Circumpolar structure and distribution of the Antarctic Circumpolar Current fronts: 1. Mean circumpolar paths

Sokolov, Serguei; Rintoul, Stephen R.

doi:10.1029/2008jc005108

Cited by 374 publications

(451 citation statements)

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“…Location of the ACC fronts south of Tasmania for each of the cruises following the definitions of Sokolov and Rintoul (2002) for hydrographic data. * The range in the location of the SAF for the 2011 cruise could be related to a diversification of the PF or SAF into different jets (Sokolov and Rintoul, 2009) but also to crossing the meander of the front twice. Moore and Abbott, 2000;Sambrotto and Mace, 2000;Trull et al, 2001a).…”

Section: Changes In the Carbon Systemmentioning

confidence: 99%

Carbon uptake and biogeochemical change in the Southern Ocean, south of Tasmania

et al. 2017

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Abstract. Biogeochemical change in the water masses of the Southern Ocean, south of Tasmania, was assessed for the 16-year period between 1995 and 2011 using data from four summer repeats of the WOCE-JGOFS-CLIVAR-GO-SHIP (Key et al., 2015;Olsen et al., 2016) SR03 hydrographic section (at ∼ 140 • E). Changes in temperature, salinity, oxygen, and nutrients were used to disentangle the effect of solubility, biology, circulation and anthropogenic carbon (C ANT ) uptake on the variability of dissolved inorganic carbon (DIC) for eight water mass layers defined by neutral surfaces (γ n ). C ANT was estimated using an improved back-calculation method. Warming (∼ 0.0352 ± 0.0170 • C yr −1 ) of Subtropical Central Water (STCW) and Antarctic Surface Water (AASW) layers decreased their gas solubility, and accordingly DIC concentrations increased less rapidly than expected from equilibration with rising atmospheric CO 2 (∼ 0.86 ± 0.16 µmol kg −1 yr −1 versus ∼ 1 ± 0.12 µmol kg −1 yr −1 ). An increase in apparent oxygen utilisation (AOU) occurred in these layers due to either remineralisation of organic matter or intensification of upwelling. The range of estimates for the increases in C ANT were 0.71 ± 0.08 to 0.93 ± 0.08 µmol kg −1 yr −1 for STCW and 0.35 ± 0.14 to 0.65 ± 0.21 µmol kg −1 yr −1 for AASW, with the lower values in each water mass obtained by assigning all the AOU change to remineralisation. DIC increases in the Sub-Antarctic Mode Water (SAMW, 1.10 ± 0.14 µmol kg −1 yr −1 ) and Antarctic Intermediate Water (AAIW, 0.40 ± 0.15 µmol kg −1 yr −1 ) layers were similar to the calculated C ANT trends. For SAMW, the C ANT increase tracked rising atmospheric CO 2 . As a consequence of the general DIC increase, decreases in total pH (pH T ) and aragonite saturation ( Ar ) were found in most water masses, with the upper ocean and the SAMW layer presenting the largest trends for pH T decrease (∼ −0.0031 ± 0.0004 yr −1 ). DIC increases in deep and bottom layers (∼ 0.24 ± 0.04 µmol kg −1 yr −1 ) resulted from the advection of old deep waters to resupply increased upwelling, as corroborated by increasing silicate (∼ 0.21 ± 0.07 µmol kg −1 yr −1 ), which also reached the upper layers near the Antarctic Divergence (∼ 0.36 ± 0.06 µmol kg −1 yr −1 ) and was accompanied by an increase in salinity. The observed changes in DIC over the 16-year span caused a shoaling (∼ 340 m) of the aragonite saturation depth (ASD, Ar = 1) within Upper Circumpolar Deep Water that followed the upwelling path of this layer. From all our results, we conclude a scenario of increased transport of deep waters into the section and enhanced upwelling at high latitudes for the period between 1995 and 2011 linked to strong westerly winds. Although enhanced upwelling lowered the capacity of the AASW layer to uptake atmospheric CO 2 , it did not limit that of the newly forming SAMW and AAIW, which exhibited C ANT storage rates (∼ 0.41 ± 0.20 mol m −2 yr −1 ) twice that of the upper layers.

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Section: Changes In the Carbon Systemmentioning

confidence: 99%

Carbon uptake and biogeochemical change in the Southern Ocean, south of Tasmania

et al. 2017

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“…11. Sokolov and Rintoul (2009) argue that the frontal location can be determined by the contour lines of SSH. In Fig.…”

Section: Results Of Global Assimilation Of Dot In Southern Oceanmentioning

confidence: 99%

Impact of combining GRACE and GOCE gravity data on ocean circulation estimates

Janjić

Schröter

Savcenko³

et al. 2012

Ocean Sci.

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Abstract. With the focus on the Southern Ocean circulation, results of assimilation of multi-mission-altimeter data and the GRACE/GOCE gravity data into the finite element ocean model (FEOM) are investigated. We use the geodetic method to obtain the dynamical ocean topography (DOT). This method combines the multi-mission-altimeter sea surface height and the GRACE/GOCE gravity field. Using the profile approach, the spectral consistency of both fields is achieved by filtering the sea surface height and the geoid. By combining the GRACE and GOCE data, a considerably shorter filter length can be used, which results in more DOT details. We show that this increase in resolution of measured DOT carries onto the results of data assimilation for the surface data. By assimilating only absolute dynamical topography data using the ensemble Kalman filter, we were able to improve modeled fields. Results are closer to observations which were not used for assimilation and lie outside the area covered by altimetry in the Southern Ocean (e.g. temperature of surface drifters or deep temperatures in the Weddell Sea area at 800 m depth derived from Argo composite.)

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“…However, there are some large latitudinal shifts within the Antarctic Circumpolar Current associated with strong steering by bathymetry (Orsi et al, 1995;Sokolov and Rintoul, 2009a;De Broyer and Koubbi, 2014). This is particularly marked in the Scotia Sea, which lies to the East of Drake Passage.…”

Section: Physical Conditions and Circulation In The Antarcticmentioning

confidence: 99%

Advection in polar and sub-polar environments: Impacts on high latitude marine ecosystems

Hunt

Drinkwater

Arrigo

et al. 2016

Progress in Oceanography

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a b s t r a c tWe compare and contrast the ecological impacts of atmospheric and oceanic circulation patterns on polar and sub-polar marine ecosystems. Circulation patterns differ strikingly between the north and south. Meridional circulation in the north provides connections between the sub-Arctic and Arctic despite the presence of encircling continental landmasses, whereas annular circulation patterns in the south tend to isolate Antarctic surface waters from those in the north. These differences influence fundamental aspects of the polar ecosystems from the amount, thickness and duration of sea ice, to the types of organisms, and the ecology of zooplankton, fish, seabirds and marine mammals. Meridional flows in both the North Pacific and the North Atlantic oceans transport heat, nutrients, and plankton northward into the Chukchi Sea, the Barents Sea, and the seas off the west coast of Greenland. In the North Atlantic, the advected heat warms the waters of the southern Barents Sea and, with advected nutrients and plankton, supports immense biomasses of fish, seabirds and marine mammals. On the Pacific side of the Arctic, cold waters flowing northward across the northern Bering and Chukchi seas during winter and spring limit the ability of boreal fish species to take advantage of high seasonal production there. Southward flow of cold Arctic waters into sub-Arctic regions of the North Atlantic occurs mainly through Fram Strait with less through the Barents Sea and the Canadian Archipelago. In the Pacific, the transport of Arctic waters and plankton southward through Bering Strait is minimal.In the Southern Ocean, the Antarctic Circumpolar Current and its associated fronts are barriers to the southward dispersal of plankton and pelagic fishes from sub-Antarctic waters, with the consequent evolution of Antarctic zooplankton and fish species largely occurring in isolation from those to the north. The Antarctic Circumpolar Current also disperses biota throughout the Southern Ocean, and as a result, the biota tends to be similar within a given broad latitudinal band. South of the Southern Boundary of the ACC, there is a large-scale divergence that brings nutrient-rich water to the surface. This divergence, along with more localized upwelling regions and deep vertical convection in winter, generates elevated nutrient levels throughout the Antarctic at the end of austral winter. However, such elevated nutrient levels do not support elevated phytoplankton productivity through the entire Southern Ocean, as iron concentrations are rapidly removed to limiting levels by spring blooms in deep waters. However, coastal http://dx

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Circumpolar structure and distribution of the Antarctic Circumpolar Current fronts: 1. Mean circumpolar paths

Cited by 374 publications

References 44 publications

Carbon uptake and biogeochemical change in the Southern Ocean, south of Tasmania

Carbon uptake and biogeochemical change in the Southern Ocean, south of Tasmania

Impact of combining GRACE and GOCE gravity data on ocean circulation estimates

Advection in polar and sub-polar environments: Impacts on high latitude marine ecosystems

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