scholarly journals Arctic Ocean Gas Hydrate Stability in a Changing Climate

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Michela Giustiniani ◽  
Umberta Tinivella ◽  
Martin Jakobsson ◽  
Michele Rebesco
Keyword(s):  
Arctic Ocean ◽  
Sea Level ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Arctic Region ◽  
Geothermal Gradient ◽  
The Arctic ◽  
Ocean Bottom ◽  
The Arctic Ocean ◽  
Hydrate Stability

Recent estimations suggest that vast amounts of methane are locked in the Arctic Ocean bottom sediments in various forms of gas hydrates. A potential feedback from a continued warming of the Arctic region is therefore the release of methane to the atmosphere. This study addresses the relationship between a warming of the Arctic ocean and gas hydrate stability. We apply a theoretical model that estimates the base of the gas hydrate stability zone in the Arctic Ocean considering different bottom water warming and sea level scenarios. We model the present day conditions adopting two different geothermal gradient values: 30 and 40°C/km. For each geothermal gradient value, we simulate a rise and a decrease in seafloor temperature equal to 2°C and in sea level equal to 10 m. The results show that shallow gas hydrates present in water depths less than 500 m would be strongly affected by a future rise in seafloor temperature potentially resulting in large amounts of gas released to the water column due to their dissociation. We estimate that the area, where there could be complete gas hydrate dissociation, is about 4% of the area where there are the conditions for gas hydrates stability.

scholarly journals Postglacial response of Arctic Ocean gas hydrates to climatic amelioration

2017 ◽  
Vol 114 (24) ◽  
pp. 6215-6220 ◽  
Author(s):  
Pavel Serov ◽  
Sunil Vadakkepuliyambatta ◽  
Jürgen Mienert ◽  
Henry Patton ◽  
Alexey Portnov ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Bottom Water ◽  
Environmental Changes ◽  
Thermal Dissociation ◽  
Ice Sheet ◽  
The Arctic ◽  
Ocean Bottom ◽  
Methane Release

Seafloor methane release due to the thermal dissociation of gas hydrates is pervasive across the continental margins of the Arctic Ocean. Furthermore, there is increasing awareness that shallow hydrate-related methane seeps have appeared due to enhanced warming of Arctic Ocean bottom water during the last century. Although it has been argued that a gas hydrate gun could trigger abrupt climate change, the processes and rates of subsurface/atmospheric natural gas exchange remain uncertain. Here we investigate the dynamics between gas hydrate stability and environmental changes from the height of the last glaciation through to the present day. Using geophysical observations from offshore Svalbard to constrain a coupled ice sheet/gas hydrate model, we identify distinct phases of subglacial methane sequestration and subsequent release on ice sheet retreat that led to the formation of a suite of seafloor domes. Reconstructing the evolution of this dome field, we find that incursions of warm Atlantic bottom water forced rapid gas hydrate dissociation and enhanced methane emissions during the penultimate Heinrich event, the Bølling and Allerød interstadials, and the Holocene optimum. Our results highlight the complex interplay between the cryosphere, geosphere, and atmosphere over the last 30,000 y that led to extensive changes in subseafloor carbon storage that forced distinct episodes of methane release due to natural climate variability well before recent anthropogenic warming.

scholarly journals Pan-Arctic aerosol number size distributions: seasonality and transport patterns

2017 ◽  
Vol 17 (13) ◽  
pp. 8101-8128 ◽  
Author(s):  
Eyal Freud ◽  
Radovan Krejci ◽  
Peter Tunved ◽  
Richard Leaitch ◽  
Quynh T. Nguyen ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Regional Scale ◽  
Arctic Region ◽  
The Arctic ◽  
Research Station ◽  
Size Distributions ◽  
Back Trajectories ◽  
Accumulation Mode ◽  
Source Regions ◽  
The Arctic Ocean

Abstract. The Arctic environment has an amplified response to global climatic change. It is sensitive to human activities that mostly take place elsewhere. For this study, a multi-year set of observed aerosol number size distributions in the diameter range of 10 to 500 nm from five sites around the Arctic Ocean (Alert, Villum Research Station – Station Nord, Zeppelin, Tiksi and Barrow) was assembled and analysed.A cluster analysis of the aerosol number size distributions revealed four distinct distributions. Together with Lagrangian air parcel back-trajectories, they were used to link the observed aerosol number size distributions with a variety of transport regimes. This analysis yields insight into aerosol dynamics, transport and removal processes, on both an intra- and an inter-monthly scale. For instance, the relative occurrence of aerosol number size distributions that indicate new particle formation (NPF) event is near zero during the dark months, increases gradually to  ∼ 40 % from spring to summer, and then collapses in autumn. Also, the likelihood of Arctic haze aerosols is minimal in summer and peaks in April at all sites.The residence time of accumulation-mode particles in the Arctic troposphere is typically long enough to allow tracking them back to their source regions. Air flow that passes at low altitude over central Siberia and western Russia is associated with relatively high concentrations of accumulation-mode particles (Nacc) at all five sites – often above 150 cm−3. There are also indications of air descending into the Arctic boundary layer after transport from lower latitudes.The analysis of the back-trajectories together with the meteorological fields along them indicates that the main driver of the Arctic annual cycle of Nacc, on the larger scale, is when atmospheric transport covers the source regions for these particles in the 10-day period preceding the observations in the Arctic. The scavenging of these particles by precipitation is shown to be important on a regional scale and it is most active in summer. Cloud processing is an additional factor that enhances the Nacc annual cycle.There are some consistent differences between the sites that are beyond the year-to-year variability. They are the result of differences in the proximity to the aerosol source regions and to the Arctic Ocean sea-ice edge, as well as in the exposure to free-tropospheric air and in precipitation patterns – to mention a few. Hence, for most purposes, aerosol observations from a single Arctic site cannot represent the entire Arctic region. Therefore, the results presented here are a powerful observational benchmark for evaluation of detailed climate and air chemistry modelling studies of aerosols throughout the vast Arctic region.

scholarly journals Mapping of the maritime jurisdiction for Arctic Navigation

2019 ◽  
Vol 1 ◽  
pp. 1-1
Author(s):  
Haiyan Liu ◽  
Xiaoping Pang
Keyword(s):  
Arctic Ocean ◽  
Route Planning ◽  
Arctic Region ◽  
The Arctic ◽  
Law Of The Sea ◽  
The Arctic Ocean ◽  
United Nations Convention ◽  
Arctic Navigation ◽  
Navigation Planning ◽  
International Conventions

<p><strong>Abstract.</strong> In recent years, Arctic glaciers have gradually melted due to the global warming, which makes the exploitation of Arctic and its seabed resources possible. Though numerous disagreements and potentials over Arctic maritime jurisdiction still exist, the surround-Arctic nations have agreed the United Nations' Convention on the Law of the Sea to divide the Arctic Ocean into zones that can be regulated and exploited. The IBRU of Durham University has mapped the known claims, agreed boundaries and potential claims of the surround-Arctic nations in the Arctic to clear the maritime jurisdiction in the region. However, different countries may have different requirements within their jurisdictional areas. Clarifying these requirements is essential for Arctic Navigation of investigation ships and merchant ships for their route planning.</p><p>In this paper, based on the map of maritime jurisdiction and boundaries in Arctic region (IBRU), we analysed the international conventions and relevant laws of the surround-Arctic nations to find out the rights and obligations of ships in different zones. The limitations on activities and recommendations on navigation planning are marked for different zones according to different purposes, i.e. science or commerce. The map could not only provide navigational guidance for the activities in the Arctic Ocean, but offer references for the countries not surrounding the Arctic in the formulation of the Arctic strategies.</p>

scholarly journals Role of Salt Migration in Destabilization of Intra Permafrost Hydrates in the Arctic Shelf: Experimental Modeling

Geosciences ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 188 ◽  
Author(s):  
Evgeny Chuvilin ◽  
Valentina Ekimova ◽  
Boris Bukhanov ◽  
Sergey Grebenkin ◽  
Natalia Shakhova ◽  
...  
Keyword(s):  
Gas Hydrates ◽  
Methane Emission ◽  
Gas Hydrate ◽  
Negative Temperature ◽  
Arctic Shelf ◽  
The Arctic ◽  
Permafrost Degradation ◽  
Stability Zone ◽  
Local Pressure ◽  
Hydrate Stability

Destabilization of intrapermafrost gas hydrate is one possible reason for methane emission on the Arctic shelf. The formation of these intrapermafrost gas hydrates could occur almost simultaneously with the permafrost sediments due to the occurrence of a hydrate stability zone after sea regression and the subsequent deep cooling and freezing of sediments. The top of the gas hydrate stability zone could exist not only at depths of 200–250 m, but also higher due to local pressure increase in gas-saturated horizons during freezing. Formed at a shallow depth, intrapermafrost gas hydrates could later be preserved and transform into a metastable (relict) state. Under the conditions of submarine permafrost degradation, exactly relict hydrates located above the modern gas hydrate stability zone will, first of all, be involved in the decomposition process caused by negative temperature rising, permafrost thawing, and sediment salinity increasing. That’s why special experiments were conducted on the interaction of frozen sandy sediments containing relict methane hydrates with salt solutions of different concentrations at negative temperatures to assess the conditions of intrapermafrost gas hydrates dissociation. Experiments showed that the migration of salts into frozen hydrate-containing sediments activates the decomposition of pore gas hydrates and increase the methane emission. These results allowed for an understanding of the mechanism of massive methane release from bottom sediments of the East Siberian Arctic shelf.

scholarly journals Pan-Arctic Aerosol Number Size Distributions: Seasonality and Transport Patterns

2017 ◽  
Author(s):  
Eyal Freud ◽  
Radovan Krejci ◽  
Peter Tunved ◽  
Richard Leaitch ◽  
Quynh T. Nguyen ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Annual Cycle ◽  
Arctic Region ◽  
The Arctic ◽  
Research Station ◽  
Size Distributions ◽  
Back Trajectories ◽  
Accumulation Mode ◽  
Source Regions ◽  
The Arctic Ocean

Abstract. The Arctic environment has an amplified response to global climatic change. It is sensitive to human activities that mostly take place elsewhere. For this study, a multi-year set of observed aerosol number size distributions in the diameter range of 10 to 500 nm from five sites around the Arctic Ocean (Alert, Villum Research Station – Station Nord, Zeppelin, Tiksi and Barrow) was assembled and analysed. A cluster analysis of the aerosol number size distributions, revealed four distinct distributions. Together with Lagrangian air parcel back-trajectories, they were used to link the observed aerosol number size distributions with a variety of transport regimes. This analysis yields insight into aerosol dynamics, transport and removal processes, on both an intra- and inter-monthly scales. For instance, the relative occurrence of aerosol number size distributions that indicate new particle formation (NPF) event is near zero during the dark months, and increases gradually to ~ 40 % from spring to summer, and then collapses in autumn. Also, the likelihood of Arctic Haze aerosols is minimal in summer and peaks in April at all sites. The residence time of accumulation-mode particles in the Arctic troposphere is typically long enough to allow tracking them back to their source regions. Air flow that passes at low altitude over central Siberia and Western Russia is associated with relatively high concentrations of accumulation-mode particles (Nacc) at all five sites – often above 150 cm−3. There are also indications of air descending into the Arctic boundary layer after transport from lower latitudes. The analysis of the back-trajectories together with the meteorological fields along them indicates that the main driver of the Arctic annual cycle of Nacc, on the larger scale, is when atmospheric transport covers the source regions for these particles in the 10-day period preceding the observations in the Arctic. The scavenging of these particles by precipitation is shown to be important on a regional scale and it is most active in summer. Cloud processing is an additional factor that enhances the Nacc annual cycle. There are some consistent differences between the sites that are beyond the year-to-year variability. They are the result of differences in the proximity to the aerosol source regions and to the Arctic Ocean sea-ice edge, as well as in the exposure to free tropospheric air and in precipitation patterns – to mention a few. Hence, for most purposes, aerosol observations from a single Arctic site cannot represent the entire Arctic region. Therefore, the results presented here are a powerful observational benchmark for evaluation of detailed climate and air chemistry modelling studies of aerosols throughout the vast Arctic region.

scholarly journals Exploration of the Gas Hydrates on the Southwestern Continental Slope of the Chukchi Plateau in the Arctic Ocean

2021 ◽  
Vol 58 (5) ◽  
pp. 418-432
Author(s):  
Seung-Goo Kang ◽  
Ugeun Jang ◽  
Sookwan Kim ◽  
Yeonjin Choi ◽  
Young-Gyun Kim ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Continental Slope ◽  
Gas Hydrates ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Chukchi Plateau

Fractal Economy of Arctic

2013 ◽  
pp. 41-47
Author(s):  
M. Slipenchuk
Keyword(s):  
Arctic Ocean ◽  
International Cooperation ◽  
Arctic Region ◽  
Environmental Safety ◽  
The Arctic ◽  
International Agreement ◽  
Northwest Passage ◽  
Northern Sea Route ◽  
The Arctic Ocean ◽  
The Status

In recent decades Arctic attracts the attention of a growing number of states. For effective international cooperation it is necessary to undertake several important steps, including legal work and adoption of documents regulating the statuses and activities of state in Arctic region. It is also needed to undertake a delimitation of sea spaces in the Arctic Ocean, to determine the measures for providing environmental safety in the regions, to reach international agreement on the status of the Northern Sea Route and Northwest Passage, to establish an innovation hub clusters and several others.

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