Thickness Of Ice Cover Research Articles

Determination of occurrence of atmospheric blockings over the Caspian Sea region in winters of 1959–2022, and influence of them on the ice regime of the Northern Caspian Sea

The ice regime of the Caspian Sea has pronounced influence on the heat and moisture exchange of the reservoir with the atmosphere, the state of the ecosystem, as well as human marine activities, including shipping, fishing, construction of hydraulic structures, etc. Consequently, the development of existing ideas about the causes of changes in the characteristics of the ice regime of such water bodies is actual and socially significant problem of limnology, hydrometeorology, ecology, and navigation. This study was aimed at determination the frequency of occurrence of atmospheric blockings over the Caspian region with standings longer 5 days in winter period of 1959–2022, and investigation of influence of them on the ice regime in the Northern area of the Sea. The following information and data were used: changes in hourly mean values of atmospheric pressure at the sea level, geopotential of isobaric surfaces 850, 500 and 300 hPa, presented in the ERA5 reanalysis; and observational data on air temperature and ice cover from hydrometeorological stations located in the Caspian region of Kazakhstan and Russia. It has been established that in the winter during a long standing of atmospheric blockings the mean daily air temperatures noticeably drop. The values of all the studied characteristics of every atmospheric blocking which occurred in 1959–2022 were estimated as well the influence of them on the ice regime in the North of the Caspian Sea was analyzed. The relationship between a decrease in the frequency of atmospheric blockings (AB), sums of negative air temperatures on its coasts, and the ice cover thickness in the corresponding areas of coastal waters has been revealed in the region. The longer the total AB duration, the lower is the air temperature, and the ice thickness in February is larger.

Synthetic aperture radar backscatter is influenced by bubbles at the ice/water interface of an Antarctic lake

Synthetic aperture radar is an invaluable tool for monitoring lake ice. This study utilizes synthetic aperture radar to analyze the 2019-2023 backscatter time series of perennially ice-covered Lake Untersee in East Antarctica. We observed stark seasonal backscatter variations, averaging –9.6 dB from December to March and –3.7 dB from May to November. These fluctuations correspond to the abundance of sub-centimeter bubbles at the ice/water interface. Notably, the backscatter increase in April-May aligns closely with variations in ice thickness across the lake. Our findings suggest that ice cover thickness influences the timing and duration of ice accretion at the bottom, the accumulation of dissolved gases and bubbles, and the resultant changes in surface roughness at the ice/water interface. These factors collectively impact the backscatter response. This study enhances our understanding of the interactions between subsurface processes and synthetic aperture radar backscatter, shedding light on the seasonal dynamics of perennially ice-covered lakes.

Dispersion of waves propagating in the ice-covered Arctic Ocean

The Arctic Ocean was modeled as an ice–seawater–sediment system, where the ice cover and seawater were assumed to be inhomogeneous solid and liquid, respectively, while the sediment was assumed to be homogeneous liquid. Transfer matrixes relating the displacements and stresses at the lower surface and those at the upper surface for a thin solid layer, and a thin liquid layer were derived. Furthermore, a dispersion equation for waves propagating in the ice-covered Arctic Ocean was derived using the transfer matrix technique. The phase- and group-velocity dispersion curves were obtained by solving the dispersion equation numerically. The results show that the dispersion curves for the Arctic Ocean with ice cover are much more complex than those without ice cover. Except for the new mode, the phase-velocity curve for the n-th (n > 2) mode exhibited a slight distortion, which caused a sharp peak in the group-velocity curve. These peak values, which depend on the order of the mode, may be significantly higher than the speed of sound in seawater. The variation of the ice cover thickness had significant influence on the dispersion curves of the first and second modes. Moreover, the influence of the seawater depth on the dispersion curves were investigated.

Change trends of mean ice thickness, water level, and surface salinity in the Laptev Sea in winter-spring period under further climate warming conditions

he purpose of the paper is to identify the most likely trends in interannual changes of the ice cover thickness on sections of the Northern Sea Route in the Laptev Sea in the winter-spring months under conditions of further climate warming. A hypothesis that in the modern period such changes can be significantly impacted by melting of submarine permafrost layers located inside the sea shelf, — a process caused by their heat exchange with bottom sea waters, is put forward. To verify the hypothesis, trends in interannual changes in ice thickness are compared with trends in variations in sea level and surface salinity. As factual material, data from the global reanalysis GLORYS12v1 is used. The research methodology is based on the standard methods of mathematical statistics. A correlation between the trends of the above processes has been found. It allows us to confirm the hypothesis put forward. The results obtained indicate that, under the conditions of ongoing climate warming, there remains a high probability that the average thickness of the ice cover will not decrease, and the ice situation in the Laptev Sea in the winter-spring months will not improve significantly. The latter confirms the need and feasibility of further development of the Russian icebreaker fleet

Celerity of Ice Breakup Front in the Regulated Peace River, Canada, and Implications for the Recharge of the Peace–Athabasca Delta

Timely release of flow from upstream hydropower generation facilities on the Peace River can enhance potential ice-jam flooding near the drying Peace–Athabasca Delta (PAD), a Ramsar wetland of international importance and homeland to Indigenous Peoples. An important consideration in deciding whether and when to commence a release is the celerity of the breakup front as it advances along the Peace River. Relevant historical data for a key stretch of the river are analyzed to determine average celerities, which can vary by an order of magnitude from year to year. Seven breakup events are identified that might have been candidates for a release, and the predictability of associated celerities is explored in terms of antecedent hydroclimatic variables, including cumulative winter snowfall, snow water equivalent on 1 April, ice cover thickness, coldness of the winter, and freezeup level. It is shown that celerity can be predicted to within a factor of two or less, with the freezeup level giving the best results. Three of the seven “promising” events culminated in PAD floods and were associated with the three highest celerities. The empirical findings are shown to generally align with physical understanding of breakup driving and resisting factors.

Climate change reductions in lake ice cover duration and thickness help regulate the carbon sink potential of plateau type lakes

Climate change reductions in lake ice cover duration and thickness help regulate the carbon sink potential of plateau type lakes

Fluctuations of ice in a lake due to the impact of the North Atlantic Oscillation (1960/61–2009/10) – a case study of Łebsko Lake

The paper represents an attempt to understand the impacts produced by the North Atlantic Oscillation on the ice cover regime of the largest coastal lake in Poland situated in the northern part of the country. The purpose of the study was to estimate the impact of the North Atlantic Oscillation on selected ice cover parameters. The study also attempts to examine other factors that may affect its significant impact on observed changes in the climate. Water temperature data are used to assess temperature conditions in aqueous ecosystems as well as determine the heat absorption capacity of these systems. This allows one to then determine cooling rates in the event of ice cover formation. The data analysis provided in the paper focuses on selected characteristics of ice cover conditions (i.e. dependent variables) including the number of days with ice and maximum ice thickness in relation to NAO index changes (i.e. independent variables) for the reference period 1960/61–2009/10. In addition, the paper divides the studied period into 10-year subperiods in order to capture the weakest and strongest phases of NAO and assess the extent to which they affect the duration of ice cover. A large increase in the mean air temperature (1.8°C) occurred in the years 1960–2010. Trendline analysis indicates that the number of days with ice cover declined by about 60 days and the maximum thickness of ice cover decreased by about 10 cm. Oceanographic research employs satellite image data in order to accurately assess human impact. Therefore, ice cover forecasts generated for consecutive winter seasons may become an important tool in this type of assessment.

A Horizontal Distribution Model of Static Ice Cover Generated by Static and Dynamic Water Considering the Heat Transfer of Riverbanks

The thermal factor is the main reason for winter ice cover with a low Froude number flow, and the heat transfer to narrow and deep river banks accelerates ice cover formation and ice thickness change. The freezing of water flow to freezing thickening is a nonisothermal-flow phase transition process coupled with the water flow temperature, environment and riverbank. Here, the Nusselt number and viscous dissipation are used to consider the flow velocity influence on icing, and a thermodynamic model of static ice cover horizontal distribution considering riverbed heat transfer is established. The initial ice time, freezing time and static ice cover thickness formed by static and dynamic water calculated by the model were consistent with measured data. The model reflects the horizontal growth process of the static ice cover, which was significant for narrow and deep channels. The horizontal distribution of the static ice cover was thin in the center and thick on both sides. The maximum horizontal thickness difference of −20 °C indoor freezing for 24 h reached 15% of the central ice thickness. Compared with the degree-day method for calculating ice thickness, the numerical model and dimensionless formula better reflect the growth law and horizontal distribution characteristics of static ice cover and provide a theoretical basis for safe water conveyance under ice cover in winter and ice cover formation in reservoirs and lakes in cold regions.

Transmission line icing thickness prediction model based on ISSA-CNN-LSTM

The prediction of transmission line ice cover thickness can effectively guide the scientific operation and maintenance of the power sector. An improved sparrow search algorithm, convolutional neural network and long short-term memory fusion ice cover prediction model is proposed in this paper. Environmental temperature, humidity, wind speed and other data are firstly normalised, CNN is used to both learn the data signature as well as input the results into LSTM, and then ISSA is used to optimise the parameters of LSTM such as the numeration of the neuron, the initial learning rate, and the regularisation coefficient, etc., and then the final output is the predicted value of the icing thickness of the transmission line cover. The simulation results show that the MSE and MAE of the ISSA-CNN-LSTM model are 0.23 and 0.37, respectively, which are much better than the prediction results of the SSA and CNN models.

Diversity and Variability of the Course of Ice Phenomena on the Lakes Located in the Southern and Eastern Part of the Baltic Sea Catchment Area

The aim of the study is to determine the scale of differentiation and variability of ice phenomena on the lakes in the south-eastern part of the Baltic Sea catchment area. The analysis was performed based on data from the period 1961–2020 from 15 lakes located in Poland (10) and Belarus (5). The characteristics of ice phenomena were characterized, i.e., the length of their occurrence and ice cover, the thickness of ice cover and the number of breaks occurring in the ice cover in the given years were characterized. The analysis of the course of ice phenomena made it possible to distinguish three regions with an increasing length of ice phenomenon occurrence from west to east. The zones were the west of the Vistula, the east of it and the eastern part of the Belarusian Lake District. In the analyzed multi-year period, a shortening of the duration of ice phenomena and ice cover, a decrease in the maximum thickness of the ice and an increasing number of breaks in ice cover were observed. These data correlate with the upward trend in air temperature.

The response of aquatic ecosystems to the interactive effects of stratospheric ozone depletion, UV radiation, and climate change

Variations in stratospheric ozone and changes in the aquatic environment by climate change and human activity are modifying the exposure of aquatic ecosystems to UV radiation. These shifts in exposure have consequences for the distributions of species, biogeochemical cycles, and services provided by aquatic ecosystems. This Quadrennial Assessment presents the latest knowledge on the multi-faceted interactions between the effects of UV irradiation and climate change, and other anthropogenic activities, and how these conditions are changing aquatic ecosystems. Climate change results in variations in the depth of mixing, the thickness of ice cover, the duration of ice-free conditions and inputs of dissolved organic matter, all of which can either increase or decrease exposure to UV radiation. Anthropogenic activities release oil, UV filters in sunscreens, and microplastics into the aquatic environment that are then modified by UV radiation, frequently amplifying adverse effects on aquatic organisms and their environments. The impacts of these changes in combination with factors such as warming and ocean acidification are considered for aquatic micro-organisms, macroalgae, plants, and animals (floating, swimming, and attached). Minimising the disruptive consequences of these effects on critical services provided by the world’s rivers, lakes and oceans (freshwater supply, recreation, transport, and food security) will not only require continued adherence to the Montreal Protocol but also a wider inclusion of solar UV radiation and its effects in studies and/or models of aquatic ecosystems under conditions of the future global climate.Graphical abstract

Winter dynamics of abiotic and biotic parameters in eutrophic temperate lakes

Winter conditions in lakes of temperate climatic zones, especially the duration and thickness of ice and snow cover, are strongly influenced by climate changes. The aim of this study was to follow the dynamics of abiotic (organic carbon, total phosphorus, total nitrogen) and biotic (chlorophyll a, cyanobacteria, algae, nanoflagellates, ciliates, rotifers, crustaceans) parameters during two consecutive winters in three eutrophic lakes of different mixing regime (northeastern Poland). Our results showed that dissolved organic carbon was highly stable during both winters and practically did not differ among the studied lakes. Total phosphorus and chlorophyll a concentrations differed significantly between the dimictic and meromictic lakes. The concentrations of nutrients and chlorophyll a and the biomass of phytoplankton, protists, rotifers and crustaceans reached higher values in late winter than in early winter, depending on the lake type (morphometry, mixing regime) and the year of the study. The composition of phytoplankton and ciliates was more or less similar throughout the study in all lakes during both years, but the share of individual groups in the total biomass differed between early and late winter. A high cyanobacterial biomass in January under the ice in the meromictic lake was probably a legacy of the summer/autumn community. Small prostomatid ciliates were the most important group in late winter in the shallow lake. Cladocerans (Bosmina coregoni and B. longispina) were an important component of winter crustacean community on some occasions, especially in the shallow lake. Phosphorus was the major factor determining phytoplankton biomass. Heterotrophic nanoflagellates and rotifers were negatively related to ice cover, while ciliates were positively related to the water temperature. Our study demonstrated that the dynamics, abundance, and structure of the phytoplankton and zooplankton communities in eutrophic lakes changed from one winter to the next despite similar environmental conditions.

Ice age composition in the Barents sea

The paper presents the key results of investigating Barents Sea ice age composition during the winter season, from the beginning of ice formation in October to its termination in May. To analyze the seasonal and interannual changes in the amount of ice of different age categories, we used ice charts for the Barents Sea for the period 1997–2021, produced by the Arctic and Antarctic Research Institute. The age composition of the ice cover in the Barents Sea is represented by seven standard ice categories (thickness ranges). The areas of ice of different age categories were calculated for a ten-day time interval (in percentage of the total ice area). The results are provided for three parts of the Barents Sea: western, northeastern and southeastern.The interannual changes in the amount of ice in relative fractions of ice of different age categories in the ice cover of the Barents Sea do not show significant trends for the period 1997–2021. Thus, with the observed reduction in the Barents Sea total ice area, the amount of ice of different age categories ranges within the limits of its own natural variability. Therefore, it is impossible to draw a definite conclusion about a decrease in ice cover thickness in the Barents Sea based only on data on the ice age composition over a 24-year period of observations analyzed in this study. On comparing the estimates obtained in this study of the age structure of the ice cover in the Barents Sea with those of the previous studies on this subject, we can argue that its average thickness at the beginning of the 21st century decreased, compared to the period 1971–1976. Taking into account the statistical insignificance of the trends in interannual variations in the amount of ice of different age gradations, one can maintain that quantitative changes in the age structure of the Barents Sea ice cover began earlier than 1997.

Determinants of Spatial Variability of Ice Thickness in Lakes in High Mountains of the Temperate Zone—The Case of the Tatra Mountains

Vertical and horizontal variation in the ice cover of mountain lakes in the temperate climate zone has not been thoroughly studied. The study concerned ice phenomena in four lakes located in the Tatra National Park in the Tatra Mountains (the Czarny Staw Gąsienicowy, Czarny Staw pod Rysami, Morskie Oko, and Smreczyński Staw). The research, which was conducted in the 2018/2019 winter season, included an analysis of variability in atmospheric conditions, an analysis of presence of ice phenomena on satellite images, field work (measurements of ice layer and of snow and slush layer thickness were conducted at a total of 151 sites), and statistical analyses. It was determined that negative air temperature was just one factor among those that determined the maximum thickness of the ice forming on lakes in high mountains. It was found that in addition to ambient thermal conditions, a major factor affecting the magnitude of variation in lake ice thickness was the thickness of the snow overlying the ice and its spatial variability. Thicker ice cover tended to form in areas where a thick layer of snow was deposited. The decisive factor that contributed to a significant variation in ice thickness between lakes was the uneven accretion of snow ice from above. The maximum ice thickness values modeled using Stefan’s formula were significantly underestimated (accounting for 38–61% of the ice thickness measured) relative to the highest ice thickness values found empirically at the end of the winter season. Study results fill a gap in our knowledge and methodology related to vertical and horizontal variation in the ice cover of mountain lakes; they also have significant applications, indicating the risk of winter use of water bodies with different ice cover structure, thickness, and extent.

ICE COVER OF THE EUROPEAN SECTOR OF THE ARCTIC AND SURFACE HEIGHTS OF THE ATLANTIC INNER SEAS (ON THE EXAMPLE OF THE BLACK SEA)

ICE COVER OF THE EUROPEAN SECTOR OF THE ARCTIC AND SURFACE HEIGHTS OF THE ATLANTIC INNER SEAS (ON THE EXAMPLE OF THE BLACK SEA)

Well-Posedness of Hibler’s Dynamical Sea-Ice Model

This paper establishes the local-in-time well-posedness of solutions to an approximating system constructed by mildly regularizing the dynamical sea-ice model of {\it W.D. Hibler, Journal of Physical Oceanography, 1979}. Our choice of regularization has been carefully designed, prompted by physical considerations, to retain the original coupled hyperbolic-parabolic character of Hibler's model. Various regularized versions of this model have been used widely for the numerical simulation of the circulation and thickness of the Arctic ice cover. However, due to the singularity in the ice rheology, the notion of solutions to the original model is unclear. Instead, an approximating system, which captures current numerical study, is proposed. The well-posedness theory of such a system provides a first-step groundwork in both numerical study and future analytical study.

The Impact of Ice Caps on the Mechanical Stability of Magmatic Systems: Implications for Forecasting on Human Timescales

Monitoring the activity of subglacial volcanoes along the Aleutian Arc in Alaska is important to the safety of local populations, as well as air traffic flying through the region. However, observations of volcanic unrest are limited by accessibility and resources, particularly at glacier-covered systems, making investigations of their stability challenging. Westdahl Peak, a subglacial volcano on Unimak Island in the Aleutian Arc has experienced significant unrest and uplift since its most recent VEI three eruption in 1991-1992. Given the magnitude of observed uplift, previous investigations suggested the potential for eruption by 2010, but no such event has occurred. One hypothesis to explain this prolonged unrest is that the 1-km thick glacier may increase the stability of the magma system. However, the impact of ice caps and glaciers on the short-term stability of volcanoes is not well understood. In this study, thermomechanical finite element models are used to evaluate how the stability of a glaciated volcano is impacted by variations in ice cap thickness, magma chamber depth, geometry, magma flux rate, and seasonal changes in ice cover thickness. Our numerical experiments indicate that the presence of an ice cap (1–3 km thick) increases the average repose interval for a magma system. Among models with different magma chamber geometries, depths, and flux rates, the greatest increases in repose interval are observed in prolate systems where the increase is up to 57% for a chamber located at 5 km-depth. Spherical and oblate also experience smaller, yet significant, increases in repose interval. Additionally, the percentage increase in repose interval is not impacted by variations in magma flux rate for a given ice cap thickness and magma chamber geometry. However, flux rates do influence the timing of eruptions when the system is experiencing seasonal variations in ice thickness. Our results show that systems with low flux rates are more likely to fail when the ice thickness is at its lowest. The numerical estimates further suggest that the ice cap on Westdahl Peak, which is ∼1 km, may slightly increase the stability of the magma system. In general, given flux rates and magma chamber geometries estimated for the Westdahl system, the repose interval can increase by ∼7 years due to the Westdahl glacier. This increase is small on a geologic scale but is significant on human time scales and the impact of glaciers must be considered in future forecasting efforts.

Rotational failure of concrete lining slabs induced by water level changes in ice-covered reservoirs in cold regions: Mechanism, patterns, and prevention measures

Reservoirs lined with concrete slabs are very common in the northern cold regions of China. Failures such as the rotation and the dislocation of concrete lining slabs are usually found in those ice-covered reservoirs each year in winter. In this study, the interaction processes between water, ice, and lining when water level changes in ice-covered reservoirs are evaluated based on the theory of beams on elastic foundation. In general, ice cover can generate a rotation effect (bending moment) on concrete lining slabs when water level changes in ice-covered reservoirs. Under such conditions, the bending moment at the ice edge increases with the increase of the ice cover width and thickness. Once the tensile stress at the interface between concrete slab and its base layer exceeds the tensile strength of the interface itself, the concrete slab separates from its base layer and the support condition of the ice cover changes from fix-supported to hinge-supported. Then the rotational failure of the concrete slab may occur due to the rotation effect acted by ice cover. The calculated rotation angle of the concrete lining slab is in agreement with the angle observed at a reservoir in northwest China. In addition, prevention measures such as concrete lining slabs with hydrophobic coating on the surface, concrete lining slabs with dark surface, anchoring concrete slabs to reservoir slope, and integral large-scale lining modules are proposed to mitigate such rotational lining failures in ice-covered reservoirs. The results can help to improve the performance and service life of reservoirs in cold environments.

Determination of ice cover thickness using compression standing waves

Information about the ice cover thickness is necessary for solving many practical problem, from ensuring the safe movement of people and transport over frozen water bodies to assessing the reserves of glacial water. The purpose of this study is to assess the possibilities of using the passive standing wave method to determine the thickness of the ice layer on the water surface or frozen ground. The method is based on the generation of the compression standing waves family from acoustic noise in the ice layer. With regards to the problem under consideration, this phenomenon is confirmed by the results of laboratory experiments and numerical simulations for an ice layer in contact with water and frozen saturated sand. It is shown that the accumulation of amplitude spectra of noise records made on the surface of the ice layer makes it possible to determine the frequencies of several lower modes formed in the layer of compression standing waves. At a known velocity of longitudinal waves in ice, these frequencies can be used to estimate both the thickness of the ice layer and the type of underlying medium (water or frozen ground). The method was tested in natural conditions on two reservoirs, a small river and in the coastal part of the reservoir.

Моделирование характеристик ледяного покрова Каспийского моря на основе модели CICE

The characteristics of the ice cover in the northern part of the Caspian Sea are simulated using the CICE model. The general structure of the model and the experience of its operational application in leading forecast centers are described. Calculations of the ice cover characteristics in the northern Caspian Sea for four winter seasons (October–March) in 2005–2009 are performed. The values of ice concentration and ice thickness are calculated. The comparison of the calculation results with observational data showed that the model satisfactorily reproduces the processes of ice build-up and melting. Keywords: Caspian Sea, ice cover, CICE model, ice concentration and ice thickness