Drivers of decadal variability in the Tasman Sea

Sloyan, Bernadette M.; O’Kane, Terence J.

doi:10.1002/2014jc010550

Cited by 49 publications

(75 citation statements)

References 34 publications

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“…Clearly the length of the EAC time series available is relatively short, and while this application of CEOF analysis is beginning to distinguish EAC modes, a longer time series will improve the separation and important characteristics of the dominant modes. Indeed, Sloyan and O'Kane (2015), show that decadal variability in the EAC is associated with the baroclinic instability of the Pacific basin. Thus, determining and characterizing the modes of EAC variability will require a multidecadal time series.…”

Section: March 2016 S L O Y a N E T A Lmentioning

confidence: 99%

“…While previous work, using the available observations and ocean models, has documented long-term trends and variability of the EAC and suggested a link between the EAC variability with the large-scale Pacific Gyre forcing (e.g., Ridgway et al 2008;O'Kane et al 2011;Cetina-Heredia et al 2014;Oliver and Holbrook 2014;Sloyan and O'Kane 2015), an understanding of the fulldepth EAC property transport and its temporal variability is far from complete. What is lacking from the observational network is a sustained time series of fulldepth property observations of the boundary flow of the EAC across its entire offshore extent and of sufficient duration to resolve seasonal, interannual, and decadal signals.…”

Section: Introductionmentioning

confidence: 99%

“…The western boundary currents provide a link between the remote basin-scale forcing variability and the coastal boundary circulation (Sloyan and O'Kane 2015). Monitoring of the EAC will further improve our understanding of the impacts and influences of the large-scale remotely driven variability of the EAC and the response of the Australian east coast slope and shelf circulation systems.…”

Section: Introductionmentioning

confidence: 99%

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The East Australian Current and Property Transport at 27°S from 2012 to 2013

Sloyan

Ridgway

Cowley

2016

Journal of Physical Oceanography

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The East Australian Current (EAC) is the complex and highly energetic poleward western boundary current of the South Pacific Ocean. A full-depth current meter and property (temperature and salinity) mooring array was deployed from the continental shelf to the abyssal waters off Brisbane Australia (278S) for 18 months from April 2012 to August 2013. The EAC mooring array is an essential component of the Australian Integrated Marine Observing System (IMOS). During this period the EAC was coherent with an eddy kinetic to mean kinetic energy ratio of less than 1. The 18-month, mean, poleward-only mass transport above 2000 m is 22.1 6 7.5 Sverdrups (Sv; 1 Sv [ 10 6 m 3 s 21). The mean, poleward-only heat transport and flow-weighted temperature above 2000 m are 21.35 6 0.42 PW and 15.338C, respectively. A difference in the poleward-only and net poleward mass and heat transports above 2000 m of 6.3 Sv and 0.24 PW reflects the presence of an equatorward EAC retroflection at the eastern (offshore) end of the mooring array. A complex empirical orthogonal function (EOF) analysis of the along-slope velocity anomalies finds that the first two modes explain 72.1% of the velocity variance. Mode 1 is dominant at periods of approximately 60 days, and mode 2 is dominant at periods of 120 days. These dominant periods agree with previous studies in the Tasman Sea south of 278S and suggest that variability of the EAC in the Tasman Sea may be linked to variability north of 278S.

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Section: March 2016 S L O Y a N E T A Lmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The East Australian Current and Property Transport at 27°S from 2012 to 2013

Sloyan

Ridgway

Cowley

2016

Journal of Physical Oceanography

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“…Hill et al () found that the EAC extension and Tasman Front transport are anticorrelated in response to basin‐scale winds with a time lag of ∼3 years. Using observations and models, several other studies (Chiswell & Sutton, ; Hu et al, ; Oliver & Holbrook, ; Sloyan & O'Kane, ) have made similar findings; however, the underlying roles of nonlinear dynamics and bathymetry warrant further investigation.…”

Section: Introductionmentioning

confidence: 63%

The Role of the New Zealand Plateau in the Tasman Sea Circulation and Separation of the East Australian Current

et al. 2018

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The East Australian Current (EAC) plays a major role in regional climate, circulation, and ecosystems, but predicting future changes is hampered by limited understanding of the factors controlling EAC separation. While there has been speculation that the presence of New Zealand may be important for the EAC separation, the prevailing view is that the time‐mean partial separation is set by the ocean's response to gradients in the wind stress curl. This study focuses on the role of New Zealand, and the associated adjacent bathymetry, in the partial separation of the EAC and ocean circulation in the Tasman Sea. Here utilizing an eddy‐permitting ocean model (NEMO), we find that the complete removal of the New Zealand plateau leads to a smaller fraction of EAC transport heading east and more heading south, with the mean separation latitude shifting >100 km southward. To examine the underlying dynamics, we remove New Zealand with two linear models: the Sverdrup/Godfrey Island Rule and NEMO in linear mode. We find that linear processes and deep bathymetry play a major role in the mean Tasman Front position, whereas nonlinear processes are crucial for the extent of the EAC retroflection. Contrary to past work, we find that meridional gradients in the basin‐wide wind stress curl are not the sole factor determining the latitude of EAC separation. We suggest that the Tasman Front location is set by either the maximum meridional gradient in the wind stress curl or the northern tip of New Zealand, whichever is furthest north.

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“…This study was undertaken in the coastal‐pelagic environment adjacent to south‐eastern Australia (Figure ). The oceanography of this region is dominated by the poleward‐flowing East Australian Current (EAC), which is strengthening due to increased wind stress over a broad region of the South Pacific associated with climate change (Cai, Shi, Cowan, Bi, & Ribbe, ; Sloyan & O'Kane, ). Subsequently, south‐eastern Australia's marine environment is among the most rapidly warming regions of the global ocean (Hobday & Pecl, ).…”

Section: Methodsmentioning

confidence: 99%

Oceanographic habitat suitability is positively correlated with the body condition of a coastal‐pelagic fish

Champion

Hobday

Pecl

et al. 2019

Fisheries Oceanography

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Species distribution models are commonly used to determine a species’ probability of occurrence but have not been used to examine the effect of environmental habitat suitability on fish condition, which is considered to be an integrated measure of physiological status. Here, we test for a relationship between oceanographic habitat suitability and the body condition of kingfish (Seriola lalandi) from eastern Australia. We (a) test whether individuals sampled from areas of high‐quality habitat were in better condition than individuals sampled from areas of low‐quality habitat, and (b) assess whether the condition of kingfish responded to oceanographic habitat suitability predicted at varying time‐before‐capture periods. Kingfish habitat was modelled as a function of sea surface temperature, sea‐level anomaly and eddy kinetic energy in a generalized additive modelling framework. Model predictions were made over one‐ to six‐week time‐before‐capture periods and compared to field‐derived kingfish condition data measured using bioelectrical impedance analysis. Oceanographic habitat suitability was significantly correlated with kingfish condition at time‐before‐capture periods ranging from one to four weeks and became increasingly correlated at shorter lead‐times. Our results highlight that (a) fish condition can respond sensitively to environmental variability and this response can be detected using oceanographic habitat suitability models, and (b) climate change may drive extensions in species range limits through spatial shifts in oceanographic habitat quality that allow individuals to persist beyond historical range boundaries without their body condition being compromised.

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Drivers of decadal variability in the Tasman Sea

Cited by 49 publications

References 34 publications

The East Australian Current and Property Transport at 27°S from 2012 to 2013

The East Australian Current and Property Transport at 27°S from 2012 to 2013

The Role of the New Zealand Plateau in the Tasman Sea Circulation and Separation of the East Australian Current

Oceanographic habitat suitability is positively correlated with the body condition of a coastal‐pelagic fish

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