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The spatial and temporal distributions of rain-on-snow (ROS) events across the Canadian Arctic Archipelago (CAA) remain poorly understood owing to their sporadic nature in time and space. This situation motivated the development of remote sensing detection algorithms. This paper uses a large meteorological dataset across the CAA to adapt an existing ROS-detection algorithm developed in a previous study by our group. Results highlight the spatial distribution and evolution of ROS occurrences reported since 1985 at 14 weather stations across the CAA. Results show that >600 ROS events were inventoried since 1985, for which >70% were classified as pure rain (liquid form) and 30% as mixed precipitation (solid/liquid). Of the pure rain events, 75% occurred during spring, 14% during fall, 8% during summer and <1% during winter. Such events can have significant impacts on ungulate grazing conditions through the creation of ice layers, causing serious problems for caribou calf survival, especially during the migration period. This paper introduces an adaptation for larger scale Arctic application of a detection algorithm (sensitivity analysis on the detection threshold) with an error of ~5%. The validation, however, remains limited due to a short study period and limited number of sites. [ABSTRACT FROM AUTHOR]

This paper introduces a series of articles assembled in a special issue that explore Holocene climate evolution, as recorded in lakes on the Island of Amsterdamøya on the westernmost fringe of the Arctic Svalbard archipelago. Due to its location near the interface of oceanic and atmospheric systems sourced from Arctic and Atlantic regions, Amsterdamøya is a key site for recording the terrestrial response to marine and atmospheric changes. We employed multi-proxy approaches on lake sediments, integrating physical, biogeochemical, and isotopic analyses to infer past changes in temperature, precipitation, and glacier activity. The results comprise a series of quantitative Holocene-length paleoclimate reconstructions that reveal different aspects of past climate change. Each of the four papers addresses various facets of the Holocene climate history of north-western Svalbard, including a reconstruction of the Annabreen glacier based on the sedimentology of the distal glacier-fed lake Gjøavatnet, a reconstruction of changing hydrologic conditions based on sedimentology and stratigraphy in Lake Hakluytvatnet, reconstruction of summer temperature based on alkenone paleothermometry from lakes Hakluytvatnet and Hajeren, and a hydrogen isotope-based hydrological reconstruction from lake Hakluytvatnet. We also present high-resolution paleomagnetic secular variation data from the same lake, which document important regional magnetic field variations and demonstrate the potential for use in synchronizing Holocene sedimentary records in the Arctic. The paleoclimate picture that emerges is one of early Holocene warmth from ca. 10.5 ka BP interrupted by transient cooling ca. 10-8ka BP, and followed by cooling that mostly manifested as two stepwise events ca. 7 and 4 ka BP. The past 4ka were characterized by dynamic glaciers and summer temperature fluctuations decoupled from the declining summer insolation. [ABSTRACT FROM AUTHOR]

The Canadian Arctic has been undergoing profound and damaging environmental changes in recent decades at an ever-accelerating rate. In addition to climate change, a wide variety of other factors are dramatically affecting water quality, biodiversity, land stability and ice reliability. These changes have a particularly negatively impact upon population health, local transportation, traditional knowledge, cultural identity, food supply and lifestyle of the Inuit. This paper examines the threats being imposed upon the Inuit in the Canadian Arctic and their capacity to respond directly through exercising opportunities available through recent land claim settlements and northern governments in which they play a dominant role. The paper then considers the limited capacity of the federal government to deal with northern environmental issues and the potential available through enforcing international environmental agreements and human rights. [ABSTRACT FROM AUTHOR]

The Canadian Arctic Archipelago is a vast region of approximately 1,420,000 km2, with a flora characterized by low species diversity, low endemicity, and little influence by alien species. New records of vascular plant species are documented here based on recent fieldwork on Victoria and Baffin Islands; additional records based on recent literature sources are mentioned. This paper serves as an update to the 2007 publication Flora of the Canadian Arctic Archipelago, and brings the total number of vascular plants for the region to 375 species and infraspecific taxa, an increase of 7.7%. Three families (Amaranthaceae, Juncaginaceae, Pteridaceae) and seven genera (Cherleria L., Cryptogramma R. Br., Platanthera Rich., Sabulina Rchb., Suaeda Forssk. ex J.F. Gmel., Triglochin L., Utricularia L.) are added to the flora, and one genus is deleted (Minuartia L.). Five species are first records for Nunavut (Arenaria longipedunculata Hultén, Cryptogramma stelleri (S.G. Gmel.) Prantl, Puccinellia banksiensis Consaul, Saxifraga eschscholtzii Sternb., Utricularia ochroleuca R.W. Hartm.). [ABSTRACT FROM AUTHOR]

The Canadian Arctic Archipelago (CAA) is a complex area formed by narrow straits and islands in the Arctic. It is an important pathway for freshwater and sea-ice transport from the Arctic Ocean to the Labrador Sea and ultimately to the Atlantic Ocean. The narrow straits are often crudely represented in coupled sea-ice-ocean models, leading to a misrepresentation of transports through these straits. Unstructured meshes are an alternative in modelling this complex region, since they are able to capture the complex geometry of the CAA. This provides higher resolution in the flow field and allows for more accurate transports (but not necessarily better modelling). In this paper, a finite element sea-ice model of the Arctic region is described and used to estimate the sea-ice fluxes through the CAA. The model is a dynamic-thermodynamic sea-ice model with elastic-viscous-plastic rheology and is coupled to a slab ocean, where the temperature and salinity are restored to climatology, with no velocities and surface elevation. The model is spun-up from 1973 to 1978 with NCEP/NARR reanalysis data. From 1979 to 2007, the model is forced by NCEP/DoE reanalysis data. The large scale sea-ice characteristics show good agreement with observations. The total sea-ice area agrees very well with observations and shows a sensitivity to the Arctic oscillation (AO). For 1998-2002, we find estimates for the sea-ice volume and area fluxes through Admunsen Gulf, McClure Strait and the Queen Elizabeth Islands that compare well with observation and are slightly better than estimates from other models. For Nares Strait, we find that the fluxes are much lower than observed, due to the missing effect of topographic steering on the atmospheric forcing fields. The 1979-2007 fluxes show large seasonal and interannual variability driven primarily by variability in the ice velocity field and a sensitivity to the AO and other large-scale atmospheric variability, which suggests that accurate atmospheric forcing might be crucial to modelling the CAA. [ABSTRACT FROM AUTHOR]

This paper provides ethnographic and historical evidence for the existence, in time and space, of a network of well-established trails connecting most Inuit settlements and significant places across the Canadian Arctic. The geographic and environmental knowledge relating to trails (and place names associated with the trails) has been orally transmitted through many generations of Inuit. I use historical documents, ethnographic research, and new geographic tools such as GPS, GIS and Google Earth, to show the geographic extent of the network and its historical continuity. I particularly draw on a trip following Inuit along a traditional trail connecting the communities of Iglulik and Naujaat (Repulse Bay). Inuit have made systematic use of the Arctic environment as a whole and trails are, and have been, significant channels of communication and exchange across the Arctic. There are some types of oral history and knowledge that can be accurately transmitted through generations, and I propose that some aspects of Inuit culture are better understood in terms of moving as a way of living. [ABSTRACT FROM AUTHOR]

Research on climate change impacts, vulnerability and adaptation, particularly projects aiming to contribute to practical adaptation initiatives, requires active involvement and collaboration with community members and local, regional and national organizations that use this research for policy-making. Arctic communities are already experiencing and adapting to environmental and socio-cultural changes, and researchers have a practical and ethical responsibility to engage with communities that are the focus of the research. This paper draws on the experiences of researchers working with communities across the Canadian Arctic, together with the expertise of Inuit organizations, Northern research institutes and community partners, to outline key considerations for effectively engaging Arctic communities in collaborative research. These considerations include: initiating early and ongoing communication with communities, and regional and national contacts; involving communities in research design and development; facilitating opportunities for local employment; and disseminating research findings. Examples of each consideration are drawn from climate change research conducted with communities in the Canadian Arctic. [ABSTRACT FROM AUTHOR]

The author presents a survey of writings on Nunavut since 1976.The paper focuses on a critical literature review of scholarly works centred on geopolitical boundaries and on Inuit collective identity in the Canadian Central and Eastern Arctic.The author proposes a theoretical model that outlines the interconnection between borders, symbols and collective identity.The model shows that Inuit collective identity is being redefined in Nunavut.It is argued that the land claims / self-government processes in Canada, aimed at creating large-scale political units such as Nunavut, are contributing to the re-construction of collective identity among Inuit groups. [ABSTRACT FROM AUTHOR]

Visibility studies in archaeology have been criticized because they tend to emphasize the importance of vision over other senses. The burgeoning field of sensory anthropology argues that the relative significance of visual, olfactory, acoustic and haptic (touch) senses varies cross-culturally, and is a function of how human beings interact with their particular environments. The Canadian Arctic is a unique sensory environment because prolonged periods of winter darkness make artificial light essential for everyday tasks. In this paper, we use 3D computer modelling to simulate the levels of light produced by the small stone lamps used inside pre-contact Thule Inuit winter dwellings. The results demonstrate that interior light levels fall well below those recommended by Western architectural standards for tasks requiring high levels of visual acuity. We conclude that this may have influenced where activities were situated inside the dwelling and encouraged greater use of touch relative to vision when performing tasks such as sewing and carving. [ABSTRACT FROM AUTHOR]

Observed reduction in recent sea ice areal extent and thickness has focused attention on the fact that the Arctic marine system appears to be responding to global-scale climate variability and change. Passive microwave remote-sensing data are the primary source underpinning these reports, yet problems remain in geophysical inversion of information on ice type and concentration. Uncertainty in sea-ice concentration (SIC) retrievals is highest in the summer and fall, when water occurs in liquid phase within the snow-sea-ice system. Of particular scientific interest is the timing and rate of new ice formation due to the control that this form of sea ice has on mass, energy and gas fluxes across the ocean-sea-ice-atmosphere interface. In this paper we examine the critical fall freeze-up period using in situ data from a ship-based and aerial survey programme known as the Canadian Arctic Shelf Exchange study combined with microwave and optical Earth observations data. Results show that: (1) the overall physical conditions observed from aerial survey photography were well matched with coincident moderate-resolution imaging spectroradiometer data and Radarsat ScanSAR imagery; (2) the shortwave albedo was linearly related to old ice concentration derived from survey photography; (3) the three SSM/I SIC algorithms (NASA Team (NT), NASA Team 2 (NT2), and Bootstrap (BT)) showed considerable discrepancies in pixel-scale comparison with the Radarsat ScanSAR SICs well calibrated by the aerial survey data. The major causes of the discrepancies are attributed to (1) the inherent inability to detect the new thin ice in the NT and BT algorithms, (2) mismatches of the thin-ice tie point of the NT2 algorithm, and (3) sub-pixel ambiguity between the thin ice and the mixture of open water and sea ice. These results suggest the need for finer resolution of passive microwave sensors, such as AMSR-E, to improve the precision of the SSM/I SIC algorithms in the marginal ice zone during early fall freeze-up. [ABSTRACT FROM AUTHOR]

Studies shifts in the subsistence economy of Paleoeskino groups in the Arctic Archipelago in the Northwest Territories. Characteristics of animal resource base; Paleoeskimo patterns of settlement and subsistence; Reliance on ringed seal populations at coastal sites; Implications of walrus hunting; Role of walrus hunting on development of Dorset cultural identity.

Discusses the harvesting of bowhead whales by prehistoric Thule eskimo villages located in the Canadian Arctic Archipelago. Impact of settlement position on volume of bowhead harvest; Bowhead migration patterns; Impact of settlement position on yearling and adult whale harvests.

Warming of the Arctic due to climate change means the Arctic Ocean is now ice-free for longer as sea ice melts earlier and refreezes later. It remains unclear how the extended ice-free period will impact carbon dioxide (CO2) fluxes due to scarcity of surface ocean CO2 measurements. Baseline measurements are urgently needed to understand how air−sea CO2 fluxes will spatially and temporally vary in a changing Arctic Ocean. It is uncertain whether the previous basin-wide surveys are representative of the many smaller bays and inlets that make up the Canadian Arctic Archipelago. By using a research vessel that is based in the remote Inuit community of Cambridge Bay (Ikaluqtuutiak, Nunavut), we have been able to reliably survey p CO2 shortly after ice melt and access previously unsampled bays and inlets in the nearby region. We present four years of consecutive summertime p CO2 measurements collected in the Kitikmeot Sea in the southern Canadian Arctic Archipelago. Overall, we found that this region is a sink for atmospheric CO2 in August (average of all calculated fluxes over the four cruises was -8.3 mmol m-2 d-1) but the magnitude of this sink varies substantially between years and locations (average calculated fluxes of 0.41, -7.70, -21.26 and -2.08 mmol m-2 d-1 during the 2016, 2017, 2018 and 2019 cruises respectively). Surface ocean p CO2 varied by up to 142 μatm between years; this highlights the importance of repeat observations in the Arctic as this high interannual variability would not have been captured by sparse and infrequent measurements. We find that the p CO2 value of the surface ocean at the time of ice melt is extremely important in constraining the magnitude of the air−sea flux throughout the ice-free season. Further constraining the flux in the Kitikmeot Sea will require a better understanding of how p CO2 changes outside of the summer season. Surface ocean p CO2 measurements made in the bays and inlets in the Kitikmeot Sea were ~20–40 μatm lower than in the main channels, and p CO2 measurements made close to ice breakup (i.e. within 2 weeks) were 50–100 μatm lower than measurements made >4 weeks after breakup. As basin-wide surveys of the CAA have focused on the deeper shipping channels and rarely measure close to the ice break-up date, we hypothesize that there may be an observational bias in previous studies, leading to an underestimate of the CO2 sink in the Canadian Arctic Archipelago. These high-resolution measurements constitute an important new baseline for gaining a better understanding of the role this region plays in the uptake of atmospheric CO2. [ABSTRACT FROM AUTHOR]

Abstract: The story of oil and gas exploration in the Arctic Islands of Canada and in the Sverdrup Basin of that region is largely the story of Panarctic Oils Limited. Panarctic was incorporated May 27, 1966 by Federal Letters Patent and operations started in 1968 with the first seismic work. J.C. Sproule of Calgary was a major force behind its formation. Panarctic was an industry/government consortium established to explore for oil and gas in the Canadian Arctic Islands, with up to 37 participating companies. Panarctic drilled 150 wells over an area measuring some 850 by 1200km. The most northerly well was located approximately 80°45′ N on Ellesmere Island and the most southerly well was at 72°40′ N on Prince of Wales Island. 38 of these wells were drilled offshore from floating ice platforms in water depths of up to 550m. 500km3 (17.5trillionft3) of natural gas reserves was discovered over this period and small oil reserves were discovered at Bent Horn. All of the offshore wells attempted were drilled, logged and tested as planned, a proof of the viability of using ice as a support for drilling. In spite of large distances, extreme weather and permafrost, the operations were successful and had no lasting effect on the environment. This paper summarizes the significant achievements over Panarctic''s history from inception to 1986 when operations ceased. [Copyright &y& Elsevier]

In the eastern Canadian Arctic, a shift in toolstone selection strategies from pre-dorset (4500-2800 B.P.) to dorset (2500-1000 B.P.) has been interpreted as one line of evidence indicating culture change within the palaeo-Eskimo continuum. pre-dorset toolmakers appear to have relied on readily available local cherts while dorset toolmakers were more discriminating, frequently using scarce or non-local toolstones such as chalcedony from northern labrador, crystal quartz, and nephrite, among others. our recent analysis of a debitage assemblage from ledx-42, a multi-component palaeo-Eskimo site located in the interior of southern Bafin island, aimed to see if similar raw material signatures could be isolated using a newly developed methodological approach for sourcing chert toolstone. one of our objectives in this preliminary study was to evaluate if diversity in chert selection strategies could be used as a proxy to assess possible links between cultural affiliation and activity areas within the site. this paper describes the sourcing protocol and discusses our results as they relate to the palaeo-Eskimo exploitation of chert toolstone at LeDx-42. [ABSTRACT FROM AUTHOR]

Abstract: The adjoint of an ocean general circulation model is at the heart of the ocean state estimation system of the Estimating the Circulation and Climate of the Ocean (ECCO) project. As part of an ongoing effort to extend ECCO to a coupled ocean/sea-ice estimation system, a dynamic and thermodynamic sea-ice model has been developed for the Massachusetts Institute of Technology general circulation model (MITgcm). One key requirement is the ability to generate, by means of automatic differentiation (AD), tangent linear (TLM) and adjoint (ADM) model code for the coupled MITgcm ocean/sea-ice system. This second part of a two-part paper describes aspects of the adjoint model. The adjoint ocean and sea-ice model is used to calculate transient sensitivities of solid (ice and snow) freshwater export through Lancaster Sound in the Canadian Arctic Archipelago (CAA). The adjoint state provides a complementary view of the dynamics. In particular, the transient, multi-year sensitivity patterns reflect dominant pathways and propagation timescales through the CAA as resolved by the model, thus shedding light on causal relationships, in the model, across the Archipelago. The computational cost of inferring such causal relationships from forward model diagnostics alone would be prohibitive. The role of the exact model trajectory around which the adjoint is calculated (and therefore of the exactness of the adjoint) is exposed through calculations using free-slip vs no-slip lateral boundary conditions. Effective ice thickness, sea surface temperature, and precipitation sensitivities, are discussed in detail as examples of the coupled sea-ice/ocean and atmospheric forcing control space. To test the reliability of the adjoint, finite-difference perturbation experiments were performed for each of these elements and the cost perturbations were compared to those “predicted” by the adjoint. Overall, remarkable qualitative and quantitative agreement is found. In particular, the adjoint correctly “predicts” a seasonal sign change in precipitation sensitivities. A physical mechanism for this sign change is presented. The availability of the coupled adjoint opens up the prospect for adjoint-based coupled ocean/sea-ice state estimation. [Copyright &y& Elsevier]

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Abstract: Victoria Island lies at the north-western limit of the former North American (Laurentide) Ice Sheet in the Canadian Arctic Archipelago and displays numerous cross-cutting glacial lineations. Previous work suggests that several ice streams operated in this region during the last (Wisconsinan) glaciation and played a major role in ice sheet dynamics and the delivery of icebergs into the Arctic Ocean. This paper produces the first detailed synthesis of their behaviour from the Last Glacial Maximum through to deglaciation (∼21–9.5calkaBP) based on new mapping and a previously published radiocarbon-constrained ice sheet margin chronology. Over 70 discrete ice flow events (flow-sets) are ‘fitted’ to the ice margin configuration to allow identification of several ice streams ranging in size from large and long-lived (thousands of years) to much smaller and short-lived (hundreds of years). The reconstruction depicts major ice streams in M''Clure Strait and Amundsen Gulf which underwent relatively rapid retreat from the continental shelf edge at some time between ∼15.2 and 14.1calkaBP: a period which encompasses climatic warming and rapid sea level rise (meltwater pulse-1a). Following this, overall retreat was slower and the ice streams exhibited asynchronous behaviour. The Amundsen Gulf Ice Stream continued to operate during ice margin retreat, whereas the M''Clure Strait Ice Stream ceased operating and was replaced by an ice divide within ∼1000 years. This ice divide was subsequently obliterated by another short-lived phase of ice streaming in M''Clintock Channel ∼13calkaBP. The timing of this large ice discharge event coincides with the onset of the Younger Dryas. Subsequently, a minor ice divide developed once again in M''Clintock Channel, before final deglaciation of the island shortly after 9.5calkaBP. It is concluded that large ice streams at the NW margin of the Laurentide Ice Sheet, equivalent in size to the Hudson Strait Ice Stream, underwent major changes during deglaciation, resulting in punctuated delivery of icebergs into the Arctic Ocean. Published radiocarbon dates constrain this punctuated delivery, as far as is possible within the limits imposed by their precision, and we note their coincidence with pulses of meltwater delivery inferred from numerical modelling and ocean sediment cores. [Copyright &y& Elsevier]

The site BAF-5 is located on the summit of Resolution Island, Nunavut, just southeast of Baffin Island at 61° 35′N and 60° 40′W. The site was part of a North American military defense system established in the 1950s that became heavily contaminated with PCBs during and subsequent, its operational years. Remediation through excavation of the PCB contaminated soil at Resolution Island began in 1999 and at its completion in 2006 approximately 5 tonnes of pure PCBs in approximately 20,000 m3 of soil were remediated. Remediation strategies were based on both quantity of soil and level of contamination in the soil. Excavation removed 96% of the PCB contaminated soil on site. In 2003, a surface funnel-and-gate permeable reactive barrier was design and constructed to treat the remaining contamination left in rock crevices and inaccessible areas of the site. Excavation had destabilized contaminated soil in the area, enabling contaminant migration through erosion and runoff pathways. The barrier was designed to maximize sedimentation through settling ponds. This bulk removal enabled the treatment of highly contaminated fines and water through a permeable gate. The increased sediment loading during excavation required both modifications to the funnel and a shift to a more permeable, granular system. Granulated activated charcoal was chosen for its ability to both act as a particle retention filter and adsorptive filter. The reduction in mass of PCB and volume of soils trapped by the funnel of the barrier indicate that soils are re-stabilizing. In 2007, nonwoven geotextiles were re-introduced back into the filtration system as fine filtering could be achieved without clogging. Monitoring sites downstream indicate that the barrier system is effective. This paper describes the field progress of PCB remediation at Resolution Island. [Copyright &y& Elsevier]

Summary: Small basin studies in the remote Canadian Arctic Archipelago have revealed the general nature of runoff processes and the annual rhythms and magnitude of streamflow in the region, but widespread monitoring of hydrological cycle components is absent. The result is that an understanding of large scale freshwater fluxes from the Arctic Archipelago does not exist. Such understanding is important for sound domestic water management decisions and international obligations to quantify Canada’s freshwater supply to the oceans. The study summarized by this paper, initiated under the auspices of the International Polar Year, extrapolated observed streamflow attributes across the Arctic Archipelago using statistical regionalization tools. The paucity of hydrometric data necessitated the construction of a dataset, which was limited to the period from 1972 to 1994. Reliable estimates of mean May–October freshwater flux were possible from ∼70% of the Archipelago and these total ∼190km3. Maximum daily runoff can be up to 13% of the total annual flux from some catchments. Flows were highest from southern Baffin Island, decreasing westward. The scarcity of data compelled an error analysis that showed average confidence intervals around constructed and regionalized data of ±123% and ±63%, respectively. Dataset construction errors were inversely related to basin area. There was no spatial pattern to the dataset construction errors, but regionalization error tended to be higher in the west. It will be argued that our community has little to no idea of the current freshwater flux from the Arctic Archipelago, or if it is changing. Much work is needed to improve these estimates, including establishing a sustainable, effective and efficient monitoring and research program of high arctic freshwater systems that can build upon the legacy of the International Polar Year. [Copyright &y& Elsevier]

This paper discusses the development of simple multiple linear regression (MLR) models for developing seasonal forecasts of the annual minimum sea-ice extent in the Beaufort/Chukchi Seas, the Laptev/East Siberian Seas, the Kara/Barents Seas, and the Canadian Arctic Archipelago regions. The potential predictor data are based on mean monthly weighted indices of sea-ice concentration, multiyear sea-ice concentration, surface skin temperature, surface albedo, and downwelling longwave radiation flux at the surface. Predictions are developed based on data available in March (spring forecast), to coincide with the National American Ice Service''s annual outlooks, and based on data available in June (summer forecast), which would provide a seasonal revision. The final regression equations retain one to three predictors, and each of the MLR models is superior to climatology. The r 2 for the MLR models range from a low of 0.44 (for the spring forecast in the Canadian Arctic Archipelago) to a high of 0.80 (for the summer forecast in the Beaufort/Chukchi Seas). [Copyright &y& Elsevier]

Abstract: This paper brings together unpublished historical data sets and published literature to review the role of climatic, oceanographic and ecological processes in the marine ecosystem of the eastern Canadian Archipelago. Physical data include characteristics of the water masses, circulation patterns, sea ice conditions, and climatic records from 1950s onward. Biological data include unpublished data sets on nutrients, primary and secondary production, and sedimentation, which were collected during the 1980–1990s in the eastern Canadian Archipelago. These results show high year-to-year variability in nutrient inventories and ratios, the magnitude of the ice algae and phytoplankton bloom, the timing of ice algae sedimentation in the spring, and the composition of the zooplankton community. The significance of this high interannual variability and its effect on pelagic–benthic coupling processes is discussed in the context of climatic and oceanographic forcing, with emphasis on recent (past decade) Arctic changes. An estimate of total primary production in the Archipelago is also presented, along with published production estimates for other Arctic shelves, showing that the Archipelago may support up to 32% of the total primary production of Arctic shelves. The high year-to-year variability in production and carbon transfer pathways (e.g. pelagic versus benthic) in the Archipelago suggest that the system might be resilient to the increased variability in climatic conditions occurring in the past decade. However, this increased variability combined with directional change in climatic and oceanographic conditions might also modify the existing balance of ecological processes. For example, shifts in the timing of events appear to have already occurred in the past decade, with potential cascading effects throughout the ecosystem. [Copyright &y& Elsevier]

In recent years in the Canadian Arctic, participatory and pluralistic approaches have become common in several areas of environmental management relevant to the resolution of multiple-use conflicts: fish and wildlife, protected area planning, integrated coastal zone management, ecosystem health monitoring, contaminants research, environmental assessment, and climate change. This paper analyzes the emergence and development of aboriginal participation in resource management in each of these areas, with emphasis on the Canada Oceans Act. Policy change seems to parallel the emergence of aboriginal land claims and the general political movement towards greater self-government. Increasing political power of northern populations in general, and aboriginal groups in particular, have led to a modification of the environmental decision-making process, and to the incorporation of local values, priorities, and traditional environmental knowledge in environmental research and management. Especially important in this process has been the emergence of traditional environmental knowledge as a mechanism by which participatory approaches can be implemented. [ABSTRACT FROM AUTHOR]

Discusses the implications for paleoclimate and for formation of hummocky moraine of the major end moraines of Younger Dryas age on Wollaston Peninsula, Victoria Island and the Canadian Arctic. Analysis of ice-cored topography; Details on the till layers forming the cap of the ice-cored moraines on the Tuktoyaktuk Peninsula; Evidence that shows ice-cored moraines would become classical hummocky moraine.

The sedimentological, geochemical, physical and magnetic properties of 40 surface and basal sediment samples of box cores collected throughout the Canadian Arctic Archipelago (CAA) from the Canadian Beaufort Shelf to Lancaster Sound were analyzed to determine the sedimentary processes that operate within the CAA during the pre‐ and post‐industrial periods (i.e., before and after 1900 Common Era or CE). In addition, the chronology of seven selected regional cores was established using 210Pb measurements, where the base is dated between 1550 and 1820 CE. These cores provide an opportunity to robustly compare post‐1900 sedimentary conditions with those of the colder Little Ice Age period (LIA; ∼1500–1900 CE). The different properties combined with multivariate statistical analyses result in the identification of three regional provinces with distinct sedimentary characteristics: (a) the West province (Mackenzie Shelf/Slope, west Banks Island and M'Clure Strait) typified by detrital associations (Fe‐Rb‐Ti‐Zn), high organic matter inputs, dominance of magnetite and low‐coercivity minerals and high aluminosilicate contents; (b) the Intermediate Zone (Amundsen and Coronation gulfs) distinguished by Si‐Al‐Zr‐Sr‐K associations, Mn oxyhydroxides precipitation, constant high magnetic grain concentrations and a mixture between marine and terrigenous organic matter; and (c) the East Province (Queen Maud Gulf, Victoria and Barrow straits, and Lancaster and Eclipse sounds) described by high detrital carbonate inputs, marine organic matter, a dominance of high‐coercivity minerals and high magnetic concentrations in pre‐industrial samples. Our results confirm that the pre‐ and post‐industrial sedimentary dynamics are controlled by sediment supplies from the river discharges in the West and Intermediate provinces, whereas the East province is more influenced by sea ice and coastal erosion. Basal sediment samples from the seven 210Pb‐dated cores suggest an intensification of the Mackenzie, Coppermine, and Ellice rivers runoff, extensive sea‐ice cover and consequently sediment transport by the latter during the LIA period. Plain Language Summary: The Arctic is a region where the seafloor composition is the least studied and understood. Indeed, the vast majority of the channels within the Canadian Arctic Archipelago (CAA) and their adjoining continental shelves and slopes exhibit a substantial knowledge gap regarding sediment composition. This information is essential to provide fundamental baseline data on the physical and chemical sediment properties as well as to determinate fingerprints for sediment source areas and sediment transport processes in this Arctic region. In this regard, the present study is interested in the sedimentary processes regional heterogeneity that operate within the CAA during the pre‐ and post‐industrial periods, which was investigated through magnetic, geochemical and sedimentological analyses of 40 surface and 40 basal sediments retrieved from the Canadian Beaufort Shelf to Lancaster Sound. Pre‐ and post‐industrial sedimentary processes are mainly influenced by river discharge in the west and central CAA, and by coastal erosion and sediment‐laden sea ice in the east CAA. The results obtained here provide a basis for future studies using the sedimentological, geochemical and magnetic signatures of longer sediment records from the CAA to reconstruct variations in sediment dynamics related to late Quaternary climatic and oceanographic changes. Key Points: Sedimentological, geochemical and magnetic baseline data are reported in the Canadian Arctic ArchipelagoSedimentary processes that operate within Canadian Arctic Archipelago during the pre‐ and post‐industrial periods are documentedRegional 210Pb‐dated box cores provide clues about the sedimentary dynamics that operated during the Little Ice Age [ABSTRACT FROM AUTHOR]

Melt ponds form on the surface of Arctic sea ice during spring, influencing how much solar radiation is absorbed into the sea ice–ocean system, which in turn impacts the ablation of sea ice during the melt season. Accordingly, melt pond fraction (fp) has been shown to be a useful predictor of sea ice area during the summer months. Sea ice dynamic and thermodynamic processes operating within the narrow channels and inlets of the Canadian Arctic Archipelago (CAA) during the summer months are difficult for model simulations to accurately resolve. Additional information on fp variability in advance of the melt season within the CAA could help constrain model simulations and/or provide useful information in advance of the shipping season. Here, we use RADARSAT-2 imagery to predict and analyze peak melt pond fraction (fpk) and evaluate its utility to provide predictive information with respect to sea ice area during the melt season within the CAA from 2009–2018. The temporal variability of RADARSAT-2 fpk over the 10-year record was found to be strongly linked to the variability of mean April multi-year ice area with a statistically significant detrended correlation (R) of R=- 0.89. The spatial distribution of RADARSAT-2 fpk was found to be in excellent agreement with the sea ice stage of development prior to the melt season. RADARSAT-2 fpk values were in good agreement with fpk observed from in situ observations but were found to be ∼ 0.05 larger compared to MODIS fpk observations. Dynamically stable sea ice regions within the CAA exhibited higher detrended correlations between RADARSAT-2 fpk and summer sea ice area. Our results show that RADARSAT-2 fpk can be used to provide predictive information about summer sea ice area for a key shipping region of the Northwest Passage. [ABSTRACT FROM AUTHOR]

Precise knowledge of wintertime sea ice production in Arctic polynyas is not only required to enhance our understanding of atmosphere‐sea ice‐ocean interactions but also to verify frequently utilized climate and ocean models. Here, a high‐resolution (2‐km) Moderate Resolution Imaging Spectroradiometer (MODIS) thermal infrared satellite data set featuring spatial and temporal characteristics of 17 Arctic polynya regions for the winter seasons 2002/2003 to 2017/2018 is directly compared to an akin low‐resolution Advanced Microwave Scanning Radiometer‐EOS (AMSR‐E) passive microwave data set for 2002/2003 to 2010/2011. The MODIS data set is purely based on a 1‐D energy‐balance model, where thin‐ice thicknesses (≤ 20 cm) are directly derived from ice‐surface temperature swath data and European Centre for Medium‐Range Weather Forecasts Re‐Analysis‐Interim atmospheric reanalysis data on a quasi‐daily basis. Thin‐ice thicknesses in the AMSR‐E data set are derived empirically. Important polynya properties such as areal extent and potential thermodynamic ice production can be estimated from both pan‐Arctic data sets. Although independently derived, our results show that both data sets feature quite similar spatial and temporal variations of polynya area (POLA) and ice production (IP), which suggests a high reliability. The average POLA (average accumulated IP) for all Arctic polynyas combined derived from both MODIS and AMSR‐E are 1.99×105 km2 (1.34×103 km3) and 2.29×105 km2 (1.31×103 km3), respectively. Narrow polynyas in areas such as the Canadian Arctic Archipelago are notably better resolved by MODIS. Analysis of 16 winter seasons provides an evaluation of long‐term trends in POLA and IP, revealing the significant increase of ice formation in polynyas along the Siberian coast. Plain Language Summary: The term "polynya" essentially describes the appearance of "holes" in an otherwise closed sea ice cover, that are kept free of thick sea ice due to strong physical forcing mechanisms such as wind or warmer ocean temperatures. The size of such a polynya can sometimes exceed several tens of thousands of square kilometers, indicating a high physical and biological importance. The contrast between the relatively warm ocean and the cold atmosphere creates a flow of heat to the atmosphere that causes intense freezing at the ocean surface. Gaining a more detailed knowledge about the total amount of new sea ice that is formed in these polynyas during the Arctic winter is highly important to understand the large‐scale characteristics of the Arctic sea ice cover. Using different kinds of satellite data, this study follows the aim to analyze the difference in Arctic‐wide polynya monitoring between two independent and previously published data sets. Our results show that both data sets show highly similar estimations of polynya size and new sea ice production, with the overall Arctic‐wide difference being in the range of 2–15%. The results of this study enhance the confidence when using the data sets for other applications and when analyzing long‐term developments and trends of Arctic polynyas. Key Points: Overall high agreement between independent MODIS and AMSR‐E data sets on observed Arctic polynya characteristicsHigh‐resolution MODIS data set beneficial in narrow coastal areas and the evaluation of long‐term trends in polynya area and ice productionAnalysis of 16 winter seasons reveals significantly increasing ice formation in polynyas along the Siberian coast [ABSTRACT FROM AUTHOR]

This study provides 6 years of high‐resolution underway measurements of the sea surface partial pressure of CO2 (pCO2sw), sea surface temperature, and salinity across the Canadian Arctic Archipelago (CAA). Observed pCO2sw varied regionally, with the northern and central channels of the CAA undersaturated in pCO2sw (with respect to the atmosphere), while the western regions were typically saturated to supersaturated in pCO2sw. This apparent spatial variability was caused to some extent by the timing of our ship transit through the CAA, as we also found a general seasonal trend of pCO2sw being undersaturated in the early summer, followed by saturation to supersaturation in late summer, and a return to undersaturation during the autumn. Sea surface temperature was significantly correlated with pCO2sw at various locations across the CAA, but we also observed the effects of other regional processes like upwelling, primary production, riverine input, and sea ice melt. These processes are linked to each other, and hence, it is impossible to pinpoint only one dominant factor controlling pCO2sw variability in the CAA. However, we found that sea ice dominates the seasonal cycle of all these processes, thus making the timing of sea ice breakup a useful predictor of pCO2sw variability in the CAA. We calculated an average net oceanic sink of 14 mmol CO2 · m−2 · day−1 for the CAA during the summer and autumn seasons, but caution that a more rigorous budgeting approach is required to fully account for biases in dates and locations of our measurements. Plain Language Summary: Studying seawater carbon dioxide (CO2) concentration in the Arctic Ocean helps us understand the impact of ocean acidification and estimate the region's response to increased human emissions. This study presents 6 years of data from icebreaker research cruises to study the main factors responsible for differences in measured seawater CO2 concentration in the Canadian Arctic Archipelago (CAA). Overall, we found that the seawater CO2 concentration is low with respect to CO2 in the atmosphere during the summer and autumn seasons due to influences of increasing water temperature and sea ice melt, as well as the regional effects of other variables such as river inputs and biological activity. We observed that the CAA was absorbing atmospheric CO2, acting as a net oceanic sink. However, it is important to note that the ship sampling was limited to specific locations and timing every year due to logistical difficulties associated with navigating sea ice. Therefore, we cannot say that the entire CAA acts as an atmospheric CO2 sink in the same way everywhere. To solve this problem, we found a significant relationship between sea ice conditions and seawater CO2 concentration that could be very useful in estimating the seawater CO2 concentration elsewhere in the CAA. Key Points: The Canadian Arctic Archipelago is mainly undersaturated in surface water pCO2swWater temperature and sea ice conditions are the main drivers of pCO2sw variabilityThe timing of sea ice breakup can be used as a proxy for pCO2sw variability [ABSTRACT FROM AUTHOR]

We use a numerical model forced with high temporal and spatial resolution atmospheric forcing to evaluate the volume and freshwater transport through the Canadian Arctic Archipelago (CAA). On average, the simulated inflow through the Queen Elizabeth Islands represents 40% of the transport entering the CAA through M'Clure Strait. The transport through Admunsden Gulf represents less than 10% of the total inflow. The impact of sea ice and winds on the volume and freshwater transports into and through this region is also investigated. At Nares Strait and West Lancaster Sound, the transport is overestimated due to too‐mobile sea ice but different physical processes related to surface stress. The ice is driving larger ocean flow in the first case, while causing less flow reduction in the second case. While the transport through the Queen Elizabeth Islands responds to the changes in surface stress over the Beaufort Gyre and northern Baffin Bay, local surface stress opposed to the mean flow over the straits tends to reduce the throughflow transport. In Parry Channel and the southern CAA, the surface stress tends to enhance the transport and have a greater impact locally. Finally, the surface stress related to sea ice motion can significantly change the transport in the CAA during the winter months. Plain Language Summary: We use a numerical computer model including high temporal and spatial resolution atmospheric forcing to evaluate the amount of water and freshwater flowing through the Canadian Arctic Archipelago (CAA). On average, we show that the inflow through the Queen Elizabeth Islands represents about slightly less (40%) than M'Clure Strait, which has historically been considered to be the main source of the inflow. We also show that the flow through the Amundsen Gulf is low (10% of the total), in agreement with previous studies. In addition, we demonstrate how the sea ice motion drives too much flow through West Lancaster Sound and Nares Strait and show the importance of the sea ice motion on the water and freshwater flows through key gates in and out of the CAA. This provides hints on how the dynamics of the flow through the CAA might change in the future with less sea ice cover in a warming world. The flux of freshwater through the CAA is potentially important as it may impact deep water formation in the Atlantic Ocean. Key Points: To correctly model transport through the CAA, ice velocity, and probably landfast ice, needs to be properly represented in numerical modelsIncreasing surface stress reduces the flow through the Queen Elizabeth Islands but increases the flow through the central and southern CAAFreshwater transport is more sensitive to surface stress changes than volume transport [ABSTRACT FROM AUTHOR]

This observational study compares seasonal variations of surface fluxes (turbulent, radiative, and soil heat) and other ancillary atmospheric/surface/permafrost data based on in-situ measurements made at terrestrial research observatories located near the coast of the Arctic Ocean. Hourly-averaged multiyear data sets collected at Eureka (Nunavut, Canada) and Tiksi (East Siberia, Russia) are analyzed in more detail to elucidate similarities and differences in the seasonal cycles at these two Arctic stations, which are situated at significantly different latitudes (80.0°N and 71.6°N, respectively). While significant gross similarities exist in the annual cycles of various meteorological parameters and fluxes, the differences in latitude, local topography, cloud cover, snowfall, and soil characteristics produce noticeable differences in fluxes and in the structures of the atmospheric boundary layer and upper soil temperature profiles. An important factor is that even though higher latitude sites (in this case Eureka) generally receive less annual incoming solar radiation but more total daily incoming solar radiation throughout the summer months than lower latitude sites (in this case Tiksi). This leads to a counter-intuitive state where the average active layer (or thaw line) is deeper and the topsoil temperature in midsummer are higher in Eureka which is located almost 10° north of Tiksi. The study further highlights the differences in the seasonal and latitudinal variations of the incoming shortwave and net radiation as well as the moderating cloudiness effects that lead to temporal and spatial differences in the structure of the atmospheric boundary layer and the uppermost ground layer. Specifically the warm season (Arctic summer) is shorter and mid-summer amplitude of the surface fluxes near solar noon is generally less in Eureka than in Tiksi. During the dark Polar night and cold seasons (Arctic winter) when the ground is covered with snow and air temperatures are sufficiently below freezing, the near-surface environment is generally stably stratified and the hourly averaged turbulent fluxes are quite small and irregular with on average small downward sensible heat fluxes and upward latent heat and carbon dioxide fluxes. The magnitude of the turbulent fluxes increases rapidly when surface snow disappears and the air temperatures rise above freezing during spring melt and eventually reaches a summer maximum. Throughout the summer months strong upward sensible and latent heat fluxes and downward carbon dioxide (uptake by the surface) are typically observed indicating persistent unstable (convective) stratification. Due to the combined effects of day length and solar zenith angle, the convective boundary layer forms in the High Arctic (e.g., in Eureka) and can reach long-lived quasi-stationary states in summer. During late summer and early autumn all turbulent fluxes rapidly decrease in magnitude when the air temperature decreases and falls below freezing. Unlike Eureka, a pronounced zero-curtain effect consisting of a sustained surface temperature hiatus at the freezing point is observed in Tiksi during fall due to wetter and/or water saturated soils. [ABSTRACT FROM AUTHOR]

Abstract: The Canadian Arctic Archipelago is a key conduit for comparatively fresh Arctic waters flowing to the Atlantic. Model estimates of the freshwater outflow, which is strongly correlated with the volume flux, contain major uncertainties because most existing models exclude tides, marginally resolve the internal Rossby radius, or both. At the same time, barotropic tidal models preclude stratified flow effects. Here we assess the relative importance of barotropic and baroclinic processes to water mass transformation, friction, and energy losses motivated by processes observed in a fine‐scale survey in the central Archipelago. A sharp separation of warmed Canada Basin water and locally formed water is observed over a long sill in a narrow channel and coincides with an internal hydraulic jump caused by the mean flow. Tidal currents, however, modulate the jump, as demonstrated by both scale analysis and a two‐dimensional simulation. The jump, together with internal tides propagating as Kelvin waves, leads to isopycnal displacements up to 50 m. The generation of these internal Kelvin waves has a leading‐order role in a regional energy budget. It is small, however, relative to bottom boundary layer dissipation, which accounts for an estimated 50% of the total tidal energy losses. Consequently, adding tides needs to be a priority for regional models. [ABSTRACT FROM AUTHOR]

Abstract: Analysis of current temperature data in the Canadian Arctic Archipelago results in the recognition of two major thermal regimes. High temperature regions are observed where salt diapirs and salt cored anticlines are present. Low temperature fields are observed along the western and southern basin margins and around Cornwall‐Amund Ringnes islands, where regional Mesozoic aquifers are exposed to surface, connected to basin boundary faults, or regional unconformities. Meteoric and Holocene sub‐glacial water recharge are inferred to be responsible for the low geothermal regime and low formation water salinity. Neither exhumation associated with the Eocene “Eurekan” orogeny nor volcanic intrusion associated with opening of Amerasia Basin in late Jurassic‐early Cretaceous have been interpreted to be a significant influence on the present day temperature field, although thermal indicators show evidence of elevated thermal alteration of organic matter pointing to earlier, but now dissipated, thermal anomalies. [ABSTRACT FROM AUTHOR]

An increasing number of boreal marine species are expected to invade the warming Arctic Ocean with the potential to displace endemic species. We provide first evidence that Pacific sand lance ( Ammodytes hexapterus) is expanding its range in the Canadian Arctic Archipelago, a region far outside the species temperate-boreal traditional range south of the Bering Strait. To the best of our knowledge, supported by local Inuit knowledge, the species was not present in the area until the present decade. We observed an increasing density of larval Pacific sand lance with time over the 2011-2016 period, suggesting that environmental conditions are becoming increasingly favorable for the species to reproduce in the Central Canadian Arctic. The northward distribution change of Pacific sand lance is occurring earlier than predicted by current models and could trigger abrupt shifts in Arctic marine food webs if the boreal invader displaces polar cod, a key prey species for top predators in Arctic marine ecosystems. [ABSTRACT FROM AUTHOR]

Sea surface temperature (SST) data from the Copernicus Marine Environment Monitoring Service are assimilated into a pan-Arctic ice-ocean coupled model using the ensemble-based local singular evolutive interpolated Kalman (LSEIK) filter. This study found that the SST deviation between model hindcasts and independent SST observations is reduced by the assimilation. Compared with model results without data assimilation, the deviation between the model hindcasts and independent SST observations has decreased by up to 0.2°C at the end of summer. The strongest SST improvements are located in the Greenland Sea, the Beaufort Sea, and the Canadian Arctic Archipelago. The SST assimilation also changes the sea ice concentration (SIC). Improvements of the ice concentrations are found in the Canadian Arctic Archipelago, the Beaufort Sea, and the central Arctic basin, while negative effects occur in the west area of the eastern Siberian Sea and the Laptev Sea. Also, sea ice thickness (SIT) benefits from ensemble SST assimilation. A comparison with upward-looking sonar observations reveals that hindcasts of SIT are improved in the Beaufort Sea by assimilating reliable SST observations into light ice areas. This study illustrates the advantages of assimilating SST observations into an ice-ocean coupled model system and suggests that SST assimilation can improve SIT hindcasts regionally during the melting season. [ABSTRACT FROM AUTHOR]

The Canadian Arctic Islands expose a complex network of dykes and sills that belong to the High Arctic Large Igneous Province (HALIP), which intruded volatile-rich sedimentary rocks of the Sverdrup Basin (shale, limestone, sandstone and evaporite) some 130 to 120 million years ago. There is thus great potential in studying the HALIP to learn how volatile-rich sedimentary rocks respond to magmatic heating events during LIP emplacement. The HALIP remains, however, one of the least well known LIPs on the planet due to its remote location, short field season, and harsh climate. A Canadian-Swedish team of geologists set out in summer 2015 to further explore HALIP sills and their sedimentary host rocks, including the sampling of igneous and meta-sedimentary rocks for subsequent geochemical analysis, and high pressure-temperature petrological experiments to help define the actual processes and time-scales of magma-sediment interaction. The research results will advance our understanding of how climate-active volatiles such as CO2, SO2 and CH4 are mobilised during the magma-sediment interaction related to LIP events, a process which is hypothesised to have drastically affected Earth's carbon and sulphur cycles. In addition, assimilation of sulphate evaporites, for example, is anticipated to trigger sulphide immiscibility in the magma bodies and in so doing could promote the formation of Ni-PGE ore bodies. Here we document the joys and challenges of 'frontier arctic fieldwork' and discuss some of our initial observations from the High Arctic Large Igneous Province. [ABSTRACT FROM AUTHOR]

Arctic lakes, through their ice cover phenology, are a key indicator of climatic changes that the high-latitude environment is experiencing. In the case of lakes in the Canadian Arctic Archipelago (CAA), many of which are ice covered more than 10 months per year, warmer temperatures could result in ice regime shifts. Within the dominant polardesert environment, small local warmer areas have been identified. These relatively small regions - polar oases - with longer growing seasons and greater biological productivity and diversity are secluded from the surrounding barren polar desert. The ice regimes of 11 lakes located in both polardesert and polar-oasis environments, with surface areas between 4 and 542 km², many of unknown bathymetry, were documented. In order to investigate the response of ice cover of lakes in the CAA to climate conditions during recent years, a 15-year time series (1997-2011) of RADARSAT- 1/2 ScanSAR Wide Swath, ASAR Wide Swath, and Landsat acquisitions were analyzed. Results show that melt onset occurred earlier for all observed lakes. With the exception of Lower Murray Lake, all lakes experienced earlier summer ice minimum and water-clear-of-ice (WCI) dates, with greater changes being observed for polar-oasis lakes (9-24 days earlier WCI dates for lakes located in polar oases and 2-20 days earlier WCI dates for polar-desert lakes). Additionally, results suggest that some lakes may be transitioning from a perennial/multiyear to a seasonal ice regime, with only a few lakes maintaining a multiyear ice cover on occasional years. Aside Lake Hazen and Murray Lakes, which preserved their ice cover during the summer of 2009, no residual ice was observed on any of the other lakes from 2007 to 2011. [ABSTRACT FROM AUTHOR]

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The article examines the fissure in the U.S.- Canadian relations since the Caroline Incident of 1837. It mentions that the U.S. counter this passageway, consisting of varying routes through the 19,000-island Canadian Arctic Archipelago, constitutes an international strait between two high seas, affording any country the right to pass freely in accordance with the doctrine of transit passage.

Background: Sea ice across the Arctic is declining and altering physical characteristics of marine ecosystems. Polar bears (Ursus maritimus) have been identified as vulnerable to changes in sea ice conditions. We use sea ice projections for the Canadian Arctic Archipelago from 2006 – 2100 to gain insight into the conservation challenges for polar bears with respect to habitat loss using metrics developed from polar bear energetics modeling. Principal Findings: Shifts away from multiyear ice to annual ice cover throughout the region, as well as lengthening ice-free periods, may become critical for polar bears before the end of the 21st century with projected warming. Each polar bear population in the Archipelago may undergo 2–5 months of ice-free conditions, where no such conditions exist presently. We identify spatially and temporally explicit ice-free periods that extend beyond what polar bears require for nutritional and reproductive demands. Conclusions/Significance: Under business-as-usual climate projections, polar bears may face starvation and reproductive failure across the entire Archipelago by the year 2100. [ABSTRACT FROM AUTHOR]

Stratigraphical exposures of both glacial and non-glacial sediments at Morgan Bluffs, a >6-km long exposure on the east coast of Banks Island, comprise a discontinuous archive of Quaternary environmental change. A detailed facies analysis of the sediments and a new stratigraphical framework is incompatible with the many climatostratigraphical units proposed previously. Instead, three distinct intervals of sedimentation are recognized. The first records the progradation of a delta, followed by fluvial aggradation of a braided river valley perhaps ∼1 Ma. The second documents glacigenic sedimentation, including fluctuations of a tidewater glacier margin, in a marine basin more than 0.78 Ma. The third records till deposition by the NW Laurentide Ice Sheet during the Late Wisconsinan, followed by the progradation of a deglacial, ice-contact delta into an ice-dammed lake ∼12.8 cal. ka BP. The revised stratigraphical framework adds important new terrestrial observations to a sparse and fragmentary data set of Quaternary environmental change in the Canadian Arctic. This study challenges former references and correlations to the previously proposed climatostratigraphical framework and nomenclature. [ABSTRACT FROM AUTHOR]

Remarkably low mean September sea ice area in the Canadian Arctic Archipelago (CAA) was observed in 2011 (146×103 km2), a record-breaking level that was nearly exceeded in 2012 (150×103 km2). These values were lower than previous September records set in 1998 (200×103 km2) and 2007 (220×103km2), and are ∼ 60% lower than the 1981-2010 mean September climatology. In this study, the processes contributing to the extreme light years of 2011 and 2012 were investigated, compared to previous extreme minima of 1998 and 2007, and contrasted against historic summer seasons with above average September ice area. The 2011 minimum was associated with positive June through September (JJAS) surface air temperature (SAT) and net solar radiation(K" ) anomalies that facilitated rapid melt, coupled with atmospheric circulation that restricted multi-year ice (MYI) inflow from the Arctic Ocean into the CAA. The 2012 minimum was also associated with positive JJAS SAT and K" anomalies with coincident rapid melt, but further ice decline was temporarily mitigated by atmospheric circulation which drove Arctic Ocean MYI inflow into the CAA. Atmospheric circulation was comparable between 2011 and 1998 (impeding Arctic Ocean MYI inflow) and 2012 and 2007 (inducing Arctic Ocean MYI inflow). However, preconditioning was more apparent leading up to 2011 and 2012 than 1998 and 2007. The rapid melt process in 2011 and 2012 was more intense than observed in 1998 and 2007 because of the thinner ice cover being more susceptible to anomalous thermodynamic forcing. The thinner sea ice cover within the CAA in recent years has also helped counteract the processes that facilitate extreme heavy ice years. The recent extreme light years within the CAA are associated with a longer navigation season within the Northwest Passage. [ABSTRACT FROM AUTHOR]

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For more than half a century, Canada has affirmed that all of the waters within its Arctic archipelago, including the Northwest Passage, are Canadian historic internal waters over which it exercises sovereign control. Canada's detractors have qualified the Canadian position as excessive, arguing that the Northwest Passage is an international strait and that international legal regimes guarantee the preservation of the Arctic waterway. It is this contention, that international legal tools exist--specifically Article 234 of the LOSC and the IMO's PSSA mechanism--and that they would adequately protect the Northwest Passage even if it came to be recognized as an international strait, which is the subject of investigation. [ABSTRACT FROM AUTHOR]

Across the Canadian Arctic Archipelago, widespread ice retreat during the 20th century has sharply accelerated since 2004. In Sverdrup Pass, central Ellesmere Island, rapid glacier retreat is exposing intact plant communities whose radiocarbon dates demonstrate entombment during the Little Ice Age (1550-1850 AD). The exhumed bryophyte assemblages have exceptional structural integrity (i.e., setae, stem structures, leaf hair points) and have remarkable species richness (60 of 144 extant taxa in Sverdrup Pass). Although the populations are often discolored (blackened), some have developed green stem apices or lateral branches suggesting in vivo regrowth. To test their biological viability, Little Ice Age populations emerging from the ice margin were collected for in vitro growth experiments. Our results include a unique successful regeneration of subglacial bryophytes following 400 y of ice entombment. This finding demonstrates the totipotent capacity of bryophytes, the ability of a cell to dedifferentiate into a meristematic state (analogous to stem cells) and develop a new plant. In polar ecosystems, regrowth of bryophyte tissue buried by ice for 400 y significantly expands our understanding of their role in recolonization of polar landscapes (past or present). Regeneration of subglacial bryophytes broadens the concept of Ice Age refugia, traditionally confined to survival of land plants to sites above and beyond glacier margins. Our results emphasize the unrecognized resilience of bryophytes, which are commonly overlooked vis-a-vis their contribution to the establishment, colonization, and maintenance of polar terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

Since 2007, there has been a series of surface melt records over the Greenland ice sheet (GrIS), continuing the trend towards increased melt observed since the end of the 1990s. The last two decades are characterized by an increase of negative phases of the North Atlantic Oscillation (NAO) favouring warmer and drier summers than normal over GrIS. In this context, we use a circulation type classification based on daily 500 hPa geopotential height to evaluate the role of atmospheric dynamics in this surface melt acceleration for the last two decades. Due to the lack of direct observations, the interannual melt variability is gauged here by the summer (June-July-August) mean temperature from reanalyses at 700 hPa over Greenland; analogous atmospheric circulations in the past show that ~70% of the 1993-2012 warming at 700 hPa over Greenland has been driven by changes in the atmospheric flow frequencies. Indeed, the occurrence of anticyclones centred over the GrIS at the surface and at 500 hPa has doubled since the end of 1990s, which induces more frequent southerly warm air advection along the western Greenland coast and over the neighbouring Canadian Arctic Archipelago (CAA). These changes in the NAO modes explain also why no significant warming has been observed these last summers over Svalbard, where northerly atmospheric flows are twice as frequent as before. Therefore, the recent warmer summers over GrIS and CAA cannot be considered as a long-term climate warming but are more a consequence of NAO variability affecting atmospheric heat transport. Although no global model from the CMIP5 database projects subsequent significant changes in NAO through this century, we cannot exclude the possibility that the observed NAO changes are due to global warming. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)