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The results of studies on the content of aluminum and heavy metals in benthic sediments and algae in the estuaries of the Arctic island Vaygach are presented. This island is located on the Barents and Kara Sea border, and it is part of the Pay-Khoi ridge which can be called a "continuation" of the Ural Mountains to the north. The observations were conducted in Krasnaya and Varkulyakha Rivers located in the island's southern part and flow into the Yugorsky Shar Strait. Krasnaya River is located near a polymetallic ore deposit, which was developed in 1931–1934. Reconnaissance fieldwork was carried out in the river estuaries through measurements of salinity and water level. Measurements of the mass concentration of elements in the studied samples of sediments and algae were carried out by atomic emission spectrometry. The preparation of plant samples was by microwave decomposition, and that for samples of bottom sediments was carried out by acid decomposition in an open manner. The obtained concentration samples were compared using "Tukey exploratory data analysis (EDA)". The presence of anomalies in the high content of copper, manganese, and zinc in filamentous algae at the control site in the Krasnaya River estuary was revealed. For some elements, the enrichment index was calculated relative to the upper part of the earth's crust content. It is assumed that the occurrence of this situation is due to the long-term consequences of mining polymetallic ores. The accumulation of metals in river estuaries may be related to the observed warming of the climate in the western sector of the Arctic region. [ABSTRACT FROM AUTHOR]

An integrated morphological and chemical analysis of Arctic aerosols was undertaken for Icelandic dust and Svalbard aerosols to be compared by scanning electron microscopy coupled with EDS microanalysis (SEM–EDS) via imaging and chemical analysis techniques. Results of the characterization of the particles from both surface sediments and suspended dust from desert areas in Iceland confirmed that volcanic glass is an excellent marker of Icelandic dust origin. Classification diagrams of particle chemical composition clearly distinguished the volcanic glass particles from the local surface sediments at Hornsund, Svalbard. In the same diagrams, a few particles were found in the aerosols from Hornsund which were morphologically and chemically similar to the Icelandic volcanic glass particles. Such properties, in principle, cannot be considered exclusive to volcanic glass. However, since Iceland is the largest and the most active source of long-range transported dust in the northern European high latitudes, and air mass trajectories reaching Hornsund did, actually, pass Iceland before the aerosol collection in the period under consideration, these particles likely originated in Iceland. On the other hand, the comparison with local and Icelandic sediments revealed the presence in the aerosols from Hornsund of particle types that cannot be attributed to either local or Icelandic dust. This observation highlights the possibility of extending and validating the application of the proposed geochemical criterion to different dust sources across the Arctic and the sub-Arctic, provided a consistent geochemical databank of representative dust sources from these areas is arranged. [ABSTRACT FROM AUTHOR]

In recent years, there has been a notable surge in lightning events within the Arctic region. This is possibly due to the ongoing trend of global warming that is particularly pronounced in the Arctic. This study focuses on instances of rare lightning activity in the proximity to the North Pole in the last decade. We hypothesize that these occurrences are linked to augmented land heating in Eurasia rather than solely due to the increasing temperatures in the Arctic region. This assertion is substantiated by model simulations using the Weather Research and Forecasting model. [ABSTRACT FROM AUTHOR]

The recent distribution of the Ponto-Caspian calanoid copepod, Eurytemora velox, in Western and Eastern Europe has been well-documented; however, there are no studies on the genetic diversity of the recently discovered Western Siberian species population. To contribute towards filling this gap, genetic diversity and distribution were investigated for E. velox collected in the Urals and Western Siberia of the Russian Federation to compare with the European populations. In this study, 44 specimens were dissected for the morphological studies, and 22 specimens of E. velox from different geographical points were analyzed for mitochondrial cytochrome oxidase I (CO1), nuclear ITS1-ITS2 (nITS) and nuclear ribosomal RNA (18SrRNA) gene fragments. Analysis of the CO1 gene region showed that the studied populations from the Urals and Western Siberia differ significantly from European ones and represent a separate genetic line. However, the nuclear nITS and 18SrRNA genes, as well as the results of morphological analysis, did not show such isolation of the Trans-Ural populations from those in Europe. As in many studies on E. velox, we found atypical structural features of the fifth prosomal leg among females in the Ob Bay. Their share was 36% of the number of studied individuals. The CO1 shows that the divergence of genetic lines occurred approximately in the Middle Pleistocene, and the species itself is Paleogene–Neogene by origin. Based on these data, a different scenario of E. velox distribution or possible refuge survival is discussed. [ABSTRACT FROM AUTHOR]

Thermokarst lakes in permafrost regions are highly dynamic due to drainage events triggered by climate warming. This study focused on mapping lake drainage events across the Northeast Siberian coastal tundra from 2000 to 2020 and identifying influential factors. An object-based lake analysis method was developed to detect 238 drained lakes using a well-established surface water dynamics product. The LandTrendr change detection algorithm, combined with continuous Landsat satellite imagery, precisely dated lake drainage years with 83.2% accuracy validated against manual interpretation. Spatial analysis revealed the clustering of drained lakes along rivers and in subsidence-prone Yedoma regions. The statistical analysis showed significant warming aligned with broader trends but no evident temporal pattern in lake drainage events. Our machine learning model identified lake area, soil temperature, summer evaporation, and summer precipitation as the top predictors of lake drainage. As these climatic parameters increase or surpass specific thresholds, the likelihood of lake drainage notably increases. Overall, this study enhanced the understanding of thermokarst lake drainage patterns and environmental controls in vulnerable permafrost regions. Spatial and temporal dynamics of lake drainage events were governed by complex climatic, topographic, and permafrost interactions. Integrating remote sensing with field studies and modeling will help project lake stability and greenhouse gas emissions under climate change. [ABSTRACT FROM AUTHOR]

The Arctic region is well-known as a source of energy and mineral resources. Developing these resources by means of responsible practices could provide the world's economy with strategically and critically important types of minerals. As a result, the role of the Arctic's resource potential and the approaches used to develop it are gradually changing. In current conditions, it is crucial to strike a balance between existing needs and long-term demand for traditional energy sources or critical materials, such as rare and rare-earth minerals. Achieving this balance will result in sustainable growth, meeting ESG agenda targets while considering national security priorities, and devising novel approaches to sustainable project financing. However, there is controversy between existing strategies and plans based on low-carbon development and reality, which creates new macroeconomic and geopolitical obstacles that need to be overcome. The primary goal of this research is to substantiate the necessity of transforming the Russian Arctic's mineral resource exploration in the context of global and national changes. The article presents a comprehensive analysis of the contemporary trends and tendencies influencing the exploration of the Arctic's resources, as well as a general vision of the current situation in the energy sector. Research methods include content analysis and synthesis, generalization, decomposition, elements of strategic analysis, planning and forecasting, statistical methods, econometric modeling methods, and scenario planning. An upgraded concept of sustainable development based on six key components is proposed and discussed. Recommendations are provided on how to improve the existing system of long-term planning and forecasting to reduce the high level of macroeconomic and geopolitical uncertainty. The role of Russian Artic resources is determined in light of the shift in resource use. [ABSTRACT FROM AUTHOR]

Today, the issues of sustainable development are among the most pressing ones. They are particularly relevant in the context of mineral resource development as operations in this sector always have an impact on the environment and socioeconomic development. Developing the mineral resource base of the Arctic presents a difficult task, as it requires finding a balance between the growing demand in resources and the acute climatic and geopolitical challenges. In view of both the specific features of the region and the pressure caused by various trends and challenges, ensuring the sustainable development of the Arctic's mineral resource base is highly important. In 2022, the global landscape that consists of sustainable development trends, ESG agendas, and environmental awareness was supplemented by national import substitution policies introduced in many strategic industries, which led to an inevitable increase in demand for mineral resources. This substantiates the importance of the research goal—developing a model for the sustainable development of the Arctic's mineral resource base that will produce quantitative results and provide key actors with reasonable recommendations for restructuring the priority areas of development. [ABSTRACT FROM AUTHOR]

(1) Background: river ice has a significant impact on nearly 66% of rivers in the Northern Hemisphere. Ice builds up during winter when the flow gradually reduces to its lowest level before the spring melt is initiated. Ice-induced floods can happen quickly, posing a risk to infrastructure, hydropower generation, and public safety, in addition to ecological repercussions from the scouring and erosion of the riverbeds. (2) Methods: we used the annual daily hydrograph to develop a RiTiCE tool that detects the break-up date and develops indices to analyze timing characteristics of extreme flow in the Tana and Tornio Rivers. (3) Results: the study showed that low-flow periods in two rivers had a significant trend with a confidence level of 95%. Additionally, it was observed that the occurrence date of seasonal 90-day low- and high-flow periods occurred earlier in recent years. Conversely, the Tana River showed a negative trend in its annual minimum flow over the century, which is the opposite of what happened with the Tornio River. (4) Conclusions: the method can be used to detect the date when the river ice breaks up in a given year, leading to a better understanding of the river ice phenomenon. [ABSTRACT FROM AUTHOR]

The relevance of the study lies in the fact that with the depletion of conventional oil and gas reserves and an increase in the global demand for hydrocarbons, the focus of the industrial sector is gradually shifting towards the resources of the Arctic, which have tremendous potential for development. However, the current industrial policy has to take into account the concept of sustainable development, or harmony between economy, ecology, and society. Therefore, the extraction of raw materials must obey the principles of the circular economy, which aims to generate closed-loop cycles that maximize the use of the resources extracted and minimize waste generation so as not to destroy fragile ecosystems. It is necessary to drill wells for the discovery of a hydrocarbon deposit on the shelf, which entails the generation of a tremendous amount of complex waste., The use of disposal methods for drilling cuttings, which must be disposed of economically and with environmental reliability, is required to solve the problem. This study compares two methods of disposing of drilling waste. Statistical modeling results and a review of the literature show that the most effective method from both economic and environmental points of view is the thermomechanical cleaning of cuttings on site. This article discusses the advantages and disadvantages of both methods. It also evaluates drilling waste management prospects and opportunities for Russian offshore fields. [ABSTRACT FROM AUTHOR]

Recent developments in the Arctic region, mainly marked by climate change, have caused the region to receive increasing attention from regional and non-regional actors, mainly due to emerging energy-related opportunities and environmental concerns. The main reason for non-regional stakeholders to become involved in the Arctic region to pursue their interests is to obtain the observer status in the Arctic Council. Accordingly, this manuscript analyzes the long-term perspective of Türkiye's involvement in the Arctic region as a non-regional actor and reveals a set of enablers and disablers pertaining to energy and environmental domains. For this purpose, in-depth interviews with experts from Türkiye, with Arctic Council members, or with observer countries are conducted. Results of the analysis are also utilized to provide insights regarding countries with similar profiles to Türkiye, i.e., middle-power and developing countries that are geographically distant from the Arctic region. The results highlight energy security, hydrocarbon reserves, and climate change as significant factors for countries such as Türkiye. Scientific, private sector, or intergovernmental cooperation with regional actors to encourage global action and environmental initiatives are the main enablers. Challenges in the extraction and sharing of energy resources, high costs and high technology requirements of energy exploration and extraction activities, increasing human activity, and damages to the Arctic ecosystem are identified as significant disablers. [ABSTRACT FROM AUTHOR]

The urban development of areas in the Arctic zone of the Russian Federation is a relevant and important task to be tackled by contemporary urban planners. This focus is largely explained by the development of the Northern Sea Route (NSR) and its port cities. Last but not least, to develop these cities means to ensure a comfortable living environment for local residents and visiting specialists. However, given the harsh climate in the Arctic zone of the Russian Federation, this task requires a more elaborate approach. Current building techniques, designed for flatlands with relatively comfortable climates, cannot be applied to this territory without degrading the quality of the living environment. Environmental comfort is influenced by many factors, and one of them is the aeration regime. This study is aimed at researching the aeration regime of built-up areas on the sloping lands of the Arctic zone of the Russian Federation and identifying the features of its formation. The object of this study is a residential development on the sloping lands of the Arctic zone of the Russian Federation. The subject of the study is the external aeration regime at the level of 1.2 m from the ground level of the residential development on the sloping lands of the Arctic zone of the Russian Federation. These parameters were explored, and the aeration regime was assessed using such advanced software packages as QG for the GIS analysis of the area and ANSYS Fluent for the mathematical modeling of the aeration regime. The results of the research are presented in the form of graphs, dependency tables, and petal diagrams visually demonstrating the distribution of discomfortable zones for different morphotypes of development on various slopes most widely spread in the Arctic zone of the Russian Federation. The theoretical research was pilot-tested in the existing residential development area in Murmansk. The results of the study are usable in practice if respective land use documents are drafted for residential areas of settlements in the Arctic zone of the Russian Federation. [ABSTRACT FROM AUTHOR]

The objective of this study was to create a representative earthquake catalog for the Eastern Sector of the Arctic zone of the Russian Federation that combines all available data from Russian and international seismological agencies, with magnitude reduction to a uniform scale. The article describes the catalog compilation algorithm, as well as formalized procedures for removing duplicates and choosing the optimal magnitude scale. Due to different network configurations and record processing methods, different agencies may register/miss different events. This results in the absence of some events in different earthquake catalogs. Therefore, merging the data of various seismological agencies will provide the most complete catalog for the studied region. When merging catalogs, the problem of identifying duplicates (records related to the same seismic event) necessarily arises. An additional difficulty arises when distinguishing between aftershocks and duplicates since both are events that are close in space and time. To solve this problem, we used a modified nearest neighbor method developed earlier by the authors. The modified version, which is focused on identifying duplicates and distinguishing between duplicates and aftershocks, uses a probabilistic metric in the network error space to determine the epicenters and times of seismic events. In the present paper, a comparison and regression analysis of the different magnitude types of the integrated catalog is carried out, and based on the obtained ratios, the magnitude estimates are unified. [ABSTRACT FROM AUTHOR]

Surface longwave downward radiation (LWDR) plays a key role in determining the Arctic surface energy budget, especially in insolation-absent boreal winter. A reliable LWDR product is essential for understanding the intrinsic physical mechanisms of the rapid changes in the Arctic climate. The Medium-Resolution Spectral Imager (MERSI-2), a major payload of the Chinese second-generation polar-orbiting meteorological satellite, FengYun-3D (FY-3D), was designed similar to the NASA Moderate-Resolution Imaging Spectroradiometer (MODIS) in terms of the spectral bands. Although significant progress has been made in estimating clear-sky LWDR from MODIS observations using a variety of methods, few studies have focused on the retrieval of clear-sky LWDR from FY-3D MERSI-2 observations. In this study, we propose an advanced method to directly estimate the clear-sky LWDR in the Arctic from the FY-3D MERSI-2 thermal infrared (TIR) top-of-atmosphere (TOA) radiances and auxiliary information using the extremely randomized trees (ERT) machine learning algorithm. The retrieval accuracy of RMSE and bias, validated with the Baseline Surface Radiation Network (BSRN) in situ measurements, are 14.14 W/m2 and 4.36 W/m2, respectively, which is comparable and even better than previous studies. The scale effect in retrieval accuracy evaluation was further analyzed and showed that the validating window size could significantly influence the retrieval accuracy of the MERSI-2 clear-sky LWDR dataset. After aggregating to a spatial resolution of 9 km, the RMSE and bias of MERSI-2 retrievals can be reduced to 9.43 W/m2 and −0.14 W/m2, respectively. The retrieval accuracy of MERSI-2 clear-sky LWDR at the CERES SSF FOV spatial scale (approximately 20 km) can be further reduced to 8.64 W/m2, which is much higher than the reported accuracy of the CERES SSF products. This study demonstrates the feasibility of producing LWDR datasets from Chinese FY-3D MERSI-2 observations using machine learning methods. [ABSTRACT FROM AUTHOR]

Global climate change accelerates ice melting in the Arctic region, making Arctic shipping possible and revealing a new door to develop cruise tourism. The rapid expansion of cruise tourism into the Arctic region has posed substantial implications for the cruise industry, including opportunities and challenges. This study investigates the Chinese cruise industry and the encounters and obstacles that have unfolded in the Arctic cruise market. The study also explores the Chinese cruisers' travel constraints, preferences, and behavioral intention to the Arctic region. The implications of the findings are drawn to develop the entire Arctic cruise market. This study also provides invaluable insight into the cruise industry's adaptation strategies and practices and relevant supporting business sectors. [ABSTRACT FROM AUTHOR]

The Arctic region of Russia is rich with natural water resources. Some residents of this area prefer to use water from spring sources instead of tap water. However, the elemental composition for most of the springs is unknown, making it very important to regularly update water quality data. In this paper, the chemical composition of 24 natural springs near large cities of the Murmansk region were identified via titration, potentiometry, and mass spectrometry analysis with the low detection limits. The concentrations of a considerable number of micro-components have been determined for the first time. Concentrations of some hazardous pollutants have been found in spring water that exceed Russian hygienic limits by 2.5 times. In terms of chemical indicators, it was shown that in accordance with European and national water standards, only half of the tested natural water sources in the Murmansk region can be used for drinking water. The preferential spring was recommended near each major city in the region according to a set of chemical parameters. The results of chemical composition of the spring waters were disseminated publicly by placing the tags with QR codes with the link to the cloud storage near each studied spring. [ABSTRACT FROM AUTHOR]

This paper continues the Sm-Nd isotope geochronological research carried out at the two largest Paleoproterozoic ore complexes of the northeastern Baltic Shield, i.e., the Cu-Ni-Cr Monchegorsk and the Pt-Pd Fedorovo-Pansky intrusions. These economically significant deposits are examples of layered complexes in the northeastern part of the Fennoscandian Shield. Understanding the stages of their formation and transformation helps in the reconstruction of the long-term evolution of ore-forming systems. This knowledge is necessary for subsequent critical metallogenic and geodynamic conclusions. We applied the Sm-Nd method of comprehensive age determination to define the main age ranges of intrusion. Syngenetic ore genesis occurred 2.53–2.85 Ga; hydrothermal metasomatic ore formation took place 2.70 Ga; and the injection of additional magma batches occurred 2.44–2.50 Ga. The rock transformation and redeposited ore formation at 2.0–1.9 Ga corresponded to the beginning of the Svecofennian events, widely presented on the Fennoscandian Shield. According to geochronological and Nd-Sr isotope data, rocks of the Monchegorsk and the Fedorovo-Pansky complexes seemed to have an anomalous mantle source in common with Paleoproterozoic layered intrusions of the Fennoscandian Shield (enriched with lithophile elements, εNd values vary from −3.0 to +2.5 and ISr 0.702–0.705). The data obtained comply with the known isotope-geochemical and geochronological characteristics of ore-bearing layered intrusions in the northeastern Baltic Shield. An interaction model of parental melts of the Fennoscandian layered intrusions and crustal matter shows a small level of contamination within the usual range of 5–10%. However, the margins of the Monchetundra massif indicate a much higher level of crustal contamination caused by active interaction of parental magmas and host rock. [ABSTRACT FROM AUTHOR]

This paper evaluates the thermal performance of a triple-glazed glass window filled with a phase-change material (PCM) compared to the performance of a traditional triple-glazed window with air gaps. The chosen PCM was paraffin wax. A mathematical model to simulate heat transfer within the system was presented. A commercially available software, COMSOL Multiphysics, was used to numerically solve the governing equations. The analysis was carried out for the representative days of different seasons using three types of paraffin wax (5, 10, and 15) that have different melting-temperature ranges. Particularly, the study considers the unique climatic conditions of the Arctic region. Results showed that by integrating a PCM into the cavity of triple-glazing, thermal performance during summer season of the window was enhanced, while for spring and autumn thermal performance was affected by the type of paraffin selected. The thermal performance of glass windows during winter did not change with PCM integration. [ABSTRACT FROM AUTHOR]

Many biochemical processes and dynamics are strongly controlled by terrain topography, making digital elevation models (DEM) a fundamental dataset for a range of applications. This study investigates the quality of four pan-Arctic DEMs (Arctic DEM, ASTER DEM, ALOS DEM and Copernicus DEM) within the Kalix River watershed in northern Sweden, with the aim of informing users about the quality when comparing these DEMs. The quality assessment focuses on both the vertical accuracy of the DEMs and their abilities to model two fundamental elevation derivatives, including topographic wetness index (TWI) and landform classification. Our results show that the vertical accuracy is relatively high for Arctic DEM, ALOS and Copernicus and in our study area was slightly better than those reported in official validation results. Vertical errors are mainly caused by tree cover characteristics and terrain slope. On the other hand, the high vertical accuracy does not translate directly into high quality elevation derivatives, such as TWI and landform classes, as shown by the large errors in TWI and landform classification for all four candidate DEMs. Copernicus produced elevation derivatives with results most similar to those from the reference DEM, but the errors are still relatively high, with large underestimation of TWI in land cover classes with a high likelihood of being wet. Overall, the Copernicus DEM produced the most accurate elevation derivatives, followed by slightly lower accuracies from Arctic DEM and ALOS, and the least accurate being ASTER. [ABSTRACT FROM AUTHOR]

This study presents detailed suspended sediment budget for the four Siberian river deltas, representing contrasting conditions between Northern and Southern environments. Two of the studied rivers empty their water and sediments into the marine located in the permafrost zone in the Arctic region (Lena and Kolyma), and the other two (Selenga and Upper Angara) flow into Lake Baikal located in the steppe and forest-steppe zone of Southern Siberia. For the first time, these poorly monitored areas are analyzed in terms of the long-term and seasonal changes of spatial patterns of suspended sediment concentrations (SSC) over distributaries systems. Remote sensing reflectance is derived from continuous time series of Landsat images and calibrated with the onsite field measurements of SSC. Seasonal variability of suspended sediment changes over deltas was captured for the period from 1989 to 2020. We identify significant variability in the sedimentation processes between different deltas, which is explained by particularities of deltas networks and geomorphology and the existence of specific drivers—continuous permafrost impact in the North and abundant aquatic vegetation and wetland-dominated areas in the South. The study emphasizes that differences exist between Northern and Southern deltas regarding suspended sediments transport conditions. Mostly retention of suspended sediment is observed for Southern deltas due to sediment storage at submerged banks and marshlands located in the backwater zone of the delta during high discharges. In the Northern (arctic) deltas due to permafrost impacts (melting of the permafrost), the absence of sub-aquatic banks and river to ocean interactions of suspended sediment transport is mostly increased downwards, predominantly under higher discharges and along main distributary channels. These results shine light on the geochemical functions of the deltas and patterns of sequestering various metals bound to river sediments. [ABSTRACT FROM AUTHOR]

In the context of circumpolar international cooperation within the framework of the Joint Innovative Research Agenda, for the development of a systems approach, it is important to use the resources of existing platforms for multi-level mutually beneficial cooperation. The Council of Barents/Euro-Arctic Region and the University of the Arctic are unique examples of interaction and cooperation between the regions of the Arctic states. The Northern Dimension policy is also an important platform for such cooperation between Russia, the European Union, Iceland and Norway. Cross-border cooperation is integral to international relations, which stimulates the sustainable development of regions, creates growth points for innovative projects, and is focused on the evolution of international economic relationship. Universities and research institutes, as holders of expertise, and centers for studying good world practices and transferring excellence, occupy leading positions in the development of advanced ecosystems and the use of complex technologies, the training of highly qualified personnel for the Arctic, the creating of end-to-end digital technologies, the transforming of priority sectors of the states' economies, and in the social sphere. This article discusses international project activities as one of the most effective tools contributing to the development of these issues. The authors provide examples of successful practices aimed at solving common challenges in the Arctic region, and conclude that "Arctic fever", and the intensification of Arctic scientific partnerships through programs to support the introduction of technologies and innovations and the advancement of scientific stations in the Arctic, directly affect the development of local territories, give impetus to economic progress, and create new models of cooperation. [ABSTRACT FROM AUTHOR]

The Arctic seas are now of particular interest due to their prospects in terms of hydrocarbon extraction, development of marine transport routes, etc. Thus, various geohazards, including those related to seismicity, require detailed studies, especially by instrumental methods. This paper is devoted to the ocean-bottom seismographs (OBS) based on broadband molecular–electronic transfer (MET) sensors and a deployment case study in the Laptev Sea. The purpose of the study is to introduce the architecture of several modifications of OBS and to demonstrate their applicability in solving different tasks in the framework of seismic hazard assessment for the Arctic seas. To do this, we used the first results of several pilot deployments of the OBS developed by Shirshov Institute of Oceanology of the Russian Academy of Sciences (IO RAS) and IP Ilyinskiy A.D. in the Laptev Sea that took place in 2018–2020. We highlighted various seismological applications of OBS based on broadband MET sensors CME-4311 (60 s) and CME-4111 (120 s), including the analysis of ambient seismic noise, registering the signals of large remote earthquakes and weak local microearthquakes, and the instrumental approach of the site response assessment. The main characteristics of the broadband MET sensors and OBS architectures turned out to be suitable for obtaining high-quality OBS records under the Arctic conditions to solve seismological problems. In addition, the obtained case study results showed the prospects in a broader context, such as the possible influence of the seismotectonic factor on the bottom-up thawing of subsea permafrost and massive methane release, probably from decaying hydrates and deep geological sources. The described OBS will be actively used in further Arctic expeditions. [ABSTRACT FROM AUTHOR]

The Arctic region is the most sensitive region to climate change. Hydrological models are fundamental tools for climate change impact assessment. However, due to the extreme weather conditions, specific hydrological process, and data acquisition challenges in the Arctic, it is crucial to select suitable hydrological model(s) for this region. In this paper, a comprehensive review and comparison of different models is conducted based on recently available studies. The functionality, limitations, and suitability of the potential hydrological models for the Arctic hydrological process are analyzed, including: (1) The surface hydrological models Topoflow, DMHS (deterministic modeling hydrological system), HBV (Hydrologiska Byråns Vattenbalansavdelning), SWAT (soil and water assessment tool), WaSiM (water balance simulation model), ECOMAG (ecological model for applied geophysics), and CRHM (cold regions hydrological model); and (2) the cryo-hydrogeological models ATS (arctic terrestrial simulator), CryoGrid 3, GEOtop, SUTRA-ICE (ice variant of the existing saturated/unsaturated transport model), and PFLOTRAN-ICE (ice variant of the existing massively parallel subsurface flow and reactive transport model). The review finds that Topoflow, HBV, SWAT, ECOMAG, and CRHM are suitable for studying surface hydrology rather than other processes in permafrost environments, whereas DMHS, WaSiM, and the cryo-hydrogeological models have higher capacities for subsurface hydrology, since they take into account the three phase changes of water in the near-surface soil. Of the cryo-hydrogeological models reviewed here, GEOtop, SUTRA-ICE, and PFLOTRAN-ICE are found to be suitable for small-scale catchments, whereas ATS and CryoGrid 3 are potentially suitable for large-scale catchments. Especially, ATS and GEOtop are the first tools that couple surface/subsurface permafrost thermal hydrology. If the accuracy of simulating the active layer dynamics is targeted, DMHS, ATS, GEOtop, and PFLOTRAN-ICE are potential tools compared to the other models. Further, data acquisition is a challenging task for cryo-hydrogeological models due to the complex boundary conditions when compared to the surface hydrological models HBV, SWAT, and CRHM, and the cryo-hydrogeological models are more difficult for non-expert users and more expensive to run compared to other models. [ABSTRACT FROM AUTHOR]

The melting of the polar ice caps is considered to be an essential factor for global sea-level rise and has received significant attention. Quantitative research on ice cap mass changes is critical in global climate change. In this study, GRACE JPL RL06 data under the Mascon scheme based on the dynamic method were used. Greenland, which is highly sensitive to climate change, was selected as the study area. Greenland was divided into six sub-research regions, according to its watersheds. The spatial–temporal mass changes were compared to corresponding temperature and precipitation statistics to analyze the relationship between changes in ice sheet mass and climate change. The results show that: (i) From February 2002 to September 2019, the rate of change in the Greenland Ice Sheet mass was about −263 ± 13 Gt yr−1 and the areas with the most substantial ice sheet loss and climate changes were concentrated in the western and southern parts of Greenland. (ii) The mass balance of the Greenland Ice Sheet during the study period was at a loss, and this was closely related to increasing trends in temperature and precipitation. (iii) In the coastal areas of western and southern Greenland, the rate of mass change has accelerated significantly, mainly because of climate change. [ABSTRACT FROM AUTHOR]

The article presents new Sm–Nd and U–Pb geochronological data on rocks of the poorly studied Pados-Tundra Cr-bearing complex. It is part of the Notozero mafic–ultramafic complex (western Kola Peninsula) and occurs at the border of the Paleoproterozoic Lapland Granulite Belt and the Archean Belomorian composite terrain. The Pados-Tundra complex hosts two major zones, the Dunite and Orthopyroxenite Blocks. Dunites are associated with four levels of chromite mineralization. Isotope Sm–Nd studies of dunites, harzburgites, and orthopyroxenites from the central part of the complex have been carried out. The isochron Sm–Nd age on 11 whole-rock samples from a rhythmically layered series of the complex is 2485 ± 38 Ma; the mineral Sm–Nd isochron for harzburgites shows the age of 2475 ± 38 Ma. It corresponds with the time of large-scale rifting that originated in the Fennoscandian Shield. When the rhythmically layered series of the intrusion and its chromite mineralization were formed, hornblendite dykes intruded. The U–Pb and Sm–Nd research has estimated their age at ca. 2080 Ma, which is likely to correspond with the occurrence of the Lapland–Kola Ocean. According to isotope Sm–Nd dating on metamorphic minerals (rutile, amphibole), the age of postmetamorphic cooling of rocks in the complex to 650–600 °C is 1872 ± 76 Ma. The U–Pb age on rutile from a hornblendite dyke (1804 ± 10 Ma) indicates further cooling to 450–400 °C. The conducted research has determined the early Proterozoic age of rocks in the rhythmically layered series in the Pados-Tundra complex. It is close to the age of the Paleoproterozoic ore magmatic system in the Fennoscandian Shield that developed 2.53–2.40 Ga ago. Later episodes of alterations in rocks are directly related to main metamorphic episodes in the region at the turn of 1.9 Ga. Results of the current study expand the geography of the vast Paleoproterozoic East Scandinavian Large Igneous Province and can be applied for further studies of similar mafic–ultramafic complexes. [ABSTRACT FROM AUTHOR]