Experimental investigation on a two-part underwater towed system

An experimental set-up is developed and proved to be effective for laboratory study of an underwater towed system. The experimental technique gives a practical method for monitoring the kinematic and dynamic performance of an underwater towed system in a ship towing tank. Both the theoretical and experimental results in the investigation indicate that the hydrodynamic response of a towed vehicle to the wave induced motion of a towing ship can be significantly reduced by applying a two-part tow method. A comparison of the numerical and experimental results in the investigation demonstrates that the numerical simulation results are close to the experimental data, overall agreement between experimental and theoretical results is satisfactory. The results qualitatively verify the mathematical model of a two-part underwater towed system proposed by Wu and Chwang [Wu, J., Chwang, A.T., 2000. A hydrodynamic model of a two-part underwater towed system. Ocean Engineering 27 (5), 455–472].     

GPS数据采集技术及其在海洋调查中的应用

本文应用VB6．0开发了智能化的GPS数据采集软件．对该软件的功能进行了简单的介绍，同时对一些关键技术作了较详细的描述。利用该软件、GPS接收机及PC机的组合，可对走航式测量仪器(或移动设备)进行实时定位并保存定位记录，且大大减少一些不必要的数据，使得软件更为实用。     

A New Fall-Rate Equation for T-5 Expendable Bathythermograph (XBT) by TSK

The accuracy of the manufacturer’s fall-rate equation for the T-5 Model of expendable bathythermograph (XBT) has been investigated based on about 300 collocated pairs of XBT-CTD (Conductivity-Temperature-Depth profiler) measurements in various climatological regions. We found that the equation systematically overestimates depth by about 5% for the T-5 produced by Tsurumi Seiki, Co. Ltd. (TSK), but almost no bias is associated with the T-5 produced by Sippican, Inc., in USA. The cause of this difference is not clear, because the two manufacturers’ T-5 probes are reported to have identical shape and weight in water. We propose a new fall-rate equation for the TSK T-5: z(t) = 6.54071t - 0.0018691t ², where z(t) is depth in meters at time, t, in seconds.     

渤海的平均余环流

利用72个渤海石油平台、站点测流资料,阐明了渤海的平均余环流特征,并用已有的数值计算结果阐明了其形成机制。观测表明在黄河三角洲近海存在一支北-东北向的流动,可抵达秦皇岛附近水域,数值计算表明该支流动主要是潮生的;在辽东湾北部存在一顺时针向的涡旋运动,在冬半年该涡旋是风生的;在渤海湾北部存在潮生的逆时针向的余环流。     

Recorder-Dependent Temperature Error of Expendable Bathythermograph

The accuracy of temperature measurement by the expendable bathythermograph (XBT) is examined for five types of recorders by comparison with co-located CTD measurements and statistical analysis of temperature profiles including an isothermal layer. A positive temperature error increasing downward is occasionally detected for two types of Japanese recorder which have been commonly used among Japanese oceanographic institutions and marine observatories. This error resembles to that reported by Bailey et al. (1989) and Wright (1991) for a different type of recorders, although its cause is not clearly understood. The irregular occurrence of the error suggests that the problem is not solely due to the recorders but rather by some inconsistency of the whole measuring system including them, an XBT probe and sea water. The error is estimated to increase at a rate of O (0.1°C/100 m), and it could be close to 1°C at the deepest part of the profiles (760 m for Tsurumi T-7). This revised version was published online in July 2006 with corrections to the Cover Date.     

基于声学调制解调器的声速剖面遥测技术

声速是海洋声呐测量中最重要的声学参数之一。拖缆式声速剖面仪可提供实时测量功能,但其缆长不能满足深海测量要求;自容式声速剖面仪可满足深海测量要求,但工作效率低。如何提高野外深海声速剖面测量工作效率是深海调查一项非常有意义的工作。文中详细介绍了基于声学调制解调器的声速剖面遥测系统的主要结构和功能,揭示了水声通信技术在深海非铠装缆测量中的应用优势。     

ASM1中污水水质参数与化学计量系数的估测

简要介绍了活性污泥1号模型中14个污水水质参数与5个化学计量系数的估测方法和典型取值。     

Mean flow and variability in the southwestern East Sea

The Ulleung Basin is one of three deep basins that are contained within the East/Japan Sea. Current meter moorings have been maintained in this basin beginning in 1996. The data from these moorings are used to investigate the mean circulation pattern, variability of deep flows, and volume transports of major water masses in the Ulleung Basin with supporting hydrographic data and help from a high-resolution numerical model. The bottom water within the Ulleung Basin, which must enter through a constricted passage from the north, is found to circulate cyclonically—a pattern that seems prevalent throughout the East Sea. A strong current of about 6 cms⁻¹ on average flows southward over the continental slope off the Korean coast underlying the northward East Korean Warm Current as part of the mean abyssal cyclonic circulation. Volume transports of the northward East Korean Warm Current, and southward flowing East Sea Intermediate Water and East Sea Proper Water are estimated to be 1.4 Sv (1 Sv=10⁻⁶ m³ s⁻¹), 0.8 Sv, and 3.0–4.0 Sv, respectively. Deep flow variability involves a wide range of time scales with no apparent seasonal variations, whereas the deep currents in the northern East Sea are known to be strongly seasonal.     

几种测流设备的比测试验及分析

海流是基础的海洋资料,海流计是海流测量的重要仪器。文中介绍了RCM-9型安德拉海流计、中科院声学所150 kH z ADCP、RD I公司75kH z相控阵ADCP以及LADCP四种声学海流计的工作原理以及海上比测试验。通过分析比测试验的结果,验证了各仪器的测流性能,并从层厚、层深、相对流速参考物以及安装位置等方面分析了造成各设备测量差别的原因,为将来的流速测量提供了参考依据。     

单中继星单低轨卫星的联合定轨精度分析

针对由单中继星和单低轨卫星组成的联合定轨系统,给出了系统内不同轨道卫星摄动项的选取方案和卫星间的可见性判别模型。在模拟出含有白噪声的四程测距观测数据文件的基础上,研究了测距精度和采样弧段对联合定轨中高、低轨卫星定轨精度的影响。得出如下结论:联合定轨更有利于对低轨卫星的轨道改进;同样的采样时间条件下,测距噪声越小定轨精度越高,并且采样时间越短它的影响越明显;同样的测距噪声条件下,所用资料的采样时间越长精度越高,但当测距精度很高时,TDRS达到最好定轨精度所需的采样时间相应有所缩短。并在定出轨道后进行了轨道预报,分析了轨道预报的趋势及精度。