Return of the cold halocline layer to the Amundsen Basin of the Arctic Ocean: Implications for the sea ice mass balance

Björk, Göran; Söderkvist, Johan; Winsor, Peter; Nikolopoulos, Anna; Steele, Michael

doi:10.1029/2001gl014157

Cited by 63 publications

(60 citation statements)

References 13 publications

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“…Furthermore, our finding that negative NAO forcing caused the CHL to readvance toward its original position supports the observed return of the CHL to the Amundsen Basin in 2001 (Bjö rk et al 2002), following a period in the late 1990s and early 2000s when the NAO was more neutral in state.…”

Section: Discussionsupporting

confidence: 71%

“…Atlantic Water (AW) entering the Arctic via the Barents shelf and West Spitzbergen Current (WSP) have warmed since the early 1990s, producing temperature anomalies in the Nansen Basin of roughly 118C in 2004 (Polyakov et al 2005). The increased penetration of AW caused the cold halocline (CHL) to retreat from the Amundsen Basin to the Makarov Basin in the mid-1990s (Steele and Boyd 1998), although measurements showed that it had returned to the Amundsen Basin in 2001 (Bjö rk et al 2002).…”

Section: Introductionmentioning

confidence: 99%

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Simulated Response of the Arctic Freshwater Budget to Extreme NAO Wind Forcing

et al. 2009

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The authors investigate the response of the Arctic Ocean freshwater budget to changes in the North Atlantic Oscillation (NAO) using a regional-ocean configuration of the Massachusetts Institute of Technology GCM (MITgcm) and carry out several different 10-yr and 30-yr integrations. At 1 / 6 8 (;18 km) resolution the model resolves the major Arctic transport pathways, including Bering Strait and the Canadian Archipelago. Two main calculations are performed by repeating the wind fields of two contrasting NAO years in each run for the extreme negative and positive NAO phases of 1969 and 1989, respectively. These calculations are compared both with a control run and the compiled observationally based freshwater budget estimate of Serreze et al.The results show a clear response in the Arctic freshwater budget to NAO forcing, that is, repeat NAO negative wind forcing results in virtually all freshwater being retained in the Arctic, with the bulk of the freshwater content being pooled in the Beaufort gyre. In contrast, repeat NAO positive forcing accelerates the export of freshwater out of the Arctic to the North Atlantic, primarily via Fram Strait (;900 km 3 yr 21 ) and the Canadian Archipelago (;500 km 3 yr 21 ), with a total loss in freshwater storage of ;13 000 km 3 (15%) after 10 yr. The large increase in freshwater export through the Canadian Archipelago highlights the important role that this gateway plays in redistributing the freshwater of the Arctic to subpolar seas, by providing a direct pathway from the Arctic basin to the Labrador Sea, Gulf Stream system, and Atlantic Ocean.The authors discuss the sensitivity of the Arctic Ocean to long-term fixed extreme NAO states and show that the freshwater content of the Arctic is able to be restored to initial values from a depleted freshwater state after ;20 yr.

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Section: Discussionsupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Simulated Response of the Arctic Freshwater Budget to Extreme NAO Wind Forcing

et al. 2009

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“…Low salinities at the surface immediately below the sea ice cap may be a consequence of several processes, including sea ice melting cycles; inflow of water from the Pacific Ocean via the Bering Strait, which is fresher than the North Atlantic waters (Jones et al, 2008); and continental runoff primarily from the Siberian shelves (Björk et al, 2002). In our study, the halocline caused pronounced stratification, which varied due to the thaw-freeze cycle of sea ice and important freshwater inputs (Carmack and Wassmann, 2006).…”

Section: Regional Settingsmentioning

confidence: 78%

Climate relevant trace gases (N2O and CH4) in the Eurasian Basin (Arctic Ocean)

Verdugo

Damm

Snoeijs

et al. 2016

Deep Sea Research Part I: Oceanographic Research Papers

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A B S T R A C TThe concentration of greenhouse gases, including nitrous oxide (N 2 O), methane (CH 4 ), and compounds such as total dimethylsulfoniopropionate (DMSP t ), along with other oceanographic variables were measured in the icecovered Arctic Ocean within the Eurasian Basin (EAB). The EAB is affected by the perennial ice-pack and has seasonal microalgal blooms, which in turn may stimulate microbes involved in trace gas cycling. Data collection was carried out on board the LOMROG III cruise during the boreal summer of 2012. Water samples were collected from the surface to the bottom layer (reaching 4300 m depth) along a South-North transect (SNT), from 82.19°N, 8.75°E to 89.26°N, 58.84°W, crossing the EAB through the Nansen and Amundsen Basins. The Polar Mixed Layer and halocline waters along the SNT showed a heterogeneous distribution of N 2 O, CH 4 and DMSP t , fluctuating between 42-111 and 27-649% saturation for N 2 O and CH 4, respectively; and from 3.5 to 58.9 nmol L −1 for DMSP t . Spatial patterns revealed that while CH 4 and DMSP t peaked in the Nansen Basin, N 2 O was higher in the Amundsen Basin. In the Atlantic Intermediate Water and Arctic Deep Water N 2 O and CH 4 distributions were also heterogeneous with saturations between 52% and 106% and 28% and 340%, respectively. Remarkably, the Amundsen Basin contained less CH 4 than the Nansen Basin and while both basins were mostly under-saturated in N 2 O. We propose that part of the CH 4 and N 2 O may be microbiologically consumed via methanotrophy, denitrification, or even diazotrophy, as intermediate and deep waters move throughout EAB associated with the overturning water mass circulation. This study contributes to baseline information on gas distribution in a region that is increasingly subject to rapid environmental changes, and that has an important role on global ocean circulation and climate regulation.

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“…Thus to sustain a baroclinic geostrophic flow, the unobserved zone near the coast must have contained even fresher water than measured at the innermost station in the section. This would require surface salinities well below 32, which even during summer are rarely observed in the Arctic Ocean north of Fram Strait (Björk et al, 2002). Accordingly, we consider it unlikely that there were strong baroclinic flows near the coast.…”

Section: Discussionmentioning

confidence: 99%

Liquid freshwater transport and Polar Surface Water characteristics in the East Greenland Current during the AO-02 Oden expedition

Nilsson

Björk

Rudels³

et al. 2008

Progress in Oceanography

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Dynamical features of the East Greenland Current (EGC) are synthesized from a survey conducted by the Swedish icebreaker Oden during the International Arctic Ocean -02 expedition (AO-02) in May 2002 with emphasis on the liquid freshwater transport and Polar Surface Water. The data include hydrography and lowered Acoustic Doppler Current Profiler (LADCP) velocities in eight transects along the EGC, from the Fram Strait in the north to the Denmark Strait in the south. The survey reveals a strong confinement of the low-salinity polar water in the EGC to the continental slope/shelf-a feature of relevance for the stability of the thermohaline circulation in the Arctic Mediterranean. The southward transport of liquid freshwater in the EGC was found to vary considerably between the sections, ranging between 0.01 and 0.1 Sverdrup. Computations based on geostrophic as well as LADCP velocities give a section-averaged southward freshwater transport of 0.06 Sverdrup in the EGC during May 2002. Furthermore, Oden data suggest that the liquid freshwater transport was as large north of the Fram Strait as it was south of the Denmark Strait.

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Return of the cold halocline layer to the Amundsen Basin of the Arctic Ocean: Implications for the sea ice mass balance

Cited by 63 publications

References 13 publications

Simulated Response of the Arctic Freshwater Budget to Extreme NAO Wind Forcing

Simulated Response of the Arctic Freshwater Budget to Extreme NAO Wind Forcing

Climate relevant trace gases (N2O and CH4) in the Eurasian Basin (Arctic Ocean)

Liquid freshwater transport and Polar Surface Water characteristics in the East Greenland Current during the AO-02 Oden expedition

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