0.6) sectors of the Barents Sea and sea ice area of the Pechora Sea, while in other sectors the correlation was significantly smaller or even below the significance level.
Sedimentation rates on the floodplains of lowland rivers in the center of the European Part of Russia according to the study of soil-alluvial chronosequences
Authors: Aleksandrovskii A. L. , Golosov V. N. , Zamotaev I. V.
Published: April 2024

The floodplain deposition rates for the Istra, Oka and Seim rivers valleys were estimated based on a combination of dating methods (radiocarbon, radiocesium and historical-archaeological) for various time windows of the Holocene. In addition, a new method to estimated sedimentation rate, based on the assessment of the degree of soil profile development of paleosols buried in alluvium was applied. Spatio-temporal differences in the rates of floodplain sedimentation have been established based on chronological and soil-geomorphological studies. It was found that sedimentation rates on the young floodplain of Seim and Istra rivers is 1.823 mm year1), 215 mm year1, respectively. While on the ancient floodplains of Oka and Seim rivers during different periods, the floodplain deposition rate varied within the range of 0.010.7 mm year1. The periods of increased sedimentation rates were short in time. Based on the study of a young, rapidly growing Istra River floodplain, the deposits of which are dated on the basis of historical and archaeological materials, new sedimentation rates that characterize the floodplains of the center part of the East European Plain were obtained: alluvium without signs of pedogenesis is formed at a sedimentation rate of more than 15 mm year1, with signs of pedogenesis at a rate of 215 mm year1, cumulative soils at a rate of 0.52 mm year1. Cyclic fluctuations in the sedimentation rate in the Holocene were established on the basis of14C and archaeological dates for to the Nikitino section located on the Oka River floodplain, where a large series of well-developed paleosols were distinguished. It was found that during periods with active accumulation of alluvium layers, sedimentation rate was about 2 mm year1, which is 20 times higher than in longer periods soil formation, when sedimentation rates were 0.070.14 mm yr1.
Kosinsky Mesolithic sites in the context of the history of the natural environment of the upper Kama region in the Late Glacial and early Holocene
Authors: Demakov D. A. , Lychagina E. L. , Zaretskaya N. E. , Kopytov S. V. , Chernov A. V. , Lapteva E. G. , Trofimova S. S. , Kosintsev P. A.
Published: April 2024

The article presents the results of interdisciplinary (archaeological and palaeoecological) studies conducted in 20182021 in the northern part of the Perm Territory at the confluence of the Kosa and Lolog rivers. The main objects of research were the sites of the Mesolithic period and the natural environment of the Late Glacial and Early Holocene. To identify the confinement of archaeological sites to certain landforms within the river valley, the paleochannel method was used. As a result, 2 terraces and a Holocene floodplain were identified. For paleoenvironmental reconstruction palynological and paleocarpological methods were used. The radiocarbon method was used to create a chronological basis for the area of work. The study of the economic activities of Mesolithic groups was based on osteological analysis. In the Late Glacial period the study area was not yet inhabited by ancient people due to unfavorable natural environments. The settlement started only in the second half of the Boreal period of the Holocene, after the formation of the second terrace and the spread of taiga pine and birch forests with the participation of spruce. By this time, the sites of Kosa I and II, located on the banks of the Lolog river were inhabited. The population was mostly engaged in hunting and partly fishing. The natural environments at the beginning of the Atlantic period of the Holocene were still favorable for the existence of human groups here. Formation of the first terrace in the Lolog valley contributed to the colonization of this territory too. The Kosa III site dates back to this time, which population was still mainly engaged in hunting, and probably also fishing. Later, due to the continued lateral migration of the Kosa and Lolog river beds to the east and the emergence of waterlogged floodplains, people left this area and began to inhabit it again only in the Late Holocene.
Morphometric analysis of the large en- closed depression of the Southern East European plain
Authors: Konstantinov E. A. , Zakharov A. L. , Selezneva E. V. , Filippova K. G.
Published: April 2024

The results of morphometric analysis based on the SRTM digital elevation model of large enclosed depressions (LEDs) of controversial origin, commonly found on the loess interfluves in the Northern Black Sea region, around the Sea of Azov, at the Western flanks of Caucus Mountains and in the Lower Don basin, are presented in the paper. We have registered 312 LEDs landforms. The morphometric characteristics of landforms vary from 0.4 to 216 km2 for area, from 1 to 21 m for depth, from 0.5 to 13.3 km for width, from 0.7 to 27.5 km for length, from 1 to 4 for elongation coefficient, and from 3.3 to 103.3 m a.s.l for height. The most common depressions have the following parameters: area 24 km2; depth 23 m; width 1.01.5 km; length 2.53.0 km; elongation coefficient 1.21.4; height 1520 m a.s.l. There is a correlation between the area and depth of the depressions. The depressions' shape is mostly elongated, e. g. teardrop-shaped, eggshaped, elliptical, triangular, and rarely round. The sharp ends of the egg-shaped depressions always tend to point to the north, and the blunt ones to the south. We grouped the depressions into seven restricted sites where the differences in size and other morphological features of the LEDs are very small. Within all sites, there is a high consistency of orientation of the long axes of the depressions. The largest depressions around the Sea of Azov and the Western flanks of Caucus Mountains are characterized by longitudinal ridges confined to western side of LEDs. Comparison analysis of sites demonstrated a fan-shaped pattern in changing of the long axes orientation from the NW in the Northern Black Sea region; to the East in the Azov Sea region; to the N in the Western flanks of Caucus Mountains; and the NE in the Central flanks of Caucus Mountains. A radial-centripetal pattern of the erosion network is observed across the territories where LEDs are distributed. Small erosive forms flowing into the center of depressions are represented by very flat and wide gullies and hollows with intermitted channel flow. Such morphological characteristics suggest the relict origin of the erosional forms and, as a result, indicates the pre-Holocene age of the depressions themselves. Morphological and geological data suggests that wind erosion was probably the main factor in the formation of LEDs.
GEOMORPHOLOGY AND THE FORMATION HISTORY OF GLACIAL MATERIALS OF THE EV’VAYAM RIVER VALLEY (KORYAK HIGHLANDS)2
Authors: Lukyanycheva M. S.
Published: April 2024

Based on the interpretation of satellite images and field observations, three moraines of different ages and morphology were identified in the valley of Ev’vayam River. The oldest, poorly preserved and significantly eroded moraines are located in the lower reaches of the Ev’vayam River near the Bering Sea coast. A well expressed in relief complex of younger moraines consisting of three better-preserved moraine ridges (45, 62–72 and 87–95 m a. s. l.) with thin soil cover is distinguished in the middle reaches of Ev’vayam River. The youngest moraines are found in the upper reaches of the Ev’vayam River Valley at elevations of 240–320 m a. s. l., where they form longitudinal ridges, or “tongues”. Based on the preservation degree, morphology and size of the investigated glacial complex, and published data on adjacent areas, the glaciation of the territory had a mountain-valley character. The glacier apparently reached its maximum size at the beginning of the Late Pleistocene, when it moved beyond the valley of the Ev’vayam River to the coast. The moraines in the central part of the valley and in its upper reaches were formed by much smaller glaciers during the end of Late Pleistocene. The recharge area of glaciers during this period was limited to a series of glacial cirques and kars in the central part of Pylgynskiy Range. Currently, small glaciers are present in cirques at elevations from 410 m to 720 m a. s. l., and continue to form modern moraines.
MORPHOLOGY OF THE RELIEF OF THE INTRAGLACIAL PALEOVOLCANO DERBY-TAIGA AND THE ADJACENT PART OF THE AZASS PLATEAU (TODZHA BASIN, NORTH-EASTERN TUVA)1
Authors: Novikov I. S. , Miharevich M. V. , Prudnikov S. G.
Published: April 2024

The Azass Plateau in the Altai-Sayan mountain region is the only known territory in the continental Eurasia know for distribution of intraglacial volcanoes formed by the interaction of erupting lava with ice and melt waters. The orographic factor in the Todzha Basin caused the development of thick shield glaciers covering the area of approximately 13 000 km2 during cold epochs.The variety of geomorphological units reflecting the history of neotectonic evolution, volcanism and Quarternary glaciations creates a unique opportunity to perform paleogeographic reconstructions. The geomorphological map is constructed based on the selection of genetically homogeneous surfaces. Morphometrical indicators, paragenesis and time series were obtained for the later. A special attention was paid to the relief of intraglacial volcanoes and traces of glaciations of different ages.The lower level of intraglacial volcanoes formed in the second half of the Late Pleistocene was subdivided into three levels. These volcanoes formed under a few hundreds of meters of ice. The glacial-exaration genesis of microrelief under the influence of the inland ice was established as appose to the previously accepted water-glacial (catafluvial) genesis. The age of the upper slopes of volcanoes (except the Derbi-Taiga volcano) is the Late Pleistocene. Consequently, glacial valleys and kars complicating them are rejuvenated .The study of the rockfall bodies triggered by an earthquake and rockfalls rupture surfaces in glacial valleys of the Derbi-Taiga mountain massif and their comparison with the traces of the Chuya earthquake (2003) allowed to estimate the Ms = 7.5 magnitude of the Holocene earthquake that caused them.Presented results of the geomorphological investigation contradict the paleogeographic reconstructions performed earlier on the basis of absolute dating.
FORMATION OF RIVER DELTAS OF INTRA-CONTINENTAL RESERVOIR OF THE ARAL-CASPIAN ARID ZONE (ON THE EXAMPLE OF THE TEREK, AMUDARYA AND ILI RIVERS)1
Authors: Korotaev V. N.
Published: April 2024

The study of the geomorphological and sedimentary systems forming at mouth of large rivers flowing into the inland seas and lakes of the arid zone shows that they have passed a long evolutionary path of development, repeatedly accumulating and reworking alluvial deposits depending on the position of the receiving reservoir level. Following the level fluctuations, the rivers moved their deltas, Pleistocene relics of which are found in the range of absolute marks from +50 to –20 m on the shores of the Caspian Sea, from +50 to 110 m of the Aral Sea and from +370 to 400 m of Lake Balkhash.
The Aral-Caspian arid zone is distinguished by following natural factors affecting the processes of delta formation: aridity of the climate, formation of river flow in the upper reaches and lack of inflow in the lower reaches, increased water turbidity and a huge runoff of suspended sediments, as well as significant influence of human economic activity associated with intensive irrigation. The most common morphogenetic type of river deltas on the coasts of intracontinental reservoirs of the arid zone are huge alluvial outflow cones in the form of extension deltas and “dry internal deltas” in the form of alluvial outflow cones.
The delta arms and the lower reaches of the rivers of the arid zone are characterized by a high intensity of channel deformations due to weak resistance to erosion of fine-grained valley alluvial-proluvial deposits, high flow velocities and high saturation of the flow with suspended sediments. The oversaturation of the river flow with sediments usually leads to shallowing of the riverbed in high water and its gradual increase over the surrounding terrain. An increase in the bottom elevation and fast delta progradation provoke frequent breakthroughs of the riverbed shafts, a change in the direction of the flow of delta arms, the creation of new branching nodes and the formation of regional jointed deltas of the breakthrough type (delta blades) on the periphery of the old delta (subdelta according to American terminology). Partially superimposed or superimposed deltas can also form inside delta systems after the breakthroughs of channel shafts (or enclosing dams).
The poor preservation of ancient deltas is noted due to intensive economic development and high dynamics of the coast and the hydrographic network of river deltas in conditions of huge runoff of suspended sediments and significant variability of the level of the receiving reservoir.