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Predicting the East Australian Current

Citation

O'Kane, TJ and Oke, PR and Sandery, PA, Predicting the East Australian Current, Ocean Modelling, 38, (3-4) pp. 251-266. ISSN 1463-5003 (2011) [Refereed Article]

Copyright Statement

Copyright 2011 Crown Copyright

DOI: doi:10.1016/j.ocemod.2011.04.003

Abstract

Results are presented from an ensemble prediction study (EPS) of the East Australian Current (EAC) with a specific focus on the examination of the role of dynamical instabilities and flow dependent growing errors. The region where the EAC separates from the coast, is characterized by significant mesoscale eddy variability, meandering and is dominated by nonlinear dynamics thereby representing a severe challenge for operational forecasting. Using analyses from OceanMAPS, the Australian operational ocean forecast system, we explore the structures of flow dependent forecast errors over 7. days and examine the role of dynamical instabilities. Forecast ensemble perturbations are generated using the method of bred vectors allowing the identification of those perturbations to a given initial state that grow most rapidly. We consider a 6. month period spanning the Austral summer that corresponds to the season of maximum eddy variability. We find that the bred vector (BV) structures occur in areas of instability where forecast errors are large and in particular in regions associated with the Tasman Front and EAC extension. We also find that very few BVs are required to identify these regions of large forecast error and on that basis we expect that even a small BV ensemble would prove useful for adaptive sampling and targeted observations. The results presented also suggest that it may be beneficial to supplement the static background error covariances typically used in operational ocean data assimilation systems with flow dependent background errors calculated using a relatively cheap EPS.

Item Details

Item Type:Refereed Article
Keywords:East Australian Current, ensemble prediction, ocean forecasting
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical Oceanography
Objective Division:Environment
Objective Group:Other Environment
Objective Field:Marine Oceanic Processes (excl. climate related)
Author:O'Kane, TJ (Dr Terry O'Kane)
Author:Oke, PR (Dr Peter Oke)
ID Code:119135
Year Published:2011
Web of Science® Times Cited:24
Deposited By:Centre for Ecology and Biodiversity
Deposited On:2017-07-26
Last Modified:2017-10-16
Downloads:0

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