综合客运交通枢纽换乘距离与布局评价研究

依托综合客运枢纽建设研究项目,运用行人步行理论和层次分析法,探讨了交通客运枢纽内不同换乘方式换乘距离、枢纽立体空间优化等评价指标。研究结果对交通综合客运枢纽的规划建设和优化评价具有很好的实用性和可操作性。     

渤海湾冰区航行问题解决策略研究

根据多位船长的航行经验及相关建议,文章在分析渤海湾冰情的基础上,系统阐述了渤海湾冰区航行问题的解决策略,对于提高船舶航行安全性和渤海湾港口的使用率有一定的借鉴意义。     

基于航电一体化的梯级枢纽运行模式优化*

提出一种基于航电一体化的梯级枢纽运行模式优化研究方法。对整个航道进行断面划分,并在各枢纽处设置虚化断面,对航道天然断面和枢纽所在的虚化断面分别采用求解圣维南方程和考虑枢纽调度的水量平衡计算方法,确定断面水位和流量过程,实现全航道断面水力要素的同步计算,满足梯级通航枢纽联合调度对航道水位和口门区流速的高计算精度要求;并在此基础上构建梯级通航枢纽联合优化调度模型,渠化航道,改善口门区和引航道水流条件,同时优化发电策略,实现梯级通航和发电综合利用效益最大化。衢江梯级通航枢纽结果表明,构建模型具有较高的模拟精度,有效提高了梯级通航保证率和总发电量。     

Decommissioning forecast in the deepwater Gulf of Mexico, 2013–2033

One hundred and ten fixed, tensioned, and moored structures have been installed in the Gulf of Mexico in water depth greater than 400 ft, and through 2012, 15 structures have been decommissioned. Decommissioning is the final stage of an assets life cycle, where all wells are plugged and abandoned, the structure and associated production facilities are removed, and the seafloor cleared of all debris created by the operations. The purpose of this paper is to describe a decommissioning forecast for deepwater structures in the Gulf of Mexico. Three approaches (“simple models”) based on lease status, gross revenue, and production forecasting are applied to infer a short, medium, and long-term decommissioning forecast. Model assumptions are outlined along with a discussion of the limitations and uncertainty of analysis. About two dozen deepwater fixed platforms are expected to be removed over the next decade, but only 5 floaters are expected to be decommissioned through 2032.     

北部湾油类污染及防治措施

文章基于北部湾海域油类污染防治的紧迫性和艰巨性,探讨了北部湾海域油类污染的成因,分析了现阶段北部湾海洋油类污染防治存在的问题,并提出了防治北部湾海洋油类污染的措施。     

Distribution of total dissolved and C18 extractable copper and nickel in relation to dissolved organic matter sources, in the Thermaikos Gulf (eastern Mediterranean)

Organically complexed and total dissolved copper and nickel were measured in the Thermaikos Gulf waters during winter 1998. Total concentrations ranged from 1.13 nmol/L to 7.02 nmol/L for copper and from 3.04 nmol/L to 9.50 nmol/L for nickel. The C18 Sep-Pak solid phase extraction technique was used in order to determine the amount of copper and nickel complexed with the hydrophobic component of the dissolved organic matter (DOM). Up to 32.4% of total copper and 4.57% of total nickel were complexed with the DOM extracted by C18. By applying HPLC analysis it was shown that the majority of the organic compounds retained by C18 had intermediate to low polarity. Using the absorbance ratio a₂₅₄/a₄₃₆ it was possible to unravel that humic substances of both terrestrial and marine origin were present in the Thermaikos Gulf and their distribution followed the dilution of riverine waters. Moreover our results indicated that organic binding of both Cu and Ni was stronger with the hydrophobic compounds of terrestrial origin than with those of marine origin.     

A numerical investigation of phytoplankton and Pseudocalanus elongatus dynamics in the spring bloom time in the Gda sk Gulf

A nutrient–phytoplankton–zooplankton–detritus (1D-NPZD) ‘phytoplankton {Phyt} and Pseudocalanus elongatus {Zoop} dynamics in the spring bloom time in the Gda sk Gulf. The 1D-NPZD model consists of three coupled, partial second-order differential equations of the diffusion type for phytoplankton {Phyt}, zooplankton {Zoop}, nutrients {Nutr} and one ordinary first-order differential equation for benthic detritus pool {Detr}, together with initial and boundary conditions. In this model, the {Zoop} is presented by only one species of copepod (P. elongatus) and {Zoop} is composed of six cohorts of copepods with weights (W_i) and numbers (Z_i); where . The calculations were made for 90 days (March, April, May) for two stations at Gda sk Gulf with a vertical space step of 0.5m and a time step of 900 s. The flow field and water temperature used as the inputs in the biological model 1D-NPZD were reproduced by the prognostic numerical simulation technique using hydrographic climatological data. The results of the numerical investigations described here were compared with the mean observed values of surface chlorophyll-a and depth integrated P. elongatus biomass for 10 years, 1980–1990. The slight differences between the calculated and mean observed values of surface chlorophyll-a and zooplankton biomass are ca. 10–60 mg C m⁻³ and ca. 5–23 mg C m⁻², respectively, depending on the location of the hydrographic station. The 1D-NPZD model with a high-resolution zooplankton module for P. elongatus can be used to describe the temporal patterns for phytoplankton biomass and P. elongatus in the centre of the Gda sk Gulf.     

广西北部湾港口保税物流业务培训现状研究

文章针对广西北部湾港口保税物流业务培训现状，介绍了德国、新加坡职业培训模式及其共性和特点，分析了广西北部湾港口保税物流业务培训中存在的问题，并提出完善广西北部湾港口保税物流业务培训的相关措施。     

防风网技术在广西北部湾港的应用研究

文章通过对广西北部湾港粉尘污染类型和防治措施的研究,提出粉尘污染控制存在的问题,指出防风网在防风抑尘方面的应用优势,对防风网的抑尘机理及应用情况进行了总结,并提出了广西北部湾港应用防风网技术的对策。     

Assimilation of altimetric data in the mid-latitude oceans using the Singular Evolutive Extended Kalman filter with an eddy-resolving, primitive equation model

A new data assimilation scheme has been elaborated for ocean circulation models based on the concept of an evolutive, reduced-order Kalman filter. The dimension of the assimilation problem is reduced by expressing the initial error covariance matrix as a truncated series of orthogonal perturbations. This error sub-space evolves during the assimilation so as to capture the growing modes of the estimation error. The algorithm has been formulated in quite a general fashion to make it tractable with a large variety of ocean models and measurement types. In the present paper, we have examined three possible strategies to compute the evolution of the error subspace in the so-called Singular Evolutive Extended Kalman (SEEK) filter: the steady filter considers a time-independent error sub-space, the apprentice filter progressively enriches the error sub-space with the information learned from the innovation vector after each analysis step, and the dynamical filter updates the error sub-space according to the model dynamics. The SEEK filter has been implemented to assimilate synthetic observations of the surface topography in a non-linear, primitive equation model that uses density as vertical coordinate. A simplified box configuration has been adopted to simulate a Gulf Stream-like current and its associated eddies and gyres with a resolution of 20 km in the horizontal, and 4 levels in the vertical. The concept of twin experiments is used to demonstrate that the conventional SEEK filter must be complemented by a learning mechanism in order to model the misrepresented tail of the error covariance matrix. An approach based on the vertical physics of the isopycnal model, is shown particularly robust to control the velocity field in deep layers with surface observations only. The cost of the method makes it a suitable candidate for large-size assimilation problems and operational applications.