Search Results (55)

Wintertime extratropical cyclones frequently traverse the Kuroshio–Oyashio Extension frontal system. However, their net impacts on synoptic sea-surface temperature (SST) variability and mixed-layer structure remain uncertain in the presence of strong fronts and intrinsic ocean variability. Using reanalysis data, we classify extreme events into cyclone cold-sector and warm-sector types based on synoptic air–sea flux anomalies. With ensembles of single-column model experiments, we decompose the upper-ocean response into surface heat-flux forcing, wind-driven mechanical mixing, Ekman temperature advection, wave-breaking mixing, and freshwater effects. Cold-sector events amplify synoptic SST variability and deepen the mixed layer, whereas warm-sector events suppress SST variability and shoal the mixed layer. Surface heat flux is the primary driver of both responses. Ekman advection provides crucial modulation within the frontal zone. Wave-breaking mixing generally damps temperature perturbations. Freshwater forcing exerts a pronounced regional influence southeast of the subarctic front. The combined effects yield an asymmetric spatial fingerprint on SST variability and mixed-layer depth across the frontal system. Comparison between forced variability and total reanalysis variability indicates that within the frontal zone, atmospheric impacts can be redistributed or partly offset by intrinsic ocean processes, while outside the frontal zone, the behavior is closer to an externally forced response. Full article

Wood and coal cofiring holds great potential for reducing greenhouse gas emissions from grate-fired combustion systems, as well as being widely technically feasible. This research was among the first to evaluate CO and NO_x levels within grate-fired cofiring at small utility scales. We evaluated two wood fuel types—high-quality aspen chips and lower-quality pellet mill residues. Each wood fuel was evaluated at two cofiring rates. Over 6 days of testing, CO contents ranged from 40 to 620 ppm, and NO_x contents ranged from 82 to 145 ppm. We found statistically significant differences in CO content when comparing low versus high cofiring rates, with high cofiring having greater CO concentrations. Relatively high CO emissions were attributed to greater moisture within the combustion chamber at higher levels of wood. Combustion efficiency versus cofiring rate was generally modeled the best as a quadratic relationship; carbon monoxide content versus cofiring rate was best modeled linearly. There were very few changes in combustion efficiency, fuel handing, or plant operation at the utility scale when cofiring at up to 15 percent of the energy value (versus no cofiring). From an operational standpoint, cofiring was relatively easy to implement and well received by plant managers. Full article

The transition toward sustainable energy in Arctic and subarctic regions requires innovative approaches that account for both the unique geographical conditions and the economic and policy challenges associated with isolated power systems. This study examines how net energy metering (NEM) and net billing schemes influence distributed solar photovoltaic (PV) adoption and financial performance among utilities in Alaska’s Railbelt. The Railbelt, which supplies power to three-quarters of the state’s population, remains heavily reliant on natural gas and exhibits limited renewable penetration compared to other arctic regions. Using a stochastic risk-based modeling framework with Monte Carlo simulations and the Bass diffusion model, the analysis estimates the 15-year financial impacts of different NEM adoption scenarios on utilities. Results show that while NEM drives PV adoption through higher compensation for exported generation, it also increases potential revenue losses for utilities compared to net billing. Policy innovations like those introduced in Alaska’s House Bill 164 (HB 164), which establishes a reimbursement fund to mitigate utility revenue losses, indicate that regulatory work is being designed to balance distributed generation incentives with economic sustainability. This work provides a baseline for understanding how a policy framework influences both utility and consumer economics in terms of NEM and solar PV adoption in Arctic and subarctic systems. Full article

The future of marine sustainability depends on public understanding and trust in the policy recommendations that emerge from scientific research. For common pool marine resource decisions made by the people who depend on these resources for their food, employment, and economic future, understanding the current status of these marine systems and change is essential to ensure these resources will persist into the future. As such, the informal learning infrastructure is essential to increasing marine science literacy in a changing world. This mixed-methods research study analyzed the distribution and accessibility of marine science education and research across Alaska’s five geographic regions. Using the PRISMA framework, we synthesized data from 198 institutions and analyzed peer-reviewed literature on marine ecosystems to identify geographic and thematic gaps in access to informal science learning and research focus. In parallel, we undertook geospatial analysis and resource availability to describe the distribution of resources, types of informal learning infrastructure present across the state, regional presence, and resources to support informal marine science learning opportunities. Findings from this multifactor research revealed a concentration of resources in urban hubs and a lack of consistent access to learning resources for rural and Indigenous communities. The configurative literature review of 9549 publications identified topical underrepresentation of the Bering Sea and Aleutian Islands, as well as a lack of research on seabirds across all regions. Considered together, these results recommend targeted investments in rural engagement with marine science programming, culturally grounded partnerships, and research diversification. This review concludes that disparities in learning resource support and government-funded priorities in marine wildlife research have created conditions that undermine the local people’s participation in the sustainability of sensitive resources and are likely exacerbating declines driven by rapid change in Arctic and sub-Arctic waters. Full article

Electricity in rural Alaska is provided by more than 200 standalone microgrid systems powered predominantly by diesel generators. Incorporating renewable energy generation and storage to these systems can reduce their reliance on costly imported fuel and improve sustainability; however, uncertainty remains about optimal grid architectures to minimize cost, including how and when to incorporate long-duration energy storage. This study implements a novel, multi-pronged approach to assess the techno-economic feasibility of future energy pathways in the community of Kotzebue, which has already successfully deployed solar photovoltaics, wind turbines, and battery storage systems. Using real community load, resource, and generation data, we develop a series of comparison models using the HOMER Pro software tool to evaluate microgrid architectures to meet over 90% of the annual community electricity demand with renewable generation, considering both battery and hydrogen energy storage. We find that near-term planned capacity expansions in the community could enable over 50% renewable generation and reduce the total cost of energy. Additional build-outs to reach 75% renewable generation are shown to be competitive with current costs, but further capacity expansion is not currently economical. We additionally include a cost sensitivity analysis and a storage capacity sizing assessment that suggest hydrogen storage may be economically viable if battery costs increase, but large-scale seasonal storage via hydrogen is currently unlikely to be cost-effective nor practical for the region considered. While these findings are based on data and community priorities in Kotzebue, we expect this approach to be relevant to many communities in the Arctic and Sub-Arctic regions working to improve energy reliability, sustainability, and security. Full article

Energy transition is a challenge for remote northern communities mainly relying on diesel for electricity generation and space heating. Solar-assisted ground-coupled heat pump (SAGCHP) systems represent an alternative that was investigated in this study for the Kuujjuaq Forum, a multi-activity facility in Nunavik, Canada. The energy requirements of community buildings facing a subarctic climate are poorly known. Based on energy bills, technical documents, and site visits, this study provided an opportunity to better document the energy consumption of such building, especially considering the recent solar photovoltaic (PV) system installed on part of the roof. A comprehensive model was developed to analyze the building’s heating demand and simulate the performance of a ground-source heat pump (GSHP) coupled with PV panels. The air preheating load, accounting for 268,200 kWh and 47% of the total heating demand, was identified as an interesting and realistic load that could be met by SAGCHP. The GSHP system would require a total length of at least 8000 m, with boreholes at depths between 170 and 200 m to meet this demand. Additional PV panels covering the entire roof could supply 30% of the heat pump’s annual energy demand on average, with seasonal variations from 22% in winter to 53% in spring. Economic and environmental analysis suggest potential annual savings of CAD 164,960 and 176.7 tCO₂eq emissions reduction, including benefits from exporting solar energy surplus to the local grid. This study provides valuable insights on non-residential building energy consumption in subarctic conditions and demonstrates the technical viability of SAGCHP systems for large-scale applications in remote communities. Full article

Highly conserved among eukaryotes, the chemical defensome protects organisms against chemical stressors and helps to reestablish the altered homeostatic state. The defensome includes genes such as transporters (e.g., adenosine triphosphate ATP-binding cassette), phase I and phase II detoxification enzymes, and antioxidant enzymes. During their life cycle, planktonic copepods, the most abundant and ubiquitous metazoans on Earth, are exposed to many environmental stressors that impair their survival and fitness. Here, using high-quality publicly available transcriptomic data, defensome genes were searched in copepods belonging to different orders and living in different environments (e.g., Antarctic, Subarctic, Mediterranean). Gene expression responses were investigated in four calanoids exposed to different stresses to identify a common and species-specific detoxification system. Our results confirm that the defensome is highly conserved among copepods but also report differences in the relative contribution of genes among species living in different habitats, suggesting a fitness adaptation to environmental pressures. The genes provided here can be used as biomarkers of chemical defense and can also be tested in other planktonic organisms to assess the “health” of marine organisms, which is useful for understanding environmental adaptations and they can be used to assess changes and make predictions at the population and community levels. Full article

Fires significantly influence the ecosystems of Western Siberia’s forest–tundra zone. Namely, they alter soil processes, including the transformation of different forms of iron and the redistribution of carbon flows. Recent climate change, associated with increased fire frequency, has had a long-term effect on the Arctic and sub-Arctic soil systems. Iron plays a key role in stabilizing organic carbon through the sorption and coagulation processes, yet the long-term changes in iron’s fractional composition under post-fire conditions remain insufficiently studied. This research investigates the impact of natural fires on the transformation of iron forms (amorphous, crystalline, and mobile), as well as on the dynamics of organic carbon in soils within the northern boundary of the forest–tundra natural zone in Western Siberia, between the Pur and Taz rivers. In our study, we have relied on granulometric and chemical analyses, magnetic susceptibility measurements, and iron fraction extractions. Our findings reveal that in post-fire areas, the depth of the seasonally thawed layer increases, accompanied by changes in the thermal and water regimes. This leads to reduced organic carbon content, particularly in intermediate horizons (5–30 cm), and the transformation of amorphous iron into a crystalline form. Crystallization growth is confirmed by increased magnetic susceptibility. Our results highlight the dual role of iron compounds: they contribute to the long-term stabilization of organic carbon, as well as causing its accelerated mineralization by affecting redox conditions. This study is crucial for understanding the biogeochemical processes associated with climate change and increasing fire frequency. Full article

The Tibetan Plateau (TP) is the largest glacier reserve outside the Antarctic and Arctic regions. Climate warming has affected the reserve of freshwater resources and led to frequent glacier disasters. However, due to its extreme environment of hypoxia and low pressure, it is extremely difficult to obtain data. Compared with other traditional monitoring methods such as makers and satellite remote sensing technology, Ground-Based (GB) radar systems have the advantages of convenient carrying and installation, sub-second level sampling, and sub-millimeter measurement accuracy. They can be used as an effective way to study the short-term rapid movement changes in glaciers. Based on a self-built GB radar system, monitoring experiments were conducted on two glacier termini on the TP. The movement speed of the Rongbuk glacier terminus on Mount Qomolangma was obtained through time-series interferometric measurement as 4.10 cm/day. When the altitude was about 5200 m, the glacier movement speed was 7.74 cm/day, indicating the spatial differences with altitude changes. And in another region, the movement speed of the Yangbulake glacier terminus on Mount Muztag Ata was 198.96 cm/day, indicating significant changes in glacier movement. The cross-validation of Sentinel-1 data during the same period proved the effectiveness of GB radar system interferometry in measuring glacier movement speed and also provided field validation data for remote sensing inversion. Full article

Modern climatic changes have an impact on the bearing capacity of permafrost soils at the base of the foundations of buildings and structures in the urbanized territories of the Arctic and Subarctic. The activation of cryogenic processes leads to the destruction of infrastructure and to social, economic, and environmental consequences for the population. Based on the results for the geothermy of frozen and thawing soil, and on the georadar profiling of the city of Anadyr, it was concluded that the main risks of permafrost degradation are associated with the spread of hydrogenic melting zones. Maps of the soil temperature in imaginary cross-sections with depths of 3, 5, and 10 m were compiled, along with maps of the capacity of thawing soils, the permafrost aquifer, and the dangerous spread zones for exogenous cryogenic processes. The total area of talik zones with a depth of 6 m or more in the urban area was 2.34 km², or 67% of the built-up area. The system of permafrost monitoring in the territory of Anadyr was substantiated, and is based on monitoring the boundaries of talik zones. It consists of an automated network of observations of the ground temperature in 35 wells at the boundary and in the center of 20 zones of the dangerous development of exogenous cryogenic processes, as well as 12 control GPR profiles at the intersection of linear hydrogenic taliks. Full article

The aim of this paper is to assess the correlation of groundwater level changes (or groundwater level anomalies (GWLA)) obtained from direct measurements in wells with groundwater storage anomalies (GWSA) calculated using Gravity Recovery and Climate Experiment (GRACE) products and Global Land Data Assimilation Systems (GLDAS) models across different climate zones, from temperate Poland to Arctic Sweden. We recognize that such validation studies are needed to increase the understanding of the spatio-temporal limits of remote sensing model applicability, not least in data-scarce sub-Arctic and Arctic environments where processes are complex due to the impacts of snow and (perma) frost. Results for temperate climates in Poland and southern Sweden show that, whereas one of the models (JPL_NOAH_GWSA) failed due to water balance term overestimation, the other model (CSR_CLM_GWSA) produced excellent results of monthly groundwater dynamics when compared with the observations in 387 groundwater wells in the region during 2003–2022 (cross-correlation coefficient of 0.8). However, for the sub-Arctic and Arctic northern Sweden, the model suitable for other regions failed to reproduce typical northern groundwater regimes (of the region’s 85 wells), where winter levels decrease due to the blocking effect of ground frost on groundwater recharge. This suggests, more generally, that conventional methods for deriving GWSA and its seasonality ceases to be reliable in the presence of considerably infiltration-blocking ground frost and permafrost (whereas snow storage modules perform well), which hence need further attention in future research. Regarding long-term groundwater level trends, remote sensing results for southern Sweden show increasing levels, in contrast with observed unchanged to decreasing (~10 mm/a) levels, which may not necessarily be due to errors in the remote sensing model but may rather emphasize impacts of anthropogenic pressures, which are higher near the observation wells that are often located in eskers used for water supply. For sub-Arctic and Arctic Sweden, the (relatively uncertain) trend of the remote sensing results nevertheless agrees reasonably well with the groundwater well observations that show increasing groundwater levels of up to ~14 mm/a, which, e.g., is consistent with reported trends of large Siberian river basins. Full article

This study presents a high-resolution record of δ¹⁵N_sed, which serves as a proxy for water column denitrification and oxygen minimum zone (OMZ) intensity, from the Soledad Basin in the Eastern Tropical North Pacific OMZ. The Soledad Basin δ¹⁵N_sed record is compared to the Pescadero Slope and Santa Barbara Basin (SBB) δ¹⁵N_sed records to gain insight into regional variations in the ETNP OMZ. During the Medieval Climate Anomaly (MCA; 950–1250 CE), Soledad Basin, Pescadero Slope, and SBB records exhibit coherent trends suggesting that there was general water column oxygenation stability. During the Little Ice Age (LIA; 1350–1850 CE), Soledad Basin and SBB showed a similar decreasing trend in δ¹⁵N_sed values while the Pescadero Slope δ¹⁵N_sed exhibited an increasing trend until values abruptly declined between 1740 and 1840 CE. We suggest that increased δ¹⁵N_sed variability and the different trends at the Pescadero Slope during the LIA are due to the influence of the North American monsoon (NAM), which can suppress upwelling when enhanced and result in OMZ contraction. The decoupling between the Soledad Basin, SBB, and the Pescadero Slope could also be due to the increased influence of enriched ¹⁵NO₃⁻ subarctic waters in the California Current System. Since each site is influenced by local productivity, basin morphology, and regional atmospheric and ocean circulation patterns, we suggest that assessing OMZ fluctuations from multiple sites provides a more comprehensive view of regional OMZ dynamics in response to climate variations. Full article

Interest in more sustainable energy sources has increased rapidly in the maritime industry, and ambitious goals have been set for decreasing ship emissions. All industry stakeholders have reacted to this with different approaches including the optimisation of ship power plants, the development of new energy-improving sub-systems for existing solutions, or the design of entirely novel power plant concepts employing alternative fuels. This paper assesses the feasibility of different ship energy sources for an icebreaking Arctic research ship. To that end, possible energy sources are assessed based on fuel, infrastructure availability and operational endurance criteria in the operational area of interest. Promising alternatives are analysed further using the evidence-based Strengths, Weaknesses, Opportunities, and Threats (SWOT) method. Then, a more thorough investigation with respect to the required fuel tank space, life cycle cost, and CO₂ emissions is implemented. The results demonstrate that marine diesel oil (MDO) is currently still the most convenient solution due to the space, operational range, and endurance limitations, although it is possible to use liquefied natural gas (LNG) and methanol if the ship’s arrangement is radically redesigned, which will also lead to reduced emissions and life cycle costs. The use of liquefied hydrogen as the only energy solution for the considered vessel was excluded from the potential options due to low volumetric energy density, and high life cycle and capital costs. Even if it is used with MDO for the investigated ship, the reduction in CO₂ emissions will not be as significant as for LNG and methanol, at a much higher capital and lifecycle cost. The advantage of the proposed approach is that unrealistic alternatives are eliminated in a systematic manner before proceeding to detailed techno-economic analysis, facilitating the decision-making and investigation of various options in a more holistic manner. Full article

There has been a growth in the number of composite indicator tools used to assess community risk, vulnerability, and resilience, to assist study and policy planning. However, existing research shows that these composite indicators vary extensively in method, selected variables, aggregation methods, and sample size. The result is a plethora of qualitative and quantitative composite indices to choose from. Despite each providing valuable location-based information about specific communities and their qualities, the results of studies, each using disparate methods, cannot easily be integrated for use in decision making, given the different index attributes and study locations. Like many regions in the world, the Arctic is experiencing increased variability in temperatures as a direct consequence of a changing planetary climate. Cascading effects of changes in permafrost are poorly characterized, thus limiting response at multiple scales. We offer that by considering the spatial interaction between the effects of permafrost, infrastructure, and diverse patterns of community characteristics, existing research using different composite indices and frameworks can be augmented. We used a system-science and place-based knowledge approach that accounts for sub-system and cascade impacts through a proximity model of spatial interaction. An estimated ‘permafrost vulnerability surface’ was calculated across Alaska using two existing indices: relevant infrastructure and permafrost extent. The value of this surface in 186 communities and 30 military facilities was extracted and ordered to match the numerical rankings of the Denali Commission in their assessment of permafrost threat, allowing accurate comparison between the permafrost threat ranks and the PVI rankings. The methods behind the PVI provide a tool that can incorporate multiple risk, resilience, and vulnerability indices to aid adaptation planning, especially where large-scale studies with good geographic sample distribution using the same criteria and methods do not exist. Full article

The East Siberian Sea (ESS) is a large and the shallowest part of the Arctic Ocean. It is characterized by high biogeochemical activity, but the seawater carbonate system remains understudied, especially during the late autumn season. Data from the research vessel (RV) “Professor Multanovsky” cruise were used to assess the dynamics of the seawater carbonate system, air–sea CO₂ fluxes, and the calcium carbonate corrosive waters in the two biogeochemical provinces of the ESS shortly before freeze-up. The ESS waters were mainly a sink for atmospheric CO₂ due to the limited dispersion of river waters, autumn water cooling, and phytoplankton blooms in its eastern autotrophic province. The mean value of the CO₂ air–sea flux was 11.2 mmol m⁻² day⁻¹. The rate of CO₂ uptake in the eastern ESS was an order of magnitude larger than that in the western ESS. The specific waters and ice cover dynamics determined intensive photosynthesis processes identified on the eastern shelf and in the northern deep oligotrophic waters. A part of the surface and most of the bottom ESS waters were corrosive with respect to calcium carbonate, with the lowest saturation state of aragonite (0.22) in the bottom layer of the eastern ESS. The eastern ESS was the main source of these waters into the deep basin. The observed export of corrosive shelf waters to the deep sea can have a potential impact on the ocean water ecosystem in the case of mixing with layers inhabited by calcifying organisms. Full article