Anti-cyclonic circulation driven by the estuarine circulation in a gulf type ROFI

Fujiwara, Tateki; Sanford, Lawrence P.; Nakatsuji, Keiji; Sugiyama, Youichi

doi:10.1016/s0924-7963(96)00090-5

Cited by 43 publications

(20 citation statements)

References 5 publications

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“…Thus, observations during 2012-13 when maximum discharge was 274 m 3 s −1 are representative of the Firth ROFI response during high discharge years. The most similar system, in scale and mechanics, is Ise and nearby Bays on the SE side of Japan (Fujiwara et al, 1997). An important distinction being the smaller magnitudes of freshwater discharges into the Firth ROFI, which has meant that vertical and horizontal density gradients have, until now, been assumed to be negligible.…”

Section: Discussionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

“…For example, in the Ise Bay gulf-type ROFI a stagnation point exists between rotation and estuarine circulation that varies seasonally (Fujiwara et al, 1997). Higher winter discharges induce stronger horizontal divergence and densitydriven flows close to the river source are more important for material transport (Kasai et al, 2002).…”

Section: Introductionmentioning

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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“…In order to define the model boundary conditions, the salinity and temperature dataset was complemented with data from Hur et al (1999) and Isobe et al (2004). In this second phase the response of the system was gauged upon existing knowledge of circulation as effected by tides and baroclinicity in tidal embayments (Simpson, 1997;Fujiwara et al, 1997). Due to the lack of in situ density and velocity measurements, …”

Section: Hydrodynamic Sub-modelmentioning

confidence: 99%

Assessment of coastal management options by means of multilayered ecosystem models

Nobre

Ferreira

Nunes

et al. 2010

Estuarine, Coastal and Shelf Science

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This paper presents a multilayered ecosystem modelling approach that combines the simulation of the biogeochemistry of a coastal ecosystem with the simulation of its main forcing functions such as catchment loading and aquaculture activities. This modelling approach was developed as a tool for the sustainable management of coastal ecosystems. A key feature is to simulate management scenarios that account for changes in multiple uses and enable assessment of cumulative impacts of coastal activities. The model was applied to a coastal zone in China with large aquaculture production and multiple catchment uses, and where management efforts to improve water quality are under way. Development scenarios designed together with local managers and aquaculture producers include the reduction of fish cages and treatment of wastewater. Despite the reduction in nutrient loading simulated in three different scenarios, inorganic nutrient concentrations in the bay still exceed the thresholds for poor quality according to the Chinese seawater quality standards.There are still other management options to be considered given that for any of the scenarios there is still a moderate high to high portion of nutrient loads from the catchment and fish cages that can be reduced. The model predicts that overall, shellfish production decreases using any of these development scenarios (less 10% to 28%). Main reason is that shellfish growth is being sustained by the substances to be reduced for improvement of water quality. To counteract this effect the model outcomes indicate that zoning of shellfish aquaculture should be implemented at the ecosystem level to optimize productivity ratios. The present case study exemplified the value of multilayered ecosystem modelling as a tool for Integrated Coastal Zone Management and for the adoption of ecosystem approaches for marine resource management. This modelling approach can be applied worldwide, and maybe particularly useful for the application of coastal management regulation, such as in implementing the European Marine Strategy Directive.3

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“…The outflow which 661 is more stratified propagates in the surface layer until reaching the 662 area of Laesø Island and the shallows to the east of it, where it deflects 663 to the right. Thus for the outflow conditions the theoretical consid-664 erations of Fujiwara et al (1997) can apply. According to this theory 665 an anti-cyclonic vorticity is generated in the upper layer by the hor-666 izontal divergence associated with the upward entrainment.…”

mentioning

confidence: 99%