共查询到20条相似文献，搜索用时 906 毫秒
1.
一种模拟三维海流运动的差分方法 总被引：1，自引：0，他引：1
提出了一种模拟三维海流运动的隐式差分方法,并给出其计算步骤。通过对该差分方法的稳定性分析可以发现,它的时间步长取值有较大的灵活性。该方法被用于崖门海域的海流模拟。实例计算表明,该差分方法计算过程稳定,计算结果合理,能较好地反映出三维海流运动的特征。 相似文献
2.
斜压海洋动力学的一种三维数值模式 Ⅰ.动力学方程数值格式 总被引：1，自引：0，他引：1
依据自由海面海洋动力学原始方程建立了一种三维有限差分数值模式,可用于潮波、风暴潮和海流的数值模拟和预报。运动方程和连续方程的数值格式采用内、外模态分离的技术。外模态采用交替方向隐格式,用于计算海面高度和垂直平均流速,时间步长不受Ｃｏｕｒａｎｔ－Ｆｒｉｄｅｒｉｃｈｓ－Ｌｅｗｙ条件限制;内模态采用半隐格式,用于计算海流的垂直２颁布,其时间步长可大于外模态时间步长。模式的计算程度比一般显式模式可快１０倍 相似文献
3.
4.
8309号台风风暴潮和风海流的三维数值模拟 总被引：3，自引：0，他引：3
本文采用Liu and Leendertse的三维有限差分格式,模拟了8309号台风在南海北部引起的风暴潮和风海流。垂直涡动粘性系数采用混合长度理论。计算与实测的台风风暴潮的增水曲线形状趋势和峰值均符合良好。本文着重分析了台风风海流的水平和垂直变化。 相似文献
5.
6.
深海释放器是海洋观测仪器、海洋工程中关键设备。研究考虑海流、释放器部件碰撞等因素的深海释放器释放过程的动力学情况,采用多体动力方法建立某深海释放机构的动力学模型,模拟释放机构的释放过程中各构件的运动情况和运动轨迹,计算释放机构在释放过程各组成构件的运动参数,该方法可以用于模拟深海释放器释放过程状况,分析释放器失效的原因和指导释放机构的设计。 相似文献
7.
掌握海流和风暴潮的规律,对于海洋开发、港工建设、航运、军事和防御海洋气象灾害,都具有重大的经济和社会效益.由上海计算技术研究所副研究员徐学荣研究的“海流和风暴潮数值模拟研究及软件”课题(海流部分工作曾和中科院大气所副研究员季仲贞协作),历时五年多,现巳在沪通过技术鉴定。这项成果的主要贡献是:采用数值模拟方法,通过典型实例,成功地模拟了南海海流和风暴潮,科学计算出诸因素与机制是如何互相影响而发生作用的,从而揭示出海流和风暴潮的若干运动规律。 相似文献
8.
掌握海流和风暴潮的规律,对于海洋开发、港工建设、航运、军事和防御海洋气象灾害,都具有重大的经济和社会效益。由上海计算技术研究所副研究员徐学荣研究的“海流和风暴潮数值模拟研究及其软件”课题（海流部分工作曾和中科院大气所副研究员季伸贞协作）,历时五年多,现已在沪通过技术鉴定。 这项成果的主要贡献是: 采用数值模拟方法,通过典型实例,成功地模拟了南海海流和风暴潮,科学计算出诸因素与机制是如何互相影响而发生作用的,从而揭示出海流和风暴潮的若干运动规律。 取得的重要成果有: 相似文献
9.
10.
迎风有限元法在三维潮流数值模拟中的应用 总被引：4，自引：0，他引：4
为研究和开发迎风有限元法在河口海岸三维波数值模拟中的应用，并为建立三维物质扩散模型，最终为解决实际工程问题打下基础，以非线性浅水波方程为基础，采用一咱平面迎风有奶元与垂向工有限差分相结合地数值计算方法建立三维潮流数学模型，基地实际的物理过程，在计算中将三维流动分成外重力波和内重力波，耦联求解潮位和流速的空间分布。应用本模式计算了天津新港附近渤海海域的三维潮流运动，以较高的分辩率揭示了潮流空间结构特 相似文献
11.
We present a simplified method for solving the local equilibrium carbonate chemistry in numerical ocean biogeochemistry models. Compared to the methods typically used, the scheme is fast, efficient and compact. The accuracy of the solution is dictated by the number of species retained in the expression for alkalinity and there is almost no computational penalty for retaining minor contributions. We demonstrate that this scheme accurately reproduces the results of the commonly used method in the context of a three-dimensional global ocean carbon cycle model. Using this model we also show that neglecting the regional variations in surface dissolved inorganic phosphorus and silicic acid concentrations can lead to significant systematic bias in regional estimates of air–sea carbon fluxes using such models. 相似文献
12.
利用资料同化方法优化观测系统的空间布局:以泰国湾为例 总被引：1，自引：0，他引：1
海洋观测费用高昂,设计科学高效的观测系统可以充分发挥观测的效能。本文以泰国湾高频地波雷达观测系统为例,利用数据同化方法对观测系统进行了最优布局。首先基于FVCOM海洋数值模式建立了泰国湾海域高分辨率三维斜压水动力模式,在此基础上利用一种改进的高效集合卡曼滤波同化方法对岸基高频地波雷达表层海流观测系统开展观测效能评估数值实验。通过观测区域的不同组合方式将3个区域的雷达表层海流数据同化到数值模式中,实验结果表明,岸基高频地波雷达表层海流观测系统可有效降低高分辨数值模式的海流模拟误差。但不同观测区域的组合提供的观测数据对改善海流模拟的作用存在明显差别,泰国湾现有观测系统雷达站位布设方式应进一步优化。本文最后给出了研究区域最优观测站位的布局方案,可作为下一步观测系统进行布局调整的指导。 相似文献
13.
Three-D numerical simulation of wind-driven current and density current in the Beibu Gulf 总被引：4，自引：2，他引：4
The Beibu Gulf circulation plays an imPOrtant role in the long--term water rnass transportinside the gulf. It is also closely related to the Guangxi untal water mass transport and self-purification. Hence, it is of practical imPOrtance to study the circulation in the gUlf. The cir-culation in the gUlf is very comlicated, and is rnainly gOverned by wind, water density gradi-ent, the current outside the gulf and the bathpoetry. In spring, a cold water rnass generatesln the center of the gulf… 相似文献
14.
The upper ocean response to a moving typhoon 总被引：1，自引：0，他引：1
The upper ocean response to the translation speed of typhoons is studied using a three-dimensional primitive equation model.
Similar models studied previously have applied stability criteria rather than the diffusion term to simulate the vertical
mixing process. This study retains the diffusion term and uses the level-2 turbulence closure scheme to estimate the vertical
eddy viscosity. The model results indicate that in the forced period, the mixed-layer temperature decrease is greater for
a slow-moving storm due to stronger upwelling caused by the longer residence time. A fast-moving storm can attain a similar
cooling intensity in the wake period if its residence time allows the wind to resonate with the current. The significant downward
momentum diffusion and advection in the first few inertial periods of these events leads to strong, persistent inertial pumping
throughout the upper ocean in the wake period. The mixed layer is further cooled by turbulent mixing supported by vertical
current shears. Meanwhile, the upper thermocline exhibits a compensating temperature increase. The vertical transfer magnitude
and penetration scale are smaller in the slow-moving case, when the inertial motion decays rapidly. The model results also
indicate that the dominant cooling process can be inferred from the non-dimensional storm speed. However, this value may be
misleading for rapidly moving storms in which the current response is so distant from the storm that little wind work is performed
on the ocean. 相似文献
15.
一个两时间层分裂显格式海洋环流模式(MASNUM)及其检验 总被引：1，自引：0，他引：1
HAN Lei 《海洋学报(英文版)》2014,33(11):11-35
A two-time-level, three-dimensional numerical ocean circulation model（named MASNUM） was established with a two-level, single-step Eulerian forward-backward time-differencing scheme. A mathematical model of large-scale oceanic motions was based on the terrain-following coordinated, Boussinesq, Reynolds-averaged primitive equations of ocean dynamics. A simple but very practical Eulerian forward-backward method was adopted to replace the most preferred leapfrog scheme as the time-differencing method for both barotropic and baroclinic modes. The forward-backward method is of second-order of accuracy, computationally efficient by requiring only one function evaluation per time step, and free of the computational mode inherent in the three-level schemes. This method is superior to the leapfrog scheme in that the maximum time step of stability is twice as large as that of the leapfrog scheme in staggered meshes thus the computational efficiency could be doubled. A spatial smoothing method was introduced to control the nonlinear instability in the numerical integration. An ideal numerical experiment simulating the propagation of the equatorial Rossby soliton was performed to test the amplitude and phase error of this new model. The performance of this circulation model was further verified with a regional（northwest Pacific） and a quasi-global（global ocean simulation with the Arctic Ocean excluded） simulation experiments. These two numerical experiments show fairly good agreement with the observations. The maximum time step of stability in these two experiments were also investigated and compared between this model and that model which adopts the leapfrog scheme. 相似文献
16.
Diapycnal mixing is important in oceanic circulation. An inverse method in which a semi-explicit scheme is applied to discretize the one-dimensional temperature diffusion equation is established to estimate the vertical temperature diffusion coefficient based on the observed temperature profiles. The sensitivity of the inverse model in the idealized and actual conditions is tested in detail. It can be found that this inverse model has high feasibility under multiple situations ensuring the stability of the inverse model, and can be considered as an efficient way to estimate the temperature diffusion coefficient in the weak current regions of the ocean. Here, the hydrographic profiles from Argo floats are used to estimate the temporal and spatial distribution of the vertical mixing in the north central Pacific based on this inverse method. It is further found that the vertical mixing in the upper ocean displays a distinct seasonal variation with the amplitude decreasing with depth, and the vertical mixing over rough topography is stronger than that over smooth topography It is suggested that the high-resolution profiles from Argo floats and a more reasonable design of the inverse scheme will serve to understand mixing processes. 相似文献
17.
南海环流的三维数值模拟 总被引：1，自引：0，他引：1
本文采用Backhaus的三维海流模式,运用半隐式及C-网格方法求解基本方程,对南海各季的平均海流流场进行了数值模拟。将模拟结果与已有的研究结果进行比较,其主要流系基本上是相符的,夏季表层基本上为一反气旋型环流;冬季则转变成气旋型;在冬季,从50m层起开始显露出“南海暖流”的存在。这些表明南海海流的某些主要特征基本上已经被此模型成功地再现出来,同时此模型又给出了垂直方向各层的海流情况,在目前尚缺乏深层实测海流资料的情况下,上述深层海流的模拟结果有一定参考意义。 相似文献
18.
19.
An optimisation scheme is developed to accurately represent the sub-grid scale forcing of a high dimensional chaotic ocean system. Using a simple parameterisation scheme, the velocity components of a 30 km resolution shallow water ocean model are optimised to have the same climatological mean and variance as that of a less viscous 7.5 km resolution model. The 5 day lag-covariance is also optimised, leading to a more accurate estimate of the high resolution response to forcing using the low resolution model.The system considered is an idealised barotropic double gyre that is chaotic at both resolutions. Using the optimisation scheme, we find and apply the constant in time, but spatially varying, forcing term that is equal to the time integrated forcing of the sub-grid scale eddies. A linear stochastic term, independent of the large-scale flow, with no spatial correlation but a spatially varying amplitude and time scale is used to represent the transient eddies. The climatological mean, variance and 5 day lag-covariance of the velocity from a single high resolution integration is used to provide an optimisation target. No other high resolution statistics are required. Additional programming effort, for example to build a tangent linear or adjoint model, is not required either.The focus of this paper is on the optimisation scheme and the accuracy of the optimised flow. However the forcing can provide insights in the design of deterministic and stochastic parameterisations. In the present study, we found that the stochastic parameterisation correcting the model variance is associated with the spatial pattern of eddy-decorrelation timescales rather than the spatial pattern of the amplitude of the variance. The method can be applied in future investigations into the physical processes that govern barotropic turbulence and it can perhaps be applied to help understand and correct biases in the mean and variance of a more realistic coarse or eddy-permitting ocean model. The method is complementary to current parameterisations and can be applied at the same time without modification. 相似文献
20.
A new method of assimilating sea surface height (SSH) data into ocean models is introduced and tested. Many features observable by satellite altimetry are approximated by the first baroclinic mode over much of the ocean, especially in the lower (but non-equatorial) and mid latitude regions. Based on this dynamical trait, a reduced-dynamics adjoint technique is developed and implemented with a three-dimensional model using vertical normal mode decomposition. To reduce the complexity of the variational data assimilation problem, the adjoint equations are based on a one-active-layer reduced-gravity model, which approximates the first baroclinic mode, as opposed to the full three-dimensional model equations. The reduced dimensionality of the adjoint model leads to lower computational cost than a traditional variational data assimilation algorithm. The technique is applicable to regions of the ocean where the SSH variability is dominated by the first baroclinic mode. The adjustment of the first baroclinic mode model fields dynamically transfers the SSH information to the deep ocean layers. The technique is developed in a modular fashion that can be readily implemented with many three-dimensional ocean models. For this study, the method is tested with the Navy Coastal Ocean Model (NCOM) configured to simulate the Gulf of Mexico. 相似文献