P06 The Southern Ocean: where Ocean, Ice and Atmosphere Meet

IAPSO (Physical Oceanography)

01-Jul-2015, 08:30 - 10:00

Abstract content:

Formation of Antarctic bottom water on the continental shelf off larsen ice shelf

The dense water flowing out from the Weddell Sea (WS) significantly contributes to Antarctic Bottom Water (AABW) and plays an important role in the Meridional Overturning Circulation. The larger amount of this dense water consists of Weddell Sea Deep Water (WSDW) formed in the WS, mainly in front of the Filchner-Ronne Ice Shelves and the Larsen Ice Shelf (LIS). We performed model simulations and analysis of hydrographic data that highlight the importance of the second source. Model simulations indicate that dense waters placed on the continental shelf off LIS flow down the slope and contribute to the WSDW that renews the AABW further downstream. Measurements made during the Polarstern cruise ANT XXIX-3 (2013) add evidence to the importance of the source in the western Weddell Sea. Using Optimum Multiparameter Analysis we show that the dense water found on the continental shelf in front of the former Larsen A and B together with water originating from Larsen C increases the thickness of the WSDW layer in 50%, and changes the temperature and salinity of this water mass. These modifications occur close to the WSDW outflow paths and therefore have high influence on the AABW properties.

M. van Caspel1, R. Timmermann1, M. Schröder1, H. Hellmer1.
1Alfred Wegener Institute- Helmholtz Centre for Polar and Marine Research, Oceanography, Bremerhaven, Germany.


Antarctic Bottom Water     Weddell Sea     Larsen Ice Shelf     Weddell Sea Deep Water