Hobart

Seminar abstract

Friday 8 December 2006, 11.30 am (Tas time)
CSIRO Auditorium, Hobart

Claus Böning
CMAR Frohlich Fellow,
Leibniz Institute of Marine Sciences at the University of Kiel

Mechanisms of decadal variability in the Atlantic meridional overturning circulation

The potential threat to the MOC and its related northward transport of heat due to anthropogenic climate change has led to major efforts in designing a monitoring system able to detect MOC changes in the subtropical North Atlantic (NA).

The characteristics and mechanisms of interannual to decadal MOC variations in the NA are investigated here using a suite of basin-scale to global models, varying in resolution from 1/2-deg to 1/12-deg. The focus is on the role of different forcing mechanisms in the generation of low-frequency transport variability, and their implication for the detectability of a potential (multi-)decadal MOC signal. The model experiments suggest that part of the transport changes in the subtropical and mid-latitude NA can be related to the variability in subarctic deep water formation, and a fast propagation of the corresponding dynamical signals to the tropics. This thermohaline signal is, however, effectively masked by intraseasonal to interannual variations in wind-driven transports: for all latitudes, the amplitude of wind-driven MOC anomalies exceeds the thermohaline variability. The model analysis suggests, however, that mid-latitude MOC signals of subarctic origin can be traced back to changes in the deep western boundary current of the subpolar NA, suggesting the potential of a subpolar transport index as an element of a MOC monitoring system.

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Location:
CSIRO = Marine Laboratories Auditorium, Castray Esplanade, Hobart

For further information, or to schedule a seminar, contact:
To schedule a seminar, contact:
Karen Wild-Allen, (Oceanographic seminars) CSIRO Marine and Atmospheric Research (03) 6232 5010
Piers Dunstan, (Biological seminars) CSIRO Marine and Atmospheric Research
(03) 6232 5382
Annabel Ozimec (seminar administrator) CSIRO Marine and Atmospheric Research (03) 6232 5462
Sandra Zicus, Antarctic Climate and Ecosystems CRC (03) 6226 7888
Margaret Hazelwood, Institute of Antarctic and Southern Ocean Studies (IASOS) University of Tasmania (03) 6226 2971

Last updated 27/11/06