scholarly journals A Steady Regime of Volume and Heat Transports in the Eastern Arctic Ocean in the Early 21st Century

2021 ◽  
Vol 8 ◽  
Author(s):  
A. V. Pnyushkov ◽  
I. V. Polyakov ◽  
G. V. Alekseev ◽  
I. M. Ashik ◽  
T. M. Baumann ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Freezing Temperature ◽  
Atlantic Water ◽  
Volume Transport ◽  
The Arctic ◽  
Positive Trend ◽  
Steady Regime ◽  
Early 21St Century ◽  
Volume Transports

Mooring observations in the eastern Eurasian Basin of the Arctic Ocean showed that mean 2013–2018 along-slope volume and heat (calculated relative to the freezing temperature) transports in the upper 800 m were 4.8 ± 0.1 Sv (1 Sv = 106 m3/s) and 34.8 ± 0.6 TW, respectively. Volume and heat transports within the Atlantic Water (AW) layer (∼150–800 m) in 2013–2018 lacked significant temporal shifts at annual and longer time scales: averaged over the two periods of mooring deployment in 2013–2015 and 2015–2018, volume transports were 3.1 ± 0.1 Sv, while AW heat transports were 31.3 ± 1.0 TW and 34.8 ± 0.8 TW. Moreover, the reconstructed AW volume transports over longer, 2003–2018, period of time showed strong interannual variations but lacked a statistically significant trend. However, we found a weak positive trend of 0.08 ± 0.07 Sv/year in the barotropic AW volume transport estimated using dynamic ocean topography (DOT) measurements in 2003–2014 – the longest period spanned by the DOT dataset. Vertical coherence of 2013–2018 transports in the halocline (70–140 m) and AW (∼150–800 m) layers was high, suggesting the essential role of the barotropic forcing in constraining along-slope transports. Quantitative estimates of transports and their variability discussed in this study help identify the role of atlantification in critical changes of the eastern Arctic Ocean.

scholarly journals Variability of the thermohaline structure and transport of Atlantic water in the Arctic Ocean based on NABOS (Nansen and Amundsen Basins Observing System) hydrography data

Ocean Science ◽  
2020 ◽  
Vol 16 (2) ◽  
pp. 405-421
Author(s):  
Nataliya Zhurbas ◽  
Natalia Kuzmina
Keyword(s):  
Time Series ◽  
Arctic Ocean ◽  
Atlantic Water ◽  
Volume Transport ◽  
The Arctic ◽  
Makarov Basin ◽  
The Arctic Ocean ◽  
Anna Trough ◽  
Eurasian Basin ◽  
Volume Transports

Abstract. Conductivity–temperature–depth (CTD) transects across continental slope of the Eurasian Basin and the St. Anna Trough performed during NABOS (Nansen and Amundsen Basins Observing System) project in 2002–2015 and a transect from the 1996 Polarstern expedition are used to describe the temperature and salinity characteristics and volume flow rates (volume transports) of the current carrying the Atlantic water (AW) in the Arctic Ocean. The variability of the AW on its pathway along the slope of the Eurasian Basin is investigated. A dynamic Fram Strait branch of the Atlantic water (FSBW) is identified in all transects, including two transects in the Makarov Basin (along 159∘ E), while the cold waters on the eastern transects along 126, 142, and 159∘ E, which can be associated with the influence of the Barents Sea branch of the Atlantic water (BSBW), were observed in the depth range below 800 m and had a negligible effect on the spatial structure of isopycnic surfaces. The geostrophic volume transport of AW decreases farther away from the areas of the AW inflow to the Eurasian Basin, decreasing by 1 order of magnitude in the Makarov Basin at 159∘ E, implying that the major part of the AW entering the Arctic Ocean circulates cyclonically within the Nansen and Amundsen basins. There is an absolute maximum of θmax (AW core temperature) in 2006–2008 time series and a maximum in 2013, but only at 103∘ E. Salinity S(θmax) (AW core salinity) time series display a trend of an increase in AW salinity over time, which can be referred to as an AW salinization in the early 2000s. The maxima of θmax and S(θmax) in 2006 and 2013 are accompanied by the volume transport maxima. The time average geostrophic volume transports of AW are 0.5 Sv in the longitude range 31–92∘ E, 0.8 Sv in the St. Anna Trough, and 1.1 Sv in the longitude range 94–107∘ E.

scholarly journals Heat, salt, and volume transports in the eastern Eurasian Basin of the Arctic Ocean, from two years of mooring observations

2018 ◽  
Author(s):  
Andrey Pnyushkov ◽  
Igor Polyakov ◽  
Robert Rember ◽  
Vladimir Ivanov ◽  
Matthew B. Alkire ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Heat Transport ◽  
Atlantic Water ◽  
Salt Transport ◽  
The Arctic ◽  
Boundary Current ◽  
The Arctic Ocean ◽  
Eurasian Basin ◽  
The Laptev Sea ◽  
Volume Transports

Abstract. This study discusses along-slope volume, heat, and salt transports derived from observations collected in 2013–15 using a cross-slope array of six moorings ranging from 250 m to 3900 m in the eastern Eurasian Basin (EB) of the Arctic Ocean. These observations demonstrate that in the upper 780 m layer, the along-slope boundary current advected, on average, 5.1 ± 0.1 Sv of water, predominantly in the eastward (shallow-to-right) direction. Monthly net volume transports across the Laptev Sea slope vary widely, from ~ 0.3 ± 0.8 in April 2014 to ~ 9.9 ± 0.8 Sv in June 2014. 3.1 ± 0.1 Sv (or 60 %) of the net transport was associated with warm and salty intermediate-depth Atlantic Water (AW). Calculated heat transport for 2013–15 (relative to −1.8 °C) was 46.0 ± 1.7 TW, and net salt transport (relative to zero salinity) was 172 ± 6 Mkg/s. Estimates for AW heat and salt transports were 32.7 ± 1.3 TW (71 % of net heat transport) and 112 ± 4 Mkg/s (65 % of net salt transport). The variability of currents explains ~ 90 % of the variability of the heat and salt transports. The remaining ~ 10 % is controlled by temperature and salinity anomalies together with temporal variability of the AW layer thickness. The annual mean volume transports decreased by 25 % from 5.8 ± 0.2 Sv in 2013–14 to 4.4 ± 0.2 Sv in 2014–15 suggesting that changes of the transports at interannual and longer time scales in the eastern EB may be significant.

scholarly journals Variability in Atlantic water temperature and transport at the entrance to the Arctic Ocean, 1997–2010

2012 ◽  
Vol 69 (5) ◽  
pp. 852-863 ◽  
Author(s):  
Agnieszka Beszczynska-Möller ◽  
Eberhard Fahrbach ◽  
Ursula Schauer ◽  
Edmond Hansen
Keyword(s):  
Water Temperature ◽  
Arctic Ocean ◽  
Seasonal Variability ◽  
Atlantic Water ◽  
Volume Transport ◽  
The Arctic ◽  
Fram Strait ◽  
Mean Temperature ◽  
The Arctic Ocean

Abstract Beszczynska-Möller, A., Fahrbach, E., Schauer, U., and Hansen, E. 2012. Variability in Atlantic water temperature and transport at the entrance to the Arctic Ocean, 1997–2010. – ICES Journal of Marine Science, 69: 852–863. The variability in Atlantic water temperature and volume transport in the West Spitsbergen Current (WSC), based on measurements by an array of moorings in Fram Strait (78°50′N) over the period 1997–2010, is addressed. The long-term mean net volume transport in the current of 6.6 ± 0.4 Sv (directed northwards) delivered 3.0 ± 0.2 Sv of Atlantic water (AW) warmer than 2°C. The mean temperature of the AW inflow was 3.1 ± 0.1°C. On interannual time-scales, a nearly constant volume flux in the WSC core (long-term mean 1.8 ± 0.1 Sv northwards, including 1.3 ± 0.1 Sv of AW warmer than 2°C, and showing no seasonal variability) was accompanied by a highly variable transport of 2–6 Sv in the offshore branch (long-term mean of 5 ± 0.4 Sv, strong seasonal variability, and 1–2 Sv of warm AW). Two warm anomalies were found in the AW passing through Fram Strait in 1999–2000 and 2005–2007. For the period 1997–2010, there was a positive linear trend in the AW mean temperature of 0.06°C year−1, but no statistically significant trend was observed in the AW volume transport. A possible impact of warming on AW propagation in the Arctic Ocean and properties of the outflow to the North Atlantic are also discussed.

scholarly journals Heat, salt, and volume transports in the eastern Eurasian Basin of the Arctic Ocean from 2 years of mooring observations

Ocean Science ◽  
2018 ◽  
Vol 14 (6) ◽  
pp. 1349-1371 ◽  
Author(s):  
Andrey V. Pnyushkov ◽  
Igor V. Polyakov ◽  
Robert Rember ◽  
Vladimir V. Ivanov ◽  
Matthew B. Alkire ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Heat Transport ◽  
Atlantic Water ◽  
Salt Transport ◽  
The Arctic ◽  
Boundary Current ◽  
The Arctic Ocean ◽  
Eurasian Basin ◽  
The Laptev Sea ◽  
Volume Transports

Abstract. This study discusses along-slope volume, heat, and salt transports derived from observations collected in 2013–2015 using a cross-slope array of six moorings ranging from 250 to 3900 m in the eastern Eurasian Basin (EB) of the Arctic Ocean. These observations demonstrate that in the upper 780 m layer, the along-slope boundary current advected, on average, 5.1±0.1 Sv of water, predominantly in the eastward (shallow-to-right) direction. Monthly net volume transports across the Laptev Sea slope vary widely, from ∼0.3±0.8 in April 2014 to ∼9.9±0.8 Sv in June 2014; 3.1±0.1 Sv (or 60 %) of the net transport was associated with warm and salty intermediate-depth Atlantic Water (AW). Calculated heat transport for 2013–2015 (relative to −1.8 ∘C) was 46.0±1.7 TW, and net salt transport (relative to zero salinity) was 172±6 Mkg s−1. Estimates for AW heat and salt transports were 32.7±1.3 TW (71 % of net heat transport) and 112±4 Mkg s−1 (65 % of net salt transport). The variability of currents explains ∼90 % of the variability in the heat and salt transports. The remaining ∼10 % is controlled by temperature and salinity anomalies together with the temporal variability of the AW layer thickness. The annual mean volume transports decreased by 25 % from 5.8±0.2 Sv in 2013–2014 to 4.4±0.2 Sv in 2014–2015, suggesting that changes in the transports at interannual and longer timescales in the eastern EB may be significant.

scholarly journals Attribution of the Recent Winter Sea Ice Decline over the Atlantic Sector of the Arctic Ocean*

2015 ◽  
Vol 28 (10) ◽  
pp. 4027-4033 ◽  
Author(s):  
Doo-Sun R. Park ◽  
Sukyoung Lee ◽  
Steven B. Feldstein
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Environmental Changes ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Positive Trend ◽  
Ir Radiation ◽  
Atlantic Sector ◽  
Sea Ice Decline ◽  
The Arctic Ocean

Abstract Wintertime Arctic sea ice extent has been declining since the late twentieth century, particularly over the Atlantic sector that encompasses the Barents–Kara Seas and Baffin Bay. This sea ice decline is attributable to various Arctic environmental changes, such as enhanced downward infrared (IR) radiation, preseason sea ice reduction, enhanced inflow of warm Atlantic water into the Arctic Ocean, and sea ice export. However, their relative contributions are uncertain. Utilizing ERA-Interim and satellite-based data, it is shown here that a positive trend of downward IR radiation accounts for nearly half of the sea ice concentration (SIC) decline during the 1979–2011 winter over the Atlantic sector. Furthermore, the study shows that the Arctic downward IR radiation increase is driven by horizontal atmospheric water flux and warm air advection into the Arctic, not by evaporation from the Arctic Ocean. These findings suggest that most of the winter SIC trends can be attributed to changes in the large-scale atmospheric circulations.

Exploring the Role of Shelf Sediments in the Arctic Ocean in Determining the Arctic Contamination Potential of Neutral Organic Contaminants

2012 ◽  
Vol 47 (2) ◽  
pp. 923-931 ◽  
Author(s):  
James M. Armitage ◽  
Sung-Deuk Choi ◽  
Torsten Meyer ◽  
Trevor N. Brown ◽  
Frank Wania
Keyword(s):  
Arctic Ocean ◽  
Organic Contaminants ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Shelf Sediments

scholarly journals Eastern Arctic Ocean Diapycnal Heat Fluxes through Large Double-Diffusive Steps

2019 ◽  
Vol 49 (1) ◽  
pp. 227-246 ◽  
Author(s):  
Igor V. Polyakov ◽  
Laurie Padman ◽  
Y.-D. Lenn ◽  
Andrey Pnyushkov ◽  
Robert Rember ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Dissipation Rate ◽  
Critical Role ◽  
Density Ratio ◽  
Atlantic Water ◽  
Heat Fluxes ◽  
The Arctic ◽  
Eurasian Basin ◽  
Average Flux ◽  
Double Diffusive

AbstractThe diffusive layering (DL) form of double-diffusive convection cools the Atlantic Water (AW) as it circulates around the Arctic Ocean. Large DL steps, with heights of homogeneous layers often greater than 10 m, have been found above the AW core in the Eurasian Basin (EB) of the eastern Arctic. Within these DL staircases, heat and salt fluxes are determined by the mechanisms for vertical transport through the high-gradient regions (HGRs) between the homogeneous layers. These HGRs can be thick (up to 5 m and more) and are frequently complex, being composed of multiple small steps or continuous stratification. Microstructure data collected in the EB in 2007 and 2008 are used to estimate heat fluxes through large steps in three ways: using the measured dissipation rate in the large homogeneous layers; utilizing empirical flux laws based on the density ratio and temperature step across HGRs after scaling to account for the presence of multiple small DL interfaces within each HGR; and averaging estimates of heat fluxes computed separately for individual small interfaces (as laminar conductive fluxes), small convective layers (via dissipation rates within small DL layers), and turbulent patches (using dissipation rate and buoyancy) within each HGR. Diapycnal heat fluxes through HGRs evaluated by each method agree with each other and range from ~2 to ~8 W m−2, with an average flux of ~3–4 W m−2. These large fluxes confirm a critical role for the DL instability in cooling and thickening the AW layer as it circulates around the eastern Arctic Ocean.

The use of Cs and Sr isotopes as tracers in the Arctic Mediterranean Seas

1988 ◽  
Vol 325 (1583) ◽  
pp. 161-176 ◽  
Keyword(s):  
Deep Water ◽  
Thermohaline Circulation ◽  
Atlantic Water ◽  
The Arctic ◽  
Coastal Current ◽  
Intermediate Water ◽  
Sr Isotopes ◽  
Arctic Ice ◽  
Norwegian Coastal Current

The Arctic Mediterranean Seas constitute an oceanic region in which the thermohaline circulation has a strong advective component and deep ventilation processes are very active relative to other oceanic areas. Details of the nature of these circulation and ventilation processes have been revealed through use of Cs and Sr isotopes from bomb-fallout and nuclear-waste sources as ocean tracers. In both cases, their regional input is dominated by advective supply in the Norwegian Atlantic Current and Norwegian Coastal Current, respectively. The different temporal, spatial, and compositional input patterns of these tracers have been used to study different facets of the regional circulation. These input differences and some representative applications of the use of these tracers are reviewed. The data discussed derive from samples collected both from research vessels and from Arctic ice camps. The topics addressed include: ( a ) the role of Arctic Intermediate Water as source, supplying recent surface water to North Atlantic Deep Water via the Denmark Strait overflow; ( b ) deep convective mixing in the Greenland Sea; ( c ) circulation or recirculation of Atlantic water in the Arctic basins; and ( d ) the role of Arctic shelfwaters in the ventilation of intermediate and deep water in the Eurasian and Canadian basins.

Sign in / Sign up

Export Citation Format

Share Document