10.1594/PANGAEA.729117
Huhn, Oliver
Oliver
Huhn
0000-0003-3626-9135
Hellmer, Hartmut H
Hartmut H
Hellmer
0000-0002-9357-9853
Rhein, Monika
Monika
Rhein
0000-0003-1496-2828
Roether, Wolfgang
Wolfgang
Roether
Rodehacke, Christian
Christian
Rodehacke
Schodlok, Michael P
Michael P
Schodlok
Schröder, Michael
Michael
Schröder
Chlorofluorocarbons, helium, and neon measured on water bottle samples during POLARSTERN cruise ANT-XXII/2 (ISPOL)
PANGAEA
2008
CTD from ice float
CTD/Rosette
Ice station
ANT-XXII/2
Polarstern
Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas (SPP1158)
2004-11-20T00:10:00/2005-01-07T11:40:00
en
Supplementary Publication Series of Datasets
10.1016/j.dsr2.2007.12.015
2 datasets
application/zip
Creative Commons Attribution 3.0 Unported
During Ice Station POLarstern (ISPOL; R.V. Polarstern cruise ANT XXII/2, November 2004-January 2005), hydrographic and tracer observations were obtained in the western Weddell Sea while drifting closely in front of the Larsen Ice Shelf. These observations indicate recently formed Weddell Sea Bottom Water, which contains significant contributions of glacial melt water in its upper part, and High-Salinity Shelf Water in its lower layer. The formation of this bottom water cannot be related to the known sources in the south, the Filchner-Ronne Ice Shelf. We show that this bottom water is formed in the western Weddell Sea, most likely in interaction with the Larsen C Ice Shelf. By applying an Optimum Multiparameter Analysis (OMP) using temperature, salinity, and noble gas observations (helium isotopes and neon), we obtained mean glacial melt-water fractions of about 0.1% in the bottom water. On sections across the Weddell Gyre farther north, melt-water fractions are still on the order of 0.04%. Using chlorofluorocarbons (CFCs) as age tracers, we deduced a mean transit time between the western source and the bottom water found on the slope toward the north (9±3 years). This transit time is larger and the inferred transport rate is small in comparison to previous findings. But accounting for a loss of the initially formed bottom water volume due to mixing and renewal of Weddell Sea Deep Water, a formation rate of 1.1±0.5 Sv in the western Weddell Sea is plausible. This implies a basal melt rate of 35±19 Gt/year or 0.35±0.19 m/year at the Larsen Ice Shelf. This bottom water is shallow enough that it could leave the Weddell Basin through the gaps in the South Scotia Ridge to supply Antarctic Bottom Water. These findings emphasize the role of the western Weddell Sea in deep- and bottom-water formation, particularly in view of changing environmental conditions due to climate variability, which might induce enhanced melting or even decay of ice shelves.
See doi:10.1594/PANGAEA.729699 for the physical oceanography.
Supplement to: Huhn, Oliver; Hellmer, Hartmut H; Rhein, Monika; Rodehacke, Christian; Roether, Wolfgang; Schodlok, Michael P; Schröder, Michael (2008): Evidence of deep- and bottom-water formation in the western Weddell Sea. Deep Sea Research Part II: Topical Studies in Oceanography, 55(8-9), 1098-1116
-57.47149999999999
-36.3023
-68.2687
-59.9102
Weddell Sea
Scotia Sea, southwest Atlantic
German Research Foundation
https://doi.org/10.13039/501100001659
5472008
Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas