FN Archimer Export Format
PT J
TI The glacial mid-depth radiocarbon bulge and its implications for the overturning circulation
BT 
AF BURKE, Andrea
   STEWART, Andrew L.
   ADKINS, Jess F.
   FERRARI, Raffaele
   JANSEN, Malte F.
   THOMPSON, Andrew F.
AS 1:1,2;2:2,3;3:2;4:4;5:5;6:2;
FF 1:;2:;3:;4:;5:;6:;
C1 Univ St Andrews, Dept Earth & Environm Sci, St Andrews, Fife, Scotland.
   CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA.
   Univ Calif Los Angeles, Dept Atmospher & Ocean Sci, Los Angeles, CA USA.
   MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA.
   Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA.
C2 UNIV ST ANDREWS, UK
   CALTECH, USA
   UNIV CALIF LOS ANGELES, USA
   MIT, USA
   UNIV CHICAGO, USA
IF 3.433
TC 58
UR https://archimer.ifremer.fr/doc/00497/60855/64245.pdf
   https://archimer.ifremer.fr/doc/00497/60855/64248.pdf
LA English
DT Article
CR VT 90 / SOUC
BO Marion Dufresne
DE ;radiocarbon;overturning circulation;Last Glacial Maximum
AB Published reconstructions of radiocarbon in the Atlantic sector of the Southern Ocean indicate that there is amid-depth maximum in radiocarbon age during the Last Glacial Maximum (LGM). This is in contrast to the modern ocean where intense mixing between water masses results in a relatively homogenous radiocarbon profile. Ferrari et al. (2014) suggested that the extended Antarctic sea ice cover during the LGM necessitated a shallower boundary between the upper and lower branches of the meridional overturning circulation. This shoaled boundary lay above major topographic features associated with strong diapycnal mixing, isolating dense southern sourced water in the lower branch of the overturning circulation. This isolation would have allowed radiocarbon to decay and thus provides a possible explanation for the mid-depth radiocarbon age bulge. We test this hypothesis using an idealized, 2-D, residual-mean dynamicalmodel of the global overturning circulation. Concentration distributions of a decaying tracer that is advected by the simulated overturning are compared to published radiocarbon data. We find that a 600 km (similar to 5 degrees of latitude) increase in sea ice extent shoals the boundary between the upper and lower branches of the overturning circulation at 45 degrees S by 600 m and shoals the depth of North Atlantic Deep Water convection at 50 degrees N by 2500m. This change in circulation configuration alone decreases the radiocarbon content in the mid-depth South Atlantic at 45 degrees S by 40%, even without an increase in surface radiocarbon age in the source region of deep waters during the LGM. 
PY 2015
PD JUN
SO Paleoceanography
SN 0883-8305
PU Amer Geophysical Union
VL 30
IS 7
UT 000360058100015
BP 1021
EP 1039
DI 10.1002/2015PA002778
ID 60855
ER

EF