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NPZ Models of Plankton Dynamics: Their Construction, Coupling to Physics, and Application 总被引：9，自引：0，他引：9
Peter J. S. Franks 《Journal of Oceanography》2002,58(2):379-387
Nutrient-phytoplankton-zooplankton (NPZ) models have been in use in oceanography for at least three decades, and are still
a common research tool. Given the discoveries of the last two decades, particularly concerning the role of bacteria in the
plankton, there are questions as to whether NPZ models can still be supported as a useful tool in planktonic research. Here
I review the construction of NPZ models, and some of the physical platforms they have been coupled to. I then discuss the
applications of NPZ-physical models, and conclude that they still constitute an important and viable research tool, provided
that the questions being explored are clearly stated.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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The literature on ocean wave forecasting falls into two categories, physics-based models and statistical methods. Since these two approaches have evolved independently, it is of interest to determine which approach can predict more accurately, and over what time horizons. This paper runs a comparative analysis of a well-known physics-based model for simulating waves near shore, SWAN, and two statistical techniques, time-varying parameter regression and a frequency domain algorithm. Forecasts are run for the significant wave height, over horizons ranging from the current period (i.e., the analysis time) to 15 h. Seven data sets, four from the Pacific Ocean and three from the Gulf of Mexico, are used to evaluate the forecasts. The statistical models do extremely well at short horizons, producing more accurate forecasts in the 1–5 hour range. The SWAN model is superior at longer horizons. The crossover point, at which the forecast error from the two methods converges, is in the area of 6 h. Based on these results, the choice of statistical versus physics-based models will depend on the uses to which the forecasts will be put. Utilities operating wave farms, which need to forecast at very short horizons, may prefer statistical techniques. Navies or shipping companies interested in oceanic conditions over longer horizons will prefer physics-based models. 相似文献
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Hermann Albert J.; Hinckley Sarah; Megrey Bernard A.; Napp Jeffrey M. 《ICES Journal of Marine Science》2001,58(5):1030-1041
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Emanuele Di Lorenzo Andrew M. Moore Hernan G. Arango Bruce D. Cornuelle Arthur J. Miller Brian Powell Boon S. Chua Andrew F. Bennett 《Ocean Modelling》2007,16(3-4):160-187
We describe the development and preliminary application of the inverse Regional Ocean Modeling System (ROMS), a four dimensional variational (4DVAR) data assimilation system for high-resolution basin-wide and coastal oceanic flows. Inverse ROMS makes use of the recently developed perturbation tangent linear (TL), representer tangent linear (RP) and adjoint (AD) models to implement an indirect representer-based generalized inverse modeling system. This modeling framework is modular. The TL, RP and AD models are used as stand-alone sub-models within the Inverse Ocean Modeling (IOM) system described in [Chua, B.S., Bennett, A.F., 2001. An inverse ocean modeling system. Ocean Modell. 3, 137–165.]. The system allows the assimilation of a wide range of observation types and uses an iterative algorithm to solve nonlinear assimilation problems. The assimilation is performed either under the perfect model assumption (strong constraint) or by also allowing for errors in the model dynamics (weak constraints). For the weak constraint case the TL and RP models are modified to include additional forcing terms on the right hand side of the model equations. These terms are needed to account for errors in the model dynamics.Inverse ROMS is tested in a realistic 3D baroclinic upwelling system with complex bottom topography, characterized by strong mesoscale eddy variability. We assimilate synthetic data for upper ocean (0–450 m) temperatures and currents over a period of 10 days using both a high resolution and a spatially and temporally aliased sampling array. During the assimilation period the flow field undergoes substantial changes from the initial state. This allows the inverse solution to extract the dynamically active information from the synthetic observations and improve the trajectory of the model state beyond the assimilation window. Both the strong and weak constraint assimilation experiments show forecast skill greater than persistence and climatology during the 10–20 days after the last observation is assimilated.Further investigation in the functional form of the model error covariance and in the use of the representer tangent linear model may lead to improvement in the forecast skill. 相似文献
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Recently, the technology has been developed to make wave farms commercially viable. Since electricity is perishable, utilities will be interested in forecasting ocean wave energy. The horizons involved in short-term management of power grids range from as little as a few hours to as long as several days. In selecting a method, the forecaster has a choice between physics-based models and statistical techniques. A further idea is to combine both types of models. This paper analyzes the forecasting properties of a well-known physics-based model, the European Center for Medium-Range Weather Forecasts (ECMWF) Wave Model, and two statistical techniques, time-varying parameter regressions and neural networks. Thirteen data sets at locations in the Atlantic and Pacific Oceans and the Gulf of Mexico are tested. The quantities to be predicted are the significant wave height, the wave period, and the wave energy flux. In the initial tests, the ECMWF model and the statistical models are compared directly. The statistical models do better at short horizons, producing more accurate forecasts in the 1-5 h range. The ECMWF model is superior at longer horizons. The convergence point, at which the two methods achieve comparable degrees of accuracy, is in the area of 6 h. By implication, the physics-based model captures the underlying signals at lower frequencies, while the statistical models capture relationships over shorter intervals. Further tests are run in which the forecasts from the ECMWF model are used as inputs in regressions and neural networks. The combined models yield more accurate forecasts than either one individually. 相似文献
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Data needs for ecosystem modelling 总被引：1，自引：0，他引：1
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We briefly analyze some characteristics of the behavior in very shallow waters i.e. near the shoreline of high-order (dispersive-nonlinear) Boussinesq-type equations. By using the Carrier and Greenspan (1958) solution as test flow conditions we illustrate the behavior of both purely dispersive and dispersive-nonlinear contributions near the shoreline. It is also shown that Boussinesq-type equations can be more usefully handled in the swash zone if written in terms of the total water depth. 相似文献
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Comparison of wind and wave measurements and models in the Western Mediterranean Sea 总被引：2，自引：0，他引：2
Fabrice Ardhuin Luciana Bertotti Jean-Raymond Bidlot Luigi Cavaleri Valentina Filipetto Jean-Michel Lefevre Paul Wittmann 《Ocean Engineering》2007,34(3-4):526-541
We have hindcast the wind and wave conditions in the Mediterranean Sea for two one month periods. Four different meteorological models and three different wave models have been used. The results have been compared with satellite and buoy wind and wave observations.Several conclusions concerning both the instruments and the models have been derived. The quality of both wind and wave results has been assessed. Close to the coasts high resolution, nested wave models are required for sufficient reliability.A wave threshold analysis suggests a sufficient reliability only off the coast, with a substantial decrease for low wave heights. 相似文献
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Michael Devine 《Estuarine, Coastal and Shelf Science》1983,16(3):271-289
A boundary layer formulation for the dynamic structure of a deep estuary is developed. Cross-stream averages are used, but the boundary layer structure is shown to depend on the cross-stream geostrophic constraint. A similarity transformation and a weighted residual method are used to derive an approximate solution for the velocity and salinity structure of the upper layer. This solution indicates that, in the central regime of the estuary, outflow extends through the entire halocline. Inflow takes place in a much less stratified lower layer, and mass exchange between the layers is by upwelling. This structure is modified in the outer regime of the estuary, where mixing between the layers develops, and in the inner regime, where a sharp halocline develops and where the dynamics are dominated by river runoff. The implications of the dynamics for the flushing process and for pollutant movement and dispersion are discussed. 相似文献
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气液界面气体传输问题对于科学和工程的许多领域是至关重要的。本文在简述了主要影响气液界面处气体传输的因素后，重点评述了气液界面处气体传输的研究现状和讨论了目前研究热点剪切气液界面附近湍流相干结构及其对界面气体传输的影响，最后指出了今后发展的可能方向。 相似文献
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剩余产量模型在不同渔业中的应用 总被引：4，自引：0，他引：4
剩余产量模型因其简单和所需数据较少的特点为渔业资源评估广泛采用.本文应用目前常用的四种剩余产量模型对五种渔业下的渔业生物种群及北大西洋箭鱼种群xiphias gladius评估效果作了比较.四种剩余产量模型在渔业1中的评估效果较好,而在渔业2中的效果较差;Schnute模型在充分捕捞的渔业,如渔业3、4、5,尤其是在低生物量的渔业3中评估效果较好,但不适合评估未充分捕捞的渔业.Walters-Hilborn模型(W-H模型)适用于各种渔业,尤其是渔业1、4、5.在过度捕捞渔业中如渔业3、4,模型对参数q的估计较其它参数接近真值.在北大西洋箭鱼(xiphias gladius)渔业的评估中,W-H模型对MSY的估计约为14000吨,接近于Prager(1996)的结果. 相似文献
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D. H. Peterson M. J. Perry K. E. Bencala M. C. Talbot 《Estuarine, Coastal and Shelf Science》1987,24(6)
A simple exponential equation is used to describe photosynthetic rate as a function of light intensity for a variety of unicellular algae and higher plants where photosynthesis is proportional to (1-e−β1). The parameter β (
) is derived by a simultaneous curve-fitting method, where I is incident quantum-flux density. The exponential equation is tested against a wide range of data and is found to adequately describe P vs. I curves. The errors associated with photosynthetic parameters are calculated. A simplified statistical model (Poisson) of photon capture provides a biophysical basis for the equation and for its ability to fit a range of light intensities. The exponential equation provides a non-subjective simultaneous curve fitting estimate for photosynthetic efficiency (a) which is less ambiguous than subjective methods: subjective methods assume that a linear region of the P vs. I curve is readily identifiable. Photosynthetic parameters β and a are used widely in aquatic studies to define photosynthesis at low quantum flux. These parameters are particularly important in estuarine environments where high suspended-material concentrations and high diffuse-light extinction coefficients are commonly encountered. 相似文献
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北极海冰数值模拟研究述评 总被引：7，自引：0，他引：7
根据国内外近年发表的主要文献,详细介绍北极海冰数值模拟工作的最新进展。综合评述各种主要动力学模式的特点和不足,指出与数值模式有关的主要物理问题,重点介绍海冰模式所特有的问题以及海冰数值模拟工作的发展方向。对以往的数值工作和海冰数值模拟的主要问题进行了总结,并在理论和实践方面进行了深入探讨,有助于我国相关工作的开展。 相似文献
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On the rational utilization of the Icelandic cod stock 总被引：1，自引：2，他引：1
Baldursson Fridrik M.; Danielsson Asgeir; Stefansson Gunnar 《ICES Journal of Marine Science》1996,53(4):643-658
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基于海洋锋空间位置、水平分布结构和垂直扩展特征等时空特征参数,结合海洋锋空间结构几何模型,建立了区域海洋锋温盐三维结构快速重构特征模型,对黄海西部沿岸锋和东海黑潮中段锋锋区温度场进行了仿真计算,并与实测数据进行了比较分析,实验结果表明：仿真结果与实测数据符合较好,实验结果验证了特征模型的有效性和可推广性。海洋锋区声速具有明显的水平梯度变化,对声纳的水下探测和反探测产生显著影响,因此,需要建立实时估计获取锋区水下温、盐结构的方法。海洋锋特征模型能够快速有效地重构海洋锋区温度场,为实时获取海洋锋水下结构特征提供了方法。 相似文献