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Drawing from an analysis of experiences in outer space law, this paper provides insights into challenges involved with managing the global common spaces of the polar regions. The literature concerning governance of the international commons regions focuses on justice and equity concerning natural resources, climate change, the speed, uncertainty and consequences stemming from key actor activity in the Polar Regions. This usually boils down to successes and failures of treaty noncompliance and enforcement mechanisms, or the lack thereof. This paper highlights a current political process aimed at dismantling agreed upon terms outer space international agreements. This offers a snapshot of a political process, likely to influence evolving polar legal norms for the rapidly melting Arctic and Antarctic regions. This is a conceptual paper borrowing theoretical and methodological approaches from political science and international relations such as a Gramscian analysis, constructivism theory and critical discourse analysis, to present several interesting ideas. The purpose is to enable people to understand and explain that future colonisation patterns are unfolding today. It calls attention to issues likely to challenge and define our world in the twenty-first century. [ABSTRACT FROM AUTHOR]

Polar regions are attracting more public, political, economic and scientific attention than ever before, with the role of tourism becoming increasingly recognised. Tourism activities are still relatively new in polar settings with the role of tourism primarily seen as highly beneficial with a capacity to contribute to socio-economic development, especially in the Arctic. However, the growth in tourism is also regarded by some commentators as potentially damaging to the polar environments, especially when combined with the effects of climate change. Yet in order to understand future change it is important that past and present tourism numbers can be benchmarked. The purpose of this paper is to discuss the definitions and dimensions of tourism in polar regions and how the term polar tourism can be understood. The paper aims to define polar tourism in a manner that is consistent with that of international tourism statistics in order to identify gaps in our knowledge base. Based on the existing statistics and overview of current levels of tourism in polar regions it is indicated that the number of visitors to high latitudes is already substantial, especially in the Arctic, and is continuing to grow. [ABSTRACT FROM AUTHOR]

Some of the most rapidly changing ecosystems on our planet are located in the polar regions (IPCC 2007; Turner et al. 2009; SWIPA 2011). In some areas of the Arctic and Antarctic, atmospheric temperatures are rising at rates more than double the global average. In addition, there are other direct human impacts on polar regions such as pollution, exploitation and development. Polar ecosystems and the biodiversity they support are already responding to this change and it is expected that even more profound impacts will occur this century. Compounding the risk to polar biodiversity is the fact that many polar ecosystems have limited functional redundancy; in the event of the loss of a single keystone species, they may potentially be exposed to cascading effects and complete ecosystem restructuring (Post et al. 2009). Rapid climate change affecting the polar regions will also have profound physical and ecological consequences for the rest of the planet since the ice-covered Arctic Ocean, the Antarctic continent, and the globally significant Antarctic Circumpolar Current (ACC) serve a key role in regulating the Earth's climate and ocean systems. This special issue is intended to provide an overview of circumpolar change that crosses disciplines, systems, taxonomic groups and regions, and integrates papers that address a range of topics including: the monitoring of freshwater, marine, and terrestrial organisms in both the northern and southern polar regions, the role of protected areas in monitoring change in a warming world, polar resource management and development, impacts on northern indigenous peoples, case studies of the biodiversity of selected polar organisms, impacts of sea ice loss on terrestrial and marine organisms and ecosystems, interconnections with lower latitudes, and the influence of historical processes that have impacted polar diversity. This keynote paper is intended to provide background and insight into the issue by comparing and contrasting the Arctic and Antarctic regions in terms of their physical environment, human influences, indications of climate change and impacts on their biodiversity. [ABSTRACT FROM AUTHOR]

There has been a significant increase of interest in the building of a comprehensive Arctic observing system in recent years to properly and timely track the environmental and climate processes in this vast region. In this regard, a satellite observing system on highly elliptical orbit (HEO) with 12-h period (Molniya type) is of particular interest, because it enables continuous coverage of the entire Arctic region (58°-90°N) from a constellation of two satellites. Canada is currently proposing to operate such a constellation by 2017. Extending the pioneering study of S. Q. Kidder and T. H. Vonder Haar, this paper presents in-depth analysis of spatiotemporal sampling properties of the imagery from this system. This paper also discusses challenges and advantages of this orbit for various applications that require high temporal resolution and angular sampling. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate horizontal transport processes in the winter stratosphere using data with a resolution relevant for chemistry and climate modeling. For this reason the Freie Universität Berlin Climate Middle Atmosphere Model (FUB-CMAM) with its model top at 83 km altitude, increased horizontal resolution T42 and the semi-Lagrangian transport scheme for advecting passive tracers is used. A new approach of this paper is the classification of specific transport phenomena within the stratosphere into tropical-subtropical streamers (e.g. Offermann et al., 1999) and polar vortex extrusions hereafter called polar vortex streamers. To investigate the role played by these largescale structures on the inter-annual and seasonal variability of transport processes in northern mid-latitudes, the global occurrence of such streamers was calculated based on a 10- year model climatology, concentrating on the existence of the Arctic polar vortex. For the identification and counting of streamers, the new method of zonal anomaly was chosen. The analysis of the months October-May yielded a maximum occurrence of tropical-subtropical streamers during Arctic winter and spring in the middle and upper stratosphere. Synoptic maps revealed highest intensities in the subtropics over East Asia with a secondary maximum over the Atlantic in the northern hemisphere. Furthermore, tropicalsubtropical streamers exhibited a higher occurrence than polar vortex streamers, indicating that the subtropical barrier is more permeable than the polar vortex barrier (edge) in the model, which is in good correspondence with observations (e.g. Plumb, 2002; Neu et al., 2003). Interesting for the total ozone decrease in mid-latitudes is the consideration of the lower stratosphere for tropical-subtropical streamers and the stratosphere above ∼20 km altitude for polar vortex streamers, where strongest ozone depletion is observed at polar latitudes (WMO, 2003). In the lower stratosphere the FUBCMAM simulated a climatological maximum of 10% occurrence of tropical-subtropical streamers over East-Asia/West Pacific and the Atlantic during early- and mid-winter. The results of this paper demonstrate that stratospheric streamers e.g. large-scale, tongue-like structures transporting tropical-subtropical and polar vortex air masses into midlatitudes occur frequently during Arctic winter. They can therefore play a significant role on the strength and variability of the observed total ozone decrease at mid-latitudes and should not be neglected in future climate change studies. [ABSTRACT FROM AUTHOR]

This is a review of methods of passive microwave satellite monitoring of the sea-ice cover in polar regions. We briefly describe the microwave radiometers launched into the Earth's orbit and provide data used in studies of Arctic and Antarctic sea ice. We give a detailed description of currently used algorithms for determining the sea-ice concentration and cover in polar regions according to satellite microwave radiometry. The methods for constructing these algorithms and their related drawbacks are considered. The final section of this paper briefly analyzes the studies that compare current algorithms with each other, with radar data, infrared data, and data of visual ship observations. [ABSTRACT FROM AUTHOR]

The Gamburtsev Mountains, located in East Antarctica, is the direct geomorphological cause of the formation of Dome A. Drilling the core of the Gamburtsev subglacial mountains is one of the primary goals of modern polar research, which is important to understand its formation and evolution process, the ice sheet formation of Dome A, glacial motion, climate change, and so on. This paper describes the status and progress of subglacial bedrock drilling technology. Existing subglacial bedrock drilling technologies are also discussed, including common rig rotary drilling, wire-line core drilling, coiled tubing drilling, and electromechanical drilling. Results of this paper will provide valuable information for Chinese subglacial bedrock core drilling project in the Gamburtsev mountains. [ABSTRACT FROM AUTHOR]

Abstract: Polar Regions become increasingly important as places for (1) natural resources, (2) sensitive indicators of human activities and global, environment, and climate changes, (3) preserving histories of the Earth and biological evolution, and (4) space–Earth interactions and answers to many other 21st century challenges. To facilitate the research, exploration, and development for better understanding, utilizing, and protecting the Polar Regions, a Geospatial CyberInfrastructure (GCI) is needed to help us collect data, integrate information gathered or data in real time from in situ and satellite sensors, and model the geophysical, biological, ecological, and social phenomena to provide better decision support information for policymakers. This special issue of GCI and polar research captures the recent advancements in polar research and the requirements for a GCI. Through a rigorous review process, four papers were selected based on their relationships to polar research and their scientific/technical merits. This paper is a review that surveys the field, introduces the selected papers, and discusses future research. [Copyright &y& Elsevier]

Characterizing the performance of ground-based commercial radiometers in cold and/or low-pressure environments is critical for developing accurate flux measurements in the polar regions and in the upper troposphere and stratosphere. Commercially available broadband radiometers have a stated operational temperature range of, typically, -20° to +50°C. Within this range, their temperature dependencies of sensitivities change less than 1%. But for deployments on high-altitude platforms or in polar regions, which can be much colder than -20°C, information on temperature dependency of sensitivity is not always available. In this paper, the temperature dependencies of sensitivities of popular pyranometers and pyrgeometers manufactured by Kipp and Zonen were tested in a thermal-vacuum chamber. When their body temperature is lowered to -60°C, pyranometer sensitivity drops by 4%–6% from the factory-default specification. Pyrgeometer sensitivity increases by 13% from the factory-default specification during a similar temperature change. When the chamber pressure is lowered from 830 to 6 hPa, the sensitivity decreases by about 2% for the pyranometer, and increases by about 2% for the pyrgeometer. Note that these temperature and pressure dependencies of sensitivities are specific for the instruments that were tested and should not be applied to others. These findings show that for measurements suitable for climate studies, it is crucial to characterize temperature and/or pressure effects on radiometer sensitivity for deployments on high-altitude platforms and in polar regions. [ABSTRACT FROM AUTHOR]

Climate change is already occurring in the Arctic and the Arctic Climate Impact Assessment recently concluded that future climate change could be devastating for Inuit. This paper characterises vulnerability to climate change in two Inuit communities in the Canadian territory of Nunavut, focusing on the resource harvesting sector. In both communities, Inuit have demonstrated significant adaptability in the face of current changes in climatic conditions. This adaptability is facilitated by traditional Inuit knowledge, strong social networks, flexibility in resource use, and institutional support. Changing Inuit livelihoods, however, have undermined certain aspects of adaptive capacity and have resulted in emerging vulnerabilities. Global and regional climate projections indicate that climatic conditions which currently pose risks are expected to be negatively affected by future climate change. These projections are not without precedent and analysis of current vulnerability and identification of adaptation constraints by Inuit in the two communities indicate the continued importance of traditional coping mechanisms. The ability to draw on these coping mechanisms in light of future climate change, however, will be unequal and the research indicates that young Inuit and those without access to economic resources, in particular, are vulnerable. [ABSTRACT FROM AUTHOR]

Sudden stratospheric warmings (SSWs) have a long-lasting effect within the stratosphere as well as impacts on the underlying troposphere. However, sub-seasonal forecasts of the winter polar stratosphere fail to use their full potential for predictability as they tend to underestimate the magnitude and persistence of these events already within the stratosphere. The origin of this underestimation is unknown. Here, we demonstrate that the associated polar stratospheric cold bias following SSW events in sub-seasonal hindcasts can be halved by increasing vertical model resolution, suggesting a potential sensitivity to gravity wave forcing. While the predictability of the planetary Rossby wave flux into the stratosphere at lead times longer than a week is limited, the existence of a critical layer for gravity waves with a low zonal phase speed caused by the disturbed polar vortex provides predictability to the upper stratosphere. Gravity wave breaking near that critical layer can, therefore, decelerate the zonal flow consistently with anomalous subsidence over the polar cap leading to warmer temperatures in the middle polar stratosphere. Since the spectrum of gravity waves involves vertical wavelengths of less than 4000 m , as estimated by wavelet analysis, a high vertical model resolution is needed to resolve the positive feedback between gravity wave forcing and the state of the polar vortex. Specifically, we find that at a spectral resolution of TCo639 (approximate horizontal grid spacing of 18 km) at least 198 levels are needed to correctly resolve the spectrum of gravity waves in the ECMWF Integrated Forecasting System. Increasing vertical resolution in operational forecasts will help to mitigate stratospheric temperature biases and improve sub-seasonal predictions of the stratospheric polar vortex. [ABSTRACT FROM AUTHOR]

Given the rapid nature of climate change occurring in the Arctic and the difficulty climate models have in quantitatively reproducing observed changes such as sea ice loss, it is important to improve understanding of the processes leading to climate change in this region, including the role of short-lived climate pollutants such as aerosols and ozone. It has long been known that pollution produced from emissions at midlatitudes can be transported to the Arctic, resulting in a winter/spring aerosol maximum known as Arctic haze. However, many uncertainties remain about the composition and origin of Arctic pollution throughout the troposphere; for example, many climate-chemistry models fail to reproduce the strong seasonality of aerosol abundance observed at Arctic surface sites, the origin and deposition mechanisms of black carbon (soot) particles that darken the snow and ice surface in the Arctic is poorly understood, and chemical processes controlling the abundance of tropospheric ozone are not well quantified. The International Polar Year (IPY) Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, Climate, Chemistry, Aerosols and Transport (POLARCAT) core project had the goal to improve understanding about the origins of pollutants transported to the Arctic; to detail the chemical composition, optical properties, and climate forcing potential of Arctic aerosols; to evaluate the processes governing tropospheric ozone; and to quantify the role of boreal forest fires. This article provides a review of the many results now available based on analysis of data collected during the POLARCAT aircraft-, ship-, and ground-based field campaigns in spring and summer 2008. Major findings are highlighted and areas requiring further investigation are discussed. [ABSTRACT FROM AUTHOR]

The Circumpolar Flaw Lead (CFL) system study is a Canadian-led International Polar Year (IPY) initiative with over 350 participants from 27 countries. The study is multidisciplinary in nature, integrating physical sciences, biological sciences and Inuvialuit traditional knowledge. The CFL study is designed to investigate the importance of changing climate processes in the flaw lead system of the northern hemisphere on the physical, biogeochemical and biological components of the Arctic marine system. The circumpolar flaw lead is a perennial characteristic of the Arctic throughout the winter season and forms when the mobile multi-year (MY) pack ice moves away from coastal fast ice, creating recurrent and interconnected polynyas in the Norwegian, Icelandic, North American and Siberian sectors of the Arctic. The CFL study was 293 days in duration and involved the overwintering of the Canadian research icebreaker CCGS Amundsen in the Cape Bathurst flaw lead throughout the annual sea-ice cycle of 2007-2008.In this paper we provide an introduction to the CFL project and then use preliminary data from the field season to describe the physical flaw lead system, as observed during the CFL overwintering project. Preliminary data show that ocean circulation is affected by eddy propagation into Amundsen Gulf (AG). Upwelling features arising along the ice edge and along abrupt topography are also detected and identified as important processes that bring nutrient rich waters up to the euphotic zone. Analysis of sea-ice relative vorticity and sea-ice area by ice type in the AG during the CFL study illustrates increased variability in ice vorticity in late autumn 2007 and an increase in new and young ice areas in the AG during winter. Analysis of atmospheric data show that a strong northeast-southwest pressure gradient present over the AG in autumn may be a synoptic-scale atmospheric response to sensible and latent heat fluxes arising from areas of open water persisting into late November 2007. The median atmospheric boundary layer temperature profile over the Cape Bathurst flaw lead during the winter season was stable but much less so when compared to Russian ice island stations.[Traduit par la rédaction] L'étude du système du chenal de séparation circumpolaire (CSC) est une initiative de l'Année polaire internationale (API) menée par le Canada et à laquelle 350 participants provenant de 27 pays ont pris part. L'étude, de nature multidisciplinaire, fait appel aux sciences physiques et biologiques ainsi qu'au savoir traditionnel Inuvialuit. L'étude du CSC vise à examiner les répercussions des processus climatiques changeants dans le système du chenal de séparation de l'hémisphère Nord sur les composantes physiques, biogéochimiques et biologiques du système marin arctique. Le CSC est une caractéristique permanente de l'Arctique durant la saison d'hiver et se forme quand la banquise mobile de glace de plusieurs années s'éloigne de la banquise côtière fixe en créant des polynies récurrentes et interconnectées dans les secteurs norvégien, islandais, nord-américain et sibérien de l'Arctique. Pour mener l'étude du CSC, qui a duré 293 jours, le brise-glace de recherche canadien NGCC Amundsen est demeuré dans le chenal de séparation du cap Bathurst tout l'hiver, c'est-à-dire pendant tout le cycle annuel des glaces de mer de 2007-2008.Dans cet article, nous fournissons une introduction au projet du CSC, puis nous utilisons les données préliminaires de la saison sur le terrain pour décrire le système physique du chenal de séparation, tel qu'observé durant l'hiver du projet du CSC. Les données préliminaires montrent que la circulation océanique est influencée par la propagation de tourbillon dans le golfe d'Amundsen (GA). Des caractéristiques de remontée d'eau le long de la lisière des glaces et le long d'éléments topographiques abrupts ont aussi été observées et identifiées comme des processus importants apportant des eaux riches en nutriments jusqu'à la zone euphotique. L'analyse de la vorticité relative de la glace de mer et de la superficie de la glace de mer par type dans le GA durant l'étude du CSC révèle une variabilité accrue dans la vorticité de la glace à la fin de l'automne 2007 et un accroissement des superficies de nouvelle et de jeune glace dans le GA durant l'hiver. L'analyse des données atmosphériques montre que la présence d'un fort gradient de pression nord est - sud ouest au-dessus du GA en automne peut être une réponse atmosphérique d'échelle synoptique aux flux de chaleur sensible et latente à partir des zones d'eaux libres qui ont persisté jusque vers la fin de novembre 2007. Le profil thermique de la couche limite atmosphérique médiane au-dessus du chenal de séparation du cap Bathurst durant la saison hivernale était stable, mais beaucoup moins que les profils observés aux stations des îles de glace russes. [ABSTRACT FROM AUTHOR]

Sea ice is influential in regulating energy exchanges between the ocean and the atmosphere, and has figured prominently in scientific studies of climate change and climate feedbacks. However, sea ice is also a vital component of everyday life in Inuit communities of the circumpolar Arctic. Therefore, it is important to understand the links between the potential impacts of climate change on Arctic sea ice extent, distribution, and thickness as well as the related consequences for northern coastal populations. This paper explores the relationship between sea ice and climate change from both scientific and Inuit perspectives. Based on an overview of diverse literature the experiences, methods, and goals which differentiate local and scientific sea ice knowledge are examined. These efforts are considered essential background upon which to develop more accurate assessments of community vulnerability to climate, and resulting sea ice, change. Inuit and scientific perspectives may indeed be the ideal complement when investigating the links between sea ice and climate change, but effective and appropriate conceptual bridges need to be built between the two types of expertise. The complementary nature of these knowledge systems may only be realized, in a practical sense, if significant effort is expended to: (i) understand sea ice from both Inuit and scientific perspectives, along with their underlying differences; (ii) investigate common interests or concerns; (iii) establish meaningful and reciprocal research partnerships with Inuit communities; (iv) engage in, and improve, collaborative research methods; and, (v) maintain ongoing dialogue. [ABSTRACT FROM AUTHOR]

Cloud detection is the first step in studying the role of polar clouds in the global climate system with satellite data. In this paper, the cloud detection algorithm for the Moderate Resolution Imaging Spectrometer (MODIS) is evaluated with model simulations and satellite data collocated with radar/lidar observations at three Arctic and Antarctic stations. Results show that the current MODIS cloud mask algorithm performs well in polar regions during the day but does not detect more than 40% of the cloud cover over the validation sights at night. Two new cloud tests utilizing the 7.2 μm water vapor and 14.2 μm carbon dioxide bands, one new clear-sky test using the 7.2 μm band, and changes to the thresholds of several other tests are described. With the new cloud detection procedure, the misidentification of cloud as clear decreases from 44.2% to 16.3% at the two Arctic stations, and from 19.8% to 2.7% at the Antarctic station. [Copyright &y& Elsevier]

Environmental conditions in Polar Regions are becoming more dynamic due to climate change. As sea ice melts, the range of human activities in Polar Regions are projected to increase, while weather conditions are becoming more extreme and unpredictable. Provision and use of weather, water, ice and climate (WWIC) information plays a key role in ensuring that polar activities are conducted as safely as possible and can contribute to a reduction of the environmental footprint of human activities. In this article, we explore the WWIC information provider landscape in a polar context, drawing on a database we compiled to characterize the diversity of providers. The database is built on available literature and on an extensive desk-based research of WWIC information provider websites. We analyse the 374 providers categorized by (a) institutional background (public vs private), (b) the position of the provider relative to activities in the WWIC information space, and (c) the users they serve. While governmental institutions have a strong presence in information provision, new types of providers are now entering the scene. Scientific actors seem to play a substantial role as users as well as major providers of WWIC information services. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics including the adaptations of life forms in extreme environments, impacts of rapidly changing polar regions on organisms, and science-based management of the Arctic and Antarctic ecosystems.

The article offers information for science teachers about teaching global climate change in the classroom. It provides details on a project to help biology students think critically about climate change from a polar or global perspective as well as discusses the uniqueness of the polar regions, the changing ecosystems of Palmer Station and the use online climate change education resources.

The determinants of the structure, functioning and resilience of pelagic ecosystems across most of the polar regions are not well known. Improved understanding is essential for assessing the value of biodiversity and predicting the effects of change (including in biodiversity) on these ecosystems and the services they maintain. Here we focus on the trophic interactions that underpin ecosystem structure, developing comparative analyses of how polar pelagic food webs vary in relation to the environment. We highlight that there is not a singular, generic Arctic or Antarctic pelagic food web, and, although there are characteristic pathways of energy flow dominated by a small number of species, alternative routes are important for maintaining energy transfer and resilience. These more complex routes cannot, however, provide the same rate of energy flow to highest trophiclevel species. Food-web structure may be similar in different regions, but the individual species that dominate mid-trophic levels vary across polar regions. The characteristics (traits) of these species are also different and these differences influence a range of food-web processes. Low functional redundancy at key trophic levels makes these ecosystems particularly sensitive to change. To develop models for projecting responses of polar ecosystems to future environmental change, we propose a conceptual framework that links the life histories of pelagic species and the structure of polar food webs. [ABSTRACT FROM AUTHOR]

Considerable progress has been made using experimental approaches and spatial surveys to better understand and manage shallow lake ecosystems. Meanwhile, research on the environmental histories of shallow lakes has lagged behind paleolimnological studies conducted on deeper systems, with most studies on shallow systems being completed over the last decade or so. Although shallow lakes may pose additional challenges to paleoenvironmental assessments, these potential shortcomings can often be identified and addressed. Due to their size, shallow lakes may act as amplifiers for a variety of environmental stressors, while dampening others. This overview summarizes a few recent studies assessing the long-term effects of multiple stressors on shallow lake ecosystems, with a particular focus on Arctic and Sub-Arctic ponds. Issues related to climatic change (e.g., the rapid transformation of shallow ponds in polar regions), as well as recent paleolimnological studies using shallow lake sediments to track past flooding frequencies, assessing the effects of seabirds and other biovectors on terrestrial ecosystems, blending archaeology and paleolimnology, and investigating the paths and trajectories of different pollutants (e.g., contaminants from the burgeoning petroleum industry) are highlighted. Some potential avenues for future research are also discussed. [ABSTRACT FROM AUTHOR]

The article focuses on role of the polar prediction systems towards advancements for prediction capacity in polar regions. It mentions issues concerning climatic changes across the Arctic and Antarctica regions. It also highlights contribution for making the polar regions a target for application of improved environmental prediction science.

Water vapor and clouds are among the most important greenhouse components whose radiative features cover all the broad spectral range of the thermal emission of the atmosphere. Typically more than 40% of the total thermal emission of Earth occurs in the far-infrared (FIR) spectral region from 100 to 667 cm-1 (wavelengths from 100 to 15 µm). Nevertheless, this spectral region has not ever been fully covered down to 100 cm-1 by space missions, and only a few ground-based experiments exist because of the difficulty of performing measurements from high altitude and very dry locations where the atmosphere is sufficiently transparent to observe the FIR emission features. To cover this lack of observations, the Italian experiment "Radiative Properties of Water Vapor and Clouds in Antarctica" has collected a 2-yr dataset of spectral measurements of the radiance emitted by the atmosphere and by clouds, such as cirrus and polar stratospheric clouds, from 100 to 1,400 cm-1 (100-7 µm of wavelength), including the underexplored FIR region, along with polarization-sensitive lidar observations, daily radiosondes, and other ancillary information to characterize the atmosphere above the site. Measurements have been performed almost continuously with a duty cycle of 6 out of 9 h, from the Italian-French base of Concordia at Dome C over the Antarctic Plateau at 3,230 m MSL, in all-sky conditions since 2012. Because of the uniqueness of the observations, this dataset will be extremely valuable for evaluating the accuracy of atmospheric absorption models (both gas and clouds) in the underexplored FIR and to detect possible daily, seasonal, and annual climate signatures. [ABSTRACT FROM AUTHOR]

The Arctic and Antarctic polar regions are subject to multiple environmental threats, arising from both local and ex-situ human activities. We review the major threats to polar ecosystems including the principal stressor, climate change, which interacts with and exacerbates other threats such as pollution, fisheries overexploitation, and the establishment and spread of invasive species. Given the lack of progress in reducing global atmospheric greenhouse- gas emissions, we suggest that managing the threats that interact synergistically with climate change, and that are potentially more tractable, is all the more important in the short to medium term for polar conservation. We show how evidence-based lessons learned from scientific research can be shared between the poles on topics such as contaminant mitigation, biosecurity protocols to reduce species invasions, and the regulation of fisheries and marine environments. Applying these trans-polar lessons in tandem with expansion of international cooperation could substantially improve environmental management in both the Arctic and Antarctic. [ABSTRACT FROM AUTHOR]

Many drivers of polar-region change originate in mid-latitude industrial societies, so public perceptions there matter. Building on earlier surveys of US public knowledge and concern, a series of New Hampshire state surveys over 2011–2015 tracked public knowledge of some basic polar facts. Analysis indicates that these facts subjectively fall into two categories: those that are or are not directly connected to beliefs about climate change. Responses to climate-linked factual questions, such as whether Arctic sea ice area has declined compared with 30 years ago, are politicized as if we were asking for climate-change opinions. Political divisions are less apparent with factual questions that do not suggest climate change, such as whether the North Pole is on land or sea ice. Only 38% of respondents could answer that question correctly, and even fewer (30%) knew or guessed correctly that melting of Greenland and Antarctic land ice, rather than Arctic sea ice, could potentially do the most to raise sea levels. At odds with the low levels of factual knowledge, most respondents say they have a moderate amount or a great deal of understanding about climate change. A combination of low knowledge with high self-assessed understanding characterizes almost half our sample and correlates with political views. The low knowledge/high understanding combination is most prevalent among Tea Party supporters, where it reaches 61%. It also occurs often (60%) among people who do not believe climate is changing. These results emphasize that diverse approaches are needed to communicate about science with people having different configurations of certainty and knowledge. [ABSTRACT FROM PUBLISHER]

Dynamical coupling between the stratospheric and tropospheric circumpolar circulations in the Arctic has been widely documented on month-to-month and interannual time scales, but not on longer time scales. In the Antarctic, both short- and long-term coupling extending from the stratosphere to the surface has been identified. In this study, changes in Arctic temperature, geopotential height, and ozone observed since the satellite era began in 1979 are examined, comparing dynamically quiescent years in which major sudden stratospheric warmings did not occur to all years. It is shown that this approach clarifies the behavior for years without major warmings and that dynamically quiescent years are marked by a strengthening of the Arctic polar vortex over the past 30 years. The associated declines in stratospheric temperatures, geopotential height, and ozone are qualitatively similar to those obtained in the Antarctic (albeit weaker), and propagate downward into the Arctic lowermost stratosphere during late winter and early spring. In sharp contrast to the Antarctic, the strengthening of the Arctic stratospheric vortex appears to originate at a higher altitude, and the propagation to the Arctic troposphere is both very limited and confined to the uppermost troposphere, even when only dynamically quiescent years are considered in the analysis. [ABSTRACT FROM AUTHOR]

The seasonal cycle of the main lunar tidal constituent M is studied globally by an analysis of a high-resolution ocean circulation and tide model (STORMTIDE) simulation, of 19 years of satellite altimeter data, and of multiyear tide-gauge records. The barotropic seasonal tidal variability is dominant in coastal and polar regions with relative changes of the tidal amplitude of 5-10 %. A comparison with the observations shows that the ocean circulation and tide model captures the seasonal pattern of the M tide reasonably well. There are two main processes leading to the seasonal variability in the barotropic tide: First, seasonal changes in stratification on the continental shelf affect the vertical profile of eddy viscosity and, in turn, the vertical current profile. Second, the frictional effect between sea-ice and the surface ocean layer leads to seasonally varying tidal transport. We estimate from the model simulation that the M tidal energy dissipation at the sea surface varies seasonally in the Arctic (ocean regions north of 60°N) between 2 and 34 GW, whereas in the Southern Ocean, it varies between 0.5 and 2 GW. The M internal tide is mainly affected by stratification, and the induced modified phase speed of the internal waves leads to amplitude differences in the surface tide signal of 0.005-0.0150 m. The seasonal signals of the M surface tide are large compared to the accuracy demands of satellite altimetry and gravity observations and emphasize the importance to consider seasonal tidal variability in the correction processes of satellite data. [ABSTRACT FROM AUTHOR]

Polar surface temperatures are expected to warm 2-3 times faster than the global-mean surface temperature: a phenomenon referred to as polar warming amplification. Therefore, understanding the individual process contributions to the polar warming is critical to understanding global climate sensitivity. The Coupled Feedback Response Analysis Method (CFRAM) is applied to decompose the annual- and zonal-mean vertical temperature response within a transient 1% yr−1 CO2 increase simulation of the NCAR Community Climate System Model, version 4 (CCSM4), into individual radiative and nonradiative climate feedback process contributions. The total transient annual-mean polar warming amplification (amplification factor) at the time of CO2 doubling is +2.12 (2.3) and +0.94 K (1.6) in the Northern and Southern Hemisphere, respectively. Surface albedo feedback is the largest contributor to the annual-mean polar warming amplification accounting for +1.82 and +1.04 K in the Northern and Southern Hemisphere, respectively. Net cloud feedback is found to be the second largest contributor to polar warming amplification (about +0.38 K in both hemispheres) and is driven by the enhanced downward longwave radiation to the surface resulting from increases in low polar water cloud. The external forcing and atmospheric dynamic transport also contribute positively to polar warming amplification: +0.29 and +0.32 K, respectively. Water vapor feedback contributes negatively to polar warming amplification because its induced surface warming is stronger in low latitudes. Ocean heat transport storage and surface turbulent flux feedbacks also contribute negatively to polar warming amplification. Ocean heat transport and storage terms play an important role in reducing the warming over the Southern Ocean and Northern Atlantic Ocean. [ABSTRACT FROM AUTHOR]

Climate-driven changes are expected to alter the hydrography of the Sub-Antarctic Zone (SAZ) and Polar Frontal Zone (PFZ) south of Australia, in which distinct regional environments are believed to be responsible for the differences in phytoplankton biomass in these regions. Here, we report how the dynamic influences of light, iron and temperature, which are responsible for the photophysiological differences between phytoplankton in the SAZ and PFZ, contribute to the biomass differences in these regions. High effective photochemical efficiency of photosystem II (/0.4), maximum photosynthesis rate (), light-saturation intensity (), maximum rate of photosynthetic electron transport (1/), and low photoprotective pigment concentrations observed in the SAZ correspond to high chlorophyll and iron concentrations. In contrast, phytoplankton in the PFZ exhibits low / ( 0.2) and high concentrations of photoprotective pigments under low light environment. Strong negative relationships between iron, temperature, and photoprotective pigments demonstrate that cells were producing more photoprotective pigments under low temperature and iron conditions, and are responsible for the low biomass and low productivity measured in the PFZ. As warming and enhanced iron input is expected in this region, this could probably increase phytoplankton photosynthesis in this region. However, complex interactions between the biogeochemical processes (e.g. stratification caused by warming could prevent mixing of nutrients), which control phytoplankton biomass and productivity, remain uncertain. [ABSTRACT FROM AUTHOR]

The polar regions are experiencing rapid climate change with implications for terrestrial ecosystems. Here, despite limited knowledge, we make some early predictions on soil invertebrate community responses to predicted twenty-first century climate change. Geographic and environmental differences suggest that climate change responses will differ between the Arctic and Antarctic. We predict significant, but different, belowground community changes in both regions. This change will be driven mainly by vegetation type changes in the Arctic, while communities in Antarctica will respond to climate amelioration directly and indirectly through changes in microbial community composition and activity, and the development of, and/or changes in, plant communities. Climate amelioration is likely to allow a greater influx of non-native species into both the Arctic and Antarctic promoting landscape scale biodiversity change. Non-native competitive species could, however, have negative effects on local biodiversity particularly in the Arctic where the communities are already species rich. Species ranges will shift in both areas as the climate changes potentially posing a problem for endemic species in the Arctic where options for northward migration are limited. Greater soil biotic activity may move the Arctic towards a trajectory of being a substantial carbon source, while Antarctica could become a carbon sink. [ABSTRACT FROM AUTHOR]

Observations and model runs indicate trends in dissolved oxygen (DO) associated with current and ongoing global warming. However, a large-scale observation-tomodel comparison has been missing and is presented here. This study presents a first global compilation of DO measurements covering the last 50 yr. It shows declining upperocean DO levels in many regions, especially the tropical oceans, whereas areas with increasing trends are found in the subtropics and in some subpolar regions. For the Atlantic Ocean south of 20º N, the DO history could even be extended back to about 70 yr, showing decreasing DO in the subtropical South Atlantic. The global mean DO trend between 50º S and 50º N at 300 dbar for the period 1960 to 2010 is --0.066 µmol kg-1 yr-1. Results of a numerical biogeochemical Earth system model reveal that the magnitude of the observed change is consistent with CO2-induced climate change. However, the pattern correlation between simulated and observed patterns of past DO change is negative, indicating that the model does not correctly reproduce the processes responsible for observed regional oxygen changes in the past 50 yr. A negative pattern correlation is also obtained for model configurations with particularly low and particularly high diapycnal mixing, for a configuration that assumes a CO2-induced enhancement of the C :N ratios of exported organic matter and irrespective of whether climatological or realistic winds from reanalysis products are used to force the model. Depending on the model configuration the 300 dbar DO trend between 50º S and 50º N is --0.027 to --0.047 µmol kg-1 yr-1 for climatological wind forcing, with a much larger range of --0.083 to +0.027 µmol kg-1 yr-1 for different initializations of sensitivity runs with reanalysis wind forcing. Although numerical models reproduce the overall sign and, to some extent, magnitude of observed ocean deoxygenation, this degree of realism does not necessarily apply to simulated regional patterns and the representation of processes involved in their generation. Further analysis of the processes that can explain the discrepancies between observed and modeled DO trends is required to better understand the climate sensitivity of oceanic oxygen fields and predict potential DO changes in the future. [ABSTRACT FROM AUTHOR]

The ocean and sea ice in both polar regions are important reservoirs of freshwater within the climate system. While the response of these reservoirs to future climate change has been studied intensively, the sensitivity of the polar freshwater balance to natural forcing variations during preindustrial times has received less attention. Using an ensemble of transient simulations from 1500 to 2100 AD we put present-day and future states of the polar freshwater balance in the context of low frequency variability of the past five centuries. This is done by focusing on different multi-decadal periods of characteristic external forcing. In the Arctic, freshwater is shifted from the ocean to sea ice during the Maunder Minimum while the total amount of freshwater within the Arctic domain remains unchanged. In contrast, the subsequent Dalton Minimum does not leave an imprint on the slow-reacting reservoirs of the ocean and sea ice, but triggers a drop in the import of freshwater through the atmosphere. During the twentieth and twenty-first century the build-up of freshwater in the Arctic Ocean leads to a strengthening of the liquid export. The Arctic freshwater balance is shifted towards being a large source of freshwater to the North Atlantic ocean. The Antarctic freshwater cycle, on the other hand, appears to be insensitive to preindustrial variations in external forcing. In line with the rising temperature during the industrial era the freshwater budget becomes increasingly unbalanced and strengthens the high latitude's Southern Ocean as a source of liquid freshwater to lower latitude oceans. [ABSTRACT FROM AUTHOR]

The intrinsic seasonal predictability of Arctic sea ice is investigated in a 400-yr-long preindustrial simulation performed with the Centre National de Recherches Météorologiques Coupled Global Climate Model, version 3.3 (CNRM-CM3.3). The skill of several predictors of the pan-Arctic sea ice area was quantified: the sea ice area itself, the pan-Arctic sea ice volume, and some areal predictors built from the subgrid ice thickness distribution (ITD). Sea ice area provides a potential predictability of about 3 months, which is consistent with previous studies using model and observation data. Sea ice volume predictive skill for winter sea ice area prediction is weak. Nevertheless, there is a higher potential to predict the September ice area with the June volume anomaly than with the June area anomaly. Using ITD-based predictors, two 'regimes' of predictability were highlighted. The first one, a 'persistence regime,' applies to winter/early spring sea ice seasonal predictability. The winter sea ice cover can be predicted in late fall/early winter from the amount of young ice formed since the freeze-up onset in the margins. However, sea ice area itself is potentially the best predictor of winter sea ice area at seasonal time scales. The second regime is a 'memory regime.' It applies to the predictability of summer sea ice area. An ice area anomaly in September is potentially predictable up to 6 months in advance, using the area covered by ice thicker than a critical thickness lying between 0.9 and 1.5 m. Results of this study are preliminary; however, they provide information for the design of future prediction systems and highlight the need for observations and a state-of-the-art sea ice model. [ABSTRACT FROM AUTHOR]

ABSTRACT We have examined the atmospheric water cycle of both Polar Regions, polewards of 60°N and 60°S, using the ERA-Interim reanalysis and high-resolution simulations with the ECHAM5 model for both the present and future climate based on the IPCC, A1B scenario. The annual precipitation in ERA-Interim amounts to ∼17000 km3 and is more or less the same in the Arctic and the Antarctic, but it is composed differently. In the Arctic the annual evaporation is ∼8000 km3 but ∼3000 km3 less in the Antarctica where the net horizontal transport is correspondingly larger. The net water transport of the model is more intense than in ERA-Interim, in the Arctic the difference is 2.5% and in the Antarctic it is 6.2%. Precipitation and net horizontal transport in the Arctic has a maximum in August and September. Evaporation peaks in June and July. The seasonal cycle is similar in Antarctica with the highest precipitation in the austral autumn. The largest net transport occurs at the end of the major extra-tropical storm tracks in the Northern Hemisphere such as the eastern Pacific and eastern north Atlantic. The variability of the model is virtually identical to that of the re-analysis and there are no changes in variability between the present climate and the climate at the end of the 21st century when normalized with the higher level of moisture. The changes from year to year are substantial with the 20- and 30-year records being generally too short to identify robust trends in the hydrological cycle. In the A1B climate scenario the strength of the water cycle increases by some 25% in the Arctic and by 19% in the Antarctica, as measured by annual precipitation. The increase in the net horizontal transport is 29% and 22%, respectively, and the increase in evaporation correspondingly less. The net transport follows closely the Clausius-Clapeyron relation. There is a minor change in the annual cycle of the Arctic atmospheric water cycle with the maximum transport and precipitation occurring later in the year. There is a small imbalance of some 4-6% between the net transport and precipitation minus evaporation. We suggest that this is mainly due to the fact that the transport is calculated from instantaneous six hourly data while precipitation and evaporation is accumulated over a 6-h period. The residual difference is proportionally similar for all experiments and hardly varies from year to year. [ABSTRACT FROM AUTHOR]

An important challenge in current climate modeling is to realistically describe small-scale weather statistics, such as topographic precipitation and coastal wind patterns, or regional phenomena like polar lows. Global climate models simulate atmospheric processes with increasingly higher resolutions, but still regional climate models have a lot of advantages. They consume less computation time because of their limited simulation area and thereby allow for higher resolution both in time and space as well as for longer integration times. Regional climate models can be used for dynamical down-scaling purposes because their output data can be processed to produce higher resolved atmospheric fields, allowing the representation of small-scale processes and a more detailed description of physiographic details (such as mountain ranges, coastal zones, and details of soil properties). However, does higher resolution add value when compared to global model results? Most studies implicitly assume that dynamical downscaling leads to output fields that are superior to the driving global data, but little work has been carried out to substantiate these expectations. Here a series of articles is reviewed that evaluate the benefit of dynamical downscaling by explicitly comparing results of global and regional climate model data to the observations. These studies show that the regional climate model generally performs better for the medium spatial scales, but not always for the larger spatial scales. Regional models can add value, but only for certain variables and locations-particularly those influenced by regional specifics, such as coasts, or mesoscale dynamics, such as polar lows. Therefore, the decision of whether a regional climate model simulation is required depends crucially on the scientific question being addressed. [ABSTRACT FROM AUTHOR]

The atmospheric moisture budget from the Modern Era Retrospective-Analysis for Research and Applications (MERRA) is evaluated in polar regions for the period 1979--2005 and compared with previous estimates, accumulation syntheses over polar ice sheets, and in situ Arctic precipitation observations. The system is based on a nonspectral background model and utilizes the incremental analysis update scheme. The annual moisture convergence from MERRA for the north polar cap is comparable to previous estimates using 40-yr European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-40) and earlier reanalyses but it is more than 50%% larger than MERRA precipitation minus evaporation ( P −− E) computed from physics output fields. This imbalance is comparable to earlier reanalyses for the Arctic. For the south polar cap, the imbalance is 20%%. The MERRA physics output fields are also found to be overly sensitive to changes in the satellite observing system, particularly over data-sparse regions of the Southern Ocean. Comparisons between MERRA and prognostic fields from two contemporary reanalyses yield a spread of values from 6%% of the mean over the Antarctic Ice Sheet to 61%% over a domain of the Arctic Ocean. These issues highlight continued problems associated with the representation of cold-climate physical processes in global data assimilation models. The distribution of MERRA surface fluxes over the major polar ice sheets emphasizes larger values along the coastal escarpments, which agrees more closely with recent assessments of ice sheet accumulation using regional models. Differences between these results and earlier assessments illustrate a continued ambiguity in the surface moisture flux distribution over Greenland and Antarctica. The higher spatial and temporal resolution as well as the availability of all budget components, including analysis increments in MERRA, offer prospects for an improved representation of the high-latitude water cycle in reanalyses. [ABSTRACT FROM AUTHOR]

We present tropospheric H16 2 O and HD16O/H16 2 O vapour profiles measured by ground-based FTIR (Fourier Transform Infrared) spectrometers between 1996 and 2008 at a northern hemispheric subarctic and subtropical site (Kiruna, Northern Sweden, 68° N and Izaña, Tenerife Island, 28° N, respectively). We compare these measurements to an isotope incorporated atmospheric general circulation model (AGCM). If the model is nudged towards meteorological fields of reanalysis data the agreement is very satisfactory on time scales ranging from daily to inter-annual. Taking the Izaña and Kiruna measurements as an example we document the FTIR network's unique potential for investigating the atmospheric water cycle. At the subarctic site we find strong correlations between the FTIR data, on the one hand, and the Arctic Oscillation index and the northern Atlantic sea surface temperature, on the other hand. The Izaña FTIR measurements reveal the importance of the Hadley circulation and the Northern Atlantic Oscillation index for the subtropical middle/ upper tropospheric water balance. We document where the AGCM is able to capture these complexities of the water cycle and where it fails. [ABSTRACT FROM AUTHOR]

The impact and significance of uncertainties in model calculations of stratospheric ozone loss resulting from known uncertainty in chemical kinetics parameters is evaluated in trajectory chemistry simulations for the Antarctic and Arctic polar vortices. The uncertainty in modeled ozone loss is derived from Monte Carlo scenario simulations varying the kinetic (reaction and photolysis rate) parameters within their estimated uncertainty bounds. Simulations of a typical winter/spring Antarctic vortex scenario and Match scenarios in the Arctic produce large uncertainty in ozone loss rates and integrated seasonal loss. The simulations clearly indicate that the dominant source of model uncertainty in polar ozone loss is uncertainty in the Cl2O2 photolysis reaction, which arises from uncertainty in laboratory-measured molecular cross sections at atmospherically important wavelengths. This estimated uncertainty in JCl2O2 from laboratory measurements seriously hinders our ability to model polar ozone loss within useful quantitative error limits. Atmospheric observations, however, suggest that the Cl2O2 photolysis uncertainty may be less than that derived from the lab data. Comparisons to Match, South Pole ozonesonde, and Aura Microwave Limb Sounder (MLS) data all show that the nominal recommended rate simulations agree with data within uncertainties when the Cl2O2 photolysis error is reduced by a factor of two, in line with previous in situ ClOx measurements. Comparisons to simulations using recent cross sections from Pope et al. (2007) are outside the constrained error bounds in each case. Other reactions producing significant sensitivity in polar ozone loss include BrO + ClO and its branching ratios. These uncertainties challenge our confidence in modeling polar ozone depletion and projecting future changes in response to changing halogen emissions and climate. Further laboratory, theoretical, and possibly atmospheric studies are needed. [ABSTRACT FROM AUTHOR]

Detection, attribution and understanding of temperature changes in the high northern latitudes depend on constraining uncertainties and resolving apparent discrepancies in observational data sets. We quantitatively compare four of the most widely used data sets of surface air temperature (SAT), and present a newly produced SAT data set, called NansenSAT. The existing data sets are highly correlated ( r∼ 0.8–0.9), except for some ocean areas. The evolution of SAT anomalies indicates differences reaching 3 °C during the 1920s–1930s warming period for the polar region (60–90°N). Substantial errors in trends also result from spatial sampling limitations, especially during the early–20th-century. Maximum differences between the data sets reaching 0.64 °C/100 yr are found in 1900–1999 linear trends in July and October for 60–90°N. We produced a new SAT data set for the region north of 40°N for the period 1900–2000, using all available data and Objective Analysis methods. The new data set has been compared with existing SAT data. For the polar region, the magnitude of temperature-trend errors caused by sparse data coverage is about 0.5 °C/100 yr. The advantage of the new data set is its enhanced spatial coverage in high latitudes. The NansenSAT data set is available for the research community. [ABSTRACT FROM AUTHOR]

Many plants growing in polar and alpine regions clearly solve serious problems of life under extreme climatic conditions, as low temperatures, strong winds, unstable soils and in the North partly 24-h of light. [ABSTRACT FROM AUTHOR]

Generalized stability theory is applied to a simple dynamical model of interannual ocean–atmosphere variability in the southern midlatitudes to determine the perturbations that create the most rapid growth of energy in the system. The model is composed of a barotropic quasigeostrophic atmosphere coupled to a 1.5-layer quasigeostrophic ocean, each linearized about a zonally invariant mean state, and with atmospheric and ocean surface temperature obeying a simple heat balance. Eigenanalysis of the system reveals modes of interannual variability that resemble the so-called Antarctic Circumpolar Wave (ACW), consistent with an earlier analytical study of the system. The optimal excitation of these modes relative to an energy norm is found to be a perturbation almost entirely restricted to the ocean momentum field and is shown to resemble strongly the optimal perturbations in energy for the system. Over interannual time scales most rapid growth is seen in zonal wavenumbers 4–6, despite the fact that the least-damped eigenmodes of the system are of a lower zonal wavenumber. The rapid transient growth in energy occurs by extracting perturbation energy from the mean state through advection of the mean meridional oceanic temperature gradient. This transient growth of high-zonal-wavenumber modes dominates the model’s variability when it is forced by noise that is white in space or time. A dominant low-zonal-wavenumber response, consistent with the observed and modeled ACW, occurs only when the forcing is red in space or time, with decorrelation scales greater than 3 yr or 10 000 km. It is concluded that, if the ACW is a coupled mode analogous to that supported in this simple model, then it is excited by other large-scale phenomena such as ENSO rather than by sources of higher-frequency forcing. [ABSTRACT FROM AUTHOR]

Climate variability in the Southern Hemisphere is receiving increasing attention due to both the large greenhouse gas-forced response that many climate models exhibit in polar regions and observed recent trends in the southern annular mode (SAM) index. The overwhelming dominance of this mode in the interannual-to-interdecadal variability of the model's atmosphere and ocean led the authors to the hypothesis that most of the interannual climate variability of the real world would also be associated with the SAM.

The global occurrence of methane hydrate in outer continental margins and in polar regions, and the magnitude of the amount of methane sequestered in methane hydrate suggest that methane hydrate is an important component in the global organic carbon cycle. Various versions of this cycle have emphasized the importance of methane hydrate, and in the latest version the role of methane hydrate is considered to be analogous to the workings of an electrical circuit. In this circuit the methane hydrate is a condenser and the consequences of methane hydrate dissociation are depicted as a resistor and inductor, reflecting temperature change and changes in earth surface history. These consequences may have implications for global change including global climate change. Terra Nova, 14, 302–306, 2002. [ABSTRACT FROM AUTHOR]

ABSTRACT A global atmosphere-ocean-sea ice general circulation model (GCM) is used in simulations of climate with present-day atmospheric CO[sub 2] concentrations, and with CO[sub 2] increasing to double the present-day values. The Parallel Climate Model includes the National Center for Atmospheric Research (NCAR) atmospheric GCM, the Los Alamos National Laboratory ocean GCM, and the Naval Postgraduate School dynamic-thermodynamic sea ice model. The ocean and sea ice grids are at substantially higher resolution than has been previously used in global climate models. The model is implemented on distributed, parallel computer architectures to make computation on the high-resolution grids feasible. The sea ice dynamics uses an elastic-viscous-plastic ice rheology with an explicit solution of the ice stress tensor, which has not previously been used in a coupled, global climate model. The simulations of sea ice and the polar climate in the present-day experiment are compared with observed ice and climate data. The ice cover is too extensive in both hemispheres, leading to a large area of lower-than-observed surface temperatures. The Arctic exhibits a persistent high pressure system that drives the ice motion anticyclonically around the central Arctic. The ice thickness is greatest near the Chukchi Peninsula. Ice is exported through the Fram Strait, though the Canadian Archipelago, and inward through the Bering Strait... [ABSTRACT FROM AUTHOR]