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Towards a dynamically balanced eddy-resolving ocean reanalysis: BRAN3


Oke, PR and Sakov, P and Cahill, ML and Dunn, JR and Fiedler, R and Griffin, DA and Mansbridge, JV and Ridgway, KR and Schiller, A, Towards a dynamically balanced eddy-resolving ocean reanalysis: BRAN3, Ocean Modelling, 67 pp. 52-70. ISSN 1463-5003 (2013) [Refereed Article]

Copyright Statement

Copyright 2013 Elsevier Ltd.

DOI: doi:10.1016/j.ocemod.2013.03.008


The generation and evolution of eddies in the ocean are largely due to instabilities that are unpredictable, even on short time-scales. As a result, eddy-resolving ocean reanalyses typically use data assimilation to regularly adjust the model state. In this study, we present results from a second-generation eddy-resolving ocean reanalysis that is shown to match both assimilated and with-held observations more closely than its predecessor; but involves much smaller adjustments to the model state at each assimilation. We compare version 2 and 3 of the Bluelink ReANalysis (BRAN) in the Australian region. Overall, the misfits between the model fields in BRAN3 and observations are 5-28% smaller than the misfits for BRAN2. Specifically, we show that for BRAN3 (BRAN2) the sea-level, upper ocean temperature, upper-ocean salinity, and near-surface velocity match observations to within 7.7. cm (9.7. cm), 0.68. C (0.95. C), 0.16. psu (0.18. psu), and 20.2. cm/s (21.3. cm/s) respectively. We also show that the increments applied to BRAN3 - the artificial adjustments applied at each assimilation step - are typically 20-50% smaller than the equivalent adjustments in BRAN2. This leads us to conclude that the performance of BRAN3 is more dynamically consistent than BRAN2, rendering it more suitable for a range of applications, including analysis of ocean variability, extreme events, and process studies.

Item Details

Item Type:Refereed Article
Keywords:ocean reanalysis, data assimilation, ensemble optimal interpolation, GODAE, operational oceanography
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical oceanography
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Oceanic processes (excl. in the Antarctic and Southern Ocean)
UTAS Author:Oke, PR (Dr Peter Oke)
UTAS Author:Schiller, A (Dr Andreas Schiller)
ID Code:119370
Year Published:2013
Web of Science® Times Cited:106
Deposited By:Oceans and Cryosphere
Deposited On:2017-07-31
Last Modified:2017-08-29

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