The influence of different turbulence schemes on modelling primary production in a 1D coupled physical–biological model

A one-dimensional (1D) coupled physical–microbiological model has been applied to a site in the central North Sea. The impact of the choice of the turbulence closure scheme on the modelling the primary production has been investigated.The model was run with four different parameterisations of vertical mixing of heat, momentum and dissolved and suspended matters, using M2 tidal forcing and the hourly mean meteorological forcing of 1989 to reproduce the annual thermal structure and primary production. The four mixing parameterisations are: Level 2 turbulence closure scheme [Mellor, G.L., Yamada, T., 1974. A hierarchy of turbulence closure models for planetary boundary layers. J. Atmos. Sci. 31, 1791–1806; Mellor, G.L., Yamada, T., 1982. Development of a turbulence closure model for geophysical Fluid problems. Rev. Geophys. Space Phys. 20 (4) 851–875] using an explicit numerical scheme [Sharples, J., Tett, P., 1994. Modelling the effect of physical variability on the midwater chlorophyll maximum. J. Mar. Res. 52, 219–238]; a version of the Level 2.5 turbulence closure scheme [Galperin, B., Kantha, L.H., Hassid, S., Rosati, A., 1988. A quasi-equilibrium turbulent energy model for geophysical flows. J. Atmos. Sci. 45, 55–62; Ruddick, K.G., Deleersnijder, E., Luyten, P.J., Ozer, J., 1995. Haline stratification in the rhine/meuse freshwater plume: a 3D model sensitivity analysis. Cont. Shelf Res. 15 (13) 1597–1630] simplified to use an algebraic mixing length by Sharples and Simpson [Sharples, J., Simpson, J.H., 1995. Semidiurnal and longer period stability cycles in the Liverpool Bay region of freshwater influence. Cont. Shelf Res. 15, 295–313], also solved explicitly; the same simplified L2.5 scheme with an implicit numerical solution and modified vertical discretisation scheme [Annan, J.D., 1999. Numerical methods for the solution of the turbulence energy equations in the shelf seas. Int. J. Numer. Methods Fluids 29, 193–206]; and another version of the same scheme (but using a different algebraic mixing length) as described by Xing and Davies [Xing, J., Davies, A.M., 1996a. Application of turbulence energy models to the computation of tidal currents and mixing intensities in the shelf edge regions. J. Phys. Oceanogr. 26, 417–447; Xing, J., Davies, A.M., 1996b. Application of a range of turbulence models to the computation of tidal currents and mixing intensities in shelf edge regions. Cont. Shelf. Res. 16, 517–547; Xing, J., Davies, A.M., 1998. Application of a range of turbulence energy models to the computation of the internal tide. Int. J. Numer. Methods Fluids 26, 1055–1084]. Various model outputs at the sea surface and in depth profiles have been compared with data collected in 1989 as part of the North Sea Project [Huthnance, J.M., 1990. Progress on North Sea Project. NERC News, vol. 12, pp. 25–29, UK]. It is shown that the biological results are extremely sensitive to the small changes in the physical conditions, which arise due to the different turbulence schemes tested. The timing of the spring bloom and the maintenance of the midwater chlorophyll maximum all differ greatly between model runs, and the gross primary production varies by a factor of two from the highest to lowest results. The simplified Level 2.5 scheme, implemented using the numerical methods of Annan [Annan, J.D., 1999. Numerical methods for the solution of the turbulence energy equations in the shelf seas. Int. J. Numer. Methods Fluids 29, 193–206], produces results, which give the best agreement with the available data.     

贯彻"三个代表"重要思想做好离退休干部工作

离退休干部工作是党的基层组织建设的重要内容,做好离退休干部工作体现了对历史的尊重,有利于保证工作的连续性。新时期做好离退休干部工作,一要加强思想政治工作;二要积极创造条件,使离退休干部老有所乐,老有所学,老有所为;三要加强支部建设。     

港口拥挤的经济影响及解决方法

针对港口拥挤现象对经济的消极影响进行了分析,从港口的战略规划、港口的生产组织及外部营销等方面提出了消除港口拥挤的措施和方法。     

论安全文化及企业安全生产

安全是航运企业的永恒主题。人们的安全理念、安全价值观和判断标准也发生了深刻的变革,以“关爱生命、关注安全”为主旨的全社会的安全文化,正在逐步形成。本文结合工作实际对建设企业的安全文化提出思考。     

中国汽车排放新法规的实施与油品的关系

针对欧洲ECE－R83规则对试验用标准燃油的要求和“世界燃油规格”对燃油的要求讨论了欧洲联盟废气排放指令91／44／EEC和93／59／EEC在中国的实施与油品的关系；列举了中国油品的不足之处以及在改善油品质量方面所必须克服的困难；指出，中国石油工业的技术进步应与排放新法规的实施保持同步运作。主题词：##4排放物;;法规;;油品制造     

港口前沿作业系统计算机模拟

采用C 建立了港口前沿作业系统的计算机仿真模型,确定了仿真模型边界、假设条件;对于不同到港船型到港时间序列的处理作了阐述,并对程序和模型的正确性进行了检验。对港口前沿作业系统的一些直接因素对于仿真结果的影响作了敏感性分析,考察随装卸能力和泊位数变化的待泊时长这个关键量化指标的变化。最后对仿真结果进行了分析并提出一些有益的结论。     

3C技术在集装箱码头生产中的应用

3C技术改造目标是在现存集装箱码头生产MIS系统基础上，实现全码头生产资源管理的无纸化和无缝隙的数据通讯；实现堆场集装箱定位数据的自动核检；实现堆场轮胎吊作业的动态追踪和码头生产作业链上的全程实时调度管理。经过改造后，露天作业的虚拟现实及远程管理的可视化使得中心调度、现场调度和轮胎吊司机的工作方便快捷、和谐有序。该项目可降低堆场仓储成本6％，提高码头生产效率15％。实践证明，3C技术改造是我国集装箱码头实现港口机械化、信息化和自动化的途径之一。     

Large-scale physical controls on phytoplankton growth in the Irminger Sea, Part II: Model study of the physical and meteorological preconditioning

The upper water column in the Irminger Sea is characterized by cold fresh arctic and subarctic waters and warm saline North Atlantic waters. In this study the local physical and meteorological preconditioning of the phytoplankton development over an annual cycle in the upper water column in four physical zones of the Irminger Sea is investigated. Data from four cruises of the UK's Marine Productivity programme are combined with results from a coupled biological–physical nitrogen–phytoplankton–zooplankton–detritus model run using realistic forcing. The observations and model predictions are compared and analyzed to identify the key parameters and processes which determine the observed heterogeneity in biological production in the Irminger Sea. The simulations show differences in the onset of the bloom, in the time of the occurrence of the maximum phytoplankton biomass and in the length of the bloom between the zones. The longest phytoplankton bloom of 90 days duration was predicted for the East Greenland Current of Atlantic origin zone. In contrast, for the Central Irminger Sea zone a phytoplankton bloom with a start at the beginning of May and the shortest duration of only 70 days was simulated. The latest onset of the phytoplankton bloom in mid May and the latest occurrence of the maximum biomass (end of July) were predicted for the Northern Irminger Current zone. Here the bloom lasted for 80 days. In contrast the phytoplankton bloom in the Southern Irminger Current zone started at the same time as in Central Irminger Sea, but peaked end of June and lasted for 80 days. For all four zones relatively low daily (0.3–0.5 g C m^− 2d^− 1) and annual primary production was simulated, ranging between 35.6 g C m^− 2y^− 1 in the East Greenland Current of Atlantic origin zone and 45.6 g C m^− 2y^− 1 in the Northern Irminger Current zone. The model successfully simulated the observed regional and spatial differences in terms of the maximum depth of winter mixing, the onset of stratification and the development of the seasonal thermocline, and the differences in biological characteristics between the zones. The initial properties of the water column and the seasonal cycle of physical and meteorological forcing in each of the zones are responsible for the observed differences during the Marine Productivity cruises. The timing of the transition from mixing to stratification regime, and the different prevailing light levels in each zone are identified as the crucial processes/parameters for the understanding of the dynamics of the pelagic ecosystem in the Irminger Sea.     

F-Decomposition of Noetherian Modules over Hyper-（Cyclic or Finite）Groups

Let F be a locally defined formation consisting of locally soluble groups，G a hyper-(cyclic or finite)locally soluble group and A a noetherian ZG-module with all irreducible ZG-factors being finite，G∈F,f(∞)≌f(p)，f(P)≠Фfor each P∈π．The following conclutions are obtained：(1)if there exists a maximal submodule B of A such that A／B is F central in G and B has no nonzero F centml ZG-factors，then A has an F decomposition；(2)if there exists an irreducible F central submodule B of A such that all ZG-composition factors of A／B are F ecentric，then A has an F decomposition．     

浅谈施工项目管理

从工程进度管理、工程质量管理、工程造价管理、安全生产管理四个方面论述了施工项目管理的要求以及应该注意的有关问题。