Holocene reef growth — One Tree Island,Great Barrier Reef

Data from investigations at One Tree Reef and from other sources suggest that post-glacial coral reefs in the Great Barrier Reef probably date from only about 9,000 years ago. They are likely to have grown on the elevated parts of an irregular karst surface, their general morphology having been largely determined by the shape and depth of this surface. Growth has been dominantly vertical because of the rapid sea-level rise, with lateral modification being quite recent and dominantly in a leeward direction.     

The non-consumptive (tourism) ‘value’ of marine species in the Northern section of the Great Barrier Reef

This paper uses the Kristrom (logit) spike model to analyse contingent valuation (payment card) data from a study of 2180 domestic and international visitors taking reef trips to the Northern section of the Great Barrier Reef. It investigates: (a) their willingness to pay for a “100% guaranteed sighting” of several different marine species; and (b) the sensitivity of final estimates to various methodological issues. It finds that final estimates are particularly sensitive to questionnaire design, but that the ranking of species (from most to least ‘valued’) is robust across a range of methodological specifications. The most valued groups of species were (in order): whales and dolphins; sharks and rays; ‘variety’; marine turtles; and finally large fish. Evidently, whale watching is not the only potentially lucrative source of tourism revenue; other marine species may be similarly appealing. These potential revenues need to be considered when making decisions about whether or not to conserve marine species.     

Reestablishment of an accretionary prism after the subduction of a spreading ridge—constraints by a geometric model for the Golfo de Penas, Chile

Seismic studies offshore southern Chile have revealed the presence of a 70–80 km wide accretionary prism seaward of the Golfo de Penas (GPAP), where the Chile Ridge collided with the South American Plate between 3 and 6 Ma ago. Using the paleo-positions of the Chile Ridge relative to South America, the maximum age of this accretionary prism, which continues to be formed in the aftermath of the ridge–continent collision, has been estimated. Building on these earlier findings, this study presents a mass balance analysis based on a 2D model of accretionary wedge and trench geometry. This model can explain the relative importance of sedimentary fluxes and deformation front migration for the wedge restoration. The proposed model can also serve to evaluate the effects of fluctuations in (1) terrigenous sediment flux related to climate change, and (2) subduction channel thickness on the accretionary prism growth. Notably, the data reveal that the key parameters controlling the rebuilding of the GPAP are the terrigenous sediment flux (75 km²/10⁶ years), the relative advance of the deformation front (39.6 km/10⁶ years), and the thickness of the subduction channel (0.1 km). Moreover, the range of possible solutions for the observed size of the accretionary prism is narrowed by fitting the present-day thickness of sediments at the deformation front. Finally, climate-induced variations in sedimentary fluxes on the margin can affect the rate of growth of the accretionary prism during short periods of time (<100,000 years).     

A hybrid model for numerical wave forecasting and its implementation——Ⅱ. The discrete part and implementation of the model

In the first part of the present paper we have explained why we manage to formulate another wave prediction model when so many of them, including the so-called third generation model, have already been in use. The wind-wave part of the proposed model has also been given. Now we proceed to discuss the swell part,the implementation of the model as a prediction method,mumerical experiments done with ideal wind fields and hindcasts made in the Bohai Sea,in the neighboring seas adjacent to China and in the Northwest Pacific.     

A three-layer model for the thermal structure in the Huanghai Sea

A one-dimentional three-layer model for the thermal structure in the Huanghai Sea is presented in this study, me model consists of the upper mixed layer caused by heating and wind mixing, the lower mixed layer driven by tidal mixing, and the thermocline with certain thickness. The entrainment velocities of the upper and lower layers are obtained respectively. The results show that the model is capable of describing the development and decline processes of the seasonal thermocline in the Huanghai Sea, simulating successfully the Huanghai Sea Cold Water Mass, the nearshore front and surface cold water off North Jiangsu and explaining reasonably their formation mechanisms as well as the strong thermocline off Qingdao. It is suggested that the tidal mixing plays key role in the formation of the nearshore front off North Jiangsu and the strong thermocline off Qingdao. The wind mixing and the tidal mixing make the lower layer water with high nutrients go up to the upper layer. This physical process may be sig     

A two-layers model for the summer circulation of the East China Sea

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A coupled ice-ocean model for the Bohai Sea Ⅰ. Study on model and parameter

According to the earlier international studies on the coupled ice-ocean model and the hydrology, meteorology, and ice features in the Bohai Sea, a coupled ice-ocean model is developed based on the National Marine Environment Forecast Center's (NMEFC) numerical forecasting ice model of the Bohai Sea and the Princeton ocean model (POM).In the coupled model, the transfer of momentum and heat between ocean and ice is two-way, and the change of ice thickness and concentration depends on heat budget not only at the surface and bottom of ice, but also at the surface of open water between ices. The dynamic and thermodynamic coupling process is expatiated emphatically. Some thermodynamic parameters are discussed as well.     

A coupled ice-ocean model for the Bohai Sea I. Study on model and parameter

1 IntroductionAs an important compartment of global cli-mate system, the development and variation ofsea ice directly affect the global atmosphere andocean environment, especially the deep watersformation and circulation. Therefore, it be-comes one of the keys of the global climatestudy to explore the coupling physical processof sea ice to atmosphere and ocean in the cli-mate system and to set up the global coupledairiceocean system. The studies on the in-teraction of iceocean and its coupled…     

A coupled ice-ocean model for the Bohai Sea Ⅰ. Study on model and parameter

According to the earlier international studies on the coupled ice-ocean model and the hydrology, meteorology, and ice features in the Bohai Sea, a coupled ice-ocean model is developed based on the National Marine Environment Forecast Center‘ s (NMEFC) numerical forecasting ice model of the Bohai Sea and the Princeton ocean model (POM). In the coupled model, the transfer of momentum and heat between ocean and ice is two-way, and the change of ice thickness and concentration depends on heat budget not only at the surface and bottom of ice, but also at the surface of open water between ices. The dynamic and thermodynamic coupling process is expatiated emphatically. Some thermodynamic parameters are discussed as well.     

A hybrid model for numerical wave forecasting and its implementation——Ⅰ. The wind wave model

The authors make an endeavor to explain why a new hybrid wave model is here proposed when several such models have already been in operation and the so- called third generation wave modej is proving attractive. This part of the paper is devoted to the wind wave model. Both deep and shallow water models have been developed, the former being actually a special case of the latter when water depth is great. The deep water model is exceptionally simple in form. Significant wave height is the only prognostic variable. In comparison with the usual methods to compute the energy input and dissipations empirically or by "tuning", the proposed model has the merit that the effects of all source terms are combined into one term which is computed through empirical growth relations for significant waves, these relations being, relatively speaking, easier and more reliable to obtain than those for the source terms in the spectral energy balance equation. The discrete part of the model and the implementation of the mode     

Evaluation of the simulation capability of the Wavewatch Ⅲ model for Pacific Ocean wave

Wave climate analysis and other applications for the Pacific Ocean require a reliable wave hindcast. Five source and sink term packages in the Wavewatch III model(v3.14 and v4.18) are compared and assessed in this study through comprehensive observations, including altimeter significant wave height, advanced synthetic aperture radar swell, and buoy wave parameters and spectrum. In addition to the evaluation of typically used integral parameters, the spectra partitioning method contributes to the detailed wave system and wave maturity validation. The modified performance evaluation method(PS) effectively reduces attribute numbers and facilitates the overall assessment. To avoid possible misleading results in the root mean square error-based validations, another indicator called HH(indicating the two authors) is also calculated to guarantee the consistency of the results. The widely used Tolman and Chalikov(TC) package is still generally efficient in determining the integral properties of wave spectra but is physically deficient in explaining the dissipation processes. The ST4 package performs well in overall wave parameters and significantly improves the accuracy of wave systems in the open ocean. Meanwhile, the newly published ST6 package is slightly better in determining swell energy variations. The two packages(ACC350 and BJA) obtained from Wavewatch III v3.14 exhibit large scatters at different sea states. The three most ideal packages are further examined in terms of reproducing waveinduced momentum flux from the perspective of transport. Stokes transport analysis indicates that ST4 is the closest to the NDBC-buoy-spectrum-based transport values, and TC and ST6 tend to overestimate and underestimate the transport magnitude, respectively, in swell mixed areas. This difference must be considered,particularly in air–wave–current coupling research and upper ocean analysis. The assessment results provide guidance for the selection of ST4 for use in a background Pacific Ocean hindcast for high wave climate research and China Sea swell type analysis.     

Marine reserves—the need for networks

Meiofauna associated with bryophyte and gravel habitats in two small alpine streams was investigated to determine its potential importance to stream communities. These invertebrates are traditionally neglected in stream surveys and their ecological roles poorly understood. Twenty‐one operational taxonomic units (OTUs) were found during the study, of which at least six were undescribed (two Copepoda and four Acarina). Meiofaunal densities were higher at the unshaded site than the shaded site, and higher within bryophyte than gravel habitats. Stepwise multiple regression analyses illustrated the importance of bryophytes to members of the meiofauna in each stream, and different meiofaunal communities were found associated with aquatic bryophytes and gravels. The high densities of Chironomidae, Nematoda, Copepoda, Tardigrada, and Rotifera associated with bryophytes may reflect the food value of the high periphyton biomass associated with these plants, and the shelter they offer from fast water currents. Although hyporheic meiofaunal taxa are known to move into interstices of mineral substratum for shelter, meiofauna associated with bryophytes dwell among stems and in leaf axils where they also find shelter. Because bryophyte‐dwelling meiofauna occur in very high densities, they probably play an important, if as yet unknown, role in energy transfer in streams.     

A three-dimensional ocean general circulation model for mesoscale eddies——Ⅱ Diagnostic analysis

A three-dimensional density field associated with mesoscaie unstable waves generated by the 3-D, primitive-equation model (Wang and Ikeda, 1996) is provided to the quasi-geostrophic pressure tendency and ω-equations, and to the (ageostrophic) Q-vector equation. Diagnostic analyses, analogous to the approaches in meteorology: ω-equation and Q-vector method, are for the first time developed to examine the mesoscaie dynamical processes and mechanisms of the unstable waves propagating in the mid-latitude ocean. The weaknesses and strengths of these two diagnostic approaches are evaluated and compared to the model results. The Q-vector method is then recommended to diagnose the vertical motion associated with the mesoscaie dynamics from a hydrographic CTD (conductivity-temperature-depth) array, while the quasi-geostrophic equations produce some small-scale features (errors) in the diagnosed fields.     

Inferred gas hydrate on the Barents Sea shelf — a model for its formation and a volume estimate

 On the southwestern Barents Sea shelf, sediments containing gas hydrates that overlie free gas have been inferred from multichannel seismic data. The volume of suspected gas hydrate is tentatively estimated to about 1.9×10⁸ m³. The gas hydrate zone probably formed from thermogenic gas leaking from a deeper source. The hydrate zone may have thickened during the Neogene by including gas originally trapped as free gas below the hydrate following a significant downward migration of the isotherms caused by erosion and/or subsidence. Within the present oceanographic conditions, gas hydrate is suspected to be stable or slowly decomposing. Received: 20 December 1996 / Revision received: 20 August 1997     

A coupled ice-ocean model for the Bohai Sea Ⅱ. Case study

1 Introduction As mentioned in the previous paper (Su et al., 2004), investigation and application of the coupled ice- ocean model play an important role in the polar and climate research. In recent years, great attention is paid to the research on coupled models of ice margin zone and regional seas and its application in marine engineering and forecasting. For example, simulation study on seasonal evolution rule of sea ice and upper layer ocean during a winter in the Labrador Sea was conduct…     

A coupled ice-ocean model for the Bohai Sea Ⅱ. Case study

The coupled ice-ocean model for the Bohai Sea is used for simulating the freezing, melting, and variation of ice cover and the heat balance at the sea-ice, air-ice, and air-sea interfaces of the Bohai Sea during the entire winter in 1998～1999 and 2000～2001. The coupled model is forced by real time numerical weather prediction fields. The results show that the thermodynamic effects of atmosphere and ocean are very important for the evolvement of ice in the Bohai Sea, especially in the period of ice freezing and melting. Ocean heat flux plays a key role in the thermodynamic coupling. The simulation also presents the different thermodynamic features in the ice covered region and the marginal ice zone. Ice thickness, heat budget at the interface, and surface sea temperature, etc. between the two representative points are discussed.     

A coupled ice-ocean model for the Bohai Sea Ⅱ. Case study

The coupled ice-ocean model for the Bohai Sea is used for simulating the freezing, melting, and variation of ice cover and the heat balance at the sea-ice, air-ice, and air-sea interfaces of the Bohai Sea during the entire winter in 1998-1999 and 2000-2001. The coupled model is forced by real time numerical weather prediction fields. The results show that the thermodynamic effects of atmosphere and ocean are very important for the evolvement of ice in the Bohai Sea, especially in the period of ice freezing and melting. Ocean heat flux plays a key role in the thermodynamic coupling. The simulation also presents the different thermodynamic features in the ice covered region and the marginal ice zone. Ice thickness, heat budget at the interface, and surface sea temperature, etc. between the two representative points are discussed.     

A combined numerical tidal model for the Hangzhou Bay and Qiantang River

-In order to avoid prescribing open boundary condition on the upstream side of the Hangzhou Bay, in numerical simulation of the tides and residual currents of the Bay, a 1-D model for the Qiantang River is connected to the 2-D model for the Hangzhou Bay. The harmonic constants of diurnal constituent [ (K1 O1)/2],semidiurnal constituent (M2) and shallow water constituent (M4) are obtained. The results produced by the combined model are in better agreement with the observed ones than those produced solely by the original 2-D model. The combined model gives much more reliable results for tide-induced residual water level and current.     

How the pollution stress acting on the phytoplankton populations——an observation by the experimental enclosed ecosystem

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The study on the bottom friction and the breaking coefficient for typhoon waves in radial sand ridges—the Lanshayang Channel as an example

Owing to the interactions among the complex terrain, bottom materials, and the complicate hydrodynamics, typhoon waves show special characteristics as big waves appeared at the high water level(HWL) and small waves emerged at low and middle water levels(LWL and MWL) in radial sand ridges(RSR). It is assumed that the mud damping, sandy bed friction and wave breaking effects have a great influence on the typhoon wave propagation in this area. Under the low wave energy, a mud layer will form and transport into the shallow area, thus the mud damping effects dominate at the LWL and the MWL. And high Collins coefficient(c around 1) can be applied to computing the damping effects at the LWL and the MWL. But under the high wave energy, the bottom sediment will be stirred and suspended, and then the damping effects disappear at the HWL. Thus the varying Collins coefficient with the water level method(VCWL) is implemented into the SWAN to model the typhoon wave process in the Lanshayang Channel(LSYC) of the RSR, the observed wave data under "Winnie"("9711") typhoon was used as validation. The results show that the typhoon wave in the RSR area is able to be simulated by the VCWL method concisely, and a constant wave breaking coefficient(γ) equaling 0.78 is better for the RSR where wide tidal flats and gentle bed slopes exist.