On the warm inflow at the eastern boundary of the Weddell Gyre

The Weddell Sea plays an important role for the global oceans and climate by being one of the biggest production and export areas of Antarctic Bottom Water (AABW). Circumpolar Deep Water (CDW) enters the Weddell Gyre (WG) at its eastern boundary. Then called Warm Deep Water (WDW), it is a major cont...

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Bibliographic Details
Published in:Deep Sea Research Part I: Oceanographic Research Papers
Main Authors: Ryan, Svenja, Schröder, Micheal, Huhn, Oliver, Timmermann, Ralph
Format: Article in Journal/Newspaper
Language:unknown
Published: Elsevier 2016
Subjects:
Antarctic
The Antarctic
Weddell Sea
Weddell
Greenwich
Antarc*
Ice Shelf
Online Access:https://epic.awi.de/id/eprint/40649/
https://epic.awi.de/id/eprint/40649/1/Ryan_at_al_2016.pdf
http://www.sciencedirect.com/science/article/pii/S0967063715300315
https://hdl.handle.net/10013/epic.48591
https://hdl.handle.net/10013/epic.48591.d001
Description
Summary:The Weddell Sea plays an important role for the global oceans and climate by being one of the biggest production and export areas of Antarctic Bottom Water (AABW). Circumpolar Deep Water (CDW) enters the Weddell Gyre (WG) at its eastern boundary. Then called Warm Deep Water (WDW), it is a major contributor to the formation of deep and bottom waters due to ocean-ice shelf interactions in the southern and soutwestern Weddell Sea. Hydrographic data collected between 0 and 30°E on the RV Polarstern cruise ANT XX/2 reveals a two-core structure for the eastern inflow of warm water at roughly 20°E but not further downstream at the Greenwich meridian (GM). Model results and climatological fields suggest that the two cores represent two separate modes of warm inflow. One mode is driven by eddy mixing in the northeastern corner of the WG and the other one is an advective mode, forming the southern branch of the inflow which extends beyond 30°E before turning westward. Both pathways are likely to carry waters from different origins within the Antarctic Circumpolar Current (ACC), where more ventilated CDW is found at the Southern Boundary (SB) compared to the centre. The southern route shows considerable interannual variability in the model. A variable inflow of two types of CDW together with admixed recirculated and cooler waters from the Weddell Sea can potentially contribute to the observed variability and warming trend of WDW over the last decade at the GM.

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