Fast Ice Research Articles

Socio-economic transformation follows environmental change on Svalbard

The European Arctic, which includes the Svalbard archipelago, is situated in one of the areas showing most notable changes due to global warming and associated cascade events and processes. The main driving factor, temperature rise, is continuing to cause a large-scale overall decline in ice, from glacier retreating, less coastal land-fast ice to thinning and shrinking of open-sea pack ice. This, together with increased inflow of Atlantic waters, is causing profound changes in the local fauna, food web and biodiversity. In parallel, changes in landscape are also notable, mainly due to increasing coastal erosion and glacial melt. Over the past decades, both the traditional hunting-trapping lifestyle and mining have declined almost to the point of non-existence. At the same time, destination tourism and scientific research have become the major industries, both associated with an increase in the size of the main settlement of Longyearbyen, and thus also service jobs and local administration. Along with the shrinking of the glaciated Arctic landscape, the archipelago exemplifies the broadest level of nature protection in Europe. Strict environmental regulations that restrict and even prohibit human activities in large areas contribute to Svalbard being one of the best formally protected wilderness environments in the entire Arctic. Thus, as Svalbard marine ecosystems continue to change, they also are becoming more accessible to humans, and so also anthropogenic pressures are both changing and increasing in extent. We provide a compilation of both ecosystem components and human activities, together with indications of how these are, in parallel, changing. This forms the basis for future ecosystem and societal valuation assessments.

Quantifying the role of iron recycling by Adélie and Emperor penguins over the austral spring and summer in Prydz Bay

In large areas of the Southern Ocean, iron limits phytoplankton production. Although biologically mediated iron recycling has been studied for the higher trophic-level whales and the lower trophic-level krill, less is known of the numerically abundant seabirds foraging in Antarctic waters. In this study, we estimate the magnitude of iron recycled by two Antarctic breeding seabirds, the Adélie and emperor penguins, across the austral spring and summer in the Prydz Bay region, East Antarctica. Their contribution to iron recycling and associated pathways differs in line with their contrasting life history strategies (summer and winter breeding) and their breeding habitat (land and fast ice). We consider their breeding cycle in relation to their terrestrial activities compared to foraging periods at sea. High iron concentration (~419 mg kg−1) in guano of both penguin species suggests that they are a source of regenerated iron. Breeding emperor penguins supplied an average of 237 μmol iron m−2 day−1 on the fast ice that they breed on that eventually ends in the ocean when the ice melts completely in summer (November–February). During their foraging trips, the adult emperor penguins contribute between 7 × 10−5 and 4 × 10−4 μmol iron m−2 day−1, as their foraging ranges increase over the breeding season. In contrast, breeding Adélie penguins supplied between 254 and 1,243 μmol iron m−2 day−1 whilst at their colony, with a fraction of guano entering the ocean via meltwater flowing into the ocean. The flux decreases to 2 × 10−3 to 6 × 10−2 μmol iron m−2 d−1, whilst they are foraging. Our study finds that penguins redistribute a large flux of iron onto their colonies, which may enter the adjacent water through sea ice melt and facilitated through katabatic winds. Despite their high abundance in Prydz Bay, the contribution of penguins to iron flux during their foraging periods is minor, due to the enormous foraging range being covered. Further research into the bioavailability of iron by marine organisms coupled with parallel measurements of seawater iron concentration and phytoplankton uptake experiments will be invaluable in refining iron budgets in both this region and other hotspots along the Antarctic coast where higher trophic-level animals are abundant.

Gross Primary Production of Antarctic Landfast Sea Ice: A Model‐Based Estimate

AbstractMuch of the Antarctic coast is covered by seasonal landfast sea ice (fast ice), which serves as an important habitat for ice algae. Fast‐ice algae provide a key early season food source for pelagic and benthic food webs, and contribute to biogeochemical cycling in Antarctic coastal ecosystems. Summertime fast ice is undergoing a decline, leading to more seasonal fast ice with unknown impacts on interconnected Earth system processes. Our understanding of the spatiotemporal variability of Antarctic fast ice, and its impact on polar ecosystems is currently limited. Evaluating the overall productivity of fast‐ice algae has historically been hampered by limitations in observations and models. By linking new fast‐ice extent maps with a one‐dimensional sea‐ice biogeochemical model, we provide the first estimate of the spatio‐seasonal variability of Antarctic fast‐ice algal gross primary production (GPP) and its annual primary production on a circum‐Antarctic scale. Experiments conducted for the 2005–2006 season provide a mean fast ice‐algal production estimate of 2.8 Tg C/y. This estimate represents about 12% of overall Southern Ocean sea‐ice algae production (estimated in a previous study), with the mean fast‐ice algal production per area being 3.3 times higher than that of pack ice. Our Antarctic fast‐ice GPP estimates are probably underestimated in the Ross Sea and Weddell Sea sectors because the sub‐ice platelet layer habitats and their high biomass are not considered.

Coastal Sea Ice Concentration Derived from Marine Radar Images: A Case Study from Utqiaġvik, Alaska

We apply the Canny edge algorithm to imagery from the Utqiaġvik coastal sea ice radar system (CSIRS) to identify regions of open water and sea ice and quantify ice concentration. The radar-derived sea ice concentration (SIC) is compared against the (closest to the radar field of view) 25 km resolution NSIDC Climate Data Record (CDR) and the 1 km merged MODIS-AMSR2 sea ice concentrations within the ∼11 km field of view for the year 2022–2023, when improved image contrast was first implemented. The algorithm was first optimized using sea ice concentration from 14 different images and 10 ice analysts (140 analyses in total) covering a range of ice conditions with landfast ice, drifting ice, and open water. The algorithm is also validated quantitatively against high-resolution MODIS-Terra in the visible range. Results show a correlation coefficient and mean bias error between the optimized algorithm, the CDR and MODIS-AMSR2 daily SIC of 0.18 and 0.54, and ∼−1.0 and 0.7%, respectively, with an averaged inter-analyst error of ±3%. In general, the CDR captures the melt period correctly and overestimates the SIC during the winter and freeze-up period, while the merged MODIS-AMSR2 better captures the punctual break-out events in winter, including those during the freeze-up events (reduction in SIC). Remnant issues with the detection algorithm include the false detection of sea ice in the presence of fog or precipitation (up to 20%), quantified from the summer reconstruction with known open water conditions. The proposed technique allows for the derivation of the SIC from CSIRS data at spatial and temporal scales that coincide with those at which coastal communities members interact with sea ice. Moreover, by measuring the SIC in nearshore waters adjacent to the shoreline, we can quantify the effect of land contamination that detracts from the usefulness of satellite-derived SIC for coastal communities.

Shore ice control on coastal geomorphic evolution in cold regions

Shore ice is a common feature on cold climate coasts, which are abundant in mid- and high-latitude regions, however it is understudied. Previous research has reported both beach protection and erosion as potential impacts from shore ice presence. Altered ice dynamics resulting from a changing climate are likely to intensify these impacts. To address this discrepancy and improve future coastal change predictions we conducted the first combined field, laboratory and modeling study of shore-ice processes and impacts. Beach and nearshore morphology mapping, experiments with a novel cryogenic wave tank, and 3D coastal evolution modeling revealed that shore ice protected the beach from storms, but scoured the nearshore at the ice edge and transported sediment offshore, likely past the depth of closure. This resulted in enhanced beach erosion during the ice-free and non-storm season, countering the protective benefit from the ice. This study indicates that shore ice plays an important and likely evolving role in geomorphic evolution along cold climate coasts.

Analysis of fast ice anomalies and their causes in 2023 in Prydz Bay, East Antarctica

In 2023, Antarctica experienced its lowest sea ice extent in the satellite era, with extreme polar events gaining widespread attention. Prydz Bay, where the Chinese Zhongshan Station is located, is the third largest embayment in Antarctica. Changes in sea ice, fast ice and polynyas directly affect local heat and mass exchanges between the ocean and atmosphere, as well as ecosystems and research activities. In 2023, substantial fast ice anomalies were observed in Prydz Bay: the extent of fast ice off Zhongshan Station (ZSFI) was anomalously low, while that within Barrier Bay (BaFI) was anomalously high. This study analysed the seasonal evolution and underlying main causes for the extreme conditions using ice charts, satellites and reanalysis data. From 2014 to 2022, the extent of ZSFI typically increased during the cold season, reaching a maximum of (9.41 ± 2.47) × 103 km2, whilst the Barrier Bay Polynya (BaP) persisted throughout this period. However, in 2023, ZSFI did not increase from June onwards, peaking at a maximum extent of only 5.49 × 103 km2, and the BaP closed in mid-winter, leading to the formation of extensive BaFI. Air temperature and wind speed continuously dropped in July, and these conditions persisted for approximately 1 month, leading to the closure of BaP. However, ZSFI did not expand further under these extreme meteorological conditions, indicating its independence from these factors. The limited expansion of ZSFI could be attributed to high ocean temperatures. Overall, this study provides valuable insights into the mechanisms driving extreme fast ice conditions.

Leaky Wave Modes and Edge Waves in Land-Fast Ice Split by Parallel Cracks

In this paper we consider flexural-gravity waves propagating in a layer of water of constant depth limited by a vertical wall simulating a straight coastline. The water surface is covered with an elastic ice sheet of constant thickness. The ice sheet is split by one or two straight cracks parallel to the coastline, simulating the structure of land-fast ice with a refrozen lead. Analytical solutions of hydrodynamic equations describing the interaction of flexural-gravity waves with the ice sheet and cracks have been constructed and studied. In this paper, the amplification of the amplitude of incident waves between the shoreline and cracks was described depending on the incident angle of the wave coming from offshore. The constructed solutions allow the existence of edge waves propagating along the coastline and attenuated offshore. The energy of edge waves is trapped between the coastline and ice cracks. The application of the constructed solutions to describe wave phenomena observed in the land-fast ice of the Arctic shelf of Alaska is discussed.

A unique warm–water oasis in the Siberian Arctic’s Chaun Bay sustained by hydrothermal groundwater discharge

Chaun Bay, located on the fringe of the East Siberian Sea, has been described since the mid-20th century to support a unique marine ecosystem that is atypical for the local Siberian Arctic. Here we use ship-board physical, biogeochemical and geological measurements taken in October 2020, along with hydrographic observations taken from land-fast ice in April 2023, to demonstrate that these warm-water biological communities are supported by hydrothermal submarine groundwater discharge that delivers heat, salinity, nutrients, and trace elements to the bay. We identify a cyclonic eddy that mixes the warm nutrient-rich groundwater with oxygen-rich surface water, resulting in a water mass within Chaun Bay that has similar physical and chemical properties to the highly productive waters of the North Pacific and Southern Chukchi Sea. The bay showed elevated concentrations of chlorophyll-a and zooplankton, and the abundance and species diversity of epibenthos significantly exceeded values observed elsewhere in the East Siberian Sea. The benthic communities contained a number of boreal species that are not typically found in the Arctic Ocean. We also observed Thysanoessa krill populations, a pelagic species generally considered an expatriate in Arctic waters.

Modeling pan-Arctic seasonal and interannual landfast sea ice thickness and snow depth between 1979 and 2021

ABSTRACT Landfast sea ice (LFSI) is sensitive to local climate change, making it an important component of the cryosphere system. In this study, the LFSI around the pan-Arctic domain was simulated from 1979 to 2021 using a well-validated snow and ice thermodynamic model (HIGHTSI) under the framework of the Fast Ice Prediction System (FIPS), forced by the ERA5 reanalysis. The simulation results agree well with the in-situ observations in the Canadian Arctic, with a mean error of −0.06 ± 0.29 m for ice thickness and −0.04 ± 0.12 m for snow depth. A decrease of −2.8 ± 0.4 cm/10a in thickness and −16.2 ± 1.5 km3/a in volume for the Arctic LFSI was modeled during this period. There was significant spatial variability among the different domains, with the fastest decline found in the Vilkitsky Strait. The modeled snow depth shows large interannual and spatial variations, which was confirmed by other modeling results. The spatiotemporal variations in both air temperature and precipitation are the driving factors for the multi-decadal variations in LFSI thickness. The decreasing air temperature during the 2010s aligned with a slower thickness decrease and a slight volume increase for LFSI, which agreed with the pan-Arctic sea ice pattern.

Factors influencing haulout behaviour of non-breeding weddell seals (Leptonychotes weddellii) at Cape Royds, Antarctica

The Weddell seal (Leptonychotes weddellii) is a fast-ice obligate species that plays an important role as both predator and prey within the high-latitude, coastal Southern Ocean. Weddell seals are affected by pressures of marine resource extraction and variation in sea-ice extent and characteristics that are affected by climate. Thus, monitoring their population dynamics provides an indicator of the effectiveness of fisheries management, and impacts of changing climate in the high latitude Southern Ocean ecosystem. Satellite imagery is increasingly being used to monitor the populations of this species, but assessment techniques require a better understanding of the environmental factors influencing the likelihood that individuals will be on the sea-ice and therefore visible in a satellite image. Addressing that goal, we captured 5054 trail camera photos during spring 2017 in the 24-h light at Cape Royds, Antarctica, and then counted seals on the fast ice every 30 min over 59 days. Using a generalised additive model (63% deviance explained) we described the haulout behaviour of non-breeding Weddell seals according to time of day, date, air temperature, pressure, solar radiation, and wind speed. We found that the seals’ haulout cycle is driven to a significant degree by weather variables, primarily temperature and wind speed. Quantifying these haulout patterns can be used to determine the time of day, and under what conditions, that most seals are hauled out. Integrating environmental parameters to correct time-of-day patterns would allow better cross-site abundance comparisons, leading to better Weddell seal population estimates for the Ross Sea region and the wider coastal Antarctica.

Cumulative Changes in Minimum Snow/Ice Extent over Canada and Northern USA for 2000–2023

The Minimum Snow/Ice (MSI) extent is an important climate and environmental indicator related to surface hydrology and freshwater resources. Variations in the MSI extent over the four first-order regions (1-4) included in the Randolph Glacier Inventory (RGI) for Canada and the Northern USA were analyzed in this study using an improved land-water mask to better discriminate landfast ice in the high Arctic coastal zone. The analysis utilized warm season snow/ice probability maps derived from MODIS clear-sky composite imagery at a 250-m spatial resolution. Results showed statistically significant declining trends in the minimum snow/ice extent with the average value of the slope for the entire area (-1,177.7 ± 362.8) km2/yr. The variations in MSI extent are well correlated with surface air temperature. The correlation coefficients are statistically significant, ranging from −0.79 to −0.82. The detailed analysis revealed a reduction of the area with snow/ice probability 100% over the RGI glaciated zones, while areas with lower probability values were increasing in size, which may be interpreted as an indication of general glacier shrinkage over the study area.

Stable isotopes of landfast sea ice as a record of La Grande River under-ice plume dispersal

Vertical profiles of salinity, and isotopic abundance ratios of hydrogen (δ2H) and oxygen (δ18O) of 18 landfast ice cores, collected along the northeast coast of James Bay in March 2019, and one ice core collected in Belcher Islands, were used to obtain the winter timeseries of the spatiotemporal evolution of the under-ice plume of La Grande River (LGR), the dominant river in the area. Variability in the isotopic composition and salinity of the ice cores indicated changes to the water source composition at the ice–water interface when the ice layers formed. The increased presence of river water beneath the ice during January–March was marked by more negative isotopic ratios in the lower portion of the ice as river discharge was increased for hydroelectric production. River water was the source of ∼43% of the ice in our ice core samples ( n = 320) with the interquartile range from 16% to 71%. The river water fractions incorporated into the ice indicate that LGR under-ice plume extended more than 75 km north and at least 30 km south of the river mouth for ∼3 months. These findings correspond well with more challenging to obtain hydrographic observations. End-of-winter ice core sampling and analysis for isotopic abundance has potential as a tool to monitor dispersal of LGR discharge into the ice-covered coastal environment.

Seasonal environmental transitions and metabolic plasticity in a sea-ice alga from an individual cell perspective

Sea-ice microalgae are a key source of energy and nutrient supply to polar marine food webs, particularly during spring, prior to open-water phytoplankton blooms. The nutritional quality of microalgae as a food source depends on their biomolecular (lipid:protein:carbohydrate) composition. In this study, we used synchrotron-based Fourier transform infra-red microspectroscopy (s-FTIR) to measure the biomolecular content of a dominant sea-ice taxa, Nitzschia frigida, from natural land-fast ice communities throughout the Arctic spring season. Repeated sampling over six weeks from an inner (relatively stable) and an outer (relatively dynamic) fjord site revealed high intra-specific variability in biomolecular content, elucidating the plasticity of N. frigida to adjust to the dynamic sea ice and water conditions. Environmental triggers indicating the end of productivity in the ice and onset of ice melt, including nitrogen limitation and increased water temperature, drove an increase in lipid and fatty acids stores, and a decline in protein and carbohydrate content. In the context of climate change and the predicted Atlantification of the Arctic, dynamic mixing and abrupt warmer water advection could truncate these important end-of-season environmental shifts, causing the algae to be released from the ice prior to adequate lipid storage, influencing carbon transfer through the polar marine system.

The effects of beach energy on sediment entrainment within the nearshore ice complex

Shore ice forms along beaches in cold climates and during its formation is capable of entraining sediment from the nearshore. Upon breakup, entrained sediment within the ice can be rafted to deeper waters, melt out and lost to the nearshore sediment budget. Previous studies have hypothesized that this sediment rafting could be a principal source of sediment loss from the nearshore sediment budget. However, fundamental questions remain about the primary mechanisms for entraining sediment within the ice, particularly differences between high and low energy beaches. In this study we collected a series of sixty-four ice cores from five different beaches along the Laurentian Great Lakes that spanned low to high energy regimes. These ice cores were analyzed for ice structure, sediment structure and entrained sediment mass. We found that low energy beaches primarily entrained sediment within the icefoot as the ice directly adhered sediments to its base. Conversely high energy beaches primarily entrained sediment when sediment laden water was washed atop the ice through wave action and subsequently incorporated into the ice structure. Overall, for a range of high energy beaches we find that in floating ice, sediment makes up approximately 1% of the total weight, which is nearly an order of magnitude greater than in low energy beaches (e.g., 0.1%). These findings provide a general description of the most important processes for sediment entrainment within nearshore ice for both high and low energy beaches, motivating a 1% approximation for estimating sediment budgets associated with shore ice.

Reconstructing dynamics of the Baltic Ice Stream Complex during deglaciation of the Last Scandinavian Ice Sheet

Abstract. Landforms left behind by the last Scandinavian Ice Sheet (SIS) offer an opportunity to investigate controls governing ice sheet dynamics. Terrestrial sectors of the ice sheet have received considerable attention from landform and stratigraphic investigations. In contrast, despite its geographical importance, the Baltic Sea remains poorly constrained due to limitations in bathymetric data. Both ice-sheet-scale investigations and regional studies at the southern periphery of the SIS have considered the Baltic depression to be a preferential route for ice flux towards the southern ice margin throughout the last glaciation. During the deglaciation the Baltic depression hosted the extensive Baltic Ice Lake, which likely exerted a considerable control on ice dynamics. Here we investigate the Baltic depression using newly available bathymetric data and peripheral topographic data. These data reveal an extensive landform suite stretching from Denmark in the west to Estonia in the east and from the southern European coast to the Åland Sea, comprising an area of 0.3 million km2. We use these landforms to reconstruct aspects of the ice dynamic history of the Baltic sector of the ice sheet. Landform evidence indicates a complex retreat pattern that changes from lobate ice margins with splaying lineations to parallel mega-scale glacial lineations (MSGLs) in the deeper depressions of the Baltic Basin. Ice margin still-stands on underlying geological structures indicate the likely importance of pinning points during deglaciation, resulting in a stepped retreat signal. Over the span of the study area we identify broad changes in the ice flow direction, ranging from SE–NW to N–S and then to NW–SE. MSGLs reveal distinct corridors of fast ice flow (ice streams) with widths of 30 km and up to 95 km in places, rather than the often-interpreted Baltic-wide (300 km) accelerated ice flow zone. These smaller ice streams are interpreted as having operated close behind the ice margin during late stages of deglaciation. Where previous ice-sheet-scale investigations inferred a single ice source, our mapping identifies flow and ice margin geometries from both Swedish and northern Bothnian sources. We anticipate that our landform mapping and interpretations may be used as a framework for more detailed empirical studies by identifying targets to acquire high-resolution bathymetry and sediment cores and also for comparison with numerical ice sheet modelling.

Advanced Sea Ice Modeling for Short-Term Forecasting for Alaska’s Coasts

Abstract In Alaska’s coastal environment, accurate information of sea ice conditions is desired by operational forecasters, emergency managers, and responders. Complicated interactions among atmosphere, waves, ocean circulation, and sea ice collectively impact the ice conditions, intensity of storm surges, and flooding, making accurate predictions challenging. A collaborative work to build the Alaska Coastal Ocean Forecast System established an integrated storm surge, wave, and sea ice model system for the coasts of Alaska, where the verified model components are linked using the Earth System Modeling Framework and the National Unified Operational Prediction Capability. We present the verification of the sea ice model component based on the Los Alamos Sea Ice Model, version 6. The regional, high-resolution (3 km) configuration of the model was forced by operational atmospheric and ocean model outputs. Extensive numerical experiments were conducted from December 2018 to August 2020 to verify the model’s capability to represent detailed nearshore and offshore sea ice behavior, including landfast ice, ice thickness, and evolution of air–ice drag coefficient. Comparisons of the hindcast simulations with the observations of ice extent presented the model’s comparable performance with the Global Ocean Forecast System 3.1 (GOFS3.1). The model’s skill in reproducing landfast ice area significantly outperformed GOFS3.1. Comparison of the modeled sea ice freeboard with the Ice, Cloud, and Land Elevation Satellite-2 product showed a mean bias of −4.6 cm. Daily 5-day forecast simulations for October 2020–August 2021 presented the model’s promising performance for future implementation in the coupled model system. Significance Statement Accurate sea ice information along Alaska’s coasts is desired by the communities for preparedness of hazardous events, such as storm surges and flooding. However, such information, in particular predicted conditions, remains to be a gap. This study presents the verification of the state-of-art sea ice model for Alaska’s coasts for future use in the more comprehensive coupled model system where ocean circulation, wave, and sea ice models are integrated. The model demonstrates comparable performance with the existing operational ocean–ice coupled model product in reproducing overall sea ice extent and significantly outperformed it in reproducing landfast ice cover. Comparison with the novel satellite product presented the model’s ability to capture sea ice freeboard in the stable ice season.

Trajectory of increased iceberg kill-off in West Antarctica’s shallows

Compared with low latitude coasts, many polar latitudes are still little impacted by intense and direct anthropogenic stressors. Climate forcing is now bringing rapid physical change to nearshore polar realms. In the shallow coastal waters adjacent to the United Kingdom's Rothera Research Station in the West Antarctic Peninsula (WAP), 225 seabed markers at 5-25 m depth have been surveyed and replaced every year from 2002-2023 (75 markers at each of 5, 10 and 25 m). This is one of the longest continuously running marine disturbance experiments in the world, in one of Earth's fastest changing environments. Different categories of sea ice are recorded (including when the sea surface freezes into fast ice) at Rothera since the 1980s, and losses of marine ice in both polar regions are one of the striking responses to a warming planet1. Five to ten years of seabed marker hit rate data (marker broken or moved) showed that reduced sea ice cover is correlated with disturbance and mortality on the seabed2,3.

A Fast Overcurrent Protection IC for SiC MOSFET Based on Current Detection

A Fast Overcurrent Protection IC for SiC MOSFET Based on Current Detection

The sudden ocean warming and its potential influences on early-frozen landfast ice in the Prydz Bay, East Antarctica

The sudden ocean warming and its potential influences on early-frozen landfast ice in the Prydz Bay, East Antarctica

Transient subglacial water routing efficiency modulates ice velocities prior to surge termination on Sít’ Kusá, Alaska

Abstract Glacier surges are opportunities to study large amplitude changes in ice velocities and accompanying links to subglacial hydrology. Although the surge phase is generally explained as a disruption in the glacier's ability to drain water from the bed, the extent and duration of this disruption remain difficult to observe. Here we present a combination of in situ and remotely sensed observations of subglacial water discharge and evacuation during the latter half of an active surge and subsequent quiescent period. Our data reveal intermittently efficient subglacial drainage prior to surge termination, showing that glacier surges can persist in the presence of channel-like subglacial drainage and that successive changes in subglacial drainage efficiency can modulate active phase ice dynamics at timescales shorter than the surge cycle. Our observations favor an explanation of fast ice flow sustained through an out-of-equilibrium drainage system and a basal water surplus rather than binary switching between states in drainage efficiency.