On the transport, variability and origin of dense water masses crossing the South Scotia Ridge

• Published in: Deep Sea Research Part II: Topical Studies in Oceanography
• Main Authors: Schodlok, Michael, Hellmer, Hartmut, Beckmann, A.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2002
• Subjects: Bransfield Strait; Prydz Bay; Scotia Sea; Sea ice; Weddell Sea
• Online Access: https://epic.awi.de/id/eprint/4380/; https://epic.awi.de/id/eprint/4380/1/Sch2001l.pdf; https://doi.org/10.1016/S0967-0645(02)00160-1; https://hdl.handle.net/10013/epic.14955; https://hdl.handle.net/10013/epic.14955.d001

The deep Scotia Sea is filled with ventilated Weddell Sea Deep Water.This in turn is an essential contributor to the ventilation of the World Ocean abyss.Depending on the formation process and/or its location along the Weddell Seaperiphery, deep and bottom water masses follow different routes to crossthe South Scotia Ridge. A primitive equation, hydrostatic, terrain-followingcoordinate ocean general circulation model (BRIOS-1) is used to investigatethe water mass export from the Weddell Sea. The model is circumpolarfocusing on the Weddell Sea, with particulary high resolution (~ 20 km)in the DOVETAIL area. 24 Sv of eastward Weddell Sea Deep Watertransport is found in the northern limb of the Weddell Gyre across 44W.Export rates of Weddell Sea Deep Water through gaps in theSouth Scotia Ridge are estimated to 6.4 Sv with a semi-annual cycleof +- 0.6 Sv which can be correlated to atmospheric cyclone activity andWeddell Gyre strength.Sensitivity studies considering extreme sea ice conditions in the WeddellSea show higher (lower) exports in years of minimum (maximum) ice extent.Lagrangian particle trajectories illustrate the pathways of water massesfrom the inner Weddell Sea into the Scotia Sea through various gaps inthe South Scotia Ridge.They highlight the existing flow divergence on the northwestern continentalshelf with one branch entering Bransfield Strait and the other continuingeastwards subsequently filling the deep Scotia and Weddell seas.Water masses flowing through the major gaps originate from thesouthwestern and southeastern Weddell Sea continental shelves.However, water masses formed east of the Weddell Sea (e.g., Prydz Bay)also seem to feed the deep Scotia Sea, since a large portion of floatsflowing northward through the gaps of the South Scotia Ridge have beenin contact with the mixed layer processes outside the inner Weddell Sea.