Downflow of the Antarctic shelf water at the shelf and continental slope of the Commonwealth Sea in the summer season and its effect on the bottom water formation in the Southern Ocean

Oceanology ◽  
2011 ◽  
Vol 51 (3) ◽  
pp. 370-384 ◽  
Author(s):  
P. N. Golovin ◽  
N. N. Antipov ◽  
A. V. Klepikov
Keyword(s):  
Southern Ocean ◽  
Continental Slope ◽  
Bottom Water ◽  
Summer Season ◽  
Shelf Water ◽  
Water Formation ◽  
Antarctic Shelf ◽  
Bottom Water Formation ◽  
The Antarctic

scholarly journals Does the sensitivity of Southern Ocean circulation depend upon bathymetric details?

2014 ◽  
Vol 372 (2019) ◽  
pp. 20130050 ◽  
Author(s):  
Andrew McC. Hogg ◽  
David R. Munday
Keyword(s):  
Southern Ocean ◽  
Wind Stress ◽  
Ocean Circulation ◽  
Bottom Water ◽  
Deep Ocean ◽  
Ocean Eddies ◽  
Oceanic Response ◽  
Water Formation ◽  
Circumpolar Current ◽  
Bottom Water Formation

The response of the major ocean currents to changes in wind stress forcing is investigated with a series of idealized, but eddy-permitting, model simulations. Previously, ostensibly similar models have shown considerable variation in the oceanic response to changing wind stress forcing. Here, it is shown that a major reason for these differences in model sensitivity is subtle modification of the idealized bathymetry. The key bathymetric parameter is the extent to which the strong eddy field generated in the circumpolar current can interact with the bottom water formation process. The addition of an embayment, which insulates bottom water formation from meridional eddy fluxes, acts to stabilize the deep ocean density and enhances the sensitivity of the circumpolar current. The degree of interaction between Southern Ocean eddies and Antarctic shelf processes may thereby control the sensitivity of the Southern Ocean to change.

scholarly journals Interannual variability of water masses in the area of bottom water formation in Рrydz Вay

2017 ◽  
pp. 87-106
Author(s):  
N. N. Antipov ◽  
A. V. Klepikov
Keyword(s):  
Interannual Variability ◽  
Continental Slope ◽  
Bottom Water ◽  
Bottom Topography ◽  
Water Masses ◽  
Prydz Bay ◽  
Adjacent Area ◽  
Water Formation ◽  
Bottom Water Formation ◽  
First Time

The results of field studies of the processes of Antarctic Bottom Water formation conducted in the period from 2004 to 2016 in the Prydz Bay of the Commonwealth Sea is discussed. During this period the oceanographic observations along the 70° E section, crossing the shelf and the continental slope, were repeated nine times. In this area in the austral summer of 2004 during the AARI expedition on the r/v “Akademik Fedorov” the process of formation of bottom water has been recorded for the first time. A further study of the structure and characteristics of water masses on this section and in the adjacent area confirmed the regularity of these processes during the summer period. At the same time, a significant interannual variability of the structure, characteristics, and mechanisms of distribution of the main water masses in the section shelf, deep and bottom waters — was found. For the first time, detailed information on the bottom topography of the ocean in the vicinity of this section made it possible to show the determining role of bottom topography features in the distribution of newly formed bottom water along the continental slope. The tendency of increasing of the volume of bottom water formed in the Prydz Bay in recent years is revealed, which is associated with the intensification of the basal melting of the ice shelf leading to an increase in the volume of the formation of supercooled Shelf Water, the most important component in the formation of bottom water.

scholarly journals Antarctic Bottom Water and North Atlantic Deep Water in CMIP6 models

Ocean Science ◽  
2021 ◽  
Vol 17 (1) ◽  
pp. 59-90
Author(s):  
Céline Heuzé
Keyword(s):  
Southern Ocean ◽  
North Atlantic ◽  
Deep Water ◽  
Bottom Water ◽  
Climate Models ◽  
Deep Convection ◽  
North Atlantic Deep Water ◽  
Antarctic Bottom Water ◽  
Water Formation ◽  
Bottom Water Formation

Abstract. Deep and bottom water formation are crucial components of the global ocean circulation, yet they were poorly represented in the previous generation of climate models. We here quantify biases in Antarctic Bottom Water (AABW) and North Atlantic Deep Water (NADW) formation, properties, transport, and global extent in 35 climate models that participated in the latest Climate Model Intercomparison Project (CMIP6). Several CMIP6 models are correctly forming AABW via shelf processes, but 28 models in the Southern Ocean and all 35 models in the North Atlantic form deep and bottom water via open-ocean deep convection too deeply, too often, and/or over too large an area. Models that convect the least form the most accurate AABW but the least accurate NADW. The four CESM2 models with their overflow parameterisation are among the most accurate models. In the Atlantic, the colder the AABW, the stronger the abyssal overturning at 30∘ S, and the further north the AABW layer extends. The saltier the NADW, the stronger the Atlantic Meridional Overturning Circulation (AMOC), and the further south the NADW layer extends. In the Indian and Pacific oceans in contrast, the fresher models are the ones which extend the furthest regardless of the strength of their abyssal overturning, most likely because they are also the models with the weakest fronts in the Antarctic Circumpolar Current. There are clear improvements since CMIP5: several CMIP6 models correctly represent or parameterise Antarctic shelf processes, fewer models exhibit Southern Ocean deep convection, more models convect at the right location in the Labrador Sea, bottom density biases are reduced, and abyssal overturning is more realistic. However, more improvements are required, e.g. by generalising the use of overflow parameterisations or by coupling to interactive ice sheet models, before deep and bottom water formation, and hence heat and carbon storage, are represented accurately.

scholarly journals Ventilation of the abyss in the Atlantic sector of the Southern Ocean

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Camille Hayatte Akhoudas ◽  
Jean-Baptiste Sallée ◽  
F. Alexander Haumann ◽  
Michael P. Meredith ◽  
Alberto Naveira Garabato ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Bottom Water ◽  
Climate Models ◽  
Deep Ocean ◽  
Analytical Framework ◽  
Weddell Sea ◽  
Global Ocean ◽  
Shelf Water ◽  
Antarctic Bottom Water ◽  
Atlantic Sector

AbstractThe Atlantic sector of the Southern Ocean is the world’s main production site of Antarctic Bottom Water, a water-mass that is ventilated at the ocean surface before sinking and entraining older water-masses—ultimately replenishing the abyssal global ocean. In recent decades, numerous attempts at estimating the rates of ventilation and overturning of Antarctic Bottom Water in this region have led to a strikingly broad range of results, with water transport-based calculations (8.4–9.7 Sv) yielding larger rates than tracer-based estimates (3.7–4.9 Sv). Here, we reconcile these conflicting views by integrating transport- and tracer-based estimates within a common analytical framework, in which bottom water formation processes are explicitly quantified. We show that the layer of Antarctic Bottom Water denser than 28.36 kg m$$^{-3}$$ - 3 $$\gamma _{n}$$ γ n is exported northward at a rate of 8.4 ± 0.7 Sv, composed of 4.5 ± 0.3 Sv of well-ventilated Dense Shelf Water, and 3.9 ± 0.5 Sv of old Circumpolar Deep Water entrained into cascading plumes. The majority, but not all, of the Dense Shelf Water (3.4 ± 0.6 Sv) is generated on the continental shelves of the Weddell Sea. Only 55% of AABW exported from the region is well ventilated and thus draws down heat and carbon into the deep ocean. Our findings unify traditionally contrasting views of Antarctic Bottom Water production in the Atlantic sector, and define a baseline, process-discerning target for its realistic representation in climate models.

Recent recovery of Antarctic Bottom Water formation in the Ross Sea driven by climate anomalies

2020 ◽  
Vol 13 (12) ◽  
pp. 780-786 ◽  
Author(s):  
Alessandro Silvano ◽  
Annie Foppert ◽  
Stephen R. Rintoul ◽  
Paul R. Holland ◽  
Takeshi Tamura ◽  
...  
Keyword(s):  
Bottom Water ◽  
Ross Sea ◽  
Antarctic Bottom Water ◽  
Climate Anomalies ◽  
Water Formation ◽  
Bottom Water Formation
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