Model evaluation experiments in the North Atlantic Basin: simulations in nonlinear terrain-following coordinates   总被引：7，自引：0，他引：7  

Dale B. Haidvogel  Hernan G. Arango  Kate Hedstrom  Aike Beckmann  Paola Malanotte-Rizzoli  Alexander F. Shchepetkin 《Dynamics of Atmospheres and Oceans》2000,32(3-4)

A primitive equation ocean circulation model in nonlinear terrain-following coordinates is applied to a decadal-length simulation of the circulation in the North Atlantic Ocean. In addition to the stretched sigma coordinate, novel features of the model include the utilization of a weakly dissipative, third-order scheme for tracer advection, and a conservative and constancy-preserving time-stepping algorithm. The objectives of the study are to assess the quality of the new terrain-following model in the limit of realistic basin-scale simulations, and to compare the results obtained with it against those of other North Atlantic models used in recent multi-model comparison studies.The new model is able to reproduce many features of both the wind-driven and thermohaline circulation, and to do so within error bounds comparable with prior model simulations (e.g., CME and DYNAMO). Quantitative comparison with comparable results obtained with the Miami Isopycnic Coordinate Model (MICOM) show our terrain-following solutions are of similar overall quality when viewed against known measures of merit including meridional overturning and heat flux, Florida Straits and Gulf Stream transport, seasonal cycling of temperature and salinity, and upper ocean currents and tracer fields in the eastern North Atlantic Basin. Sensitivity studies confirm that the nonlinear vertical coordinate contributes significantly to model fidelity, and that the global inventories and spatial structure of the tracer fields are affected in important ways by the choice of lateral advection scheme.  相似文献   

Geometrical effects on western intensification of wind-driven ocean currents: The rotated-channel Stommel model,coastal orientation,and curvature     

《Dynamics of Atmospheres and Oceans》2014

We revisit early models of steady western boundary currents [Gulf Stream, Kuroshio, etc.] to explore the role of irregular coastlines on jets, both to advance the research frontier and to illuminate for education. In the framework of a steady-state, quasigeostrophic model with viscosity, bottom friction and nonlinearity, we prove that rotating a straight coastline, initially parallel to the meridians, significantly thickens the western boundary layer. We analyze an infinitely long, straight channel with arbitrary orientation and bottom friction using an exact solution and singular perturbation theory, and show that the model, though simpler than Stommel's, nevertheless captures both the western boundary jet (“Gulf Stream”) and the “orientation effect”. In the rest of the article, we restrict attention to the Stommel flow (that is, linear and inviscid except for bottom friction) and apply matched asymptotic expansions, radial basis function, Fourier–Chebyshev and Chebyshev–Chebyshev pseudospectral methods to explore the effects of coastal geometry in a variety of non-rectangular domains bounded by a circle, parabolas and squircles. Although our oceans are unabashedly idealized, the narrow spikes, broad jets and stationary points vividly illustrate the power and complexity of coastal control of western boundary layers.  相似文献   

交会测量布站优化与数值分析     

张军  曹殿广  郑玉新  李久成  吴俊峰 《测绘科学》2011,36(3):119-121

本文基于遗传算法研究了交会测量布站方法,通过建立优化模型并用计算机进行仿真,得出了合理的布站方式;然后分别从参数精度的选取、落点的散布以及交会角的变化等角度分析了该布站方式在实际测量中的适用性.结果表明各参数在一定限度内波动所引起的误差在容许范围内,证明了该方法优化结果在靶场应用中的有效性.  相似文献   

全站仪在深基坑变形监测中的应用     

冯梅  朱怀汝  王永生  闫文政 《测绘与空间地理信息》2011,34(5):237-239

文章介绍了城市深基坑监测的目的、意义、方法及测量的精度估算等。指出了以前部分监测方法的不足,提出了利用全站仪对基坑进行的3维变形观测的方法,以及对该测量方法的精度论证。得出了该方法不但能提高测量精度、效率,而且节省了资源等结论。  相似文献   

The use of spherical coordinates in the interpretation of seismograms     

Anthony J. Lomax  Alberto Michelini 《Geophysical Journal International》1988,93(3):405-412

  相似文献   

时间传递接收机天线坐标的检测方法     

高玉平  李永萍 《时间频率学报》2002,25(1):28-34

讨论利用全球定位系统 (GPS)共视观测数据 (GGTTS格式 )测定接收机天线坐标的原理和方法 ,采用此方法 ,发现日本国家计量研究院 (NRLM )、墨西哥国家计量院 (CNM )、土耳其国家计量院 (UME)在进行TAIGPS共视观测时采用的GPS接收机天线坐标存在明显偏差。经坐标偏差改正后 ,日本国家计量研究院与日本通信综合研究所 (NRLM CRL)、墨西哥国家计量院与美国国家标准、技术研究院 (CNM NIST)、土耳其国家计量院与法国巴黎天文台 (UME OP)的比对精度分别由 1 8.6ns、7.0ns、2 83.0ns提高到 3.0ns、4 .5ns、4 .7ns。  相似文献   

Report of the IAU/IAG/COSPAR working group on cartographic coordinates and rotational elements of the planets and satellites: 1991   总被引：1，自引：1，他引：0  

M. E. Dames  V. K. Abalakin  A. Brahic  M. Bursa  B. H. CHovitz  J. H. Lieske  P. K. Seidelmann  A. T. Sinclair  Y. S. Tjuflin 《Celestial Mechanics and Dynamical Astronomy》1992,53(4):377-397

Every three years the IAU/IAG/COSPAR Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites revises tables giving the directions of the north poles of rotation and the prime meridians of the planets and satellites. Also presented are revised tables giving their sizes and shapes.  相似文献   

乌鲁木齐天文站南山GPS跟踪站的地心坐标精确测定   总被引：1，自引：0，他引：1  

张阿丽  张晋  程宗颐 《中国科学院上海天文台年刊》2003,(1)

利用GAMIT软件 ,采用有基准算法对乌鲁木齐南山观测基地新建GPS跟踪站GUAO的观测资料进行了归算 ,结果表明该站观测资料的质量是可靠的 ,并首次获得了该站在ITRF2 0 0 0中毫米级精度的地心坐标  相似文献   

三种坐标间转换的雅可比矩阵数值导数计算方法   总被引：10，自引：4，他引：6  

王解先  徐志京 《大地测量与地球动力学》2004,24(4):19-23

提出了一种用于空间大地直角坐标、大地坐标以及平面坐标与大地高之间相互转换的雅可比矩阵的数值导数的计算方法。该方法可以用较容易且精确的替代直接方法来实现不同类型间的坐标转换。在空间大地直角坐标与平面坐标与大地高之间的转换实验测试过程中，只要选取合适的增量，数值导数的精度都会满足要求，并且数值导数的精度的一致性也得到了验证。另外，该方法比采用直接方法计算速度显著加快，数值导数的精度、一致性和减少计算耗时在实验测试中效果非常好。  相似文献   

基于VC+ +的圆锥投影正解和反解软件设计与实现     

韩尤杰  尹继法  刘新华 《测绘工程》2007,16(6):58-62

随着GIS的日益发展和广泛普及,地理坐标和平面坐标之间相互转换需求不断增加。因为GIS,尤其是大型GIS中的空间数据往往来源于多种信息源,而各种信息源地图所采用的投影往往并不一致,各种坐标之间的变换就成为所有GIS软件不可避免的问题。此软件基于Visual C 开发平台,实现了在圆锥投影中(等角、等距离和等面积)地理坐标和平面坐标之间的相互转换。  相似文献