scholarly journals Seabed erosion on the Lomonosov Ridge, central Arctic Ocean: A tale of deep draft icebergs in the Eurasia Basin and the influence of Atlantic water inflow on iceberg motion?

2004 ◽  
Vol 19 (3) ◽  
pp. n/a-n/a ◽  
Author(s):  
Y. Kristoffersen ◽  
B. Coakley ◽  
W. Jokat ◽  
M. Edwards ◽  
H. Brekke ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Atlantic Water ◽  
Water Inflow ◽  
Lomonosov Ridge ◽  
Central Arctic Ocean ◽  
Eurasia Basin

scholarly journals Central Arctic Ocean paleoceanography from ~ 50 ka to present, on the basis of ostracode faunal assemblages from SWERUS 2014 expedition

2017 ◽  
Author(s):  
Laura Gemery ◽  
Thomas M. Cronin ◽  
Robert K. Poirier ◽  
Christof Pearce ◽  
Natalia Barrientos ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Large Scale ◽  
Late Quaternary ◽  
Atlantic Water ◽  
Environmental Indicators ◽  
The Arctic ◽  
Lomonosov Ridge ◽  
Central Arctic Ocean ◽  
Ice Conditions

Abstract. Late Quaternary paleoceanographic changes in the central Arctic Ocean were reconstructed from a multicore and gravity core from the Lomonosov Ridge (Arctic Ocean) collected during the 2014 SWERUS-C3 Expedition. Ostracode assemblages dated by accelerator mass spectrometry (AMS) indicate changing sea-ice conditions and warm Atlantic Water (AW) inflow to the Arctic Ocean from ~ 50 ka to present. Key taxa used as environmental indicators include Acetabulastoma arcticum (perennial sea ice), Polycope spp. (productivity and sea ice), Krithe hunti (partially sea-ice free conditions, deep water inflow), and Rabilimis mirabilis (high nutrient, AW inflow). Results indicate seasonally sea-ice free conditions during Marine Isotope Stage (MIS) 3 (~ 57–29 ka), rapid deglacial changes in water mass conditions (15–11 ka), seasonally sea-ice free conditions during the early Holocene (~ 10–7 ka) and perennial sea ice during the late Holocene. Comparisons with faunal records from other cores from the Mendeleev and Lomonosov Ridges suggest generally similar patterns, although sea-ice cover during the last glacial maximum may have been less extensive at the southern Lomonosov Ridge at our core site (~ 85.15° N, 152° E) than farther north and towards Greenland. The new data also provide evidence for abrupt, large-scale shifts in ostracode species depth and geographical distributions during rapid climatic transitions.

Glacial geomorphology of the Central Arctic Ocean: the Chukchi Borderland and the Lomonosov Ridge

2008 ◽  
Vol 33 (4) ◽  
pp. 526-545 ◽  
Author(s):  
Martin Jakobsson ◽  
Leonid Polyak ◽  
Margo Edwards ◽  
Johan Kleman ◽  
Bernard Coakley
Keyword(s):  
Arctic Ocean ◽  
Lomonosov Ridge ◽  
Glacial Geomorphology ◽  
Central Arctic Ocean ◽  
Chukchi Borderland

scholarly journals Scenario Changes of Atlantic Water in the Arctic Ocean

2015 ◽  
Vol 28 (14) ◽  
pp. 5523-5548 ◽  
Author(s):  
Zhenxia Long ◽  
Will Perrie
Keyword(s):  
Climate Change ◽  
Arctic Ocean ◽  
Heat Loss ◽  
Climate Change Scenario ◽  
Climate Model ◽  
Atlantic Water ◽  
Heat Fluxes ◽  
Change Scenario ◽  
Pressure System ◽  
Central Arctic Ocean

Abstract The authors explore possible temperature modifications of the Atlantic Water Layer (AWL) induced by climate change, performing simulations for 1970 to 2099 with a coupled ice–ocean Arctic model (CIOM). Surface fields to drive the CIOM were provided by the Canadian Regional Climate Model (CRCM), driven by outputs from the Canadian Centre for Climate Modelling and Analysis (CCCma) Coupled Global Climate Model, version 3 (CGCM3) following the A1B climate change scenario. In the present climate, represented as 1990–2009, the CIOM can reliably reproduce the AWL compared to Polar Science Center Hydrographic Climatology (PHC) data. For the future climate, assuming the A1B climate change scenario, there is a significant increase in water volume transport into the central Arctic Ocean through Fram Strait due to the weakened atmospheric high pressure system over the western Arctic and an intensified atmospheric low pressure system over the Nordic seas. The AWL temperature tends to decrease from 0.36°C in the 2010s to 0.26°C in the 2060s. In the vertical, the warm Atlantic water core slightly expands before the 2030s, significantly shrinks after the 2050s, and essentially disappears by 2070–99, in the southern Beaufort Sea. The temperature decrease after 2030 is mainly due to the reduced heat fluxes in the Kara and Barents Seas. In the northeastern Barents and Kara Seas, the loss of sea ice increases the heat loss from the Atlantic water and reduces the water temperature near the bottom, contributing to decreased heat fluxes into the central Arctic Ocean, as well as decreased AWL temperature at central Arctic Ocean intermediate layers. In addition, the vertically integrated heat loss also plays an important role in the AWL cooling process.

Bio‐optical Properties of Surface Waters in the Atlantic Water Inflow Region off Spitsbergen (Arctic Ocean)

2019 ◽  
Vol 124 (3) ◽  
pp. 1964-1987 ◽  
Author(s):  
Piotr Kowalczuk ◽  
Sławomir Sagan ◽  
Anna Makarewicz ◽  
Justyna Meler ◽  
Karolina Borzycka ◽  
...  
Keyword(s):  
Optical Properties ◽  
Arctic Ocean ◽  
Surface Waters ◽  
Atlantic Water ◽  
Water Inflow

scholarly journals Ice-shelf damming in the glacial Arctic Ocean: dynamical regimes of a basin-covering kilometre-thick ice shelf

2017 ◽  
Vol 11 (4) ◽  
pp. 1745-1765 ◽  
Author(s):  
Johan Nilsson ◽  
Martin Jakobsson ◽  
Chris Borstad ◽  
Nina Kirchner ◽  
Göran Björk ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Ice Sheet ◽  
Lomonosov Ridge ◽  
Fram Strait ◽  
Ice Shelf ◽  
Interior Region ◽  
Central Arctic Ocean ◽  
One Dimensional ◽  
Grounding Line ◽  
The Mean

Abstract. Recent geological and geophysical data suggest that a 1 km thick ice shelf extended over the glacial Arctic Ocean during Marine Isotope Stage 6, about 140 000 years ago. Here, we theoretically analyse the development and equilibrium features of such an ice shelf, using scaling analyses and a one-dimensional ice-sheet–ice-shelf model. We find that the dynamically most consistent scenario is an ice shelf with a nearly uniform thickness that covers the entire Arctic Ocean. Further, the ice shelf has two regions with distinctly different dynamics: a vast interior region covering the central Arctic Ocean and an exit region towards the Fram Strait. In the interior region, which is effectively dammed by the Fram Strait constriction, there are strong back stresses and the mean ice-shelf thickness is controlled primarily by the horizontally integrated mass balance. A narrow transition zone is found near the continental grounding line, in which the ice-shelf thickness decreases offshore and approaches the mean basin thickness. If the surface accumulation and mass flow from the continental ice masses are sufficiently large, the ice-shelf thickness grows to the point where the ice shelf grounds on the Lomonosov Ridge. As this occurs, the back stress increases in the Amerasian Basin and the ice-shelf thickness becomes larger there than in the Eurasian Basin towards the Fram Strait. Using a one-dimensional ice-dynamic model, the stability of equilibrium ice-shelf configurations without and with grounding on the Lomonosov Ridge are examined. We find that the grounded ice-shelf configuration should be stable if the two Lomonosov Ridge grounding lines are located on the opposites sides of the ridge crest, implying that the downstream grounding line is located on a downward sloping bed. This result shares similarities with the classical result on marine ice-sheet stability of Weertman, but due to interactions between the Amerasian and Eurasian ice-shelf segments the mass flux at the downstream grounding line decreases rather than increases with ice thickness.

scholarly journals Annual cycle of downward particle fluxes on each side of the Gakkel Ridge in the central Arctic Ocean

2020 ◽  
Vol 378 (2181) ◽  
pp. 20190368 ◽  
Author(s):  
Eva-Maria Nöthig ◽  
Catherine Lalande ◽  
Kirsten Fahl ◽  
Katja Metfies ◽  
Ian Salter ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Arctic Ocean ◽  
Euphotic Zone ◽  
Sediment Traps ◽  
Atlantic Water ◽  
Total Particulate Matter ◽  
Central Arctic Ocean ◽  
Gakkel Ridge ◽  
Particulate Nitrogen ◽  
Lena River

Two mooring arrays carrying sediment traps were deployed from September 2011 to August 2012 at ∼83°N on each side of the Gakkel Ridge in the Nansen and Amundsen Basins to measure downward particle flux below the euphotic zone (approx. 250 m) and approximately 150 m above seafloor at approximately 3500 and 4000 m depth, respectively. In a region that still experiences nearly complete ice cover throughout the year, export fluxes of total particulate matter (TPM), particulate organic carbon (POC), particulate nitrogen (PN), biogenic matter, lithogenic matter, biogenic particulate silica (bPSi), calcium carbonate (CaCO 3 ), protists and biomarkers only slightly decreased with depth. Seasonal variations of particulate matter fluxes were similar on both sides of the Gakkel Ridge. Somewhat higher export rates in the Amundsen Basin and differences in the composition of the sinking TPM and bPSi on each side of the Gakkel Ridge probably reflected the influence of the Lena River/Transpolar Drift in the Amundsen Basin and the influence of Atlantic water in the Nansen Basin. Low variations in particle export with depth revealed a limited influence of lateral advection in the deep barren Eurasian Basin. This article is part of the theme issue ‘The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning’.

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