EOF重构声速剖面对深水多波束的声速改正分析

声速误差是多波束水深地形测量主要误差源之一,通常采用现场声速剖面测量的方式加以改正,但在深远海多波束水深地形测量时,现场获取全深度的声速剖面并非易事。针对这一问题,利用东南印度洋海洋调查工作中采集到的17个站位的CTD数据,将所有站位声速剖面拓展到全深度,采用经验正交函数分析法(Empirical Orthogonal Functions,EOF)构建调查区声速剖面场,可获得声速剖面场内任意一点的声速值。然后通过EOF重构声速剖面场获得的声速值对测区内多波束水深地形数据进行改正,并与实测声速剖面对多波束水深地形数据的改正结果进行对比,结果表明,5000 m水深范围内2种声速改正结果相差很小,EOF重构法对深水多波束的声速改正满足水深测量的要求。     

基于浅地层剖面仪的连云港航道地质 稳定性研究

随着声学探测技术的不断提高,浅地层剖面仪具有高效、经济、穿透性强等特点,在海洋工程勘察中得到了广泛应用。基于浅地层剖面仪的工作特点,结合连云港海底航道的实际情况,对获得的浅地层剖面数据和图像进行分析和判读,得到海底航道地质结构的特征、边坡及剖面变形情况,由此判断连云港海底航道的稳定性,并分析影响数据精度的因素,为航道疏浚维护提供依据。     

Preliminary results on relationship between thermal diffusivity and porosity of sea ice in the Antarctic

The in situ sea-ice temperature, salinity and density observed from Chinese Antarctic Zhongshan Station have been applied to calculate the vertical profile of sea ice porosity. Based on numerical method, a number of schemes on sea-ice thermal diffusivity versus porosity have been accessed and one optimized scheme is identified by an optimal control model with an advanced distributing parameter system. For simplicity, the internal heating source item was neglected in the heat conduction equation during the identification procedure. In order to illustrate the applicability of this identified scheme, the vertical ice temperature profiles have been simulated and compared with measurements, respectively by using identified scheme and by classical thermodynamic formulae.The comparisons indicated that the scheme describing sea-ice thermal diffusivity and porosity is reasonable. In spite of a minor improvement of accuracy of results against in situ data, the identified scheme has a more physical meaning and could be used potentially in various applications.     

Study on the double-logarithmic profile of tidal flow velocity in the near-bed layers

Tidal current velocity profile in the near-bed layers has been widely studied. The results showed that velocity profile in the near-bed layer obviously departure from the traditional logarithmic profile, due to the acceleration or deceleration. Although the logarithmic linear profile can reduce the rate of deviation from this, only it is a lower-order approximate solution. In this paper, considering the unsteady and non-linear features of tidal motion, the double logarithmic profile near-bed layers in estuarine and coastal waters is established on the assumption that the turbulent shear stress along the water depth was parabolic distribution, and on the basis of Prandtl''s mixing length theory and von Karman''s self-similar theory. Having been verified the data observed at the West Solent in the south of England, and comparison of the logarithmic linear profile, it found that the double logarithmic profile is more precious than the latter. At last, the discussed results showed that:(1) The parabolic distribution of the tidal shear stresses verified good by the field data and experimental data, can be better reflected the basic features of the tidal shear stress deviating from linear distribution that is downward when to accelerate, upward when to decelerate. (2) The traditional logarithmic velocity profile is the zero-order approximation solution of the double logarithmic profile, the logarithmic linear profile is the first order, and the logarithmic parabolic profile is the second order. (3) Ignoring the conditions of diffusion and convection in the tidal movement, the double logarithmic profile can reflect the tidal properties of acceleration or deceleration, so that the calculation of the friction velocity and roughness length are more reasonable. When the acceleration or the deceleration is about zero, the double logarithmic profile becomes the logarithmic profile.     

基于单片机的海洋环境监测系统的控制电路设计

设计并实现了一种基于C8051F340单片机的节能型自治式多功能海洋环境监测系统的控制电路.该电路利用模块化设计方法,通过合理选用器件和设计器件的工作模式,使控制电路具有低功耗、高可靠的特点.实验表明,该控制电路实现了潜标式主浮体对浮标式搭载平台的实时控制,同时实现了浮标搭载平台单向下潜、定点测量、自由上浮、自动避碰等状态的控制,方法简单新颖,实现了对海洋要素的长期连续观测.     

基于GIS的多波束和浅地层剖面数据集成技术研究

依据同一测区地球物理资料的空间地理坐标参照关系,利用 ArcView 对栅格、矢量等多种空间数据格式的支持及内置语言Avenue 强大的二次开发功能,实现了多波束和浅地层剖面数据的集成.主要流程包括多波束测深数据的预处理和浅地层剖面的生成、元数据的获取;ArcView GIS 中编程实现浅地层剖面测线的分段矢量化;运用两个 Avenue 程序实现多波束和浅地层剖面的关联展示等.在此基础上,对多源地球物理数据的集成前景作了进一步的展望.     

多波束测深数据确定声速剖面方法研究

分析了声速剖面测量方法及其误差对多波束测深数据精度的影响.根据多波束测深仪45°倾角渡束测深数据对声速剖面误差不敏感的现象,提出了利用多波束测深仪45°倾角波束测深数据确定声速剖面的A-法并结合检查线计算测线交叉区特征点声速剖面误差,为测区声速剖面的外推提供控制,从而减小声速剖面测量误差对多波束测深的影响提高测深数据精度.     

一种专门用于低纬度洋区观测的Argo剖面浮标

早期研制的Apex型剖面浮标,由于浮力有限,不适合在上下层密度差较大的低纬度海区使用.为了实现国际Argo科学组提出的"要获取全球大洋2 000 m水深剖面资料"的目标,从2004年开始,美国Webb研究公司组织技术研究人员对普通Apex型浮标进行了技术革新,从而使得今天已经建成的全球Argo实时海洋观测网具备了覆盖全球大洋进行2 000 m水深剖面观测的能力.美国华盛顿大学海洋学院Stephen C.Riser教授专门著文详细介绍了这一改进技术,我们对全文进行了翻译和整理,以供国内浮标技术研制人员参考.     

拖曳式剖面探测拖体系统构成及运动控制试验

拖曳式剖面探测拖体是一种能做波浪式轨迹运动的载体,可对海洋进行实时多参数剖面探测.阐述国内首台拖曳式剖面探测拖体的组成、功能及运动轨迹,并对运动轨迹控制进行实船试验研究.结果表明,拖曳式剖面探测拖体具有控制性能优良,实现传感器数据的实时采集.