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Low frequency variability in an coupled ocean-sea ice general circulation model of the Southern Ocean
journal contribution
posted on 2023-05-19, 08:06 authored by Terence O'KaneTerence O'Kane, Matear, R, Chamberlain, MA, Risby, JS, Horenko, I, Bernadette SloyanBernadette SloyanA coupled ocean-sea ice general circulation model is used to identify a Southern Ocean southeast Pacific intrinsic mode of low frequency variability and its response to inter-annual atmospheric forcing. Using forcing data from the co-ordinated ocean-ice reference experiment, a comprehensive suite of experiments elucidated excitation and amplification mechanisms of this intrinsic mode by low frequency forcing and stochastic forcing due to high frequency winds. Subsurface thermocline anomalies are found to teleconnect the Pacific and Atlantic regions of the Antarctic circumpolar current (ACC). It is found that the Pacific region of the ACC is characterised by intrinsic baroclinic disturbances that respond to both zonal and latitudinal wind variations, while the Atlantic sector of the ACC is sensitive to higher frequency synoptic winds that act to amplify thermocline anomalies propagating downstream from the Pacific resonant with eastward travelling Rossby waves. This simulation study identifies plausible mechanisms that determine the predictability of the Southern Ocean climate on multi-decadal timescales.
History
Publication title
ANZIAM JournalVolume
54Issue
SUPPLPagination
C200-C216ISSN
1446-1811Department/School
Institute for Marine and Antarctic StudiesPublisher
Australian Mathematics Publ Assoc IncPlace of publication
Mathematics Dept Australian National Univ, Canberra, Australia, Act, 0200Rights statement
Copyright 2013 Austral. Mathematical Soc.Repository Status
- Restricted