scholarly journals Arctic Ocean Freshwater Changes over the Past 100 Years and Their Causes

2008 ◽  
Vol 21 (2) ◽  
pp. 364-384 ◽  
Author(s):  
I. V. Polyakov ◽  
V. A. Alexeev ◽  
G. I. Belchansky ◽  
I. A. Dmitrenko ◽  
V. V. Ivanov ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Observational Data ◽  
Thermohaline Circulation ◽  
Atmospheric Precipitation ◽  
The Arctic ◽  
Central Basin ◽  
Central Arctic Ocean ◽  
The Arctic Ocean ◽  
Long Term Variations

Abstract Recent observations show dramatic changes of the Arctic atmosphere–ice–ocean system. Here the authors demonstrate, through the analysis of a vast collection of previously unsynthesized observational data, that over the twentieth century the central Arctic Ocean became increasingly saltier with a rate of freshwater loss of 239 ± 270 km3 decade−1. In contrast, long-term (1920–2003) freshwater content (FWC) trends over the Siberian shelf show a general freshening tendency with a rate of 29 ± 50 km3 decade−1. These FWC trends are modulated by strong multidecadal variability with sustained and widespread patterns. Associated with this variability, the FWC record shows two periods in the 1920s–30s and in recent decades when the central Arctic Ocean was saltier, and two periods in the earlier century and in the 1940s–70s when it was fresher. The current analysis of potential causes for the recent central Arctic Ocean salinification suggests that the FWC anomalies generated on Arctic shelves (including anomalies resulting from river discharge inputs) and those caused by net atmospheric precipitation were too small to trigger long-term FWC variations in the central Arctic Ocean; to the contrary, they tend to moderate the observed long-term central-basin FWC changes. Variability of the intermediate Atlantic Water did not have apparent impact on changes of the upper–Arctic Ocean water masses. The authors’ estimates suggest that ice production and sustained draining of freshwater from the Arctic Ocean in response to winds are the key contributors to the salinification of the upper Arctic Ocean over recent decades. Strength of the export of Arctic ice and water controls the supply of Arctic freshwater to subpolar basins while the intensity of the Arctic Ocean FWC anomalies is of less importance. Observational data demonstrate striking coherent long-term variations of the key Arctic climate parameters and strong coupling of long-term changes in the Arctic–North Atlantic climate system. Finally, since the high-latitude freshwater plays a crucial role in establishing and regulating global thermohaline circulation, the long-term variations of the freshwater content discussed here should be considered when assessing climate change and variability.

Arctic Ocean State-Changes: Self Interests and Common Interests

2009 ◽  
Vol 1 (1) ◽  
pp. 511-525
Author(s):  
Paul Arthur Berkman
Keyword(s):  
Arctic Ocean ◽  
The Arctic ◽  
International Governance ◽  
State Change ◽  
Central Arctic Ocean ◽  
Nation States ◽  
Free Region ◽  
The Arctic Ocean ◽  
Challenges And Opportunities ◽  
State Changes

Abstract Environmental and geopolitical state-changes are the underlying first principles of the diverse stakeholder positioning in the Arctic Ocean. The Arctic Ocean is changing from an ice-covered region to an ice-free region during the summer, which is an environmental state-change. As provided under the framework of the United Nations Convention on the Law of the Sea (UNCLOS), the central Arctic Ocean currently involves “High-Seas” (beyond the “Exclusive Economic Zones”) and the underlying “Area” of the deep-sea floor (beyond the “Continental Shelves”). Governance applications of this ‘donut’ demography – with international space surrounded by sovereign sectors – would be a geopolitical state-change in the Arctic Ocean. International governance strategies and applications for the central Arctic Ocean have far-reaching implications for the stewardship of other international spaces, which between Antarctica and the ocean beyond national jurisdictions account for nearly 75 percent of the Earth’s surface. In view of planetary-scale strategies for humankind, with frameworks such as climate, the Arctic Ocean underscores the challenges and opportunities to balance the governance of nation states and international spaces centuries into the future.

Simulating the Long-Term Variability of Liquid Freshwater Export from the Arctic Ocean

2008 ◽  
pp. 405-425 ◽  
Author(s):  
Rüdiger Gerdes ◽  
Michael Karcher ◽  
Cornelia Köberle ◽  
Kerstin Fieg
Keyword(s):  
Arctic Ocean ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Freshwater Export

Comparison of the Long-Term Trends of the Largest Waves in the Ice-Free Arctic Waters From Different Reanalysis Products

2018 ◽  
Author(s):  
Takuji Waseda ◽  
Takehiko Nose ◽  
Adrean Webb
Keyword(s):  
Arctic Ocean ◽  
The Arctic ◽  
Extreme Value Analysis ◽  
Positive Trend ◽  
Value Analysis ◽  
The Arctic Ocean ◽  
Ship Route ◽  
Long Term Trends ◽  
Horizontal Grid

The long-term trends of the expected largest waves in the ice-free Arctic waters from Laptev to Beaufort Seas was studied analyzing the ERA-interim reanalysis from 1979 to 2016. The analysis showed that the positive trend is largest in October and increased almost 70 cm in 38 years. For ships navigating the Northern Ship Route, it is important to know what the possible largest waves to expect during its cruise. In view of conducting the extreme value analysis, the uncertainty of the largest wave needs to be validated. However, the observation in the Arctic Ocean is limited. We, therefore, rely on the reanalysis wave products in the Arctic Ocean, whose uncertainty is yet to be determined. ERA-Interim and ERA-5 are compared in the Laptev, the East Siberian, Chukchi and Beaufort Seas. The comparison is relevant as the two products differ in its horizontal grid resolution and availability of the satellite altimeter significant wave height data assimilation. During 2010–2016 when the ERA5 is available, only a small difference from ERA-Interim was detected in the mean. However, the expected largest waves in the domain tended to be large for the ERA-5, 8% normalized bias. The tendency was quite similar with a high correlation of 0.98.

scholarly journals Deep-Water Flow over the Lomonosov Ridge in the Arctic Ocean

2005 ◽  
Vol 35 (8) ◽  
pp. 1489-1493 ◽  
Author(s):  
M-L. Timmermans ◽  
P. Winsor ◽  
J. A. Whitehead
Keyword(s):  
Arctic Ocean ◽  
Deep Water ◽  
Thermohaline Circulation ◽  
Global Climate ◽  
Volume Flow Rate ◽  
The Arctic ◽  
Lomonosov Ridge ◽  
Geothermal Heat ◽  
The Arctic Ocean ◽  
Canadian Basin

Abstract The Arctic Ocean likely impacts global climate through its effect on the rate of deep-water formation and the subsequent influence on global thermohaline circulation. Here, the renewal of the deep waters in the isolated Canadian Basin is quanitified. Using hydraulic theory and hydrographic observations, the authors calculate the magnitude of this renewal where circumstances have thus far prevented direct measurements. A volume flow rate of Q = 0.25 ± 0.15 Sv (Sv ≡ 106 m3 s−1) from the Eurasian Basin to the Canadian Basin via a deep gap in the dividing Lomonosov Ridge is estimated. Deep-water renewal time estimates based on this flow are consistent with 14C isolation ages. The flow is sufficiently large that it has a greater impact on the Canadian Basin deep water than either the geothermal heat flux or diffusive fluxes at the deep-water boundaries.

Projected disruption in seasonal timing of Arctic Ocean pCO2

2021 ◽  
Author(s):  
James Orr ◽  
Lester Kwiatkowski
Keyword(s):  
Arctic Ocean ◽  
The Arctic ◽  
Seasonal Timing ◽  
Enhanced Sensitivity ◽  
Projected Change ◽  
The Arctic Ocean ◽  
Projected Changes ◽  
System Variables ◽  
Earth System Models

<p>Ocean acidification implies long-term changes in ocean CO<sub>2</sub> system variables modulated by changes in seasonal amplitudes. Further modulation, yet unexplored, may come from changes in timing of the annual cycle. For the CO<sub>2</sub> partial pressure (<em>p</em>CO<sub>2</sub>), a winter high and summer low are observed in Arctic Ocean surface waters because thermal effects are outweighed by those from biology. Here the same timing was found with 9 Earth system models under historical forcing. Yet under a high-end CO<sub>2</sub> emission scenario, those models project that the summer low (relative to the annual mean) eventually reverses sign across most of the Arctic Ocean. In most models, that sign reversal inverses the chronological order of the annual high and low. The high moves from spring to summer and the low moves from summer to spring. The cause is the projected dramatic warming in summer sea surface temperature provoked by earlier retreat of seasonal sea ice. The increase in the summer <em>p</em>CO<sub>2</sub> extreme over this century is 29±9% greater than if there had been no change in seasonal timing, only the enhanced sensitivity of <em>p</em>CO<sub>2</sub> to its driving variables. Thus the projected change in extreme summer <em>p</em>CO<sub>2</sub> is 150±50 μatm higher. Outside of the Arctic Ocean, projected changes in seasonal timing of <em>p</em>CO<sub>2</sub> are small.</p>

Sediment archives from the Arctic Ocean provide evidence for massive remobilization of permafrost carbon in Siberia during the last glacial termination

2020 ◽  
Author(s):  
Jannik Martens ◽  
Birgit Wild ◽  
Tommaso Tesi ◽  
Francesco Muschitiello ◽  
Matt O’Regan ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Large Scale ◽  
Sediment Cores ◽  
The Arctic ◽  
Last Deglaciation ◽  
Central Arctic Ocean ◽  
Last Glacial ◽  
The Arctic Ocean ◽  
Siberian Shelf ◽  
The Last Glacial

<p>Environmental archives and carbon cycle models suggest that climate warming during the last deglaciation (the transition from the last glacial to the Holocene) caused large-scale thaw of Arctic permafrost, followed by the release of previously freeze-locked carbon. In addition to changing oceanic circulation and outgassing of CO<sub>2 </sub>trapped in the deep glacial ocean, organic carbon (OC) release from thawing permafrost might have contributed to the rise in atmospheric CO<sub>2</sub> by 80 ppmv or ~200 Pg C between 17.5 and 11.7 kyr before present (BP). The few Arctic sediment cores to date, however, lack either temporal resolution or reflect only regional catchments, leaving most of the permafrost OC remobilization of the deglaciation unconstrained.</p><p>Our study explores the flux and fate of OC released from permafrost to the Siberian Arctic Seas during the last deglaciation. The Arctic Ocean is the main recipient of permafrost material delivered by river transport or collapse of coastal permafrost, providing an archive for current and past release of OC from thawing permafrost. We studied isotopes (Δ<sup>14</sup>C-OC, δ<sup>13</sup>C-OC) and terrestrial biomarkers (CuO-derived lignin phenols, <em>n</em>-alkanes, <em>n</em>-alkanoic acids) in a number of sediment cores from the Siberian Shelf and Central Arctic Ocean to reconstruct source and fate of OC previously locked in permafrost.</p><p>The composite record of three cores from the Laptev, East Siberian and Chukchi Seas suggest a combination of OC released by deepening of permafrost active layer in inland Siberia and by thermal collapse of coastal permafrost during the deglaciation. Coastal erosion of permafrost during the deglaciation suggests that sea-level rise and flooding of the Siberian shelf remobilized OC from permafrost deposits that covered the dry shelf areas during the last glacial. A sediment core from the Central Arctic Ocean demonstrates that this occurred in two major pulses; i) during the Bølling-Allerød (14.7-12.9 kyr BP), but most strongly ii) during the early Holocene (11-7.6 kyr BP). In the early Holocene, flooding of 80% of the Siberian shelf amplified permafrost OC release to the Arctic Ocean, with peak fluxes 10-9 kyr BP one order of magnitude higher than at other times in the Holocene.</p><p>It is likely that the remobilization of permafrost OC by flooding of the Siberian shelf released climate-significant amounts of dormant OC into active biogeochemical cycling and the atmosphere. Previous studies estimated that a pool of 300-600 Pg OC was held in permafrost covering Arctic Ocean shelves during the last glacial maximum; one can only speculate about its whereabouts after the deglaciation. Present und future reconstructions of historical remobilization of permafrost OC will help to understand how important permafrost thawing is to large-scale carbon cycling.</p>

scholarly journals The Arctic Ocean as a dead end for floating plastics in the North Atlantic branch of the Thermohaline Circulation

2017 ◽  
Vol 3 (4) ◽  
pp. e1600582 ◽  
Author(s):  
Andrés Cózar ◽  
Elisa Martí ◽  
Carlos M. Duarte ◽  
Juan García-de-Lomas ◽  
Erik van Sebille ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
North Atlantic ◽  
Thermohaline Circulation ◽  
The Arctic ◽  
The North ◽  
Dead End ◽  
The Arctic Ocean ◽  
The North Atlantic

Variability of the Intermediate Atlantic Water of the Arctic Ocean over the Last 100 Years

2004 ◽  
Vol 17 (23) ◽  
pp. 4485-4497 ◽  
Author(s):  
I. V. Polyakov ◽  
G. V. Alekseev ◽  
L. A. Timokhov ◽  
U. S. Bhatt ◽  
R. L. Colony ◽  
...  
Keyword(s):  
Water Temperature ◽  
Arctic Ocean ◽  
Observational Data ◽  
Low Frequency ◽  
Atlantic Water ◽  
The Arctic ◽  
Lower Latitude ◽  
Complex Nature ◽  
Temperature Record ◽  
The Arctic Ocean

Abstract Recent observations show dramatic changes of the Arctic atmosphere–ice–ocean system, including a rapid warming in the intermediate Atlantic water of the Arctic Ocean. Here it is demonstrated through the analysis of a vast collection of previously unsynthesized observational data, that over the twentieth century Atlantic water variability was dominated by low-frequency oscillations (LFO) on time scales of 50–80 yr. Associated with this variability, the Atlantic water temperature record shows two warm periods in the 1930s–40s and in recent decades and two cold periods earlier in the century and in the 1960s–70s. Over recent decades, the data show a warming and salinification of the Atlantic layer accompanied by its shoaling and, probably, thinning. The estimate of the Atlantic water temperature variability shows a general warming trend; however, over the 100-yr record there are periods (including the recent decades) with short-term trends strongly amplified by multidecadal variations. Observational data provide evidence that Atlantic water temperature, Arctic surface air temperature, and ice extent and fast ice thickness in the Siberian marginal seas display coherent LFO. The hydrographic data used support a negative feedback mechanism through which changes of density act to moderate the inflow of Atlantic water to the Arctic Ocean, consistent with the decrease of positive Atlantic water temperature anomalies in the late 1990s. The sustained Atlantic water temperature and salinity anomalies in the Arctic Ocean are associated with hydrographic anomalies of the same sign in the Greenland–Norwegian Seas and of the opposite sign in the Labrador Sea. Finally, it is found that the Arctic air–sea–ice system and the North Atlantic sea surface temperature display coherent low-frequency fluctuations. Elucidating the mechanisms behind this relationship will be critical to an understanding of the complex nature of low-frequency variability found in the Arctic and in lower-latitude regions.

Sign in / Sign up

Export Citation Format

Share Document