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The Arctic shelf zone is a very important region in our country due to the huge amounts of hydrocarbons, located there. The exploration of this region is difficult because of the presence of lots of various ice constructions, in particular, ice fields. While carrying out the seismic prospecting works, the reflected waves from the ice field contribute much to the seismograms. It sufficiently complicates the process of further interpretation of the seismograms. Only a few works are devoted to modelling the seismic waves spread through the geological layers of the Arctics in the presence of an ice field as this theme is rather new and needs deeper investigation. In this work we present the results of the investigation of the seismic waves spread in models with an ice field for the 3D case using the grid-characteristic method. The modelling results (wave fields of the velocity distribution and seismograms) allow to identify the reflected waves from the ice field from other waves. In addition, we carried out the comparative analysis of the wave fields and seismograms for the 2D model with an ice field on the surface of the calculated area for the problem description from the work of other authors. The results demonstrate a good qualitative coincidence under different approaches to the solution of the problem.

Azov is freezing sea it means that forecast of the time of the beginning and the end of ice fields formation needs. The ice condition limited of maritime safety. Modern condition of ice regime in the Azov Sea has been considered. The navigation of the Ukrainian ports Berdjansk and Mariupol depends on ice regime, duration and ice cover thickness. For the passage of vessels along the sea approach channels and recommended courses in the winter, the use of icebreakers is required. The demolition of confining buoys by ice fields and their restoration is reflected in the economic opportunities of the ports. Purpose of the article is to establish the characteristic winter periods of the last decade, taking into account the climatic changes for the rational using of the results of the impact on the economic activity of the marine infrastructure and hydrographic services. The specific purpose of this publication is to evaluate the displacement of the means of navigation equipment – buoys in the winter, taking into account meteorological factors. The authors set the following tasks: 1) to identify periods and vectors of buoys; 2) to define wind and ice characteristics in separate periods; 3) to reveal the basic meteorological cause of the movement of the buoys. It is important to note that there are no similar publications concerning this region. It became very actual after the climate change period was marked. The reserach is based on the data of direct and remote observations, the dates of ice formation in the area of seaports of Ukraine (Berdyansk and Mariupol) the characteristics of ice, the end of freezing, the opening and clearing of ice from the water areas of ports and bays and using the information from NAVTEX warning system, the archival materials of the weather site meteo.ua. The features of the physicochemical properties of sea water during ice formation and the general circulation of the waters of the Azov Sea are examined, which is linked with the influence of fresh runoff of Don and Kuban rivers. In the period 2013–2021 the observations were made on the displacement of navigation aids (buoys) during the winter periods from the approach channels of the port of Mariupol and Berdjansk as well as noticed buoys from the Azov-Don Marine Channel (Russian Federation). The characteristic of winter periods and conditions during the last decade are considered taking into account the influence of climatic changes. It is noted that the ice regime of the Sea of Azov is closely related with the sum of average daily air tem peratures over the sea for the season and wind power. According to this criterion, winters are usually divided into three types: severe, moderate and mild. Over the past 30 years, there were only two severe winters in the Azov Sea in 2005–2006 and 2011–2012. During these winters, the Azov Sea was completely ice covered. The influence of the ice regime to the coastal zone was examined, because it is very important for the industrial and economic needs of state building. To maintain the safety of navigation and reduce economic losses, it is necessary to consider the possibility of removing buoys, which are most often displaced by ice drift. Long-term average observations indicate the beginning of ice formation in Mariupol on December 14, and in Berdyansk on December 20. The Taganrog Bay and the ice accumulation areas are cleared of ice most recently – March 20–28. Under modern climatic changes (increasing the frequency of mild winters, actual costs for the operation of ships, hydrographic, icebreakers, etc.) are expected to be an order of magnitude lower than standard indicators.

Glaciers in the Southern Patagonia Icefield (SPI) have been shrinking in recent decades, but due to a lack of field observations, understanding of the drivers of ablation is limited. We present a distributed surface energy balance model, forced with meteorological observations from a west–east transect located in the north of the SPI. Between October 2015 and June 2016, humid and warm on-glacier conditions prevailed on the western side compared to dry and cold conditions on the eastern side. Controls of ablation differ along the transect, although at glacier-wide scale sensible heat (mean of 72 W m−2 to the west and 51 W m−2 to the east) and net shortwave radiation (mean of 54 W m−2 to the west and 52 W m−2 to the east) provided the main energy sources. Net longwave radiation was an energy sink, while latent heat was the most spatially variable flux, being an energy sink in the east (−4 W m−2) and a source in the west (20 W m−2). Ablation was high, but at comparable elevations, it was greater to the west. These results provide new insights into the spatial variability of energy-balance fluxes and their control over the ablation of Patagonian glaciers.

The Northern Patagonian Icefield (NPI) and the Southern Patagonian Icefield (SPI) have increased their ice mass loss in recent decades. In view of the impacts of glacier shrinkage in Patagonia, an assessment of the potential future surface mass balance (SMB) of the icefields is critical. We seek to provide this assessment by modelling the SMB between 1976 and 2050 for both icefields, using regional climate model data (RegCM4.6) and a range of emission scenarios. For the NPI, reductions between 1.5 m w.e. (RCP2.6) and 1.9 m w.e. (RCP8.5) were estimated in the mean SMB during the period 2005–2050 compared to the historical period (1976–2005). For the SPI, the estimated reductions were between 1.1 m w.e. (RCP2.6) and 1.5 m w.e. (RCP8.5). Recently frontal ablation estimates suggest that mean SMB in the SPI is positively biased by 1.5 m w.e., probably due to accumulation overestimation. If it is assumed that frontal ablation rates of the recent past will continue, ice loss and sea-level rise contribution will increase. The trend towards lower SMB is mostly explained by an increase in surface melt. Positive ice loss feedbacks linked to increasing in meltwater availability are expected for calving glaciers.

Since 8 April 2010 ESA’s Earth Explorer mission CryoSat-2 has been measuring marine and land ice thickness variations with a dedicated altimeter. With the effects of a fast-changing climate becoming apparent, it is increasingly important to understand exactly how Earth’s ice fields are responding and regulate climate and sea level. It is therefore of utmost importance that the quality of the CryoSat-2 altimeter data meets the highest accuracy and precision level, not only over the ice caps and sea-ice surface but over the oceans as well. The SIRAL altimeter of CryoSat-2 is capable of measuring high-resolution geophysical parameters from the open ocean to the coast. In this paper, we validate the CryoSat-2 geophysical ocean product, Baseline-B (GOP). The analyses focus on long-term monitoring, validation, and cross-calibration of these ocean altimeter data with all the concurrent altimeter data in the Radar Altimeter Database System RADS and with independent in-situ tide gauge measurements from the Permanent Service for Mean Sea Level PSMSL. The objective is to evaluate the stability of the CryoSat-2 measurement system and the identification and explanation of biases and bias drifts. A persistent monitoring of these biases in time is important to establish the data’s usefulness for investigation of long-term sea level and ice topography/volume changes. The results constitute the final status of the GOP baseline-B product for use as essential climate variables. GOP ocean data has a - 6.3 ± 0.2 cm range bias w.r.t. to all calibrated satellites in RADS and a drift of 0.14 mm yr−1 w.r.t. Jason-2. GOP data has significant wave height and sea state biases close to that of the Jasons’, and seems to be better handling the LRM-SAR transitions than the RADS CryoSat-2 product. GOP data w.r.t. PSMSL tide gauge data has an average correlation of R = 0.83, a mean st. dev. of σ = 6.30 cm, and a drift of 0.11 mm yr−1, equivalent to 40 Gt yr−1 ice sheet mass loss. It is concluded that GOP CryoSat-2 performs better than RADS CryoSat-2, which seems to suffer from a 480-day platform temperature cycle. GOP is also on a par with the altimeter data from the Jason reference missions, and well suited for ocean and climate studies.

An approach for evaluating the performance of dynamically positioned vessels in managed ice is proposed. The approach is based on implementing two Design of Experiments techniques to determine the influence of the pertinent ice field parameters on the vessel’s time-averaged thruster forces. A set of ice basin experiments was used to illustrate the manner of determining the relationship between ice forces and ice field parameters and to examine the effects of the interactions between those parameters. The results determined relationships between ice forces and ice concentration, thickness, floe size, and velocity. Future research requires examining broader sets of experimental data to increase the confidence and accuracy of thruster force predictions.

espanolLa gravimetria satelital es una herramienta que aun no se aplica en profundidad para estudiar areas relativamente extensas en los Andes de Argentina y Chile, a pesar de los esfuerzos actuales para lograr una mejor comprension de los cambios en los glaciares y sus tendencias. En este trabajo se analizan las variaciones de masa en los Hielos Patagonicos junto con las tendencias de decrecimiento en la region. El objetivo es demostrar la capacidad de la mision satelital GRACE (Gravity Recovery and Climate Experiment) para detectar los cambios en el almacenamiento de agua en areas glaciarias. Ademas, se monitorearon las variaciones del nivel hidrometrico en lagos patagonicos, combinando datos de altimetria satelital y mediciones in situ con los cambios de masa de agua observados.Para ello, se utilizaron datos GRACE para estimar la tendencia de la gravedad; y fueron usadas soluciones "mascons" de GRACE CSR RL05 de alta resolucion, para analizar los cambios en el almacenamiento de agua de los campos de hielo en la region para el periodo 2002-2017. Se utilizaron estaciones virtuales de altimetria satelital, ademas de informacion de altura hidrometrica de estaciones localizadas en lagos de la Patagonia en Argentina y Chile, con el fin de comparar el TWS de GRACE con el nivel de agua. Adicionalmente, se calcularon los coeficientes de correlacion en cada estacion.Los resultados manifiestan una disminucion significativa del almacenamiento de agua en la zona del Campo de Hielo, y ademas muestran que los Hielos Patagonicos Sur tienen una tendencia de derretimiento de las masas de hielo mas pronunciada que en la region del norte, de aproximadamente 6 cm/ano. EnglishDespite present efforts to better understand glacier changes and their trends, the satellite gravimetry is a powerful tool still not applied in-depth to study relatively large areas in the Andes of Argentina and Chile. In this work, the Patagonian Icefield mass variations are analyzed togetherwith the decrease trends of the ice layer in the region. The purpose of this study is to demonstrate the GRACE satellite mission (Gravity Recovery and Climate Experiment) ability to detect water storage changes over the glaciers area. Furthermore, the variations of the hydrometric level in some Patagonian lakes were monitored by combining satellite altimetry data and in situmeasurements with the observed water mass variations. Data retrieved from GRACE were used to estimate gravity trends; and high-resolution GRACECSR RL05 mascon solutions were used to analyze the icefields water storage change in the region under study for the 2002-2017 period. Virtual stations from satellite altimetry obtained from a lake database and hydrometric height data from in situstations, located at Patagonian lakes in Argentina and Chile, were also used in order to compare the TWS from GRACE to the water level of the specific lakes. Additionally, correlation coefficients were determined at each station. The results show a significant water storage decrease in the Icefield area, and they also demonstrate that the ice melt in southern Patagonia (of about 6cm/year) tends to be more pronounced than in the northern region.

The Callander Moraine (also known locally as the Auchenlaich Moraine) is an exceptionally well-preserved glacial landform on the outskirts of the town of Callander, in the council district of Stirling. It is part of an assemblage of neighbouring glacial landforms and sedimentary sequences which include eskers, kame terraces and kettle holes. When viewed both individually and together these features provide evidence for the interpretation of the nature, timing and extent of an ice margin at one of the south-eastern limits of the main icefield that occupied the Western Highlands during the Loch Lomond Readvance (Lowe, 1993), the last episode of glacial expansion to affect Scotland. This site description forms a new inclusion of the site into the Quaternary of Scotland Geological Conservation Review (GCR). The Callander Moraine is a key feature because it one of the best constrained of the ice limits dating to this glacial episode: sedimentary sequences within kettle hole basins closely located on both the up-valley (GCR site at Mollands) and down-valley (GCR site at Tynaspirit) sides of the moraine provide stratigraphic and independent dating evidence for the age of the feature, although recent advances in dating methods should allow significant refinement of the current age estimate. Although much remains to be clarified about the origin and age of the Callander Moraine, this very close association between a terminal moraine of Loch Lomond Readvance age and datable deposits that bracket its age makes it unique in the UK, and a key target for future research. Finally, there is presently an emerging debate over the pattern and timing of disintegration of the Loch Lomond Readvance ice masses, the last to occupy the Highlands of Scotland, an important topic in which the evidence from the nationally important site of the Callander Moraine, together with the assemblage of surrounding glacial landforms and sediments, can continue to play a pivotal role.

The influence of nonlinear wave structures on the local hardness of an ice field of a dynamic type of formation is studied. Wave structures are formed by the interference of flexural–gravitational and longitudinal waves. The source of oscillations is coherent radiation in the ice itself. The difference in the local hardness of ice in the nodes and antinodes of standing waves (up to 60%) is explained by the dynamic metamorphism of ice. The dependences of the local ice hardness on the coordinates in the longitudinal and transverse profiles of the ice field have the form of periodic curves. The texture scales were determined, and the phase surface of the wave structures was constructed, which is not monochrome and reflects the spatial heterogeneity of the strength properties of the ice field. The effect of the wave action depends on the conditions at the interface between the ice and the pool walls. The influence of wave structures on the strength properties of the ice field as one of the possible factors of the spatial variability of ice under various modes of occurrence in situ is quantified.

The exploration of the Arctic region is a very challenging and important problem today. One of the problems, connected with the Arctics’ investigation, is the ice strength change and measurement during the whole year. In this paper we present the results of the ice strength study using different numerical methods on the unstructured and structured grids. We carry out the computations of the ice strength using the discontinuous Galerkin method on unstructured grids and the Prandtl–Reuss model. For this, we compute the model, imitating the interaction between an ice field and a vertical bearing. In addition, we calculate the ice strength after the uniaxial compression and bending using the discontinuous Galerkin method. Then, we present the result strength distribution in the ice sample, computed with the help of the grid-characteristic method on the structured grids. The results demonstrate the possibility of the application of the grid-characteristic method on structured grids to the problem of the ice strength study.

The ice-resistant self-propelled platform (IRSPP) named North Pole that is currently under construction at the JSC Admiralty Shipyards is designed to carry out year-round scientific research in the Arctic Ocean. The IRSPP will be equipped with a unique ice loads monitoring system (ILMS). The technical requirements for the ILMS were developed in the Department of Ship Performance in Ice of the AARI. The ILMS should ensure a safe operation of the IRSPP in ice conditions (operational function) and serve as a measuring tool for researching of the mechanics of deformation and destruction of ice (scientific function). Analysis of ice conditions at different stages of IRSPP operation showed that the main scenario of ice interaction with the IRSPP hull will be the action of ice under compression on the middle part of the hull during drift. The monitoring of the stress-strain state of the hull is carried out by a complex system of fiber-optic strain sensors placed on different elements of the hull structures. The largest number of sensors are located on the side plating in the middle part of the IRSPP hull. The locations of the sensors were determined by finite element analysis of the stress-strain state of the IRSPP hull under the action of ice load. To monitor the stress-strain state of the surrounding ice field, up to 16 pressure sensors frozen into the ice are provided. Also, the system receives and stores data on the angles of roll, trim, yaw of IRSPP, its longitudinal, lateral and vertical accelerations, and the surrounding hydrometeorological conditions: wind speed and direction, air temperature, atmospheric pressure, and the geographical position of the platform. ILMS will significantly improve the safety of IRSPP operation during prolonged drift in ice conditions. Besides, the ILMS provides the platform hull with the functions of a measuring tool for studying the mechanics of deformation and destruction of sea ice in interaction with the engineering structures. The main purpose of this work is to create a comprehensive system for studying the processes of ice impact on structures in order to obtain new data about the parameters and nature of ice loads.

Glacial lake outburst floods (GLOFs) pose an increasing hazard to communities living downstream of glaciated areas of the Northern Patagonia Icefield (NPI). The proliferation of GLOF events poses a...

Most glaciers in Patagonia have been rapidly shrinking during the past decades in response to ongoing global warming. To extend techniques to monitor their dynamics is crucial to understand individual glacier response to climate change and its consequences. In that context, our study aims to investigate recent dynamic behaviour of two near-site outlet glaciers placed at the Southern Patagonian Icefield (Tyndall and Grey glaciers) with the usage of simple and cheap remote sensing techniques. Sentinel-1 images were used to estimate surface velocity by using the Offset-tracking algorithm, while Sentinel-2 images were used to estimate area change in the ice front. Moreover, climatic variables (e.g., accumulated precipitation and air temperature) were analysed in order to assess its influence on glacier dynamics. Our results indicates that precipitation rather then temperature changes has been playing a major role in both glaciers retreat. While Tyndall tends to stabilize its retreat, Grey exponentially enhances retreat by its east tongue. Additionally, mean ice speed was of 0.448 ± 0.242 m.day−1 for Grey and 0.439 ± 0.245 m.day−1 for Tyndall, which agrees with literature. However, high ice speeds near the ice front indicated by previous work could not be captured here. Our results also suggests that ice flow is a delayed response of precipitation in the accumulation zone, and that may be the cause of decrease in Tyndall’s retreat. Overall, Offset-tracking is an useful tool for studying time series of Patagonian glaciers dynamics. It should be used carefully, however, around high dynamical regions such as the glacier terminus.

Glaciers on Kilimanjaro are unique indicators for climatic changes in the tropical mid-troposphere of Africa. The history of severe glacier area loss raises concerns about an imminent future disappearance. Yet, the remaining ice volume is not well known. We reconstruct thickness maps for 2000 and 2011 for the Northern Icefield (NIF) and Kersten Glacier (KG) that are informed by ground-truth thickness measurements and multi-temporal satellite information. For 2011, we find mean thickness values of 26.6 and 9.3 m, respectively. The existing consensus estimate for global glacier ice thickness shows unrealistically thick values for KG in areas that are meanwhile ice-free.

One of the main scientific and practical problems in the Arctic is the study of the dynamic state of the sea ice cover. The main parameters in the general model of drifting ice are the drift velocity vector, friction stress at the air-ice and ice-water interfaces, and the forces of dynamic interaction of ice fields. Establishing the connection between the large-scale processes in the atmosphere-ice-ocean system is necessary for developing methods of forecasting ice compression and ridging and the formation of local and extended fractures and leads, which help improve the existing climate models. The main aim is to obtain results of full-scale instrumental measurements of parameters of ice large-scale mechanics and dynamics, which provide a physical basis for explaining the nature of observed large-scale ice processes and allow one to perform physical parametrization. To accomplish this aim and evaluate the physicomechanical condition of the drifting ice cover of the Arctic Ocean, the “Transarktika-2019” expedition performed a real-time ice monitoring in April 2019. The investigation was conducted using seismometers and tiltmeters installed on the ice such that they formed a triangle with the sides measuring up to two kilometers. Data has been obtained on the wave and oscillation processes of crack formation, compression and ridging of ice. The possibilities of deciphering the initial data on the physics of wave and oscillatory processes in the icewater system considerably increase when using the known methods of processing seismic signals. With use of spectral Fourier analysis wavelet-transformation of oscillations significanlty extending possibilities of the seismic method at revelation of prognostic signs of crack formation and compression was applied. It is shown that the dynamics of ice processes can be connected with oceanic swell and tidal events. A possibility is created for obtaining new results in the investigation of large-scale mechanics of sea ice.

The Russian part of the Southeastern Baltic Sea has a specific ice regime, which is determined by geographical location and climate conditions. Satellite data are widely used to study the propagation of sea ice. The advantages of radar images (RLI) from satellites equipped with synthetic aperture radar (SAR) are a large area coverage and independence from daylight and cloud-cover conditions. There were 840 SAR images of the Southeastern Baltic Sea analyzed for the period from December 1 to March 31, 2004–2019. It is shown that in modern conditions ice phenomena in the southeast Baltic do not occur every year. It is shown that in recent conditions ice phenomena do not occur every year in the Southeastern Baltic Sea. The revealed spatial and temporal variations in the ice regime are determined by the consequences of climate changes in the Southeastern part of the Baltic Sea. The intensity of ice formation depend on temperature conditions. Ice formation begins mainly in the second half of January-early February. The average duration of sea ice period is 22 days per season. The probability of observing sea ice from a satellite is maximum in February. Stable ice fields occur when the daily average air temperatures drop below –5 °C during 5 or more days. The maximum duration of ice period and maximum ice extent are observed in February.

Current warming in the Arctic is occurring at a rate two to three times higher than that of the rest of the world, leading to rapid glacier wastage. In Arctic mainland Norway, the plateau icefield Langfjordjøkelen has experienced the greatest mass loss of all Norwegian glaciers (excluding Svalbard) in recent decades. In this article, we examine this decline in a centennial-scale context through geomorphological mapping and the analysis of historical aerial photographs and maps. This allows Langfjordjøkelen’s maximum Little Ice Age extent (ca. 1925) to be reconstructed, providing an important baseline for a long-term assessment of icefield change. At the LIA maximum, Langfjordjøkelen covered an area of 14.9 km2. A comparison of the LIA dimensions with the icefield extent in 1891/1902, as displayed on a historical map, reveals a substantial overestimation of the map-based glacier outline. The post-LIA evolution of Langfjordjøkelen has been characterized by sustained high rates of glacier recession. By 2018, the icefield had lost 57% (8.5 km2) of its original LIA area, at a decadal rate of 9%, and its outlet glaciers had reduced in average length by 42% (1 km), at an annual rate of 11 m. Langfjordjøkelen’s percentage area decline has been greater than that of Norwegian ice masses at lower latitudes where comparable long-term glacier change data are available. This indicates that there is a significant latitudinal variation in Norwegian glacier response to 20th century warming, likely influenced by an enhanced warming signal in Arctic Norway compared to the rest of the Norwegian mainland.

Permafrost and glaciers are being degraded by the warming effects of climate change. The impact that this degradation has on slope stability in mountainous terrain is the subject of ongoing research efforts. The relatively new availability of high-resolution (≤ 10 m) imagery with worldwide coverage and short (≤ 30 days) repeat acquisition times, as well as the emerging field of environmental seismology, presents opportunities for making remote, systematic observations of landslides in cryospheric mountainous terrain. I reviewed the literature and evaluated landslide activity in existing imagery to select five ~ 5000-km2sites where long-term, systematic observations could take place. The five proposed sites are the northern and eastern flanks of the Northern Patagonia Ice Field, the Western European Alps, the eastern Karakoram Range in the Himalayan Mountains, the Southern Alps of New Zealand, and the Fairweather Range in Southeast Alaska. Systematic observations of landslide occurrence, triggers, size, and travel distance at these sites, especially if coupled with observations from in situ instrumental monitoring, could lead to a better understanding of changes in slope stability induced by climate change. The suggested sites are not meant to be absolute and unalterable. Rather, they are intended as a starting point and discussion starter for new work in this expanding landslide research frontier.

The prospects for the development of the Azov-Black sea region of the Russian Federation are primarily related to the development of the deep-water part of the Black Sea. In general, the forecast hydrocarbon resources are estimated at 1,5-2,4 trillion m3 in gas equivalent. Ice loads are one of the most important factors determining the stress state of the entire stationary platform when developing and designing offshore structures for the gas field in the Sea of Azov. The author of the article proposes to install special structures, such as cone icebreaking devices, at the contact points. An analytical study of the stress state of ice-breaking devices is carried out on the basis of the general provisions of the theory of elasticity of thin plates. An expression defining the strength condition of the cone shell material is obtained. The device of the Ansys17.2 software complex was used to obtaining specific results of calculations of the stress state of the ice-breaking device. Improving the platform support post by installing cone structures reinforced with concrete in the contact zone results in the destruction of the ice field from bending rather than compression. In this case, the horizontal pressure of the ice on the support is reduced. As a result, the stress level in the elements of the offshore structure support post is reduced. Due to the three-axis compression of concrete, the stress decreased in the model reinforced metal shell by 3,7 times compared to the level of stress in similar elements of the base model, and 1,7 times compared to the model with metal stiffeners. Deformations of elements in the direction of force ice action decreased from 4 cm in the base model to 1 cm in the rib-reinforced model of the ice-breaking device, i.e. by 4 times, and to 0,2 cm in the model reinforced with concrete, i.e. by 20 times. The use of composite construction leads to an increase in the rigidity and strength of the structure to protect offshore structure from the effects of ice.

En el presente estudio, se aborda el diseño y desarrollo de un modelo numérico computacional del comportamiento del ciclo oscilatorio estacional de avance y retroceso del glaciar Perito Moreno, denominado MO-ACAR. Dentro de su comportamiento oscilatorio, en algunos años el glaciar avanza y alcanza la Península de Magallanes formando un dique de hielo. Por ello, el objetivo del MO-ACAR es simular la posición frontal diaria del glaciar y la ocurrencia de eventos de formación de los diques de hielo durante el periodo 1994-2018. El modelo fue calibrado y validado a partir de un proceso de optimización iterativo, basado en la maximización de valores de correlación y minimización de errores de distancia. La simulación de la ocurrencia de la formación de diques de hielo y la oscilación de la posición frontal lograron altas prestaciones, alcanzando óptimos valores de correlación (0,99) y bajos errores de posición (9,56 ± 13,94 m), respectivamente. Los resultados demuestran que la dinámica del glaciar y la formación de los diques de hielo responden a distintas escalas temporales. En periodos cortos-intermedios de tiempo (escalas diarias-estacionales), la ocurrencia depende tanto de las características propias del evento, como de la fase e intensidad del evento previo. En periodos prolongados (escalas mayores a un año), la modulación de baja frecuencia de la velocidad del flujo de hielo, provocada por las variaciones de temperatura del aire, controla los periodos con formación de diques de hielo y libres de éstos.

We investigate a case of ocean waves through a pack ice cover captured by Sentinel-1A synthetic aperture radar (SAR) on 12 October 2015 in the Beaufort Sea. The study domain is 400 km by 300 km, adjacent to a marginal ice zone (MIZ). The wave spectra in this domain were reported in a previous study (Stopa et al., 2018b). In that study, the authors divided the domain into two regions delineated by the first appearance of leads (FAL) and reported a clear change of wave attenuation of the total energy between the two regions. In the present study, we use the same dataset to study the spectral attenuation in the domain. According to the quality of SAR-retrieved wave spectrum, we focus on a range of wave numbers corresponding to 9–15 s waves from the open-water dispersion relation. We first determine the apparent attenuation rates of each wave number by pairing the wave spectra from different locations. These attenuation rates slightly increase with increasing wave number before the FAL and become lower and more uniform against wave number in thicker ice after the FAL. The spectral attenuation due to the ice effect is then extracted from the measured apparent attenuation and used to calibrate two viscoelastic wave-in-ice models. For the Wang and Shen (2010b) model, the calibrated equivalent shear modulus and viscosity of the pack ice are roughly 1 order of magnitude greater than that in grease and pancake ice reported in Cheng et al. (2017). These parameters obtained for the extended Fox and Squire model are much greater, as found in Mosig et al. (2015) using data from the Antarctic MIZ. This study shows a promising way of using remote-sensing data with large spatial coverage to conduct model calibration for various types of ice cover.Highlights. Three key points: The spatial distribution of wave number and spectral attenuation in pack ice are analyzed from SAR-retrieved surface wave spectra. The spectral attenuation rate of 9–15 s waves varies around 10−5 m2 s−1, with lower values in thicker semicontinuous ice fields with leads. The calibrated viscoelastic parameters are greater than those found in pancake ice.

In this study, we aim to analyse the glacier dynamics of land-terminating glaciers in King George Island (Antarctica) between 1956 and 2018. Glacial fluctuations are estimated using space-borne remote sensing data (SPOT, Landsat, PlanetScope, Sentinel-1, Sentinel-2, WorldView-2 and TanDEM-X). The eastern sector of Warszawa Icefield witnessed continuous glacier retreat during 1979–2018 (surface loss of 30%). The decreases in the ice-covered areas of the Tower, Windy, Ecology, Baranowski and Sphinx glaciers were 70%, 31%, 25%, 25% and 21%, respectively, with their accumulation area ratios (AARs) exhibiting negative mass balances. The winter air temperature was cooler during the 1970s with warming trends in the 1980s and early 2000s followed by a cooling trend until the present day. However, the annual time series has shown high interannual variability in air temperature during these periods. We show that the AAR, dimensions, length, frontal elevation, maximum elevation, slope and changes in the terminus position influence the glacier response to climate change at various timescales. Furthermore, three geomorphic activity intensity zones and a complete paraglacial sequence are identified while contrasting the proglacial systems. Overall, subglacial deposits predominate and indicate that meltwater flows on the bed, producing wet-based thermal regimes.

In view of the extremely low sea ice concentration (SIC) appeared at high latitudes of the Arctic in the summer of 2010, the changes of SIC in the central Arctic from 2010 to 2017 were investigated in this paper based on the AMSR-E/AMSR-2 SIC products retrieved by the NT2 algorithm. The results show that the extremely low sea ice concentration in the central Arctic not only occurred in 2010 but also occurred again in 2016, and the daily average sea ice concentration (ASIC) reached a minimum of 0.70, which was significantly lower than the value of 0.78 in 2010 and became a new historical low record. A large area of sea ice in the sector 150°E–180° in 2010 disappeared in 2016, which was the most important difference to produce the new minimum. Also, the ice edge in 2016 retreated into the 85°N circle, whereas in 2010 it was far from the central Arctic. In 2010 and 2016, there were high correlations between the wind stress curl and the relative variation rate of ASIC , which indicates that wind stress curl (WSC) drove the divergence of sea ice. It directly leads to the decrease in the SIC and is the main cause of the extremely low SIC events. The results in this paper show that the decline of Arctic sea ice is represented by not only the reduction of sea ice coverage but also the reduction of SICs. The central Arctic has always been covered by large amount of sea ices, so the drastic reduction of SIC will not only change the structure of the ice field, but also lead to critical climatic effects that deserve further attention.

This paper reviews the glacial history of the mountains of Greece at the southernmost tip of the Balkans, providing a new synthesis of our current understanding of glaciations. The ice cover during the largest Middle Pleistocene glaciations (MIS 12/MIS 6) was more extensive than previously thought. Latest evidence from Mt Chelmos suggests that valley glaciers radiated from a central plateau ice field, whereas the findings of other glacial studies in western Balkans further indicate that extensive ice field/ice caps formed on mountains throughout this region during the Middle Pleistocene glaciations. Ice extent was considerably smaller during the Tymphian Stage (MIS 5d–MIS 2) and this has been confirmed by cosmogenic exposure ages in recent studies on Mt Olympus and Mt Chelmos. During the Holocene, only very small glaciers formed in some deep cirques where they survived because of strong local topoclimatic controls. A comparative analysis with the findings of other glacial and palaeoclimatic studies in the Balkans is also presented to highlight correlations between them. Moisture supply seems to have been the most critical factor for the formation of glaciers in the mountains of Greece. The comparison of Late Pleistocene Equilibrium Line Altitudes (ELAs) across the Balkans indicates a wetter climate in southern Greece that can be attributed to different palaeoatmospheric circulation mechanisms and precipitation regime in central Mediterranean. Conclusively, whilst important information has been added in the last 2 decades, this paper highlights the need for further research in Greece and the wider Balkans to establish the timing and extent of glaciations.

Lago Argentino hosts a series of calving glaciers originating from the Southern Patagonian Icefield, the largest temperate ice cap of the southern hemisphere. Brazo Rico and Brazo Sur are two basins located in the southern part of Lago Argentino, where a series of high-resolution seismic profiles have allowed reconstruction of its depositional setting and sedimentary architecture, and to produce the following maps: top of the acoustic basement, top of the glacial sequence, and thickness of the glacio-lacustrine deposits. Data reveal the role of basement highs in the complex dynamic behavior of the two main glaciers, Perito Moreno and Frías glaciers, which fluctuated along Brazo Rico and Brazo Sur since the end of the Last Glacial Maximum. Their advances and retreats are testified by the presence of several moraine fronts buried beneath a generally undisturbed, glacio-lacustrine and lacustrine sequence, which records the depositional history of the southern arms of Lago Argentino. Fil: Lozano, Jorge Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina Fil: Donda, Federica. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale; Italia Fil: Bran, Donaldo Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina Fil: Lodolo, Emanuele. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale; Italia Fil: Baradello, Luca. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale; Italia Fil: Romeo, Roberto. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale; Italia Fil: Vilas, Juan Francisco A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina Fil: Grossi, Maurizio. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale; Italia Fil: Tassone, Alejandro Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina

One of the most important factors influencing the planet as a whole and the continent in particular is the processes of destruction of the Antarctic ice sheets. Remote sensing images have become an important means of information acquisition. Visualization of several radar mosaics for different time substantially enhances observation of the ice sheets by showing dynamics of development of cracks, motion of icebergs, directions of streams near the surface of water along the coastline and dynamics of the ice field. This work presents the information technology of building a seamless imagery mosaic coverage of satellite radar scenes. The data under consideration are level-1 ground range detected Sentinel-1 products with dualpolarisation. Since not in all Path/Frame combinations scenes had two polarizations, HH and HV, polarization HH was chosen as the main one. As the direction of imaging, both ascending and descending scenes were chosen. For decreasing the volume of computations, scenes for the mosaic of Antarctica resampled to the spatial resolution of 120 meters and presented in the WGS-84 / Antarctic Polar Stereographic projection. 71% of the created coverage of Antarctica, when scenes are cyclically changed, reflects the changes in time of the coastline of the continent well. The key points related to the technology of preparation of the Sentinel-1 scenes for building the mosaic are presented. The first scene in each pair, save for the first pair, is a mosaic in itself. The method of stitching of the scenes into a mosaic is based on the process of geometric analysis of location of pixels overlapping in the scenes. The main results are shown in a fragment of the mosaic coverage of Antarctica. Experiments show that the technology can achieve automatic panoramic mosaic of the survey area.

Quantitative indicators of changes in 37 glaciers of the Patagonian Northern and Southern glacial fields were determined by means of decoding and analysis of photographs obtained by astronauts from the Russian segment of the International Space Station. On the basis of this information it was concluded that in 2002–2016 the glaciers of both fields of Patagonia continued to retreat. The frontal parts of the nine glaciers retained their positions, while others reduced at an average rate of several dozen up to 430 m/year. Repeated monitoring of 16 glaciers from this selection and analysis of the data obtained in 2016–2019 confirm this conclusion. The only exception was the O’Higgins Glacier, which did not change position of its frontal part for 12 years and then retreated in 2018–2019 to 1,250 m. In some cases, a gradual decrease in area of the frontal part of the glacier was accompanied by a sharp collapse of the lower zone with the formation of extensive fields of icebergs. The dynamics of the Bruggen Glacier (Pius XI) are not typical for the region under consideration: for many years this glacier has been advancing. This development cannot be explained without detailed field investigation in the area of snow and ice accumulation of the glacier. Perhaps that was due to a snow-drift transport in an extensive area of accumulation that supported the preservation of the size of the glacier tongue, and even its advance. According to our observations, the average rate of retreat of the glaciers of the Western and Eastern slopes of the Southern Ice Field significantly decreased since 2010, i.e. their degradation slowed down. At the same time, glaciers of the Northern Ice Field continued to decrease intensively.

The heterogeneity of the strength of the ice field of the dynamic type of formation with an area of 800 m2 was investigated in time and space. It is shown that stationary periodic wave structures are formed in a closed volume of an ice field lying on the surface of a liquid in a rectangular basin. In a case of absence of any external influences, the dominant source of elastic waves in the ice is the coherent radiation of them on freezing of water, i.e. the ice field itself. Another wave structures, i.e. standing waves, form secondary ice textures in the ice field with diminished strength. Local hardness of ice was chosen as the criterion of strength. The recurrence of local hardness values as a function of coordinates of the measurement points in the longitudinal and transverse profiles of the ice field was determined. The hardness values vary from 40 to 60% with an axial force measurement error of 5%. The experimental relations are approximated by periodic curves, in which the maxima and minima of local hardness correlate with the nodes and antinodes of standing waves, respectively. The decrease in local ice hardness in the secondary textures is explained by high-frequency dynamic metamorphism. The wavelengths corresponding to bending-gravitational and longitudinal waves are identified, with the interference of which stationary periodic wave structures are formed. A similar regularity of changes in local hardness was revealed also in a river ice. The results obtained allow us to consider nonlinear wave phenomena as one of the factors controlling the spatial-temporal variability of the ice strength characteristics.

The formation of an intermediate layer under hydrostatic compression at a shear appearing due to the action of converging and diverging fronts of stress momentums (pulses) is considered. Continuous monitoring of deformational changes in the structure of ice was carried out using acoustic methods. The features of contact ice breaking in the diverging fronts of stress pulses are considered by the example of the slow impact of a rigid spherical indenter on an ice plate simulating half-space. Using the piezoelectric accelerometer, an oscillogram of the impact was recorded and a generalized dependence of the reduced stress on the reduced instantaneous velocity of the impact (semi-cubic parabola) was obtained. It is established that under conditions of the experiment (smooth convex indenter surface and icy half-space) a thin intermediate layer is formed, the properties of which determine the physical similarity in the family of curves «instantaneous force-instantaneous velocity». A rheological model with due regard for the change in the microstructure of ice during the impact is proposed. Quantitative determinations of the deformation changes in structure of solid ice samples were performed under intensive plastic deformation in a matrix with a profile similar to the Laval nozzle. The deformations created by the piston caused forced vibrations in the ice. The working surface of the piston in the form of an ellipsoid together with the smooth walls of the matrix and the reverse cone created conditions for parametric resonance and the formation of fronts of highfrequency stress pulses. Under influence of these pulses, zones with a superplastic fine-crystalline structure of ice (cumulative effect) were formed in ice. In the outlet cylindrical channel, a flow around an obstacle of the ice with the structure of an intermediate layer (dynamic viscosity 20 MPa s) and the distribution of velocities of motion over the channel cross section were studied. The obtained results can be used to simulate the processes of contact destruction of deep rocks by a support or an ice-resistant platform loaded with an ice field.

In recently deglaciated soils, microbial organisms drive soil transformations by increasing carbon (C) and nitrogen (N) pools while depleting available phosphorous (P), thus improving plant colonization and soil development. However, the rate of soil development can vary in response to local environmental conditions that affect microbial abundance and activity. In this contribution we use observational and experimental approaches to evaluate the interplay between soil biogeochemical features and microbial abundance and function after approximately seventy years of soil development in the forefield of the Exploradores Glacier that is located at the northernmost end of the Northern Patagonian Ice Field. Our findings suggest that after approximately seventy years of soil development, microbial abundance and soil C and N accumulation increase with soil age, soil bulk density and pH decreased, and microbial activity measured as soil chlorophyll a and nifH gene abundance increased. In turn, decomposition increased with fungal abundance, showing higher values in the late stages of soil development where the soil C:N ratio was higher and soil pH was lower. Overall, biogeochemical changes along this chronosequence followed the predicted pattern, with gradual increases in soil nutrients and microbial abundance, in addition to decomposition processes.

The finite element method is used to simulate the navigation of an ice-area bulk carrier in broken ice fields. The ice material is defined as elastic, and the simulations are accomplished at four model speeds and three ice concentrations. The movements of ice floes in the simulation are consistent with those in the model test, and the percentage deviation of the numerical ice resistance from the ice resistance in the model test can be controlled to be less than 15 %. The key characteristics of ice loads, including the average ice loads, extreme ice loads, and characteristic frequency, are analyzed thoroughly in a comprehensive manner. Moreover, the effects of sailing speed and ice concentration on the ice loads are analyzed. In particular, the stress distribution of ice floes is presented to help understand how model speed and concentration affect the ice loads. The “ice pressure” phenomenon is observed at 90 % ice concentration, and it is realistically reflected both in the time–and frequency–domain ice force curves.

Glacier mass balance change is among the best indicators of glacier response to climate change. Due to its inaccessibility and limited observation, little is known about the change to the Dongkemadi Ice Field (DIF) in the Tanggula Mountains located in the source region of the Yangtze River in central Tibetan Plateau. Here, an enhanced temperature index–based glacier model considering glacier area change was applied to study the temporal–spatial variation in mass balance on the DIF from 1989 to 2012 and to assess its response to climate change. The model was forced by reconstructed temperature and precipitation from adjacent national meteorological stations and validated by comparing with field observations from the Xiao Dongkemadi Glacier (XDG). Results show that the simulated mass balance is in good agreement with the observations (R2 = 0.75, p

The Southeastern Pyrenees extend eastward along the north-south line that the Segre River traces with its Andorran tributary, the Valira River. The main massifs correspond to the Tossa Plana de Lles-Calmquerdos-Carlit to the west, the Puigmal-Bastiments-Costabona in the center—both within the Cerdanya basin (Upper Segre Valley)—and the Ripolles district (headwaters of the Ter Valley) to the east. The discovery and analysis of the glacial landforms existing in these massifs started at the end of the 19th century, but it was not until the end of the 20th century when remarkable advances were made, complemented in the early 21st century with the establishment of the glacial chronology. Glacial landforms are limited to the mountain regions and include a great variety of landforms, ranging from extensive areas in the higher massifs modeled by ice field, valley glaciers >10 km long, and small glacial cirques in the lower mountains of the Pre-Pyrenean massifs. The main glacial advance in the Southeastern Pyrenees took place between 80 and 35 ka. Moreover, the glacial advance occurred during the global Last Glacial Maximum (gLGM) and reached almost the same extent as the previous advance. After a massive retreat at 19–20 ka, the glaciers readvanced at c. 17–16 ka. Most of the cirques were deglaciated at c. 15 ka, and rock glaciers formed afterward. Only in the highest cirques (2800 to 2900 m), north- and east-exposed, small glaciers were formed during the Younger Dryas. No glacial activity has been detected during the Holocene. This glacial evolution is very similar to that occurred in the northeastern slope of the Pyrenees but the spatiotemporal pattern of glacial oscillations since the Last Glacial Maximum is significantly different than in the Central Pyrenees, where the climate was more influenced by the Atlantic Ocean.

The present paper reports on comparisons between results from ice basin tests and numerical simulations. The tests were conducted in the model ice basin of the National Research Council Canada in St. John’s, Newfoundland. Those tests examined the performance of a vessel controlled by a dynamic positioning (DP) system in managed ice conditions at a scale of 1:40. A numerical ice dynamics model was used to simulate ice basin test conditions. The results indicate that surge direction thrust and ice force are in good agreement. Ice basin measurements, however, produced higher sway-direction ice forces and yaw-direction moments. It appears that the treatment of sidewall boundaries and the resulting confinement of the ice cover may have contributed to that discrepancy. An additional contribution may be due to differences between the DP algorithms, which were used in the numerical simulations and ice basin tests. Numerical simulations also examined the role of floe shapes. The results indicate that floe shapes obtained from field observations reduce sway-direction ice forces and yaw-direction moments below values obtained when using near-square floe geometries.

Modeling method, Table S1 (newly obtained uplift rates for the ten continuous GNSS sites shown in Figure1A),Table S2 (slab window viscosity values and RMS data), supplemental figures, and the weekly solutions for GNSS data used in the study.

Given paper describes preliminary results of radar remote sensing East Arctic seas during the 82nd cruise of research vessel (R/V) “Academician MstislavKeldysh“on September- November 2020. For this purpose, the coherent Panoramic radar MRS-1000 Micran operating in the X-band on HH polarization located on the highest deck was used for recording the state of the sea surfaceduring R/Vmoving anddrifting. Acorresponding method for generating high spatial resolution radar maps of the sea surface and detecting different hydrophysicalprocesses is proposed in this paper. Some examples of registered processes likewind waves, ice fields with different types of ice (grease ice, pancake ice, nilas, and young ice), manifestations of internal waves observed in the Kara Gate and Vilkitsky Strait are presented here. Doppler radar images obtained by the difference-phase method demonstrate the prospects of their use for determining the surface current velocity and the orbital velocities of wind waves.

The Arctic Ocean plays an important role in the global climate system, where sea ice regulates the exchange of heat, moisture and momentum between the atmosphere and the ocean. A comprehensive analysis and forecast of the Arctic ocean system requires a detailed numerical ocean and sea ice coupled model supplemented by assimilation of observational data at appropriate time scales. A new operative ocean – ice state forecast system was developed and implemented. It consists of the INMIO4.1 ocean general circulation model and the CICE5.1 sea ice dynamics and thermodynamics model with common spatial resolution of 0.25°. For the exchange of boundary conditions and service actions (data storage, time synchronization, etc.), the coupled model uses the Compact Modeling Framework (CMF3.0). Data assimilation is implemented in the form of the Data Assimilation Service (DAS) based on the Ensemble Optimal Interpolation (EnOI) method. This technique allows to simultaneously correct the ocean (temperature, salinity, surface level) and ice (concentration) model fields in the DAS service, so they are coordinated not only through the exchange of boundary conditions, but already at the stage of data assimilation (i.e. strong coupling data assimilation). Experiments with the INMIO – CICE model show that the developed algorithm provides a significant improvement in the accuracy of forecasting the state of the ice field in the Arctic Ocean.