Hobart

Seminar Abstract

Friday 29 August 2008, 11.30am (Tas time)
CSIRO Auditorium, Hobart

Laura Herraiz Borrequero
Quantitative Marine Science PhD student
CMAR/University of Tasmania

Temporal Variability of Subantarctic Mode Water south of Australia

Subantarctic Mode Water (SAMW) is formed by deep mixing on the equatorward side of the Antarctic Circumpolar Current. The subduction and export of SAMW from the Southern Ocean plays an important role in global heat, freshwater, carbon and nutrient budgets. However, the formation process and variability of SAMW remains poorly understood largely due to a lack of observations. Here we use a 13 year time series of repeat XBT sections, 7 repeat CTD sections from 1991 to 2001 and Sea Surface Height maps to determine the temporal variability of Subantarctic Mode Water (SAMW) in the Australian sector of the Southern Ocean.

Despite the high variability found in the SAMW, the mean temperature of the SAMW core remains within 8.5 ºC to 9 ºC ranges. Changes in temperature, salinity and pycnostad strength of the mode water are related to mesoscale eddies, Ekman transport and air-sea fluxes. The internal structure of the SAMW can develop "modes" where the temperature and salinity are highly influenced by mesoscale eddies from the Subantarctic Front and the East Australian Current. Variability driven by air-sea fluxes does not show a significant influence in the inter- and intra-annual variability.

Our results suggest that infrequently repeated sections can produce misleading results due to sample aliasing of high inter-annual variability. A brief introduction of the work undergoing will be shown too.

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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:
Bernadette Sloyan, (Oceanographic seminars) CSIRO Marine and Atmospheric Research (03) 6232 5152
Thomas Kunz, (Biological seminars) CSIRO Marine and Atmospheric Research
(03) 6232 5076
Natalie Dowling, (Fisheries Modelling) CSIRO Marine and Atmospheric Research
(03) 6232 5148
Jillian Enraght-Moony, (seminar administrator) CSIRO Marine and Atmospheric Research (03) 6232 5320
Communications Manager, Antarctic Climate and Ecosystems CRC (03) 6226 2265
Margaret Hazelwood, Institute of Antarctic and Southern Ocean Studies (IASOS) University of Tasmania (03) 6226 2971

Last updated 21/07/09