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Sea ice information obtained from synthetic aperture radar (SAR) images is crucial for ensuring safe marine navigation and supporting climate change studies in polar regions. We propose a kernel principal component analysis (KPCA) local texture feature model for efficient sea ice segmentation. The proposed KPCA texture feature model is significant for several reasons. First, it takes into account the multiplicative nature of SAR speckle noise. The resulting KPCA features therefore assume independent and identically distributed (i.i.d.) Gaussian-like noise, which satisfies the assumptions inherent in classical statistical models such as thek-means algorithm. Second, the KPCA features are compact and statistically independent and therefore capable of reducing data redundancy. Third, the KPCA texture features are discriminative. Finally, the extraction of KPCA features requires less computation. Based on the KPCA model, a segmentation scheme is implemented in four steps. First, local patch-based texture descriptors are extracted from the image. Second, KPCA is performed on the patch-based texture descriptors to obtain compact and discriminative texture features with Gaussian-like noise characteristics. Third, thek-means algorithm is performed on extracted KPCA features to segment the image. Finally, a neighbourhood-based majority voting scheme is employed to determine the final label of each pixel. We compared the proposed method with several other popular sea ice segmentation approaches. The results demonstrated that our method is robust to speckle noise level, is accurate and fast and may thus better support the operational segmentation of sea ice in SAR imagery. [ABSTRACT FROM PUBLISHER]

The author comments on the emergence of a new ocean uncovered by melting ice surrounding the Arctic environment in 2014. Topics discussed include the development by the International Maritime Organization (IMO) of rules in global waters, the establishment by IMO of a Polar Code, and oil and gas activities as domestic concerns. Also mentioned are commitment to cultural and environmental protection, limitations on commercial fishery, and the conservation of the ocean's environmental well-being.

Copyright of Atmosphere -- Ocean (Taylor & Francis Ltd) is the property of Taylor & Francis Ltd 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.)

Copyright of Atmosphere -- Ocean (Taylor & Francis Ltd) is the property of Taylor & Francis Ltd 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.)

Copyright of Atmosphere -- Ocean (Taylor & Francis Ltd) is the property of Taylor & Francis Ltd 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.)

The Hong approximation, an approximation between the vertically and horizontally polarized reflectivities of specular surfaces has been useful for estimating the changes and characteristics produced in sea ice surfaces by climate change. Recently, the direct relationship (Azzam relationship) and the analytical (Azzam–Sohn–Hong (ASH)) approximation were derived and validated between two polarized reflectivities. In this study, the small-scale roughness and refractive index over sea ice are estimated using the ASH and Hong approximations with observations from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E). The ASH approximation is useful to monitor the properties of ice or snow, because those materials have a small value of the imaginary part of the refractive index (). Meanwhile, the Hong approximation is effective for estimating the melting of sea ice, because the melting of ice or snow indicates the increase in the imaginary part of the refractive index. Consequently, this study suggests that combining ASH and Hong approximations provides an effective procedure for analysing and understanding the melting sea ice surfaces in terms of the small-scale roughness and refractive index. [ABSTRACT FROM AUTHOR]

In this study, three low-resolution and three medium-resolution ice motion products were compared to ice-tethered profiler (ITP) global positioning system (GPS) data over a 2 year period. The ice motion products were the Advanced Microwave Scanning Radiometer Earth Observing System (AMSR-E), merged Advanced Scatterometer + Special Sensor Microwave/Imager (ASCAT + SSM/I), advanced synthetic aperture radar (ASAR), and Advanced Very High Resolution Radiometer (AVHRR) ice motion data. The results show that the data quality of six satellite products is better than or close to expected values. The error distributions of the satellite ice motion generally have high kurtosis and heavy tails and are not normally distributed. Low-resolution ice motion generally shows large errors in the Fram Strait. AVHRR summer ice motion shows a larger bias, probably affected by inaccurate cloud masking, while the large errors in ASAR ice motion mainly occur due to occasional geolocation errors of near-real-time ASAR images used for ice motion retrieval. Inter-comparison between satellite ice motion products with different time intervals is also discussed. [ABSTRACT FROM PUBLISHER]

Stable isotope and fatty acid trophic markers (FATMs) were used to assess carbon flow and trophic structures of sympagic, pelagic and benthic communities in high-Arctic Svalbard. Three regions were sampled: Northwest Svalbard – dominated by Atlantic water (AtW) and limited seasonal sea ice; Northern Svalbard – dominated by AtW and perennial sea ice; and Northeast Svalbard – dominated by Arctic water (ArW) and extensive seasonal sea ice. Three to four trophic levels (TL) were found in the three habitats, with a dominance of omnivores (TL = 2.4–2.7). Ice fauna relied on phytoplankton and ice algae, zooplankton primarily on phytoplankton, while benthos relied on ice algae/refractory material. Ice fauna (mean 39%; range 17–62%) and benthos (mean 25%; range 11–65%) had high proportions of diatom-FATMs, while zooplankton had equally high diatom- andPhaeocystis/dinoflagellate-FATMs (mean 11% and 15%, respectively).Calanus-FATMs were prominent in carnivorous ice fauna (up to 28%) and zooplankton (up to 38%), but also in benthic invertebrates (up to 41%). Ice fauna biomass was low. Biomass of zooplankton and benthic infauna were variable, but positively correlated to each other (r2=0.89;p<0.01) and sedimentary pigment concentrations (r2>0.40;p<0.05). The coinciding peak biomasses of zooplankton and benthos in Northeast Svalbard can be explained by allochthonous organic matter of ice algal origin and highly specialized Arctic zooplankton utilizing both ice algae and phytoplankton carbon sources. [ABSTRACT FROM AUTHOR]

A technique is demonstrated to enhance the contrast between sea ice and low-level water clouds. The approach uses the brightness temperature difference (BTD) feature from data collected in the split-window, mid-wavelength infrared (IR) region (i.e. two bands at 3.7 μm and 4.0 μm). These spectral data are available with Visible Infrared Imager Radiometer Suite (VIIRS) moderate-resolution bands M12 and M13, respectively. Under daytime conditions, the data collected in these bands contain energy that originates from both the sun and the Earth–atmosphere system. Due to the small wavelength difference between these, the terrestrial energy component in the bands is typically quite similar as are the surface reflectances for sea ice and ocean surfaces. Thus, the enhanced contrast between sea ice and water clouds, evident in a M12–M13 BTD image, results from differences in the solar energy, which decreases rapidly across this atmospheric window. Observed BTD values for water clouds can exceed 30K, while those for snow-ice fields are typically much smaller (e.g. 0–5K). Thus, water clouds appear bright in the image while sea ice, oceans, and most land surfaces are very dark. The enhanced contrast in the split-window, mid-wave IR BTD image makes it valuable for both image analysis and use in cloud algorithms. In addition, these images support the creation of manually generated cloud masks that have been shown useful for quantitatively evaluating the performance of automated cloud analysis algorithms and cloud forecast models. In this article, the value of 3.7 μm minus 4.0 μm BTD imagery for distinguishing between sea ice and low-level water clouds is shown using VIIRS data collected over the Beaufort Sea on 31 May 2012. Manually generated cloud masks, derived in part from these data, are then used to quantitatively evaluate the effectiveness of various cloud tests, including those used in the VIIRS cloud mask algorithm and the Moderate Resolution Imaging Spectroradiometer (MODIS) cloud mask algorithm. The results strongly suggest that split-window, mid-wavelength IR imagery provides valuable information to help differentiate between clouds and sea ice. It is concluded that collecting data in these mid-wavelength IR bands should be considered part of any future satellite sensor designed for environmental monitoring, especially over the polar regions. [ABSTRACT FROM PUBLISHER]

This article advances a vulnerability framework to understand how climatic risks and change are experienced and responded to by Inuit harvesters using a case study from Iqaluit, Nunavut. The article makes important contributions to methodological design in vulnerability studies, emphasizing the importance of longitudinal study design, real-time observations of human–environment interactions, community-based monitoring, and mixed methods. Fieldwork spanned five years, during which sixty-four semistructured interviews were conducted and historical records examined to develop an understanding of the processes and conditions affecting vulnerability. A local land use monitoring team was established, collecting ∼22,000 km of land use Global Positioning System (GPS) data and engaging in biweekly interviews (more than 100) on exposure, sensitivity, and adaptive capacity. This was complemented by analysis of instrumental data on sea ice and climate conditions. Results indicate that sea ice conditions are changing rapidly and affecting trail conditions, safety, and access to harvesting grounds. GPS data and biweekly interviews document real-time adaptations, with traditional knowledge and land-based skills, resource use flexibility, and mobility underpinning significant adaptability, including utilizing new areas, modifying trail routes, and taking advantage of an extended open water season. Sociospatial reorganization following resettlement in the 1950s and 1960s, however, has created dependency on external conditions, has reduced the flexibility of harvesting activities, and has affected knowledge systems. Within the context of these “slow” variables, current responses that are effective in moderating vulnerability could undermine adaptive capacity in the long term, representing overspecialized adaptations, creating the potential for further loss of response diversity and flexibility, and engendering potential downstream effects, creating trajectories of maladaptation. These findings challenge previous research that has argued that current resilience of the Inuit socioecological system is indicative of high adaptive capacity to future change and indicates that climate change might pose more serious risks to the harvesting sector than previously assumed. [ABSTRACT FROM PUBLISHER]

New procedures have been developed to help identify snow and sea ice with the Suomi-National Polar-orbiting Partnership (S-NPP) Visible Infrared Imager Radiometer Suite (VIIRS) Cloud Mask (VCM) algorithm. The accurate detection of snow and sea ice is necessary in order to apply the correct spectral tests needed to detect clouds and make accurate cloud confidence classifications. During the VCM Calibration Validation activity, it was found that the procedures in place at the time of the satellite launch occasionally produced four types of misclassifications: (1) snow and/or ice surfaces in dry atmospheric regions misclassified as clouds, (2) multi-layered clouds in humid regions misclassified as snow, (3) low-level clouds with glaciated tops misclassified as sea ice, and (4) frozen lakes not classified as ice. The new procedures presented in this article use data collected in the VIIRS mid-wavelength region, i.e. both the 3.7μm and 4.0μm bands, as well as the 12.0μm IR band to eliminate all four types of misclassifications. The results demonstrate that split window, mid-wavelength IR imagery provides valuable information for developers of automated cloud classification algorithms as well as those who generate sea ice analyses in support of ocean navigation during polar wintertime conditions. It is concluded that collecting data in these mid-wavelength IR bands should be considered part of any future satellite sensor designed for environmental monitoring. [ABSTRACT FROM AUTHOR]

Bottom-fast ice (BFI) refers to sea or lake ice that freezes to the sea or lake bed. The formation of BFI plays an important role in the Mackenzie Delta Region's seasonal environmental changes. This study involves examining the use of Synthetic Aperture Radar (SAR) images for delineating BFI from floating ice on a study site within the coastal region of the Mackenzie Delta. The ultimate aim is to establish robust BFI monitoring tools using SAR data processing techniques. BFI detection methodologies based on polarimetric SAR (PolSAR) image classification and interferometric SAR (InSAR) coherence segmentation have been examined using RADARSAT-2 data. Polarimetric analysis can use individual SAR images and is not susceptible to decorrelation factors such as weather events. By using these analysis techniques it is thus possible to delineate BFI extent throughout the winter. A limitation of these techniques is the sensitivity to the water and consequently the ice saline content. The polarimetric decompositions and classifications for delineation of BFI apply only to areas where the water has a low saline concentration. Conversely, InSAR methods for BFI delineation require interferometric datasets with high temporal coherence. The results of the interferometric datasets can eliminate false alarms in BFI maps caused by similar backscattered SAR signal from floating ice with varying degrees of salinity. The delineation results using both methods were analyzed and compared. It was found that though each method is able to detect and delineate BFI on its own, reliable and more accurate results occur when the two methods are combined, as the reliance on different phenomena allow for false alarm identification. [ABSTRACT FROM AUTHOR]

Microwave radiometric vapour density (absolute humidity) profiles over the unconsolidated sea-ice surface of Amundsen Gulf in Canada's western maritime Arctic and the moisture continuity equation were used to determine hourly latent heat flux convergence and divergence profiles from January to April 2008. Only hours with clear skies were included to eliminate moistening or drying as a result of the phase change of water. For 273 hours, latent heat flux convergence in the lower atmospheric boundary layer (ABL) was attributed to mesoscale upward latent heat flux at the surface; for 318 hours, latent heat flux divergence in the lower ABL was attributed to downward latent heat flux. The frequency distribution of latent heat flux values, determined by the integral profile method, was approximately normal; flux values ranged from −29.9 to +28.5 W m−2; the median was −0.4; the mean was −0.3, and the mode was +0.4 W m−2. It was concluded that, at the mesoscale, latent heat flux is a minor component of the surface energy budget over unconsolidated sea ice. RÉSUMÉ [Traduit par la rédaction] Nous avons utilisé des profils radiométriques hyperfréquences de densité de vapeur (humidité absolue) au-dessus de la glace de mer non consolidée dans golfe d'Amundsen, dans l'ouest de l'Arctique maritime canadien, de pair avec l’équation de continuité de l'humidité pour déterminer les profils horaires de convergence et de divergence de flux de chaleur latente de janvier à avril 2008. Nous n'avons retenu que les heures où le ciel était clair pour éliminer l'humidification ou l'assèchement résultant du changement de phase de l'eau. Pour 273 heures, nous avons attribué la convergence du flux de chaleur latente dans la basse couche limite atmosphérique au flux de chaleur latente vers le haut à mésoéchelle à la surface; pour 318 heures, nous avons attribué la divergence du flux de chaleur latente dans la basse couche limite atmosphérique au flux de chaleur latente vers le bas. La distribution de fréquences des valeurs de flux de chaleur latente, déterminée selon la méthode du profil intégral, était approximativement normale; les valeurs de flux variaient entre −29,9 et +28,5 W m−2; la médiane était −0,4; la moyenne −0,3; et le mode +0,4 W m−2. Nous avons conclu qu’à la mésoéchelle, le flux de chaleur latente est une composante mineure du bilan énergétique de surface au-dessus de la glace de mer non consolidée. [ABSTRACT FROM AUTHOR]

Dynamics of Arctic sea ice, including motion and deformation, are studied utilizing data from the Advanced Microwave Scanning Radiometer for the Earth Observing System (EOS) (AMSR-E) during 2005 and 2007. We first derive sea ice motion maps from the satellite data in a grid of 100 km × 100 km using a two-dimensional wavelet method. These sea ice motion results are compared with those derived from buoy data from the International Arctic Buoy Programme. Secondly, it is well known that sea ice deformation can be characterized by a strain-rate tensor calculated from the ice velocity field. Two components of the strain-rate tensor quantify the divergence and the shearing of the ice field, respectively. Daily maps for both sea ice motion and strain-rate tensor, as well as monthly averages and spatial sums, are computed and analysed. Comparison of the monthly ice motion maps for May 2005 and May 2007 indicates that the anti-cyclonic Beaufort Gyre and Transpolar Drift Stream in the western Arctic are relatively stronger during 2007 than 2005. Different patterns in the spring months' sea ice deformation rates as characterized by the absolute values of the strain-rate tensor are observed when we compare the data of 2007 with those of 2005 and 2006. The sea ice deformation activities in the spring of 2007 happen earlier and are relatively stronger than that of 2005 and 2006. These results might help to explain why the sea ice extent in the summer of 2007 is unprecedentedly low. [ABSTRACT FROM PUBLISHER]

Interpreting satellite microwave sea ice data during the melt season is difficult. Warm temperatures allow for a greater presence of water in the liquid phase at the surface and within the ice, resulting in similar backscattering responses for first-year ice (FYI) and multi-year ice (MYI). Differentiating these ice types is important, especially during summer, in view of the higher presence of seasonal marine traffic, functioning of the ecosystem, and the Inuit use of the marine icescape in summer. In this article, we investigate the similarities between geophysical, thermodynamic, and dielectric characteristics of the late-season MYI and FYI, and discuss how this can lead to a false detection of MYI. The study uses Radarsat-2 data for ice detection during summer. This involves an analysis of co-polarization versus cross-polarization (HH vs. HV), various incident angles (20°, 35°, and 45°), and ice types (FYI vs. MYI). Statistical analyses of the measurements obtained in 2009 identify the difficulty in differentiating ice types during summer. The results show that the physical and electromagnetic properties of the ice surfaces are virtually identical with few differences in the scattering of microwave energy. We conclude with suggestions on how a more effective differentiation of MYI and FYI types in the summer season can be accomplished. [ABSTRACT FROM AUTHOR]

What are the risks of a runaway greenhouse effect from methane release from hydrates in the Arctic? In January 2013, a dramatic increase of methane concentration up to 2000 ppb has been measured over the Arctic north of Norway in the Barents Sea. The global average being 1750 ppb. It has been suggested that methane normally trapped under the sea ice is now released more easily, especially in areas with reduced sea-ice extent. These high methane concentrations are possibly related to the destabilization of the methane gas hydrates in the Arctic shelf. Is this the start of a runaway greenhouse effect? Methane gas hydrates are solid, ice-like mixtures of water and methane. They are stable under relatively low temperatures and high pressures. These conditions can be found naturally in permafrost regions or under submarine continental slopes. Hydrates accumulate a large amount of gas. One cubic meter can include up to 160 m3of methane. Their huge amount of stored energy and the wide geographical distribution make hydrates an attractive potential energy source. However, they are also suspected to be a source of global climate change and geological hazard, but the risk is still uncertain. Due to the quasi-stability of methane hydrates, any intervention in the temperature–pressure equilibrium could trigger hydrate dissociation followed by methane emissions, a runaway greenhouse effect, and potential underwater landslides. Here, some consequences for climate change of methane emissions to the atmosphere are analyzed in a scenario study. [ABSTRACT FROM PUBLISHER]

Hourly temperature profile sequences from a time series of radiometric soundings over Amundsen Gulf in Canada's western maritime Arctic were used to establish the general shape of heat flux convergence (heat accumulation) profiles attributable to mesoscale sensible heat flux from the unconsolidated sea-ice surface. This sensible heat flux signature profile was then used to identify 520 similar heat flux convergence profiles in the January–April 2008 period. Only hours with clear skies were included to eliminate heat flux convergence resulting from enhanced downwelling longwave radiation, which often accompanies cloud cover, and heating caused by the phase change of water. The median heat flux convergence profile attributed to sensible heat flux decreased logarithmically with height. The sensible heat flux ranged from near 0 to 183 W m−2; the median was 11.4 W m−2; the average was 21.1 W m−2; the mode was 0.1 W m−2. These sensible heat flux estimates are reliable because they are based on the fundamental principle of heat conservation and measured temperature profiles. A relationship best described by a fourth-order polynomial was found between the magnitude of the sensible heat flux and the vertical extent of the heat flux convergence(h)which indicated a nearly linear increase inhfrom 50 to 350 m as the sensible heat flux increased from near 0 to 28 W m−2and a plateau inhat about 500 m for sensible heat flux above 80 W m−2. RÉSUMÉ [Traduit par la rédaction] Nous avons utilisé des séquences de profils de température horaire d'une série chronologique de sondages radiométriques au-dessus du golfe d'Amundsen dans l'Arctique maritime de l'ouest du Canada pour établir la forme générale des profils de convergence de flux de chaleur (accumulation de chaleur) attribuable au flux de chaleur sensible à mésoéchelle provenant de la surface non consolidée de la glace de mer. Nous avons ensuite employé ce profil signature de flux de chaleur sensible pour identifier 520 profils de convergence de flux de chaleur semblables au cours de la période de janvier à avril 2008. Nous n'avons pris en compte que les heures de ciel clair pour éliminer la convergence de flux de chaleur résultant du rayonnement accru de grandes longueurs d'onde qui accompagne souvent les ciels couverts de même que le réchauffement dû au changement de phase de l'eau. Le profil médian de convergence de flux de chaleur attribué au flux de chaleur sensible diminuait de façon logarithmique avec la hauteur. Le flux de chaleur sensible variait de près de 0 jusqu’à 183 W m−2; la médiane était de 11.4 W m−2; la moyenne était de 21.1 W m−2; le mode était 0.1 W m−2. Ces estimations de flux de chaleur sensible sont fiables parce qu'elles sont basées sur le principe fondamental de la conservation de la chaleur et sur des profils de température mesurés. Nous avons trouvé une relation, bien décrite par un polynome du quatrième ordre, entre la grandeur du flux de chaleur sensible et l'extension verticale de la convergence de flux de chaleur(h), qui indique un accroissement quasi linéaire dehde 50 à 350 m lorsque le flux de chaleur sensible passe de près de 0 jusqu’à 28 W m−2, et un plateau dehà environ 500 m pour un flux de chaleur sensible supérieur à 80 W m−2. [ABSTRACT FROM AUTHOR]

The consistency in first-year sea ice classification potential of C-band SAR polarimetric parameters was analyzed by comparing the results of two studies conducted for the same ice types under different geophysical settings. The SAR images used in the comparison were acquired at an incidence angle difference of 4°. Probability density functions, grey level parameter images, and classification statistics derived using k-means classifier were used in the comparative analysis. The investigation showed that not all polarimetric parameters exhibit consistency in their classification performance under different geophysical settings. Out of the 20 polarimetric parameters analyzed, 12 demonstrated high levels of classification consistency between the two studies. Among these 12 parameters, only four possessed high classification accuracy and could be applicable for sea ice classification under variable environmental conditions. The parameters that showed the highest classification accuracies in both the studies were found to be inconsistent in their ice type separation capabilities. The signatures of these parameters differed for one or more ice types when compared between the two studies. The utility of these parameters in individual sea ice classification studies is recommended but their relevance in generalized sea ice classification scheme is unclear. [ABSTRACT FROM AUTHOR]

Clustering is a technique that can be applied for unsupervised classification of polarimetric synthetic aperture radar (POLSAR) data, an important analysis technique of radar polarimetry. Six matrix distance measures have been investigated and compared through an agglomerative clustering of RADARSAT-2 POLSAR data. The considered matrix distance measures were used as similarity criteria for merging clusters hierarchically into an appropriate number of classes. In this study, the considered distances are Manhattan, Euclidean, Bartlett, revised Wishart, Wishart test statistic, and Wishart Chernoff. Results show that the Bartlett, revised Wishart, and Wishart Chernoff distances all produce identical classification results. The Manhattan distance retrieved classification results close to those obtained by the Euclidean distance. The Bartlett, revised Wishart, and Wishart Chernoff distances produced the most accurate classification results. The study area is located in Hudson Bay offshore Churchill, Manitoba, Canada. [ABSTRACT FROM PUBLISHER]

One of the routes for thick, multi-year sea ice (MYI) exiting the Arctic Ocean is through the Queen Elizabeth Islands (QEI) in the Canadian Arctic. Quantifying the volume of MYI that passes through the QEI and the associated transit times is important for assessing changes in Arctic-wide MYI amount. It is also important because MYI eventually invades the Northwest Passage and affects Arctic shipping. One of the main gateways through which Arctic sea ice enters the QEI is the Prince Gustaf Adolf Sea. In this study, sea-ice influx events into the Prince Gustaf Adolf Sea during the 2010 mobile-ice season were investigated. Sea-ice motion was derived from RADARSAT imagery using the Canadian Ice Service-Automated Sea Ice Tracking System (CIS-ASITS) and validated using data from two CIS satellite-tracked beacons. Ice motion results indicate that major ice influxes through the Prince Gustaf Adolf Sea occur as a series of wind-driven pulses and that ice drift rates are approximately 1–2% of the wind speed. During intervals of southward ice drift in 2010, the drift speed along the eastern side of the Prince Gustaf Adolf Sea was up to twice as fast as that along the western side. This east–west gradient may reflect a pattern of ocean circulation in the Prince Gustaf Adolf Sea that has not yet been delineated. RÉSUMÉ [Traduit par la rédaction] Les îles de la Reine-Élizabeth dans l'Arctique canadien sont l'un des chemins qu'emprunte la glace de mer épaisse de plusieurs années quand elle sort de l'océan Arctique. Il est important de mesurer le volume de glace de plusieurs années qui traverse les îles de la Reine-Élizabeth de même que les temps de parcours pour évaluer les changements dans la quantité de glace de plusieurs années dans l'ensemble de l'Arctique. Ceci est aussi important parce que celle-ci envahit éventuellement le passage du Nord-Ouest et nuit à la navigation dans l'Arctique. L'un des principaux passages par où transite la glace de l'Arctique entre les îles de la Reine-Élizabeth est la mer du Prince-Gustaf-Adolf. Dans cette étude, nous avons examiné les événements d'afflux de glace de mer dans la mer du Prince-Gustaf-Adolf durant la saison de glace mobile de 2010. Le mouvement de la glace de mer a été dérivé des images RADARSAT au moyen du système automatisé de poursuite des glaces de mer du Service canadien des glaces (CIS-ASITS) et validé à l'aide des données de deux radiophares du Service canadien des glaces suivis par satellite. Les résultats sur le mouvement des glaces indiquent que les afflux importants de glace à travers la mer du Prince-Gustaf-Adolf se produisent comme une série d'impulsions sous l'effet du vent et que les vitesses de dérive de la glace sont approximativement de 1 à 2% de la vitesse du vent. Durant les périodes de dérive de la glace vers le sud en 2010, la vitesse de dérive le long du côté est de la mer du Prince-Gustaf-Adolf était jusqu’à deux fois plus élevée que le long du côté ouest. Ce gradient est–ouest peut être le reflet d'une circulation océanique dans la mer du Prince-Gustaf-Adolf qui n'a pas encore été délinéée. [ABSTRACT FROM AUTHOR]

This paper describes a new regional ice analysis system developed at Environment Canada. It is primarily designed to satisfy the requirements for planning of marine transportation and other marine operations in ice-infested waters around North America, including Canada's two Arctic Metareas; regional sea-ice model initialization; and the needs of regional numerical weather prediction models. A three-dimensional variational approach (3D-Var) is used to assimilate various types of observations. In this first version, only analyses of ice concentration are produced at approximately 5 km resolution using a 6 h persistence forecast from the previous analysis as the background state. The assimilated observations are sea-ice concentrations from two sources of passive microwave satellite data, Advanced Microwave Scanning Radiometer-Earth observing system (AMSR-E) and Special Sensor Microwave/Imager (SSM/I), and manually derived ice charts from the Canadian Ice Service (CIS). Objective verification scores computed from independent data are used to evaluate the accuracy of the analyses in comparison with other available sources of ice information. This comparison demonstrates that the new analyses have consistently more accurate ice extent compared with the currently operational global sea-ice analyses at the Canadian Meteorological Centre. It also shows that the early morning analysis can provide marine transportation clients with a valuable update to the most recently available CIS daily ice chart. RÉSUMÉ [Traduit par la rédaction] Cet article décrit un nouveau système d'analyse régionale des glaces mis au point à Environnement Canada. Il est principalement conçu pour répondre aux exigences de la planification du transport maritime et autres opérations maritimes dans les eaux infestées de glace entourant l'Amérique du Nord, y compris les deux régions météorologiques arctiques du Canada, pour l'initialisation du modèle régional de glaces de mer et pour les besoins des modèles régionaux de prévision météorologique numérique. Nous utilisons une approche variationnelle tridimensionnelle (3D-VAR) pour assimiler différents types d'observations. Dans cette première version, seules des analyses de la concentration de la glace sont produites avec une résolution d'environ 5 km à l'aide d'une prévision de 6 h basée sur la persistance à partir de l'analyse précédente utilisée comme l'ébauche. Les observations assimilées sont les concentrations de la glace de mer de deux sources satellitaires de données hyperfréquences passives — le radiomètre à balayage hyperfréquences de pointe du Système d'observation de la Terre (AMSR-E) et le capteur hyperfréquences spécialisé/imageur (SSM/I) — et les cartes des glaces élaborées manuellement du Service canadien des glaces (SCG). Nous utilisons des indices de vérification objectifs calculés à partir de données indépendantes pour évaluer l'exactitude des analyses par comparaison avec d'autres sources d'information sur les glaces disponibles. Il ressort que les nouvelles analyses ont constamment des étendues de glaces plus exactes que les analyses globales opérationnelles courantes des glaces de mer employées au Centre météorologique canadien. Cela montre aussi que l'analyse préliminaire du matin peut fournir aux clients du transport maritime une mise à jour valable de la plus récente carte quotidienne des glaces du SCG. [ABSTRACT FROM AUTHOR]

Based on a theoretical approach of diaspora theory and the use of ethnographical comparative analysis, it is argued that the early settlement of South Norway probably brought about diasporic conditions. Archaeological and natural science records are applied to discuss the migrations of mobile hunter-gatherers with a shamanistic reindeer culture from the Continent, after deglaciation of the Weichselian ice cap. This paper discusses the diasporic people's identity, their survival as a group, their adaptation to the new environment and the development of an independent reindeer culture characterized by relics and meeting places, after the break in the regular contact between people in the area of origin and South Norway. [ABSTRACT FROM AUTHOR]

To identify flow pathways through the Canadian Arctic Archipelago, numerical model results were examined using two configurations of the Nucleus for European Modelling of the Ocean (NEMO). After correcting for shortwave radiation, the models captured much of the observed spatiotemporal structure of the sea-ice and ocean circulation in the Canadian Arctic Archipelago, especially the southward flow in M'Clintock Channel and the cyclonic circulation in eastern Lancaster Sound. The southward flow in M'Clintock Channel is driven by ageostrophic accelerations and is controlled by topography. Vorticity dynamics analysis showed that both stratification and bathymetry have a strong impact on the circulation in eastern Lancaster Sound. RÉSUMÉPour identifier les trajets d’écoulement à travers l'archipel Arctique canadien, nous avons examiné les résultats de modèles numériques en utilisant deux configurations du NEMO (Nucleus for European Modelling of the Ocean). Après avoir appliqué une correction visant à tenir compte du rayonnement de courtes longueurs d'onde, les modèles capturent la majeure partie de la structure spatiotemporelle de la glace de mer et de la circulation océanique dans l'archipel Arctique canadien, en particulier l’écoulement vers le sud dans le détroit de M'Clintock et la circulation cyclonique dans l'est du détroit de Lancaster. L’écoulement vers le sud dans le détroit de M'Clintock est dû à des accélérations agéostrophiques et est contrôlé par la topographie. L'analyse de la dynamique tourbillonnaire a montré que tant la stratification que la bathymétrie ont un effet marqué sur la circulation dans l'est du détroit de Lancaster. [ABSTRACT FROM AUTHOR]

Foxe Basin is an Arctic inland sea located at the north of the Hudson Bay system (Canada). The characteristics of its estuarine circulation in winter differ from those in summer, mainly because of the sea-ice formation and cover. Using Lagrangian tracers and flux calculations from simulated data through a section at the outlet of the basin, we have shown that one-third of all the ice produced in winter is eventually exported toward the Labrador Sea. Foxe Basin is also a place where, in winter, latent heat polynyas to the west coexist with sensible heat polynyas around southwestern Foxe Peninsula, the latter resulting from an upwelling of intermediate water approximately 0.6°C above the freezing point of seawater. Sea ice affects circulation in the basin by adding friction at the surface layer and by shielding the sea surface from the atmosphere, which leads to an average reduction of 11% in the surface currents. Sea ice also extracts approximately 1.3 × 1014 kg of fresh water from the sea surface. Divided by Foxe Basin's surface area (0.2 × 1012 m2) and by the freshwater density, this mass represents a mean layer of 0.65 m of fresh water. The salt transport anomaly versus depth at the outlet of the basin and the mean vertical buoyancy flux were also examined; this confirmed previous assumptions that the estuarine circulation forms a positive (summer)–negative (winter) couple. We suggest that the sensitivity of this couple to climate change may be used as a proxy to evaluate the impact of global warming in Foxe Basin. RÉSUMÉ [Traduit par la rédaction] Le bassin de Foxe est une mer intérieure arctique située au nord du système de la baie d'Hudson (Canada). Les caractéristiques de sa circulation estuarienne en hiver diffèrent de celles de l’été, principalement à cause de la formation et de la couverture de glace de mer. Au moyen de traceurs lagrangiens et de calculs de flux basés sur des données simulées à travers une section à la sortie du bassin, nous avons montré que le tiers de toute la glace produite en hiver est éventuellement exporté vers la mer du Labrador. Le bassin de Foxe est aussi un endroit où, en hiver, des polynies de chaleur latente à l'ouest coexistent avec des polynies de chaleur sensible autour du sud-ouest de la péninsule de Foxe, ces dernières étant produites par des remontées d'eau intermédiaire dont la température est approximativement 0,6 °C au-dessus du point de congélation de l'eau de mer. La glace de mer influe sur la circulation dans le bassin en ajoutant du frottement dans la couche de surface et en faisant écran entre la surface de la mer et l'atmosphère, ce qui provoque une réduction de 11% dans les courants de surface. La glace de mer extrait aussi environ 1,3 × 1014 kg d'eau douce de la surface de la mer. Divisée par la superficie du bassin de Foxe (0,2 × 1012 m2) et par la masse volumique de l'eau douce, cette masse représente une couche moyenne de 0,65 m d'eau douce. Nous avons aussi examiné l'anomalie de transport de sel en fonction de la profondeur à la sortie du bassin et le flux vertical moyen de flottabilité; cela a confirmé des hypothèses précédentes selon lesquelles la circulation estuarienne forme un couple positif (été) – négatif (hiver). Nous croyons que la sensibilité de ce couple au changement climatique peut servir d'indicateur pour évaluer l'impact du réchauffement planétaire dans le bassin de Foxe. [ABSTRACT FROM AUTHOR]

This study examines the main physical processes affecting the interannual variability of circulation over the eastern Canadian continental shelf (ECS) based on numerical circulation results for the period 1988–2004 produced by a regional ocean–ice model. The regional circulation model is applied to the northwest Atlantic and uses a horizontal curvilinear grid with a horizontal resolution of approximately 1/4°. The model is forced by atmospheric reanalysis fields produced by Large and Yeager (2004) and boundary forcing based on the ocean reanalysis data produced by Smith et al. (2010). In comparison with previous observational and numerical results in the literature, the regional circulation model has reasonable skill in simulating the large-scale circulation and associated seasonal and interannual variability over the ECS. Complex Empirical Orthogonal Function (CEOF) analysis is used to examine the interannual variability in the monthly mean temperature and salinity anomalies in the model. The CEOF analysis of model results demonstrates that the interannual variability over the Labrador and northern Newfoundland shelves is significantly affected by the variability at high latitudes which propagates onto these shelves through the northern open boundary. Over the eastern Newfoundland Shelf, the interannual variability is significantly affected by the non-linear interaction of the Labrador Current with the North Atlantic Current and by the variability propagating from the southern Labrador Shelf. The interannual variability of circulation and hydrography over the Slope Water region off the Scotian Shelf is significantly affected by anomalies advected by the Gulf Stream and by the non-linear dynamics taking place in the deep waters to the south of the Tail of the Grand Banks. RÉSUMÉ[Traduit par la rédaction] La présente étude examine les principaux processus physiques ayant une influence sur la variabilité interannuelle de la circulation dans l'est du plateau continental canadien (ECS) d'après les résultats numériques de circulation pour la période 1988–2004 obtenus d'un modèle régional océan–glace. Le modèle de circulation régional est appliqué au nord-ouest de l'Atlantique et utilise une grille curvilinéaire horizontale ayant une résolution horizontale d'approximativement 1/4°. Le modèle est forcé par des champs de réanalyse atmosphériques produits par Large et Yeager (2004) et subit un forçage aux limites basé sur des données de réanalyse océaniques produites par Smith et coll. (2010). Comparativement aux résultats observationnels et numériques précédents que l'on trouve dans la littérature, le modèle de circulation régional possède une habileté raisonnable pour la simulation de la circulation à grande échelle et de la variabilité saisonnière et interannuelle associée sur l'ECS. Nous utilisons l'analyse par fonctions orthogonales empiriques complexes (CEOF) pour examiner la variabilité interannuelle des anomalies mensuelles moyennes de température et de salinité dans le modèle. L'analyse par CEOF des résultats du modèle montre que la variabilité interannuelle sur les plateaux du Labrador et du nord de Terre–Neuve est significativement influencée par la variabilité aux hautes latitudes qui se propage sur ces plateaux à travers la limite nord ouverte. Sur le plateau de l'est de Terre–Neuve, la variabilité interannuelle est significativement influencée par l'interaction non linéaire du courant du Labrador avec le courant de l'Atlantique Nord et par la variabilité se propageant depuis le plateau du sud du Labrador. La variabilité interannuelle de la circulation et de l'hydrographie dans la région du talus continental au large du plateau néo-écossais est significativement influencée par les anomalies advectées par le Gulf Stream et par la dynamique non linéaire se produisant dans les eaux profondes au sud de la queue des Grands Bancs. [ABSTRACT FROM AUTHOR]

In this study, the classification potential of polarimetric parameters derived after Cloude-Pottier decomposition, Touzi decomposition, Freeman-Durden decomposition, normalized radar cross section measurements, phase differences, and statistical synthetic aperture radar correlation measures is evaluated by relating them to three pre-identified sea ice types and wind-roughened open water. A combined approach that constitutes a visual inspection of estimated probability densities of the polarimetric parameters and quantitative analysis using supervised classifications (k means and maximum likelihood) is adopted. Polarimetric parameters are iteratively combined in pairs and triplets to test for their ice type discrimination potential. Sensitivity of polarimetric parameters to radar incidence angle is also examined. Our results demonstrated strong but variable sensitivity of polarimetric parameters to different ice types, which was dependent on radar incidence angle. Results of parameter evaluation demonstrated that no single parameter discriminates significantly (>60%) between all the ice types considered in the study. Combining two low correlated parameters increased the classification accuracy by 10%-22%. Combining the third polarimetric parameter did not necessarily improve the classification results. However, the best classification results were achieved using a combination of three parameters. [ABSTRACT FROM AUTHOR]

Dual-polarization synthetic aperture radar (SAR) image data, such as that available from RADARSAT-2, provide additional information for discriminating sea ice types compared with single-polarization data. We performed a thorough investigation of published feature extraction and fusion techniques to make optimal use of this additional information for unsupervised sea ice image segmentation. Segmentation was performed by transforming the dual-pol data (i) into a new two-channel feature space (multivariate) and (ii) into a fused single-channel feature space (univariate). Both real and synthetic dual-polarization SAR sea ice images were transformed using a variety of methods and segmented using a recognized SAR segmentation algorithm (IRGS). The results indicated that the untransformed data provides consistent and high segmentation accuracy, avoids feature extraction pre-processing, and is thus recommended for SAR sea ice image segmentation using dual-pol imagery. [ABSTRACT FROM AUTHOR]

Every year, an area of sea ice forms around the continent of Antarctica that is inhabited by communities of microbes. Although the microbial component of this habitat has been postulated to play an ecologically important role in the Southern Ocean, our understanding of the diversity of Antarctic sea-ice bacteria is limited. The aim of this study was to identify bacterial components present in sea ice at Cape Hallett. Total community DNA was isolated from sea-ice cores and the 16S ribosomal RNA genes were amplified by polymerase chain reaction (PCR) using a range of universal and targeted primer sets. PCR products were de-replicated using restriction fragment length polymorphism (RFLP) and distinct RFLP types were sequenced. The major bacterial classes identified consisted of α-proteobacteria, γ-proteobacteria, Cytophaga- Flavobacteria-Bacteroides group and a small number of Gram-positive species. Our findings indicate that the bacterial component of sea ice at Cape Hallett is primarily heterotrophic. Cyanobacteria and Archaea were not detected using the methods and primer sets employed in this study. However, bacteria whose 16S rDNA sequences cluster with species that encode phototrophic genes were detected in our sea-ice samples. This raised the possibility that bacterial phototrophy may occur in Antarctic sea ice. [ABSTRACT FROM AUTHOR]

This article examines how the Inuit of Qikiqtarjuaq, Canada, perceive and respond to risk when traveling on the land and how this may enhance safety management in Auyuittuq National Park. Twenty-five interviews and groups meetings were held with community experts and park staff in 2007–2008. The way in which the Inuit of Qikiqtarjuaq perceive and respond to risk is better understood as their safety culture, which arises from a distinct socioecological context. This safety culture is tied to the past, maintained through relationships, specialized to the arctic environment, developed through experience, and connected to Inuit identity. For Auyuittuq National Park, the safety program follows a national framework with a strong focus on planning and reporting, the capacity of the local offices being limited. Since Auyuittuq National Park depends on local capacity to fulfill its responsibilities, we discuss ways to foster a better understanding and respect of the cross-cultural dimensions of safety. [ABSTRACT FROM AUTHOR]

Arctic sea ice undergoes a very strong annual cycle. This study sets out to look at the transition when the Arctic sea ice starts to melt using satellite-obtained passive microwave brightness temperatures and satellite-derived albedo data for 13 points within the Arctic, including both first-year and multiyear ice locations, for 1995–2000. Special sensor microwave imager (SSM/I) brightness temperature differences are used to determine melt onset dates once surface temperatures approach freezing. Independently, satellite-derived albedo data are obtained and a melt onset date is derived. Generally, the two methods produce the same date for melt onset with optimum conditions. However, in most cases there are clouds present, which for the albedo data restrict observations and generate melt dates that are several days later than the passive microwave melt onset which is not affected by cloud cover. Melt onset dates, determined from the passive microwave brightness temperatures, are compared to those from the albedo observation to determine differences between the two methods. For first-year ice (FYI) locations, the average differences in melt onset dates for the study locations between the passive microwave and albedo-derived methods are +/−3 days. The average difference for multiyear ice (MYI) locations melt onset dates is around 8 days, slightly longer than the (FYI) locations, however, this is due to more cloudy conditions. The results indicate that the passive microwave-derived melt onset dates and albedo-derived dates are very close and either method could be used to determine melt. The advantage of using microwave data would be the independence of having to have cloud free conditions. [ABSTRACT FROM PUBLISHER]

Pohjola, V.A., Christoffersen, P., Kolondra, L., Moore, J.C., Pettersson, R.S., Schäfer, M., Strozzi, T. and Reijmer, C.H., 2011. Spatial distribution and change in the surface ice-velocity field of Vestfonna ice cap, Nordaustlandet, Svalbard, 1995-2010 using geodetic and satellite interferometry data. Geografiska Annaler: Series A, Physical Geography. 93, 323-335. DOI: 10.1111/j.1468-0459.2011.00441.x Abstract During 2007 we launched a geodetic campaign on the Svalbard ice cap Vestfonna in order to estimate the velocity field of the ice cap. This was done within the frame of the IPY project KINNVIKA. We present here the velocity measurements derived from our campaigns 2007-2010 and compare the geodetic measurements against InSAR velocity fields from satellite platforms from 1995/96 and 2008. We find the spatial distribution of ice speeds from the InSAR is in good agreement within the uncertainty limits with our geodetic measurements. We observe no clear indication of seasonal ice speed differences, but we find a speed-up of the outlet glacier Franklinbreen between the InSAR campaigns, and speculate the outlet is having a surge phase. [ABSTRACT FROM AUTHOR]

Kubischta, F., Knudsen, K.L., Ojala, A.E.K. and Salonen, V.-P., 2011. Holocene benthic foraminiferal record from a high-arctic fjord, Nordaustlandet, Svalbard. Geografiska Annaler: Series A, Physical Geography, 93, 227-242. DOI: 10.1111/j.1468-0459.2011.00434.x ABSTRACT This study presents the results of benthic foraminiferal analyses of a marine core record from about 100 m water depth in the fjord environment of Isvika bay, Nordaustlandet, Svalbard. During the Last Glacial Maximum, the bay was glaciated by the north-western sector of the Svalbard-Barents Sea Ice Sheet. The foraminiferal assemblages reflect glaciomarine conditions during deglaciation and early Holocene (about 11 250-9640 cal. yr bp) followed by glacier-distal environment in an open fjord with relatively high influence of Atlantic waters from the open ocean (9640-7430 cal. yr bp). A subsequent foraminiferal indication of a glacial advance was followed by deposition of a diamicton unit within a short time period at 5800-5700 cal. yr bp. The mid- and late Holocene were characterized by assemblages indicating restricted open-ocean connection and gradually more severe conditions, which are considered to be caused partly by a gradual cooling and freshening of the Atlantic water inflow to the shelf area and partly by a continuous isostatic uplift of the area. The foraminiferal record shows that the environmental changes in Murchisonfjorden are not just an effect of changes in solar insolation but are also influenced by local processes, as well as changes in the Atlantic water inflow to the northern Svalbard shelf and to the fjord via Hinlopenstretet. [ABSTRACT FROM AUTHOR]

Beaudon, E., Arppe, L., Jonsell, U., Martma, T., Möller, M., Pohjola, V.A., Scherer, D. and Moore, J.C., 2011. Spatial and temporal variability of net accumulation from shallow cores from Vestfonna ice cap (Nordaustlandet, Svalbard). Geografiska Annaler: Series A, Physical Geography, 93, 287-299. DOI: 10.1111/j.1468-0459.2011.00439.x Abstract We analyse ice cores from Vestfonna ice cap (Nordaustlandet, Svalbard). Oxygen isotopic measurements were made on three firn cores (6.0, 11.0 and 15.5 m deep) from the two highest summits of the glacier located on the SW-NE and NW-SE central ridges. Sub-annual δ18O cycles were preserved and could be counted visually in the uppermost parts of the cores, but deeper layers were affected by post-depositional smoothing. A pronounced δ18O minimum was found near the bottom of the three cores. We consider candidates for this δ18O signal to be a valuable reference horizon since it is also seen elsewhere in Nordaustlandet. We attribute it to isotopically depleted snow precipitation, which NCEP/NCAR reanalysis shows was unusual for Vestfonna, and came from northerly air during the cold winter of 1994/95. Finding the 1994/95 time marker allows establishment of a precise depth/age scale for the three cores. The derived annual accumulation rates indirectly fill a geographical gap in mass balance measurements and thus provide information on spatial and temporal variability of precipitation over the glacier for the period spanned by the cores (1992-2009). Comparing records at the two locations also reveals that the snow net accumulation at the easternmost part of Vestfonna was only half of that in the western part over the last 17 years. [ABSTRACT FROM AUTHOR]

The summer minimum extent of Arctic sea ice shrank drastically in these years, and the opportunity on Arctic international shipping emerged. The Northern Sea Route (NSR), formerly blocked by permanent ice, was completely ice-free in September in the past 3 years. Because this route is much shorter than conventional Asia-Europe shipping lane, many maritime countries have paid attention to exploit the enormous potential of the Arctic Ocean from economical consideration. This study measured the economical advantage of the seasonal NSR by calculating the shipping cost saved. [ABSTRACT FROM AUTHOR]

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The temporal and spatial variability of sea-ice radar signatures in the Southern Ocean during late winter, spring and early summer from QuikSCAT data is presented. We observe a circumpolar and broad band of sea-ice close to the marginal ice zone that is characterized by very high radar backscatter. This feature is explained through detailed in situ observations of snow and sea-ice properties as well as in relation to meteorological conditions, which were derived from US National Center for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis data. Our results indicate that high backscatter regions are caused by metamorphous snow, which forms through re-freezing after short-term melt events. This process is connected with the episodic passes of low-pressure systems entraining warmer air from the north. South of the Antarctic Circumpolar Trough, sea-ice is not affected by this influence and shows spatially homogenous microwave signatures with low backscatter. [ABSTRACT FROM AUTHOR]

Earth scientists use unmanned aerial vehicles (UAVs) to enable measurements and observations that cannot be collected by manned aircraft such as the ER-2, DC-8 or B-200. Science community interest in UAVs to date has largely been focused on the larger class of UAV such as the Global Hawk and Predator, because of the large mass of legacy airborne science instruments. With the continued miniaturization of instruments and data systems and the rapid pace of development of all classes of UAV world-wide during the past decade, smaller classes of UAV are now capable of providing important science measurements and observations. Small (<50 lbs GTOW) and medium-class UAV (>500 lbs GTOW) complement the larger platforms by enabling in situ measurements of the atmospheric boundary layer with low-altitude remote sensing or air sampling, while providing a relatively low cost platform for storm penetration and dangerous, remote missions where the system may not return. The National Aeronautics and Space Administration (NASA) Sensor Integrated Environmental Remote Research Aircraft (SIERRA) project at the Ames Research Center (ARC) has demonstrated the utility of a medium class unmanned aircraft for providing science measurements in remote and dangerous environments using active, passive and in situ earth science instrument payloads. This article describes the SIERRA project, details past and future missions, and discusses the primary requirements for small and medium class UAV. [ABSTRACT FROM AUTHOR]

A new technique is proposed for sea-ice mapping using observations from geostationary satellite over the Caspian Sea. A two end-member linear-mixture approach has been employed. A neural-network-based approach was used to simulate water and ice reflectances for all possible sun-satellite geometries. The ice-mapping technique incorporates an advanced cloud-detection algorithm with adaptive threshold values. The average percentage of cloud reduction because of the daily compositing ranged from 22% to 25%. Daily maps of ice distribution and concentration with minimal cloud coverage were produced for the winter seasons of 2007 and 2008. The retrieved ice distribution demonstrated a good agreement with Moderate Resolution Imaging Spectroradiometer (MODIS) images and National Oceanic Atmospheric Administration (NOAA) Interactive Multisensor Snow and Ice Mapping System (IMS) snow and ice charts. The obtained correlation coefficients with IMS charts for 2007 and 2008 were 0.92 and 0.83, respectively. The technique has been proposed as one of the candidate ice-mapping techniques for the future Geostationary Operational Environmental Satellite-R Series (GOES-R) Advance Baseline Imager (ABI) instrument. [ABSTRACT FROM AUTHOR]

We consider a generalized fifth-order KdV equation with time-dependent coefficients exhibiting higher-degree nonlinear terms. This nonlinear evolution equation describes the interaction between a water wave and a floating ice cover and gravity-capillary waves. By means of the subsidiary ordinary differential equation method, some new exact soliton solutions are derived. Among these solutions, we can find the well known bright and dark solitons with sech and tanh function shapes, and other soliton-like solutions. These solutions may be useful to explain the nonlinear dynamics of waves in an inhomogeneous KdV system supporting high-order dispersive and nonlinear effects. [ABSTRACT FROM AUTHOR]

This article examines the so-called 'Arctic exception,' Article 234 of the 1982 UN Convention on the Law of the Sea. Article 234 is intended to give the coastal state of ice-covered sea areas the necessary powers to prevent, reduce, and control vessel source pollution, which poses a particular risk to the highly sensitive Arctic marine environment. The aim of this article is to present a thorough interpretation of Article 234 in order to eventually evaluate the provision's significance for Arctic navigation, specifically in the Canadian Arctic and the Northwest Passage. [ABSTRACT FROM AUTHOR]

The article presents geographical perspective on geophysical and societal factors affecting the development of northern region, including Eurasia and North America, over the next 40 years. It discusses the bearings of economic and social factors of resource exploitation and migration as driving forces to climatic changes and then highlights key differences among the Northern Rim countries. It also delves on the development of hydrocarbon resources, territorial claims, and offshore sovereignty.

The Inupiat of Arctic Alaska identify themselves as the “People of the Whales.” The flesh of the bowhead whale (Balaena mysticetus) is high in vitamins and other components that traditionally sustained human physiology in a climate that is unsuitable for agriculture. Not surprisingly, the People of the Whales depend on the bowhead for sustenance and cultural meaning. The bowhead remains central to Inupiat life and culture through the hunting process, the communal distribution of meat and other body parts, and associated ceremonials and other events to sustain cultural well-being, which I call the Inupiat whaling cycle. For this study, I coined the term cetaceousness as a hybrid of cetaceous and consciousness, which links human awareness with cetaceans or whales. I use this term to refer to human-whale interactions at all levels. Particularly in Alaska, cetaceousness is a social and emotional process for the Inupiat to communicate with the whales. Based on my ethnographic fieldwork in Barrow and Point Hope, Alaska, from 2004 through 2007, this study reveals how collective uncertainty about the environment is expressed and managed in Inupiat practices and, by extension, how deeply global warming penetrates the cultural core of their society. To do so, I illustrate different aspects of Inupiat-bowhead whale relationships or the ways people make whales a central feature of their lives. By influencing the bowhead harvest and the Inupiat homeland, climate change increases environmental uncertainties that both threaten and intensify human emotions tied to identity. This emotional intensity is revealed in the prevalence of traditional and newly invented whale-related events and performances, the number of people involved, the frequency of their involvement, and the verve or feelings with which they participate. Thus, this study investigates how collective uncertainty about the future of the environment would be expressed and managed in Inupiat practices and, by extension, how deeply climate change penetrates the cultural core of their society. My findings demonstrate how the Inupiat retain and strengthen their cultural identity to survive unexpected difficulties with an unpredictable environment by reinforcing their relationship with the whales. [ABSTRACT FROM AUTHOR]

Climate change is challenging the notions of permanency and stability on which the ideal of the sovereign, territorial state historically has rested. Nowhere is this challenge more pressing than in the Arctic. As states expand their sovereignty claims northward in pursuit of potential opportunities (in many cases made possible by climate change), these same states are being confronted with the region's increasing territorial indeterminacy (which also is exacerbated by climate change). To investigate how climate change is challenging the territorial imaginaries around which notions of sovereignty historically have been based, we turn to three debates in the contemporary Arctic: the question of sovereignty in the Northwest Passage, conflicts over territorial control in the Arctic Ocean, and the potential for enhanced multilateral governance. Through our study of these debates we engage the Arctic both as a region that is undergoing climate change's most extreme impacts and as a laboratory for understanding how these and similar impacts might modify the spatial organization of political authority across the world. [ABSTRACT FROM AUTHOR]

The paper describes changes in winter gale day frequency that took place in the Shetland and Faeroe Isles between ca. AD 1866-1905. During the early part of this period, winter gale day frequencies reached values that have never been exceeded since. During the later part of this time interval, culminating in the winters of 1903-04 and 1904-05, scarcely any gales occurred. The majority of the time interval between 1866 -1895 was characterized by high-amplitude fluctuations in the sign of the North Atlantic Oscillation (NAO) index (extreme positive to extreme negative) and by extreme changes in annual sea ice extent across the Greenland Sea. Between 1866-1894, however, winter gale day frequencies remained consistently high. It is suggested that this unusual relationship may be explained through the important role of sea ice extent across the Greenland Sea affecting the extent of the polar anticyclone and hence the position of the North Atlantic storm track. By contrast, the later part of this time interval (AD 1894-1905) was characterized by very few winter gales and no extremes in the monthly NAO Index. [ABSTRACT FROM AUTHOR]

It is challenging to use traditional remote sensing techniques to accurately determine the extent and thickness of ice in the Bohai Sea, on account of the presence of sea impurities (i.e. mud, salt bubbles and sand) and shape irregularities. Accordingly, we performed a series of reflectance spectra experiments to empirically link remote measurements of surface reflectance with in situ sea ice thickness measurements in the Bohai Sea. Two years of Thematic Mapper (TM) band 2 and Moderate Resolution Imaging Spectroradiometer (MODIS) band 4 data were used to distinguish between the following sea ice types, using spectral reflectance thresholds of 6.4, 9.6, 10.3 and 12.1%: (a) clean nilas ice (a thin elastic crust of ice up to 10 cm thick that, under pressure, may deform by finger rafting; (b) nilas ice and pancake ice (roughly circular accumulations of frazil ice, usually less than about 3 m in diameter, with raised rims caused by collisions); (c) grey and grey-white ice; and (d) cumulative ice (<30 cm). By establishing a relationship between sea ice type and ice thickness, a novel, practical and low-cost remote sensing technique is introduced to estimate the extent and distribution of sea ice thickness over a large spatial scale. The results obtained by remote sensing are validated with in situ ice shape measurements. The MODIS and TM data are used to distinguish between three ice thickness grades (6-9, 10-20 and 20-30 cm). [ABSTRACT FROM AUTHOR]

Although satellite data are known to be useful for obtaining ice thickness distribution for perennial sea ice or in stable thin sea ice areas, their use in the seasonal sea ice zone (SIZ) is still unresolved. In this study, we approached the problem of ice thickness retrieval by using L-band Synthetic Aperture Radar (SAR). In the SIZ, ice thickness growth is closely related to ridging activity and therefore we expected surface roughness to be correlated to ice thickness. L-band SAR is suitable for detecting such surface roughness and should be a useful tool for obtaining ice thickness distribution. To verify this correlation, we conducted shipborne electromagnetic (EM) inductive sounding and supersonic profiling observations with an icebreaker, coordinated with airborne L-band SAR observations in the southern Sea of Okhotsk in February 2005. The surface elevation was estimated by representing the ship's motion with a low-pass filter. Backscattering coefficients correlated well with ice thickness and surface roughness, defined by the standard deviation of the surface elevation. This result sheds light on the possibility of determining ice thickness distribution in the SIZ. [ABSTRACT FROM AUTHOR]

With increasing petroleum related activity in the Barents Sea and the subsequent risk of accidents, there is a demand for knowledge about the effect of oil pollution in Arctic ecosystems. In the present study, the sea ice amphipod Gammarus wilkitzkii was exposed to a water soluble fraction (WSF) of oil in two experiments, using a rock column system. First, three groups of adult females were exposed for 36 days for control (n=9), low dose (n=10) (initial and final oil concentration: 14, 115 and 120 μ g/l) and high dose (n=10) (initial and final oil concentration: 78, 764 and 395 μ g/l). Total oxyradical scavenging capacity (TOSC), malondialdehyde (MDA), catalase activity (CAT), respiration rate and mortality were measured. In the second experiment, moulting rate was measured in immature individuals of two groups, control (n=10) and exposed (n = 20), over 113 days. No mortality was observed in either of the experiments. There was a dose-related significant increase in respiration rate (40.69 (±22.82), 55.63 (±20.98), 94.57 (±22.80)) mg O2 h-1g ww-1 in control, low dose and high dose, respectively. A higher MDA level was detected in the low dose group (25.04 (±6.00) nmol g-1 of tissue) compared to both control (20.44 (±2.62) nmol g-1 of tissue) and high dose groups (20.93 (±4.79) nmol g-1 of tissue). Likewise, the low dose group had the highest value of TOSC towards hydroxyl (727.74 (±475.58), 1157.58 (±278.62), 1067.30 (±369.22) TOSC unit value mg-1 of protein for control, low and high dose, respectively). Although no difference in the catalase activity between control and exposed groups was detected, higher activity was measured at 0 °C (average: 248 μ mol-1 min-1 mg-1 of protein) than at the standard temperature for catalase measurement of 25 °C (average: 140 μ mol-1 min-1 mg-1 of protein), indicating a need to optimise the standard operational procedure when working with Arctic organisms. No effect of WSF exposure on moulting rate was detected. In conclusion, little mortality was observed during the experiments, indicating some degree of tolerance levels. However, the biomarker results indicated sub-lethal effects in G. wilkitzkii after exposure to WSF. [ABSTRACT FROM AUTHOR]

The atmospheric effects on the retrieval of sea ice concentration from passive microwave sensors were examined using simulated data typical for the Arctic summer. The simulation includes atmospheric contributions of cloud liquid water (CLW), water vapour (WV) and surface wind on the microwave signatures. A plane parallel radiative transfer model was used to compute brightness temperatures at SSM/I frequencies over surfaces that contained open water, first-year (FY) ice, multi-year (MY) ice and their combinations. Synthetic retrievals were performed using the NASA Team (NT) algorithm for the estimation of sea ice concentrations. Our results show that if the satellite sensor's field of view is filled with only FY ice, the retrieval is hardly affected by the atmospheric conditions because of the high contrast between emission signals from the FY ice surface and the atmosphere. Pure MY ice concentration is generally underestimated because of the low MY ice surface emissivity, which results in the enhancement of emission signals from the atmosphere. In marginal ice areas, the atmospheric and surface effects tend to degrade the accuracy at low sea ice concentrations. FY ice concentration is overestimated and MY ice concentration is underestimated in the presence of atmospheric water and surface wind at low ice concentration. Moreover, strong surface wind appears to be more important than atmospheric water in contributing to the retrieval errors of total ice concentrations over marginal ice zones. [ABSTRACT FROM AUTHOR]

Dramatic changes have occurred in the Arctic over the past three decades in response to an accelerated warming that will have a significant impact on the world's climate. Snow accumulation (measured as snow water equivalent, SWE) over sea ice plays a key role in the changes observed due to its effect on the surface energy balance that dictates the timing of sea-ice freeze-up and decay. Increased awareness of the role of snow in the Arctic system has triggered numerous studies that have attempted to characterize snow accumulation from space since the early 1980s, but none has successfully quantified SWE on a seasonal basis. This work presents the first seasonally valid SWE algorithm for first-year sea ice based on in situ passive microwave radiometry. The in situ data were collected as a part of the Canadian Arctic Shelf Exchange Study (CASES) during the overwintering mission of the Canadian Coast Guard Ship (CCGS) Amundsen in 2003-2004. Previous work clearly demonstrated two different patterns of seasonal snow evolution, for which the algorithm presented in this paper accounts for. Our algorithm's results are valid for temperatures between -5 and -30°C and SWE in the range of 0-55 mm. Results show that the behaviour of the snow's thermophysical properties and brightness temperatures (T b) is quite different in the winter cooling period compared with that in the warming period, where temperature gradient metamorphism begins at a SWE value of 33 mm. The SWE algorithm successfully models this change with a high degree of correlation. [ABSTRACT FROM AUTHOR]

We examine the ability of SAR-derived landfast sea ice thermodynamic state surrounding the North Water Polynya to predict the timing of a shallow, stably stratified summer ocean mixed layer in the region. Radarsat-1 ScanSAR is used to derive melt and pond onset dates over landfast sea ice surrounding the polynya, describing its thermodynamic evolution. Salinity and temperature profiles, connected in time and space, are complemented by potential density profiles and mixed layer depths, which describe the evolution of the upper ocean mixed layer between 4 April and 21 July 1998. Surface salinity driven potential density stratification and summer mixed layer depths are temporally coincident. Sea ice-ocean connection is first described at the local scale, then regionally. At the local scale, a reduction in surface salinity occurs between the melt and pond onsets over landfast sea ice. At the polynya scale, interpolated pond onset date is highly effective at predicting the timing of a thin, stably stratified summer ocean mixed layer; this has consequences for the potential prediction of timing of maximum ecosystem productivity. [ABSTRACT FROM AUTHOR]