Physical oceanography of the deep seas around New Zealand: a review

Chiswell, Stephen M.; Bostock, Helen C.; Sutton, Philip; Williams, Michael

doi:10.1080/00288330.2014.992918

Cited by 201 publications

(269 citation statements)

References 169 publications

(258 reference statements)

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“…Intertidal flats make up approximately 65% of the estuary (Healy et al, 1996) and are exposed at low tide (mean level of the sea, MLOS À0.76 m), when the average water depth in the estuary is about 3 m (Tay et al, 2012). Tauranga Harbour is characterized by a semi-diurnal tide that ranges from 1.62 m at spring tide to 1.24 m at neap tide (Heath, 1985). Commercial development is mainly restricted to the southern basin (De Lange and Healy, 1990), which is the location of New Zealand's largest export port (the Port of Tauranga, PoT) (Foster, 1992).…”

Section: Tauranga Harbourmentioning

confidence: 99%

The links between entrance geometry, hypsometry and hydrodynamics in shallow tidally dominated basins

Ruiter

Mullarney

Bryan

2019

Earth Surf Processes Landf

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Geomorphological characteristics of tidal basins control hydrodynamics and sediment transport potential within such basins, for example, by adjusting the balance in tidal asymmetry. In this study we examine the effects of entrance geometry on tidal velocity asymmetry, slack water asymmetry, bed shear stress patterns and hypsometric profile shapes by comparison of six shallow meso‐tidal basins of Tauranga Harbour, New Zealand. Numerical model results show how tidal distortion increases with distance from a basin entrance. A simple ratio between basin width and entrance width defines levels of basin dilation. Sub‐basins with a constricted geometry and deep entrance channels are associated with small bed shear stress values and high rates of flood‐directed tidal velocity asymmetry in the sheltered basin centres, indicating a large potential for sediment deposition of larger particles. Moreover, slack water asymmetry within these basins is weakly ebb‐directed, indicating a small potential for transport of fine sediments out of the basins. The constricted depositional basins are characterized by convex hypsometric profiles with elevated intertidal regions. Unconstricted geometries are associated with larger bed shear stress values and more ebb‐directed tidal velocity asymmetry within basin centres, suggesting limited potential for overall sediment deposition. The slack tide duration asymmetry is weakly flood‐dominant indicating that limited input of fine sediment into the basins is possible. The comparatively high‐energy conditions within these exposed basins are associated with a less convex hypsometric intertidal profile. The ability to estimate tidal asymmetries is advantageous when developing management strategies related to ecosystem functioning, navigability or coastal protection in specific geomorphic settings. © 2019 John Wiley & Sons, Ltd.

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Section: Tauranga Harbourmentioning

confidence: 99%

The links between entrance geometry, hypsometry and hydrodynamics in shallow tidally dominated basins

Ruiter

Mullarney

Bryan

2019

Earth Surf Processes Landf

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“…Due to lateral and vertical mixing in the water column of the Southern Ocean, the DWBC entering the southwest Pacific is a hybrid of AABW and Lower Circumpolar Deep Water (LCDW; Carter et al, 2004;Chiswell et al, 2015;McCave et al, 2008;McCave & Carter, 1997;Talley, 2013). The signature of LCDW is a salinity maximum (34.70-34.75 psu;Orsi et al, 1999) partially reflecting the NADW component that enters the Southern Ocean from the South Atlantic.…”

Section: Bathymetry and Oceanographic Settingmentioning

confidence: 99%

A Southwest Pacific Perspective on Long‐Term Global Trends in Pliocene‐Pleistocene Stable Isotope Records

Patterson

McKay

Naish

et al. 2018

Paleoceanog and Paleoclimatol

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Continuous stable isotope records from marine sediment cores spanning the Pliocene have been used to assess the oceans' response to major perturbations in the climate system as the oceans play an integral role in regulating the global distribution of heat and gases. The Early to mid‐Pliocene has previously been characterized as a time of relative warmth followed by Late Pliocene Southern Hemisphere cooling and bipolar glaciation at ~2.7 Ma. Previous studies have predominantly focused on the Atlantic and Equatorial Pacific Oceans. In this study, we extended the deep water benthic foraminifera stable isotope record from Ocean Drilling Program (ODP) Site 1123 in the southwest Pacific, back to the warm Early Pliocene. This is a high‐latitude site at the gateway where the abyssal waters enter the Pacific Ocean and provides information about the connection between the Southern Ocean and the Pacific. We identify a dichotomy between the deep southwest Pacific and South Atlantic δ13C records spanning the mid‐Pliocene and suggest that this is most likely the result of variations in the relative contributions of Northern versus Southern Hemisphere deep waters to the different basins. At 3.6 Ma, δ13C values start to decrease; this is interpreted to represent alteration in preformed values as a result of increased remineralization of carbon caused by a reduction in deep ocean ventilation in the Southern Ocean. This is likely the consequence of a greater extent and seasonal duration of sea ice in the Southern Ocean from Antarctic Ice Sheet expansion and cooling.

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“…Semi-diurnal tides dominate in HG (Chiswell et al, 2015) and replication of tidal flows in 2D and 3D simulations can be achieved using only the M2 constituent (Sharples and Greig, 1998;Black et al, 2000). Upwelling on the NE shelf has been correlated to seasonal wind forcing in November and December (Zeldis et al, 2004).…”

Section: Field Setting: Firth Of Thames-hauraki Gulfmentioning

confidence: 99%

Evaluating the Surface Response of Discharge Events in a New Zealand Gulf-ROFI

O'Callaghan

Stevens

2017

Front. Mar. Sci.

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Using moorings with a surface expression, responses of buoyant river outflows were examined in the Firth-Hauraki Gulf system, New Zealand. The Firth region of freshwater influence (ROFI) behaves as a gulf-type ROFI where the balance of key processes lies between rotation and advection. The latter process is largely regulated by the frequency and amplitude of freshwater discharges. Using 12-months of observations from two inner Firth sites, the system was found to be salinity stratified for up to 4 months of a year. During the largest event (274 m 3 s −1 , mean daily maximum) in 2012 near-oceanic surface salinity (34 psu) freshened substantially down to 28 psu over the upper 3 m. Time lags between freshwater inflows and ROFI response were 4 and 7 days at the Waiheke and WilsonB locations, respectively. Faster seaward advection of surface layers occurred for a minimum of 3 days and up to a week after peak discharges. High frequency winds (∼3-hourly) were persistent in regulating surface flows over the annual cycle. Surface salinity had peaks in energy that were coherent with surface flows at periods of 16-32 days over the Austral winter. The duration of discharge events was O(days), yet responses by buoyancy and advection were evident for weeks to a month in the Firth ROFI.

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Physical oceanography of the deep seas around New Zealand: a review

Cited by 201 publications

References 169 publications

The links between entrance geometry, hypsometry and hydrodynamics in shallow tidally dominated basins

The links between entrance geometry, hypsometry and hydrodynamics in shallow tidally dominated basins

A Southwest Pacific Perspective on Long‐Term Global Trends in Pliocene‐Pleistocene Stable Isotope Records

Evaluating the Surface Response of Discharge Events in a New Zealand Gulf-ROFI

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