Structure of the Subtropical Front in the Tasman Sea

Hamilton, L. J.

doi:10.1016/j.dsr.2006.08.013

Cited by 64 publications

(49 citation statements)

References 18 publications

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“…1). The physical oceanography of SASW in the vicinity of New Zealand has been well described (Burlington 1961;Butler et al 1992;Chiswell 1996;Chiswell 2002;Hamilton 2006;Heath 1972;Heath 1981;Heath 1985;Jillett 1969;Morris et al 2001;Sutton 2003). Subantarctic water, like other Southern Ocean water masses, is generally high in nutrient concentration (Bradford and Taylor 1980) and low in chlorophyll concentration (Vincent et al 1991), and this has implications for ecosystem structure and function (Bradford-Grieve et al 1999).…”

Section: Characteristics Of Southwest Pacific Oceanographymentioning

confidence: 97%

Interannual variability of carbon dioxide drawdown by subantarctic surface water near New Zealand

2009

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The ocean-atmosphere flux of carbon dioxide in subantarctic surface water (SASW) east of New Zealand has been determined using data from bi-monthly cruises on a time series transect for 8 years. The 60 km long transect extends from the coast (45.770°S 170.720°E) to a station at 45.833°S 171.500°E. Sea surface temperature, salinity, nutrient concentrations and pCO 2 have been measured at a frequency of about once every 2 months from January 1998 until December 2005. Measured pCO 2 exhibits a seasonal cycle with a maximum in late winter/spring, and a minimum in late summer/ autumn, a mean 356 latm, and an amplitude of 9 latm. The magnitude of DpCO 2 (the air-sea concentration gradient) has increased over the 8 years, primarily due to the increase in atmospheric CO 2 concentration. The air-sea flux of CO 2 was determined from wind speed data and DpCO 2 . The uptake of atmospheric CO 2 by SASW in the study area changed from ? 1 and ?82 mmol m -2 in 1998 and 1999 respectively (ocean as source) to -870 and -510 mmol m -2 in 2004 and 2005 (ocean as sink). These values are substantially less in magnitude than the value obtained from the Takahashi et al. (Deep-Sea Res II, 2009) flux climatology.

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Section: Characteristics Of Southwest Pacific Oceanographymentioning

confidence: 97%

Interannual variability of carbon dioxide drawdown by subantarctic surface water near New Zealand

2009

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“…1). There are multiple types of AAIWs in the southwest Pacific (Tomczak and Godfrey, 1994;Hamilton, 2006;Bostock et al, 2013). Beneath the AAIW in the central South Pacific sits the highly corrosive PDW, with very high alkalinity and DIC, which causes the CSH to shoal to 2700 m between 130 • W and 180 • W (Bostock et al, 2011).…”

Section: Oceanographymentioning

confidence: 99%

Estimating carbonate parameters from hydrographic data for the intermediate and deep waters of the Southern Hemisphere oceans

2013

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Abstract. Using ocean carbon data from global datasets, we have developed several multiple linear regression (MLR) algorithms to estimate alkalinity and dissolved inorganic carbon (DIC) in the intermediate and deep waters of the Southern Hemisphere (south of 25 • S) from only hydrographic data (temperature, salinity and dissolved oxygen). A Monte Carlo experiment was used to identify a potential density (σ θ ) of 27.5 as an optimal break point between the two regimes with different MLR algorithms. The algorithms provide a good estimate of DIC (R 2 = 0.98) and alkalinity (R 2 = 0.91), and excellent agreement for aragonite and calcite saturation states (R 2 = 0.99). Combining the algorithms with the CSIRO Atlas of Regional Seas (CARS), we have mapped the calcite saturation horizon (CSH) and aragonite saturation horizon (ASH) for the Southern Ocean at a spatial resolution of 0.5 • . These maps are more detailed and more consistent with the oceanography than the previously gridded GLODAP data. The high-resolution ASH map reveals a dramatic circumpolar shoaling at the polar front. North of 40 • S the CSH is deepest in the Atlantic (∼ 4000 m) and shallower in the Pacific Ocean (∼ 2750 m), while the CSH sits between 3200 and 3400 m in the Indian Ocean. The uptake of anthropogenic carbon by the ocean will alter the relationships between DIC and hydrographic data in the intermediate and deep waters over time. Thus continued sampling will be required, and the MLR algorithms will need to be adjusted in the future to account for these changes.

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“…In the Southern Ocean, atmosphere-ocean coupled climate oscillations such as the Southern Annular Mode (SAM) and ENSO have been identified using biogeochemical ocean general circulation models as major drivers of inter-annual variability of pCO 2 (Le Published by Copernicus Publications on behalf of the European Geosciences Union. don (1996) and Hamilton (2006), grid nodes from the Reynolds et al (2002) sea surface temperature monthly climatology (squares), and the grid nodes of the Kalnay et al (1996) National Centers for Environmental Prediction daily wind speeds (circles). Quéré et al, 2007;Lenton and Matear, 2007;Lovenduski et al, 2007;Verdy et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Inter-annual variability of the carbon dioxide oceanic sink south of Tasmania

et al. 2008

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Abstract.We compiled a large data-set from 22 cruises spanning from 1991 to 2003, of the partial pressure of CO 2 (pCO 2 ) in surface waters over the continental shelf (CS) and adjacent open ocean (43 • to 46 • S; 145 • to 150 • E), south of Tasmania. Climatological seasonal cycles of pCO 2 in the CS, the subtropical zone (STZ) and the subAntarctic zone (SAZ) are described and used to determine monthly pCO 2 anomalies. These are used in combination with monthly anomalies of sea surface temperature (SST) to investigate inter-annual variations of SST and pCO 2 . Monthly anomalies of SST (as intense as 2 • C) are apparent in the CS, STZ and SAZ, and are indicative of strong inter-annual variability that seems to be related to large-scale coupled atmosphere-ocean oscillations. Anomalies of pCO 2 normalized to a constant temperature are negatively related to SST anomalies. A reduced winter-time vertical input of dissolved inorganic carbon (DIC) during phases of positive SST anomalies, related to a poleward shift of westerly winds, and a concomitant local decrease in wind stress is the likely cause of the negative relationship between pCO 2 and SST anomalies. The observed pattern is an increase of the sink for atmospheric CO 2 associated with positive SST anomalies, although strongly modulated by interannual variability of wind speed. Assuming that phases of positive SST anomalies are indicative of the future evolution of regional ocean biogeochemistry under global warming, we show using a purely observational based approach that some provinces of the Southern Ocean could provide a potential negative feedback on increasing atmospheric CO 2 .

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Structure of the Subtropical Front in the Tasman Sea

Cited by 64 publications

References 18 publications

Interannual variability of carbon dioxide drawdown by subantarctic surface water near New Zealand

Interannual variability of carbon dioxide drawdown by subantarctic surface water near New Zealand

Estimating carbonate parameters from hydrographic data for the intermediate and deep waters of the Southern Hemisphere oceans

Inter-annual variability of the carbon dioxide oceanic sink south of Tasmania

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