强潮河口水下地形测量潮位控制研究

钱塘江河口属于强潮河口,具有潮差大、流急、地形复杂和局地潮汐变化大等特点,对潮位控制设计与实施造成较大困难。为解决钱塘江河口水下地形测量潮位控制难题,针对强潮河口的水下地形和潮汐特征进行分析,提出了该区域潮位控制的潮位站布设方案与作业时间要求。实测数据表明,只要合理布设潮位站、选择合适的时间段作业,强潮河口水下地形测量的潮位控制可以达到规范精度要求。     

水下微地貌三维激光地形仪研制

为了高精度获取泥沙冲淤引起的地貌变化,提升滩海工程物理模拟实验研究水平,将激光三角反射原理应用于水下地形测量,基于该原理研制了微地貌三维激光地形仪。重点介绍激光三角反射原理、地形仪的组成、水下误差分析及校正。在结构设计方面,采用两轴系垂直的二维平面结构布局,利用两台伺服电机组成二维运动控制系统,通过丝杠传动带动探头实现扫描区域全覆盖,激光测量装置安装在探头上并获取高程数据,利用总线传输技术进行信号采集。在软件设计方面,基于虚拟仪器软件LABVIEW开发了三维激光测量仪测控软件。实验测试表明,该地形仪实现高精度设计要求。     

DGPS走航测深验潮技术中的潮位信息提取方法

提出了一种提取观测海域潮位信息的新方法--DGPS走航测深验潮技术,即在走航ADCP重复测量断面潮周期流场观测的同时获取潮位信息,并实现水下地形的潮位改正.该方法通过重复测量点瞬时水深数据选取、潮位差数据计算、叠加拟合和迭代逼近等预处理与算法,可在潮差约1.6 m、地形起伏高达10～20 m的台湾浅滩沙波区,获取均方根误差小于0.1 m的潮位观测结果.     

地磁感应线圈在投弃式探头水下转速测量中的应用

介绍了地磁感应线圈的工作原理,针对投弃式探头水下转速测量需要,设计专用线圈传感器及测量电路,并搭建专用试验台进行室内试验。试验结果表明,采用地磁感应线圈可以准确地得到旋转体转速信息,可应用于投弃式探头水下转速测量。     

SSA2—1便携式潮位仪的技术特点

SSA_2-1潮位仪是一种无井验潮仪,它在温度传感器、导管、分流装置及计算机程序的配合下,实时进行大气压力、温度、盐度、重力、涌潮、海流等要素补偿,能立即打印准确的潮位值,有较高的精度。由于采用了与陆地高程联测及“自校法”测量程序,既能直接打印出“潮位改正值”,又能在盐度、浊度未知的海区使用。     

水下机械手接近觉系统研究

根据水下机械手的工作需要,设计了一套高精度的水下超声波定位系统.采用超声波检测距离、三探头阵列检测方位的方案,使用超低功耗单片机MSP430精确计算超声波往返时间和控制三探头轮流工作,通过对三个探头的测量数据进行处理,实现目标测距及定位.经过实验室及水池实验表明,该系统在水下工作稳定,精度及灵敏度高,是水下机器人及机械手自主探测目标的有效手段之一.     

远距离GNSS潮位测量精度的影响因素研究

为实现远岸潮位精确监测,从天线类型、浮标姿态改正、数据处理模式等影响因素进行了远距离GNSS浮标潮位测量精度的分析研究。结果表明:相比于非扼流圈天线,采用扼流圈天线可有效提高GNSS浮标数据观测质量,获得较高精度的定位结果;姿态改正对浮标天线高误差达厘米级,潮位提取中可通过低通滤波器有效消除;远距离潮位测量(基线大于300 km)中PPP潮位精度整体优于PPK潮位;GNSS潮位测量精度受海况影响严重,四级海况以内,潮位测量精度优于10 cm,可以满足远距离潮位观测精度的要求。     

基于姿态校正的RTK潮位在琼州海峡地形测量中的应用

潮位改正是多波束地形勘测中的重要环节。琼州海峡跨海工程中分别利用验潮潮位和RTK潮位进行潮位改正,对比结果发现初始RTK潮位改正后的数据存在较大偏差,最大可达1.5 m。通过对RTK测量潮位进行姿态校正后,其结果与验潮潮位的偏差减小,可以控制在0.3 m以内。5-6月的琼州海峡正是西南季风爆发时间,海峡海流的流向具有复杂性,涨落潮都伴随着较大的风浪,RTK潮位测量忽略风浪带来的影响是出现较大误差的重要原因。     

影响潮位观测质量因素分析与研究

在全球气候变暖的影响下,中国沿海海平面上升趋势还将进一步加剧。海平面上升会给沿海地区的社会经济、自然环境以及生态系统带来重大影响。面对海平面上升带来的巨大危害,如何防止其上升带来的危害显得尤为重要。首先要掌握海平面上升速率,潮位观测数据是对海平面进行科学研究的重要依据之一,潮位数据的及时性、准确性、完整性在海平面研究中起主导作用。但由于在观测中常使用不正确的方法,所以无法计算准确的平均海平面高度。根据潮位观测理论和多年实践经验,总结了在潮位观测中影响观测质量的因素,从而得到当地准确海平面及海平面上升速率,为防灾减灾提供基本理论依据。     

沿岸多模式GNSS三维水深测量方法研究

在沿岸水下地形测量中,高程控制是难点,在远离岸边的区域,不仅布设潮位站困难,而且潮位站水位改正的精度也难以保证,为提高沿岸水域测量的可靠性和灵活性,在河口区域的水深测量项目中进行了RTK、PPK、PPP3种模式的同步作业方式研究。结果表明,基于GNSS多模式三维水深测量的方法能有效提高水位改正的精度和可靠性。无论测区离岸距离多远,可以同步采用RTK、PPK和PPP的方式进行高程控制,这3种模式的高程测量差值均方差接近0.10m,精度能满足沿岸水域一般比例尺地形测量的高程精度要求。     

Study on Nutrient Limitation of Phytoplankton in the Field Experiment of the Yangtze River Estuary in Summer

Introduction The growth of phytoplankton, which is the main primary producer in the ocean, is always limited by some nutrients such as nitrogen and phosphorus. This limitation has spacial variation, and even in the same area, the nitrogen and phosphorus limitation has seasonal alternation [1]. There are many ways to determine the nutrient limitation of phytoplankton growth. Among them, the enrichment bioassay is the closest to the natural condition and is accepted by many scholars [2-7]. In r…     

Excess pore pressure observation in marine sediment based on Fiber Bragg Grating pressure sensor

Abstract

Fiber Bragg Grating (FBG) technology has emerged as a relatively new sensing technology for engineering applications because of lots of advantages. In this study, a large diameter probe instrumented with FBG pressure sensors to monitor excess pore pressure in marine sediment is proposed. The principle of FBG differential pressure sensor was introduced. Laboratory tests were carried out to check the workability and stability of the FBG pressure sensor. Offshore field test was also conducted in a wharf in Qingdao of China to evaluate the feasibility of the proposed probe. The installation procedure of the probe was introduced in detail. The excess pore pressure in dissipation test, after installation and pulling process were reported. The permeability coefficient of marine sediment was calculated based on the measured data. The field data show that the proposed probe based on FBG pressure sensor has good feasibility and accuracy in monitoring the excess pore pressure of marine sediment. The generation and dissipation of excess pore pressure is closely related to the degree of soil disturbance. The variation of excess pore pressure after installation can reflect the tide well in the site.     

Excess pore pressure in Mississippi delta front sediments: Initial report

Abstract

In September 1975, a differential piezometer probe was successfully implanted in the soft seafloor sediments of Block 28, South Pass, Mississippi Delta. The probe sensor is located approximately 6.4 m below the mudline in a water depth of 19 m, and has essentially continuously monitored excess pore pressure (the difference between sediment pore pressure and hydrostatic pressure at that depth) since installation. Excess pore pressure will be monitored until March 1976, when the probe will be recovered.

Immediately after deployment, an excess pore pressure of 54 kPa was recorded. An ambient excess pore pressure of approximately 32 kPa remained after dissipation of that developed during probe installation. Because of the possible presence of gas in the sediments in this area, it is not known with certainty whether the measured excess pressure is pore water pressure, pore gas pressure, or some combination of the two. An excess pore pressure of about 32 ±4 kPa was monitored during Hurricane Eloise and subsequent storms. The exact magnitude and time distribution of these pressure fluctuations is presently being evaluated.     

利用核酸适配体的竞争置换作用检测溶藻弧菌(Vibrio alginolyticus)

溶藻弧菌(Vibrio alginolyticus)是水产养殖中致病性较强的一种条件致病菌,为更灵敏、高效地对其进行检测,研发出一种基于核酸适配体竞争置换作用的检测方法。首先设计并制备出磁珠-核酸适配体-荧光报告探针的检测复合物(MAP检测复合物),然后利用溶藻弧菌与其核酸适配体有较好的亲和特异性,在对样品进行检测时,样品中的溶藻弧菌就会竞争MAP检测复合物中的核酸适配体,从而置换出与该核酸适配体结合的荧光报告探针,再通过检测置换出的报告探针的荧光强度来表征溶藻弧菌的浓度,从而实现对溶藻弧菌的定量检测。结果表明,该方法对溶藻弧菌的检测限可达到1CFU/mL,与嗜水气单胞菌(Aeromonas hydrophila)、迟钝爱德华氏菌(Edwardsiella tarda)、哈维氏弧菌(Vibrio harveyi)、大肠杆菌(Escherichia coli)等水产养殖中的常见致病微生物没有交叉反应,并在1~20、20~100和100~1000 CFU/mL范围内都表现出较好的线性关系。另外还对MAP检测复合物的制备条件进行了优化,较为理想的制备条件为:100nmol/L核酸适配体与100nmol/L荧光报告探针按体积比1︰1混合结合30 min,制备出50 nmol/L的核酸适配体-荧光报告探针复合物,然后该复合物再与25μg/mL的磁珠按体积比1︰1混合结合60 min,制备出相应的MAP检测复合物。利用核酸适配体的竞争置换作用检测溶藻弧菌有较好的灵敏度和特异性,展现了较好的应用前景。     

压力传感器的自动标定技术

针对压力测量设备生产和维护过程中,对关键部件压力传感器标定处于手工操作状态、效率低、操作人员不易掌控、标定结果处置复杂的现状,开发了针对压力传感器的自动标定技术。该技术将计算机控制、智能化、曲线拟合和误差分析引入到压力传感器的标定过程中,大幅度提高了标定的效率和可靠性。经此技术标定过的压力探头,在使用中具有互换性,减轻了数据后处理工作的难度。     

On the recovery of surface wave by pressure transfer function

Except the commonly selected pressure transfer function derived from the linear wave theory, a previous study on the pressure transfer function for recovering surface wave from underwater pressure transducer suggested that the pressure transfer function is a function of frequency parameter only. With careful analysis, this study showed that the pressure transfer function should include a transducer submergence parameter as that given by the linear theory. It was found that the previously suggested empirical formula should be restricted to measurements with the pressure transducer close to the surface; otherwise overestimation of wave height would result. Field measurements were carried out with an acoustic wave gauge and a synchronized pressure transducer located at various depths with submergence parameter close to 1 (near the sea floor). It was shown that the previous one-parameter empirical formula might overestimate the significant wave height by more than 30%. This study found that with deep-water wave bursts excluded, the transfer function based on the linear wave theory provided a fairly good estimation on the significant wave heights, with an average deviation of 3.6%.     

A Robust Rapid-Response Probe for Measuring Bottom-Hole Temperatures in Deep-Ocean Boreholes

A new probe has been constructed for making temperature measurements 1.1 m ahead of the bit in Ocean Drilling Program (ODP) boreholes. Temperatures are recorded at positions 1 and 11 cm above the tip of the probe. The combination of the dual temperature records and accelerometer data provides valuable information about disturbances that may affect the quality of measurements. Long battery life, and memory access via an external communications port, allow service-free operation for the full duration of typical drilling legs. Temperature resolution varies over the 110 K measurement range, from nominally 1 mK from -5 to 20 °C, to about 10 mK at 105 °C. The small (8 mm) diameter of the probe tip allows rapid thermal equilibration after penetration. The shallow (2.5°), continuous taper of the lower part of the probe serves to reduce the tendency of the formation to be cracked when the tool is pushed into the formation. It is sufficiently robust, however, to survive penetration into highly consolidated sediment and occasional contact with igneous rock. The tool was used for a total of 44 bottom-hole temperature measurements between 38 and 573 meters below seafloor (mbsf) during Leg 168, as well as for several logging runs in open holes. We anticipate adding a port in the tip to permit measurement of formation fluid pressure, and to enhance the utility of the tool for logging temperature profiles in open holes.     

波浪作用下粉质土海床液化界面波压力的研究

波浪作用下粉质土海床的液化是影响海上平台、海底管线等海洋构筑物安全的灾害之一。在进行构筑物设计中应考虑海床液化的深度问题,而液化土体对下部海床的界面波压力是计算海床孔隙水压力增长以及液化深度的重要参量。本文基于波致粉土海床自上而下的渐进液化模式,利用双层流体波动理论,推导了考虑海床土体黏性的海床界面波压力表达式,并与不考虑黏性时的界面波压力进行了比较分析。结果表明,计算液化后土体界面波压力时,是否考虑液化土体的黏性对结果影响较大,进而可能影响粉质土海床液化深度的确定。     

MDT测试资料确定气水界面的方法研究

通过对MDT测压资料的分析,发现了造成测试点压力值存在误差的主要原因有两个方面：一方面是由于部分测压点储层物性差,测试探针抽吸地层流体后储层压力恢复需要的时间较长,然而由于实际原因测试压力恢复无法等待足够的测试时间;另一方面是由于部分物性较差储层较难形成好的泥饼,以至于受到比较严重的泥浆侵入使得测试点产生超压现象,测试得到的地层压力和实际压力相比偏大.同时分析发现物性较好的储层往往能够得到相对可靠的测试压力.合理的气水界面对于计算探明地质储量有着很重要的意义,尤其是高温高压气田,气水过渡带往往较大,可能会达到30m左右,这种情况下无法仅从钻遇情况分析气水界面,此时可以结合MDT测压资料分析气水界面,从而确定合理的地质储量.通过分析实际MDT测压资料,对不同测压点进行了误差分析并在此基础上提出了压力数据点的筛选原则.通过实际检验认为新的回归方法确定出的气水界面科学合理.     

A digitally recording probe for heat-flow measurements in lakes and oceans

Some technical problems commonly encountered in marine heat-flow measurements have been overcome with a digitally recording seabottom probe containing in its pressure case no moving parts except a stepper relay. The probe stores digitally at regular time intervals the resistances of 11 thermistors in a 240-word CMOS memory. After return to the surface, it is connected to a digital printer to read out the measured data. The probe can be reused immediately since it need not be opened or recharged.