Abstract
In the summer seasons of 2004–2007, the intensive runoff (cascading) of the Antarctic shelf water (ASW) down the shelf and continental slope was revealed thanks to the recording of numerous thermohaline profiles across the shelf and continental slope of the Commonwealth Sea and Prydz Bay. The quickly executed profiles (4–10 h) with submesoscale resolution (near the shelf’s edge, the scale was even eddy-determinative, i.e., within 1.9–5.6 km), in combination with the fine-structure sounding and fine vertical resolution of the near-bottom boundary layer, provided a qualitatively new level of understanding the natural data. The detailed analysis of the temperature, salinity, and density patterns revealed the regularities and peculiarities of the ASW shelf and slope cascading. The intensive ASW cascading near the shelf break and lower part of the slope can be forced (appearing as discrete frontal meanders) or free (appearing as discrete plumes) and often has a wave-eddy character. The field observational data confirmed the obtained representative estimates of the elements of the ASW slope cascading. The basic area of the ASW formation is near the Amery Shelf Ice, from where the ASW spreads to the northwest, goes around the Fram Bank, and flows down the continental slope. The evaluative contribution of the ASW slope cascading to the ventilation of the deep and slope water of the Southern Ocean (near the shelf break 70 km long where the ASW cascading was observed) is Q K = 0.04–0.24 Sv, which agrees well with the analogous estimates obtained in other regions of the Antarctic.
Similar content being viewed by others
References
N. N. Antipov, A. I. Danilov, and A. V. Klepikov, “Circulation and Structure of the Waters in the Western Part of the Weddell Sea according to Data of Natural Experiment ‘Drifting Station Weddell-1,’” in Antarctica: Collected Papers (Nauka, Moscow, 1998), No. 34, pp. 5–30 [in Russian].
N. N. Antipov and A. V. Klepikov, “Features of the Oceanographic Regime of Pruds Bay according to Data of Expeditions AARI in 1997–2007 Years,” Probl. Arktiki Antarktiki, 36–48 (2007).
P. N. Golovin, “Characteristics of Formation and Flow of Dense Shelf Waters (Cascading) near the Continental Slope of the Nansen Basin in the Laptev Sea,” Meteorol. Gidrol., No. 11, 44–62 (2005).
P. N. Golovin, “Efficiency of Dense Shelf Water Cascading over the Continental Slope of Severnaya Zemlya in the Laptev Sea and Its Possible Contribution to the Ventilation of the Intermediate Water in the Nansen Basin,” Okeanologiya 47(1), 49–58 (2007) [Oceanology 47 (1), 42–50 (2007)].
A. G. Zatsepin, V. L. Didkovskii, and A. V. Semenov, “Self-Oscillatory Mechanism of Inducing a Vortex Structure by a Stationary Local Source over a Sloping Bottom in a Rotating Fluid,” Okeanologiya 38(1), 47–55 (1998) [Oceanology 38 (1), 43–50 (1998)].
A. G. Zatsepin, A. G. Kostyanoi, and A. V. Semenov, “An Axisymmetric Density Current over a Sloping Bottom in a Rotating Fluid,” Okeanologiya 36(3), 339–345 (1996) [Oceanology 36 (3), 311–316 (1996)].
N. A. Maksimenko and A. G. Zatsepin, “Analysis of Dense Water Lowering along the Smooth Sloped Bottom of the Ocean,” Okeanologiya 37(4), 56–62 (1997) [Oceanology 37 (4), 461–464 (1997)].
K. N. Fedorov, Fine Thermohaline Structure of Ocean Waters (Gidrometeoizdat, Leningrad, 1976) [in Russian].
P. G. Baines and S. A. Condie, “Observations and Modelling of Antarctic Downslope Flows: a Review, in Ocean, Ice, and Atmosphere: Interactions at the Antarctic Continental Margin,” Antarctic Research Series 75, 29–49 (1998).
S. A. Condie, “Formation and Stability of Shelf-Break Fronts,” J. Geophys. Res. 98, 12405–12416 (1993).
S. A. Condie, “Descent of Dense Water Masses along Continental Slopes,” J. Mar. System. 53, 897–928 (1995).
E. Fahrbach, G. Rohardt, N. Scheele, et al., “Formation and Discharge of Deep and Bottom Water in the Northwestern Weddell Sea,” J. Mar. Res. 53, 515–538 (1995).
A. Foldvik, T. Kvinge, and T. Torresen, “Bottom Currents Near the Continental Shelf Break in the Weddell Sea,” in Oceanology of the Antarctic Continental Shelf, Antarctic Res. Ser. 43, 5–20 (AGY, Washington, 1985).
A. Foldvik, T. Gammelsrod, S. Osterhus, et al., “Ice Shelf Water Overflow and Bottom Water Formation in the Southern Weddell Sea,” J. Geophys. Res. 109, C02015, doi: 10.1029/2003JC002008 (2004).
T. D. Foster and E. C. Carmack, “Frontal Zone Mixing and Antarctic Bottom Water Formation in the Southern Weddell Sea,” Deep-Sea Res. 23, 301–317 (1976).
T. D. Foster, A. Foldvik, and J. H. Middleton, “Mixing and Bottom Water Formation in the Shelf Break Region of the Southern Weddell Sea,” Deep-Sea Res. 24(11), 301–317 (1987).
M. Hoppema, O. Klatt, W. Roether, et al., “Prominent Renewal of Weddell Sea Deep Water from a Remote Source,” J. Marine Res. 59, 257–279 (2001).
J. M. Huthnance, “Circulation, Exchange and Water Masses at the Ocean Margin: the Role of Physical Processes at the Shelf Edge,” Prog. Oceanogr. 35, 353–431 (1995).
V. V. Ivanov and P. N. Golovin, “Observations and Modeling of Dense Water Cascading from the Northwestern Laptev Sea Shelf,” J. Geophys. Res. 112, C09003, doi: 10.1029/2006JC003882 (2007).
V. V. Ivanov, G. I. Shapiro, J. M. Huthnance, et al., “Cascades of Dense Water around the World Ocean,” Prog. Oceanogr. 60, 47–98 (2004).
G. F. Lane-Serff and P. G. Baines, “Eddy Formation by Dense Flows on Slopes in a Rotation Fluid,” J. Fluid Mech. 363, 229–252 (1998).
H. Melling, “The Formation of a Haline Shelf Front in Wintertime in an Ice-Covered Sea,” Cont. Shelf Res. 13(10), 1123–1147 (1993).
J. F. Middleton, T. D. Foster, and A. Foldvik, “Low-Frequency Currents and Continental Shelf Waves in the Southern Weddell Sea,” J. Phys. Oceanogr. 12, 618–634 (1982).
R. D. Muench and A. L. Gordon, “Circulation and Transport of Water along the Western Weddell Sea Margin,” J. Geophys. Res. 100, 18503–18515 (1995).
Y. Nagata, R. Kimura, H. Honji, et al., “Laboratory Experiment of Dense Water Descending on Continental Slope,” In Deep Ocean Circulation. Physical and Chemical Aspects, 333–350 (1993).
D. Nof, “The Translation of Isolated Cold Eddies on a Sloping Bottom,” Deep-Sea Res. 30(2A), 171–182 (1983).
D. Quadfasel, B. Rudels, and K. Kurz, “Outflow of Dense Water from a Svalbard Fjord into the Fram Strait,” Deep-Sea Res. 35, 1143–1150 (1988).
G. I. Shapiro and A. E. Hill, “Dynamics of Dense Water Cascade at the Shelf Edge,” J. Phys. Oceanogr. 27, 2381–2394 (1997).
G. I. Shapiro, J. M. Huthnance, and V. V. Ivanov, “Dense Water Cascading Off the Continental Shelf,” J. Geophys. Res. 108, 3390–3409 (2003).
G. I. Shapiro and A. G. Zatsepin, “Gravity Current Down a Steeply Inclined Slope in a Rotating Fluid,” Ann. Geophys. 15(3), 366–374 (1997).
K. Tanaka and K. Akitomo, “Baroclinic Instability of Density Current along a Sloping Bottom and Associated Transport Process,” J. Geophys. Res. 106, 2621–2638 (2001).
J. A. Whitehead, “A Laboratory Model of Cooling over the Continental Shelf,” J. Phys. Oceanogr. 23, 2412–2427 (1993).
J. A. Whitehead, M. E. Stern, R. G. Flierl, and A. B. Klinger, “Experimental Observation of Baroclinic Eddies on a Sloping Bottom,” J. Geophys. Res. 95, 9585–9610 (1990).
Author information
Authors and Affiliations
Corresponding author
Additional information
Original Russian Text © P.N. Golovin, N.N. Antipov, A.V. Klepikov, 2011, published in Okeanologiya, 2011, Vol. 51, No. 3, pp. 393–408.
Rights and permissions
About this article
Cite this article
Golovin, P.N., Antipov, N.N. & Klepikov, A.V. 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 51, 370–384 (2011). https://doi.org/10.1134/S000143701103009X
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S000143701103009X