Ice Cover Research Articles

Breaking the Ice: Exploring the Changing Dynamics of Winter Breakup Events in the Beaufort Sea

AbstractThe Beaufort Sea has experienced a significant decline in sea ice, with thinner first‐year ice replacing thicker multi‐year ice. This transition makes the ice cover weaker and more mobile, making it more vulnerable to breakup during winter. Using a coupled ocean‐sea‐ice model, we investigated the impact of these changes on sea‐ice breakup events and lead formation from 2000 to 2018. The simulation shows an increasing trend in the Beaufort Sea lead area fraction during winter, with a pronounced transition around 2007. A high lead area fraction in winter leads to greater growth of new, thin ice within the Beaufort region while also leading to enhanced sea ice transport out of the area. Despite the large export, consisting primarily of thinner first‐year ice, we find little evidence that winter breakup amplifies the advection of multi‐year ice from the central Arctic into the Beaufort Sea. Overall, the export offsets ice growth, resulting in negative volume anomalies and preconditioning a thinner and weaker ice pack at the end of the cool season. Our results indicate that large breakup events may become more frequent as the sea‐ice cover thins and that such events only became common after 2007. This result highlights the need to represent these processes in global‐scale climate models to improve projections of the Arctic.

Extended ozone depletion and reduced snow and ice cover-Consequences for Antarctic biota.

Stratospheric ozone, which has been depleted in recent decades by the release of anthropogenic gases, is critical for shielding the biosphere against ultraviolet-B (UV-B) radiation. Although the ozone layer is expected to recover before the end of the 21st century, a hole over Antarctica continues to appear each year. Ozone depletion usually peaks between September and October, when fortunately, most Antarctic terrestrial vegetation and soil biota is frozen, dormant and protected under snow cover. Similarly, much marine life is protected by sea ice cover. The ozone hole used to close before the onset of Antarctic summer, meaning that most biota were not exposed to severe springtime UV-B fluxes. However, in recent years, ozone depletion has persisted into December, which marks the beginning of austral summer. Early summertime ozone depletion is concerning: high incident UV-B radiation coincident with snowmelt and emergence of vegetation will mean biota is more exposed. The start of summer is also peak breeding season for many animals, thus extreme UV-B exposure (UV index up to 14) may come at a vulnerable time in their life cycle. Climate change, including changing wind patterns and strength, and particularly declining sea ice, are likely to compound UV-B exposure of Antarctic organisms, through earlier ice and snowmelt, heatwaves and droughts. Antarctic field research conducted decades ago tended to study UV impacts in isolation and more research that considers multiple climate impacts, and the true magnitude and timing of current UV increases is needed.

ОБРАБОТКА СПУТНИКОВОЙ ИНФОРМАЦИИ В ИНТЕРЕСАХ ГИДРОМЕТЕОРОЛОГИИ С ИСПОЛЬЗОВАНИЕМ НЕЙРОСЕТЕВЫХ ТЕХНОЛОГИЙ: ПОДХОДЫ НИЦ “ПЛАНЕТА”

The paper presents an experience of using artificial intelligence techniques, in particular, neural networks to solve relevant problems of hydrometeorology. The results of the investigations at the Planeta State Research Center on Space Hydrometeorology in detecting clouds and snow cover from the Himawari, Electro-L, and Meteor-M satellite data, as well as on classifying cloud types according to the AHI instrument data (Himawari-8) are reported. The findings of the work on retrieving values of total ozone and water vapor according to the infrared sensing devices are demonstrated. The work on detecting the boundaries of the ice cover and river floods from medium- and high-resolution satellite instruments, as well as the technologies for temperature and humidity sensing in the microwave spectrum are considered. The studies have shown that the use of neural network technologies provides the required accuracy of the received hydrometeorological information and high speed of processing incoming data.

Lake Ice From Historical Records to Contemporary Science

AbstractLake ice phenology is a critical component of the cryosphere and a sensitive indicator of climate change that has some of the longest records related to climate science. Records commenced for numerous reasons including navigation, hydropower development, and individual curiosity, demonstrating the value of lake ice as a seasonal event of significant importance to a broad swath of peoples and countries. At the same time, lake ice loss has been rapid and widespread with lakes losing ice at an average rate of 17 days per century. In this Perspective, we examine the earliest known records of ice cover and the scientific studies that developed from that practice of record keeping. Studies in lake ice began in the nineteenth Century and have included relationships between climate, biology, and ice cover. Early studies developed some of the foundational principles that limnologists and climate scientists are still exploring, such as the relationship between ice phenology and climate variables, large‐scale climate oscillations, and morphological characteristics, with implications for lake ice physical structure and under‐ice ecosystems in a warming climate. We conclude with an examination of the state of the field and how these centuries‐long lake ice records can continue to inform cutting edge science by validating satellite remote sensing techniques, in addition to modeling approaches and collaborations across disciplines, that can improve our understanding of the loss of lake ice in a warmer world.

Short-term forecasting method for prevailing orientation of leads in the Laptev Sea ice cover during winter-spring season

Sea ice leads are potential routes of easier navigation in the Arctic seas during winter-spring season. Forecasts of the prevailing orientation of ice leads are required for the early selection of the optimal route of a ship in ice. An automated method for short-term forecasting of the prevailing orientation of leads in the Laptev Sea is developed in AARI based on the analog method. Data sources for making a forecast include predictive fields of atmospheric pressure up to 3 days in advance and historical data on surface atmospheric pressure, ice drift and sea ice leads. The data on ice leads are obtained by interpreting SuomiNPP satellite images in a visible and infrared range at 375 m spatial resolution for the cold seasons 2016–2022. The ice drift data are freely available OSI SAF data. In order to make a forecast of the prevailing orientation of leads by a predictive atmospheric pressure field, it is necessary to select from an electronic data archive a historical field of atmospheric pressure that is the most similar to the predictive field. The lead characteristics on the selected date are taken as the predictive ones. Automated selection of an analog consists in searching for an atmospheric pressure field from the electronic data archive which has minimal metrics for the forecast date together with 2 previous days. The metric is calculated as the sum of the squared differences between the change in atmospheric pressure per 1 km in the latitudinal and meridional directions between the predictive atmospheric pressure field and the potential analog field. Actual lead data for a date of the selected analog may not be available due to thick clouds. In this case, the direction of the minor axis of the strain ellipse calculated from ice drift data is taken as the prevailing orientation of leads. The success ratio of diagnostic forecasts by the method developed is 72 %. Comparison of the success ratio of the diagnostic forecasts with the results of inertial and climatic forecasts demonstrates a high effectiveness of the method for cases of abrupt change in the direction of air flows over the Laptev Sea within the first 1–2 days.

Iceberg danger in the seas of the Russian Federation Arctic Zone under modern climate change conditions

The aim of the research was to study the relationship between the intensity of iceberg formation in the Russian Arctic including the number of icebergs calving annually from outlet glaciers and surface air temperature anomalies. The research was carried out on the basis of satellite monitoring using non-commercial, freely distributed satellite information from optical-electronic satellites Landsat-8 (spatial resolution 15 m) and Sentinel-2 (spatial resolution 10 m) and the radar satellite Sentinel-1 (pixel size 20×40 m). To achieve the aim, an iceberg detection technique was used based on statistical criteria for searching for gradient zones in the analysis of two-dimensional fields of satellite images. Based on the analysis of satellite data of the visible spectral range of the Landsat-8 and Sentinel-2 satellites and Sentinel-1 radar data the maximum spatial dimensions of icebergs formed by the outlet glaciers of Severnaya Zemlya, Franz Josef Land (ZFI) and Novaya Zemlya in 2012–2022 were estimated. Satellite monitoring of the Severnaya Zemlya region was carried out using visible range images in the spring season (March–May), characterized by the best observation conditions in terms of cloudiness, natural light, and monitoring of icebergs most of which are located in fast ice at this time. Monitoring of the ZFI area was carried out using radar data in the period August-September, corresponding to the minimal ice cover conditions. Satellite monitoring of the Novaya Zemlya region was carried out using visible images in the summer season. In total, about 500 satellite images were analyzed. The discusses the dependence of the intensity of the iceberg formation process on the ice shelf and outlet glaciers with a floating edge on the surface air temperature and the maximum thickness of fast ice. It is shown that the abnormally warm weather that set in 2020 during the period of ice melting led to a sharp intensification of the process of glacier melting in the Russian Arctic and the formation of almost 8,000 icebergs near Severnaya Zemlya, more than 6,600 icebergs near ZFI and over 1,000 icebergs near the western coast of Novaya Zemlya. For all the areas of the Russian Arctic studied in the period 2012–2022 an increase was noted in the maximum observed sizes of icebergs calving from glaciers. The largest iceberg, whose length was 5 km, broke off in 2020 from the Matusevich ice shelf.

Spatial trend analysis of significant wave heights in the Kara Sea

Over the past decades, the extent of sea ice in the Arctic, including the Kara Sea, has been diminishing. This phenomenon has a direct impact on wind waves as the increased expansion of ice-free water influences wave height. Furthermore, alterations in the ice cover also lead to modifications in atmospheric circulation, necessitating a concurrent analysis of wind and waves to refine the understanding of their interrelationships. In this study, wave modeling data were employed using the WAVEWATCH III model and NCEP/CFSR/CFSv2 reanalyzes. Calculations were performed on a non-structural computational grid. The grid covers the Barents and Kara Seas, as well as the entire northern part of the Atlantic Ocean. The spatial resolution varies from ~ 700 m for the coastal zone of the Kara Sea, to ~ 20 km in the open part of the Kara Sea, covering the period from January 1, 1979 to December 31, 2021. Subsequently, average significant wave heights (SWH), maximum SWH, and the 95th percentile of SWH were computed for each grid node on both monthly and yearly basis. The annual values were analyzed for trends and their significance. Calculations were conducted for both the entire period and ice-free period. Positive trends in annual mean values were observed throughout the sea, with the maximum trend occurring near the boundary with the Barents Sea, barely exceeding 0.2 m/10 years. The northern and northeastern parts of the sea were characterized by significant positive trends of the maximum SWH values. Maximum trend values for the 95th percentile of SWH were also evident in the northern part of the Kara Sea. For the ice-free period, maximum trend values were notable for both the annual mean and the 95th percentile of SWH in the northern part of the sea (maximum trend values are approximately 0.25 m/10 years and 0.5 m/10 years, respectively). Significant positive trends in the annual mean SWH were characteristic of the southern part of the sea, while the largest and significant trends for maximum wave heights were observed in the northeast. The assessment of the contribution of wind and ice regimes to the variability of wind waves remains a subject of discussion.

Increasing coastal exposure to extreme wave events in the Alaskan Arctic as the open water season expands

Declining Arctic sea ice over recent decades has been linked to growth in coastal hazards affecting the Alaskan Arctic. In this study, climate model projections of sea ice are utilized in the simulation of an extratropical cyclone to quantify how future changes in seasonal ice coverage could affect coastal waves caused by this extreme event. All future scenarios and decades show an increase in coastal wave heights, demonstrating how an extended season of open water in the Chukchi and Beaufort Seas could expose Alaskan Arctic shorelines to wave hazards resulting from such a storm event for an additional winter month by 2050 and up to three additional months by 2070 depending on climate pathway. Additionally, for the Beaufort coastal region, future scenarios agree that a coastal wave saturation limit is reached during the sea ice minimum, where historically sea ice would provide a degree of protection throughout the year.

Станция подводного обслуживания гибридного необитаемого подводного аппарата системы мониторинга подводного добычного комплекса

The use of support vessels significantly increases the cost of monitoring objects of underwater production complexes (UPC), and the presence of a cable communication line significantly limits the possibility of using remote-controlled uninhabited underwater vehicles (ROV), which is reduced to zero in conditions of continuous ice coverage of the work area. An obvious alternative to the use of ROVs are autonomous uninhabited underwater vehicles (AUVs), equipped with equipment for conducting contact work with monitoring objects and communicating with the shore control post. At the same time, the necessary autonomy for the use of such hybrid autonomous uninhabited underwater vehicles (HAUVs) can be ensured by a network of bottom stations equipped with systems for contactless charging and information exchange with the shore UPC control post. The work proposes the concept of an underwater service station (USS) for a HAUV, which allows, in long-term underwater deployment conditions, to use the device not only in an autonomous mode, but also in a remote control mode from a shore control post. A model for using the station for its intended purpose and the composition of the equipment necessary for its implementation have been determined, the design of the technical solution of the station has been presented, determined taking into account the features of installation on a complex bottom surface and the requirements for docking the HAUV for contactless charging and information exchange, including in the mode of remote control from the SCP. Basic technical solutions for the USS have been developed that provide automatic adjustment of the horizontal position of the docking unit, reliable docking and holding of the HAUV charging and information exchange terminals, and control of the vehicle’s pointing process using a set of rotary video cameras with lamps and a sector-view sonar. Algorithms for interaction between the station and the HAUV have been developed for autonomous and controlled via optical communication cable operating modes of the vehicle.

Seasonal dynamics of the standard test species Lemna sp. in outdoor microcosms.

Lemna L. sp. is a free-floating aquatic macrophyte that plays a key role as a standard test species in aquatic risk assessment for herbicides and other contaminants. Population modeling can be used to extrapolate from laboratory to field conditions. However, there are insufficient data on longer-term seasonal dynamics of this species to evaluate such models. Therefore, several long-term growth experiments were conducted in outdoor microcosms (surface area 0.174 m2). Monitoring parameters included biomass, frond numbers, water parameters, and weather data. Three different datasets were generated: frond numbers and biomass from weekly to monthly destructively sampled microcosms; a year-round dataset of frond numbers from five continuously monitored microcosms; and seasonal growth rates without the effect of density dependence over 1-2 weeks in freshly inoculated microcosms. Lemna sp. reached a maximum of approximately 500 000 fronds m-2 and 190 g dry weight m-2. During the first winter, the microcosms were covered by ice for approximately four weeks, and Lemna sp. populations collapsed. The second winter was warmer, without any ice cover, and Lemna sp. populations maintained high abundance throughout the winter. Dry weight per frond was not constant throughout the year but was highest in autumn and winter. Growth rates without density dependence under outdoor environmental conditions reached 0.29 day-1 for frond number, 0.43 day-1 for fresh weight, and 0.39 day-1 for dry weight. In linear regressions, these growth rates were best explained by water temperature. For the populations continuously monitored throughout a year, the nitrogen-to-phosphorus ratio best explained the growth rate of frond numbers. This study yielded a relevant dataset for testing and refining Lemna population models used in chemical risk assessment as well as for managing ecosystems and combating the effects of eutrophication. Integr Environ Assess Manag 2024;20:1625-1638. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Analysis of rapid snow and ice cover loss in mountain glaciers of arid and semi-arid regions using remote sensing data

This article investigates the effects of climate change on snow cover and glacier in mountainous glacial areas in northern region of Iran. Due to the lack of glacier measuring stations, accurately assessing changes in snow cover over the past two decades is a challenge for water experts. This research instead utilized remote sensing data from the MODIS sensor on the Terra satellite in Google Earth Engine (GEE) system covering the period from 2000 to 2020. The annual temperature changes near the Earth's surface, using ERA5 data, showed a significant increase of 1.5 °C in average temperature over the past thirty years. The Mann-Kendall test confirms the statistical significance of the temperature rise, with a significance value of 3.5 and a p-value of 0.002. For MODIS data validation, two methods of overall accuracy and the Kappa coefficient were used with 93% and 85% of accuracy. While the annual snowfall and volume have remained relatively stable over the past 20 years, the findings indicate a decreasing trend of snow cover during warmer months (summer) due to rising air temperatures. The findings show a strong negative correlation coefficient of −0.8 between snow cover and annual average temperature. The results indicate a 30% decrease in summer snow cover compared to the spatial extent of two decades ago. The rapid snowmelt poses a significant threat to permanent glaciers in the region as the protective snow cover diminishes, putting these glaciers at risk of completely melting in the future. The loss of these glaciers will have severe consequences for the environment, including impacts on local water supplies, river flows, and the ecosystem.

CO2 sink and source zones delimited by marine fronts in the Drake Passage

Net sea-air CO2 fluxes (FCO2) in the Drake Passage (DP) were studied at a climatological scale (1999–2019) using observations from the Surface Ocean CO2 Atlas (SOCAT) database. Based on the monthly climatological position of the main circumpolar fronts of the DP (the Subantarctic Front (SAF), the Polar Front (PF) and the Southern Antarctic Circumpolar Current Front (SACCF)) and the thermal and nonthermal contributions to FCO2, we present a regional subdivision into different regimes that provide new insights into the processes controlling these fluxes. Our results indicate that the region in the north of SAF (R1) behaves as an annual CO2 sink (-1.3 ± 1.0 mmol m−2 d−1); this sink weakens between SAF-PF (R2) and PF-SACCF (R3) and the region south of SACCF (R4) acts as an annual CO2 source (2.2 ± 3.3 mmol m−2 d−1). The annual mean CO2 uptake in DP is 1.3 ± 15.5 Tg C yr-1. Analysis of thermal (TE) and nonthermal (nonTE) effects on seasonal sea surface CO2 partial pressure (pCO2sw) variability indicates that DP is mainly dominated by nonTE. Results emphasize that carbon fluxes are driven by mesoscale and submesoscale processes north of the PF and by the upwelling of Upper Circumpolar Deep Waters in the Antarctic boundary of the DP, while seasonal patterns are mostly modulated by local factors such as nutrient availability, biological activity and ice cover.

Perennial snow and ice cover change from 2001 to 2021 in the Hindu-Kush Himalayan region derived from the Landsat analysis-ready data

The changing climate directly affects spatial and temporal patterns of snow and ice cover globally and in the Hindu-Kush Himalayan (HKH) region. In the HKH, around 3.3 billion people across 11 countries depend on water originating from mountain glaciers and snowfields, and melting snow cover has a direct impact on their livelihood and well-being. Various studies have shown that the snow and ice cover in the HKH is declining at an alarming rate but have been limited in geographic, spatial and temporal scales. Here, we employed the Global Land Analysis and Discovery analysis ready Landsat time-series data (GLAD ARD) to map changes in perennial snow and ice between 2001 and 2021 at five-year epochs using decision tree ensemble models. These maps were used to create a stratified sampling design for reference data collection to estimate area and map accuracy. All five-year epoch maps have user's accuracies above 90% and producer's accuracies above 91%. Our sample data analysis showed that one-eighth of the extent of perennial snow and ice in the HKH, totalling 15,770 km2 (CI ± 3195 km2), disappeared over the last two decades with 105,935 km2 (CI ± 3396 km2) remaining in 2021. From map-based estimates, the largest decline of perennial snow and ice cover among the mountain ranges was found in the Himalayas with an estimated reduction of 5741 km2. Among HKH countries, China had the largest area of perennial snow and ice reduction of 10,654 km2, Nepal had the highest net perennial snow and ice reduction rate (31%). Among the river basins, the maximum net loss of perennial snow and ice cover between 2001 and 2021 was in the Indus (24.8%), followed by Brahmaputra (18.3%), and Tarim (15.7%). Our results confirm wide-spread loss of perennial snow and ice across the HKH region and provide both regionally consistent maps with derived area estimates at landform, national and basin-levels and methodology to continue monitoring snow and ice melt.

Interaction between ice cover and floating platform simulated by dilated-polyhedron-based DEM

This study presents a dilated-polyhedron-based discrete element method (DPDEM) aimed at investigating the interaction between the self-propelled ice-resistant platform (IRSPP) and drifting sea ice. The IRSPP is treated as a rigid body anchored by a mooring system, providing six degrees of freedom (6-DOF) in translations and rotations. The simulation of the ice-IRSPP interaction utilizes the DPDEM, incorporating contact forces and bond-failure criteria to account for sea ice collisions and fractures, respectively. To address disparities between DEM sea ice and actual sea ice, as well as the random nature of fracture and fragmentation following IRSPP interaction, an analysis of the dimensional independence of DEM calculation elements is conducted. Additionally, the validity of DEM parameters is assessed by comparing the numerical ice resistance of various previous icebreakers with the Lindqvist formula. Then, the time history of structural ice forces, ice heeling moments, and platform motion responses under varying ice floe thicknesses are investigated. Furthermore, the influences of sea ice conditions on ice load and the value of the ice heeling moment for the IRSPP are analyzed.

Biophysical coupling of seasonal chlorophyll-a bloom variations and phytoplankton assemblages across the Peninsula Front in the Bransfield Strait

Abstract. This study investigates the spatio-temporal variations in the chlorophyll-a (chl-a) blooms in the Bransfield Strait (BS) at a climatological scale (1998–2018). We propose that suitable monitoring of these blooms can be achieved through remotely sensed observations only if the BS is divided following the Peninsula Front (PF), which ultimately influences the phytoplankton assemblage. Our analysis is based on characterizing climatological fields of sea surface temperature (SST), air temperature, sea ice coverage, chl-a concentrations and wind stress, guided by synoptic novel and historical in situ observations which reveal two niches for phytoplankton assemblage: the Transitional Bellingshausen Water (TBW) and Transitional Weddell Water (TWW) pools. The TBW pool features stratified, less saline, warmer waters with shallow mixed layers, while the TWW pool features well-mixed, saltier, and colder waters. We identify that the 0.6 °C isotherm corresponds to the summertime climatological PF location, effectively dividing the BS into two different scenarios. Furthermore, the 0.5 mg m−3 chl-a isoline aligns well with the 0.6 °C isotherm, serving as a threshold for chl-a blooms of the highest concentrations around the South Shetland Islands. For the first time, these thresholds enable the monthly climatological descriptions of the two blooms developing in the BS on both sides of the PF. We think this approach underscores the potential of combining SST and chl-a data to monitor the year-to-year interplay of the chl-a blooms occurring in the TBW and TWW pools contoured by the PF.

Existence of typical winter atmospheric circulation patterns leading to high PM2.5 concentration days in East Asia

Understanding the atmospheric circulation patterns responsible for severe air pollution events in East Asia is important because East Asia is one of the most polluted regions in the world, particularly during the boreal winter (December-January-February). Here, by conducting GEOS-Chem simulation with fixed anthropogenic emission sources, we found that there exist three typical atmospheric circulation patterns conducive to leading to high concentrations of particulate matter with a diameter less than or equal to 2.5 μm (PM2.5) in East Asia. These atmospheric circulation patterns are characterized by weakened horizontal winds, which allows PM2.5 to accumulate, and by enhanced relative humidity, which can favor secondary formation of PM2.5. The occurrence of these atmospheric circulation patterns is associated with increased sea ice cover over the Barents Sea and heavy precipitation over the tropical western Indian Ocean. The existence of these atmospheric circulation patterns among typical atmospheric circulation patterns indicates high PM2.5 days in East Asia are unavoidable given current level of anthropogenic emissions in the region. This conclusion indicates that sustained efforts to reduce anthropogenic emission sources in East Asia should be warranted to avoid high PM2.5 days.

Drivers of Laptev Sea interannual variability in salinity and temperature

Abstract. Eurasian rivers provide a quarter of total fresh water to the Arctic, maintaining a persistent fresh layer that covers the surface Arctic Ocean. This freshwater export controls Arctic Ocean stratification, circulation, and basin-wide sea ice concentration. The Lena River supplies the largest volume of runoff and plays a key role in this system, as runoff outflows into the Laptev Sea as a particularly shallow plume. Previous in situ and modelling studies suggest that local wind forcing is a driver of variability in Laptev sea surface salinity (SSS) but there is no consensus on the roles of Lena River discharge and sea ice cover in contributing to this variability or on the dominant driver of variability. Until recently, satellite SSS retrievals were insufficiently accurate for use in the Arctic. However, retreating sea ice cover and continuous progress in satellite product development have significantly improved SSS retrievals, giving satellite SSS data true potential in the Arctic. In this region, satellite-based SSS is found to agree well with in situ data (r>0.8) and provides notable improvements compared to the reanalysis product used in this study (r>0.7) in capturing patterns and variability observed in in situ data. This study demonstrates a novel method of identifying the dominant drivers of interannual variability in Laptev Sea dynamics within reanalysis products and testing if these relationships appear to hold in satellite-based SSS, sea surface temperature (SST) data, and in situ observations. The satellite SSS data firmly establish what is suggested by reanalysis products and what has previously been subject to debate due to the limited years and locations analysed with in situ data; the zonal wind is the dominant driver of offshore or onshore Lena River plume transport. The eastward wind confines the plume to the southern Laptev Sea and drives alongshore transport into the East Siberian Sea, and westward wind drives offshore plume transport into the northern Laptev Sea. This finding is affirmed by the strong agreement in SSS pattern under eastward and westward wind regimes in all reanalyses and satellite products used in this study, as well as with in situ data. The pattern of SST also varies with the zonal wind component and drives spatial variability in sea ice concentration.

The range of ice thrusts and ice piles as reflected by ice scars on trees growing on the shores of coastal lagoons: The case of the Szczecin Lagoon

We studied the phenomena associated with the thrusting of ice onto the shore of the Szczecin Lagoon based on the occurrence of tree ice scars. The measurements concerned mostly the maximum height, length and width of ice scars on trees, and the distance of these trees from the shore in the period 2017–2022. It was observed that sheets of ice advanced up to 64 m inland, and piled to form hummocks reaching up to 4.3 m above the water level. These maximum values occurred mostly on eastern shores, which is where the highest numbers of damaged and broken trees were observed. This should be associated with the strongest and most frequently occurring wind blowing from the western direction in the winter-spring period. To the contrary, the lowest number of damaged trees were observed on the western shore. This is due not only to the lower frequency of wind blowing from the east, and the associated cooling (Ta < 0°C) and ice cover stabilization, but also due to the presence of extensive reed belts. Our results enable an indirect insight into the ice phenomena dynamics, especially in areas lacking systematic ice observations. Similar conclusions may be extended for all the sheltered basins as lakes or lagoons.

Regime Shifts in Lake Oxygen and Temperature in the Rapidly Warming High Arctic

AbstractGlobal warming is destabilizing the cryosphere, with consequences for glaciers, permafrost, sea ice and lake ice. Polar lakes have short ice‐free seasons, and small changes in ice cover duration have the potential to provoke alterations to ecosystem structure. However, these lakes are understudied, and the consequences for mixing regimes, thermal structures and biogeochemical processes remain unclear. We measured three annual cycles of dissolved oxygen, temperature and specific conductivity in a lake at ∼83°N to investigate limnological processes and their interannual variability. There were sharp interannual contrasts in lake dynamics, with state shifts in mixing, stratification and oxygen regimes due to air temperature variability and meteorological events. We also observed unusual thermal profiles that were associated with solute gradients. These striking differences underscore the sensitivity of high Arctic lakes to interannual variations in meteorological forcing, and their susceptibility to regime shifts in response to ongoing global change.

Transformation of the atlantic water between svalbard and Franz Joseph Land in the late winter 2018–2019

An inflow of warm and salty Atlantic origin waters (AW) from the Nordic Seas to the Arctic Ocean interior is in the list of the major external factors, which control the hydrologic regime of the East-Atlantic sector of the Arctic Ocean. Rapid decay of the sea ice cover in 2000–2010s raised questions on the possible changes in the fate of the inflow under present ice-depleted conditions: whether warm and salty AW will cool and freshen slower (due to less ice to be melted underway), or intensified heat loss to the atmosphere through the open surface will lead to the faster AW cooling on shorter distance? We present rare hydrologic data, collected during the late winter 2019 in the international expedition “Transarktika-2019” in the northern part of the Barents Sea and at the adjoining continental slope of the Nansen Basin. On the basis of field data, supported by the oceanic reanalysis product and numerical modelling we have studied the transformation of AW on its transit between Svalbard and Franz Joseph Land. We show that the observed cooling and desalination of the fraction of AW over the continental slope around this area is controlled by lateral mixing with colder and fresher waters, outflowing from cross-slope canyons, which cut the continental slope: Kvitøya Trough, Franz Victoria Trough and probably, the British Channel. The obtained results demonstrate more intensive transformation of AW on this transit compared to previous studies. Possible explanations of this contrast, which are supported by the earlier studies, may include: the season of the survey when dense water outflow through canyons is at its maximum and gradual “atlantification” of the East-Atlantic sector of the Arctic Ocean, which favours intensification of dense water formation in winter polynyas under conditions of increased seasonality of sea ice. In the latter case, faster cooling and desalination of AW en route in this part of the Arctic Ocean may be considered as a reasonable hypothesis, provided the atlantification of the Nansen Basin is progressing.