自主式深海海底溶质通量原位观测站研究进展

针对深入了解深海海底界面的物理、化学和生物动态变化过程及机制的观测需求,综述了自主式海底观测站(着陆器,lander)在深海海底溶质通量监测的研究进展。探讨了海底观测站的设计与实施技术,分析总结了深海自主式原位观测站在沉积物-水界面化学组分通量的观测机理,讨论了自主式海底观测站的国内外发展现状。自主式海底观测站具有可灵活机动选择观测地点、操作简单、便于多参数综合测量的特点,为获取深海海底长时空尺度综合参数资料提供了有效的技术支撑。根据目前深海生物地球化学循环研究特点,提出了自主式海底观测站面临的问题与发展建议。     

Precise positioning for near-bottom equipment using a relay transponder

The Marine Physical Laboratory of the Scripps Institution of Oceanography has developed an acoustic relay transponder for precise relative positioning of near-bottom instruments and geologic sampling devices. Although specifically designed to position equipment lowered on standard wire ropes without a need to maintain direct electrical contact with the surface ship, the relay transponder may be used to track free vehicles, such as deep submersibles, from the surface. The relay transponder is positioned relative to an array of bottom-anchored acoustic transponders. It is interrogated acoustically from the surface ship; it then sequentially interrogates the bottom transponders which, in turn, reply to the ship. From the measurement of the total travel time (ship to relay transponder to bottom transponder to ship) and assuming, or knowing, the sound velocity of the water, we obtain a relayed range measurement. These relayed ranges, used in conjunction with ship to bottom-transponder ranges, allow us to calculate the position of the relay transponder. A recent application of this technique is described in which several gravity core samples from the crest of the Horizon Guyot were positioned with respect to the detailed bathymetry and the geology within the area. The estimated error in positioning the samples is less than 20 m inside a navigational net extending over 100 km².Contribution of the Scripps Institution of Oceanography, new series.     

A current meter with intelligent data system, environmentalsensors, and data telemetry

To measure oceanographic parameters such as currents, temperature, conductivity, pressure, and suspended sediment concentrations, two film-recording current meters were upgraded with microprocessor-controlled data recorders and additional sensors. Two telemetry links relay data and allow the in situ operation of the remote instrument to be checked. In one configuration, the bottom-mounted current meter communicated by a 35-m-long wire to a small surface spar buoy, and then by a packet radio link to a nearby ship. In another development, the current meter relays data to a controller and buoyant data capsule on the bottom instrument package. The controller collects and processes the data from the current meter and periodically transfers these processed data to a data capsule and releases it. When released, the capsule rises to the surface and transmits its data to shore via the ARGOS satellite, while acting as a satellite tracked drifter     

Robust control for underwater vehicle systems with time delays

A robust control scheme is presented for controlling systems with time delays. The scheme is based on the Smith controller and the LQG/LTR (linear quadratic Gaussian/loop transfer recovery) methodology. The methodology is applicable to underwater vehicle systems that exhibit time delays, including tethered vehicles that are positioned through the movements of a surface ship and autonomous vehicles that are controlled through an acoustic link. An example, using full-scale data from the tethered vehicle ARGO, demonstrates the developments     

An inverse hull design approach in minimizing the ship wave

The Levenberg–Marquardt Method (LMM) and a panel code for solving the wave-making problem are utilized in an inverse hull design problem for minimizing the wave of ships. A typical catamaran is selected as the example ship for the present study. The hull form of the catamaran is described by the B-spline surface method so that the shape of the hull can be completely specified using only a small number of parameters (i.e. control points). The technique of parameter estimation for the inverse design problem is thus chosen. The LMM of parameter estimation, which is the combination of steepest descent and Newton’s methods, has been proven to be a powerful tool for the inverse shape design problem. For this reason it is adopted in the present study.In the present studies, the inverse hull design method can not only be applied to estimate the hull form based on the known wave data of the target ship but can also be applied to estimate the unknown hull form based on the reduced wave height. The optimal hull forms of minimizing wave for a typical catamaran in deep water at service speed and at the critical speed of shallow water are estimated, respectively. Moreover, a new hull form with the combining feature of the optimal hull forms for deep water and shallow water is performing well under both conditions. The numerical simulation indicates that the hull form designed by inverse hull design method can reduce the ship wave significantly in comparison with the original hull form.     

大深度近海底精细地形地貌探测技术

船载低频多波束测深声纳、侧扫声纳可以对深海海底地形地貌进行快速、高效、大面积探测,但其测量精度有限,难以满足深海科学考察、资源勘探开发对高精度海底地形地貌的需求。随着各类大深度水下移动载体(如深海拖体、水下机器人、遥控潜器和载人潜水器)的涌现,特别是各类耐高压测绘声纳的商业化,使大深度近海底精细地形地貌探测成为可能。首先分析了多波束测深声纳、侧扫声纳和测深侧扫声纳等3种测绘声纳的基本原理,然后分别介绍了各类测绘声纳的国内外典型商业化产品,并通过典型实例分析了其在大深度近海底精细测绘中的应用情况。     

深渊生物资源取样装备技术体系研究

针对深渊生物资源研究的需求，自主研发了用于全海深深度的深渊沉积物、水体和宏生物的保压取样装置，深渊沉积物保压转移装置，深渊微生物原位过滤及保存装置和高压培养高压酶学测定装置。在深海模拟环境验证了取样装置在万米深度下的工作性能。相关装置在“探索一号”科考船的TS15、TS21-1和TS21-2大洋科考航次中，搭载“奋斗者”号载人潜器、“2号”深渊着陆器、“原位实验”号着陆器于西菲律宾盆区和马里亚纳海沟进行了海上试验，成功获取了万米深度沉积物、水体和宏生物保压样品以及微生物原位过滤滤膜；成功进行了沉积物保压样品的保压转移试验。初步形成了深渊海域生物资源取样的装备技术体系，为深渊海底生物和基因资源开发，深渊生命过程等科学研究提供技术手段。     

基于弧段检测的高频地波雷达特定目标航迹跟踪方法研究

本文对现有的高频地波雷达目标跟踪方法进行了概述,提出了一种地波雷达目标长时连续跟踪的方法,基本思想是:充分挖掘航迹弧段特征,基于特征对船只运动建模,并结合杂波背景进行融合决策。进一步,为了达到长时间连续跟踪的需求,借鉴深度学习的思想,利用新获取的弧段数据对算法估计结果不断递归校正,使得随着获取数据的增加跟踪越准确。该方法适用于杂波环境且在航道附近存在众多干扰船只的情况下对机动目标航迹的实时稳定跟踪,为高频地波雷达在复杂干扰环境下特定目标持续跟踪提供理论基础和方法指导,为充分发挥地波雷达在海上监视监测中的作用提供技术支撑。     

不同方式地磁观测数据对磁测精度的影响分析

地磁日变改正数据的合理选取直接关系到海洋磁测的成果精度。通过在南海南部海域布放的一个4 000m长的地磁观测潜标及同步开展的磁力测量,并在收集周边陆域地磁台站数据的基础上,对水体中获得的地磁日变观测数据和水面磁测数据进行综合分析和研究,得到几点认识:(1)浅水海域获得的日变观测数据用于海洋磁测数据处理时,其测量准确度比深水海域的好,且与陆域地磁台站数据曲线的一致性要高;(2)船磁校正曲线是否对称与地磁日变观测数据的合理选取密切相关;(3)在远海区磁测时,为确保详尽记录局部磁扰,建议海底地磁日变观测站应布放于靠近工区、水深较浅的水体之中。     

A high-resolution seismic profiling system using a deep-towed horizontal hydrophone streamer

A seismic reflection profiling system utilising a surface air gun source and a deep-towed horizontal hydrophone streamer has been developed for high resolution studies in the deep ocean. The instrument is deployed on a conventional armoured single conductor cable at depths of up to 6 km. Seismic data from the 30 m long streamer is wide-band frequency modulated up the towing cable to the ship together with a high frequency monitor from a 3.5 kHz echo-sounder mounted on the instrument package. The geometry of the system allows an order of magnitude improvement in spatial resolution compared with that obtained from standard surface source/receiver configurations. The summed hydrophones of the streamer attenuate cable-generated mechanical noise, and the 3.5 kHz sea-surface and bottom reflected returns provide receiver positioning information. The system has been successfully deployed at depths of 5 km in the Vema Fracture Zone in the North Atlantic, and although initially difficulties were experienced in balancing the streamer, subsequent profiles across the transform fault show details of sub-bottom structure which on conventional surface records are generally masked by diffraction hyperbolae.     

Nonlinear optimization method of ship floating condition calculation in wave based on vector

Ship floating condition in regular waves is calculated. New equations controlling any ship＇s floating condition are proposed by use of the vector operation. This form is a nonlinear optimization problem which can be solved using the penalty function method with constant coefficients. And the solving process is accelerated by dichotomy. During the solving process, the ship＇s displacement and buoyant centre have been calculated by the integration of the ship surface according to the waterline. The ship surface is described using an accumulative chord length theory in order to determine the displacement, the buoyancy center and the waterline. The draught forming the waterline at each station can be found out by calculating the intersection of the ship surface and the wave surface. The results of an example indicate that this method is exact and efficient. It can calculate the ship floating condition in regular waves as well as simplify the calculation and improve the computational efficiency and the precision of results.     

Fast computation of the transient motions of moving vessels in irregular ocean waves

A fast time-domain method is developed in this paper for the real-time prediction of the six degree of freedom motions of a vessel traveling in an irregular seaway in infinitely deep water. The fully coupled unsteady ship motion problem is solved by time-stepping the linearized boundary conditions on both the free surface and body surface. A velocity-based boundary integral method is then used to solve the Laplace equation at every time step for the fluid kinematics, while a scalar integral equation is solved for the total fluid pressure. The boundary integral equations are applied to both the physical fluid domain outside the body and a fictitious fluid region inside the body, enabling use of the fast Fourier transform method to evaluate the free surface integrals. The computational efficiency of the scheme is further improved through use of the method of images to eliminate source singularities on the free surface while retaining vortex/dipole singularities that decay more rapidly in space. The resulting numerical algorithm runs 2–3 times faster than real time on a standard desktop computer. Numerical predictions are compared to prior published results for the transient motions of a hemisphere and laboratory measurements of the motions of a free running vessel in oblique waves with good agreement.     

Computer aided piloting of a deeply towed vehicle

An instrumented vehicle is towed at the end of a 5 km long cable, gathering data about the deep sea floor and near-bottom water column. Although bottom-moored acoustic transponders are used to determine the vehicle and ship positions precisely and in real time, predicting the ship manoeuvers required to bring the vehicle over an area of interest on the sea floor is far from trivial for the ship driver. Computer software has been developed which recommends courses for the ship to steer so that the vehicle will pass near a desired target. In trials at sea, the computer steered the vehicle 80, 40 and 85 m from pre-selected targets. Analysis of the causes of the misses suggests future developments which may reduce the miss distance, provide information on current structure of the water column, and reduce the level of skill and attention required of the vehicle pilot.     

Current observation system using ship drift and its applications in Kumano-nada and Enshu-nada Seas

A continuous observation system of ship drift of ferry boats was developed using Loran C, ship direction, ship speed and wind velocity measurement. A formula to estimate the wind-driven lateral drift of the boat is proposed, and a measuring system of the surface current is described, including a discussions on its usefullness to monitor day-to-day variations of the circulation patterns in the coastal boundary regions of the Kuroshio.This system was applied to observe variations of the circulation in the Kumano-nada, and Enshu-nada Seas south of Japan. Some preliminary results were obtained by using this system as well as other methods. This work focuses on the behavior of warm eddies in the Kumano-nada Sea. The surface current patterns that include these phenomena obtained by the use of the ship drift show good correspondence with currents and thermal structures observed with GEK, CTD, moored current meters and satellite thermal images.     

A synthetic aperture radar sea surface distribution estimation by n-order Bézier curve and its application in ship detection

To dates,most ship detection approaches for single-pol synthetic aperture radar(SAR) imagery try to ensure a constant false-alarm rate(CFAR).A high performance ship detector relies on two key components:an accurate estimation to a sea surface distribution and a fine designed CFAR algorithm.First,a novel nonparametric sea surface distribution estimation method is developed based on n-order Bézier curve.To estimate the sea surface distribution using n-order Bézier curve,an explicit analytical solution is derived based on a least square optimization,and the optimal selection also is presented to two essential parameters,the order n of Bézier curve and the number m of sample points.Next,to validate the ship detection performance of the estimated sea surface distribution,the estimated sea surface distribution by n-order Bézier curve is combined with a cell averaging CFAR(CA-CFAR).To eliminate the possible interfering ship targets in background window,an improved automatic censoring method is applied.Comprehensive experiments prove that in terms of sea surface estimation performance,the proposed method is as good as a traditional nonparametric Parzen window kernel method,and in most cases,outperforms two widely used parametric methods,K and G0 models.In terms of computation speed,a major advantage of the proposed estimation method is the time consuming only depended on the number m of sample points while independent of imagery size,which makes it can achieve a significant speed improvement to the Parzen window kernel method,and in some cases,it is even faster than two parametric methods.In terms of ship detection performance,the experiments show that the ship detector which constructed by the proposed sea surface distribution model and the given CA-CFAR algorithm has wide adaptability to different SAR sensors,resolutions and sea surface homogeneities and obtains a leading performance on the test dataset.     

浅谈海洋钻修井装置作业前检验存在的问题及对策

海洋钻修井装置作业前检验,是海上钻修井作业过程中的重要环节。做好作业前检验工作,使作业装置满足作业和安全的要求,是后续作业顺利、安全、高效进行的重要保障。文章根据南海西部近5年来海洋钻修井装置作业前检验工作的现状,从管理、技术层面对作业前检验存在的问题进行剖析,并给出了相关建议。如：作业前检验全生命周期管理的流程及强化措施;保持验船人员的公用机制;引进、培养一支固定的验船队伍;制定验船标准化手册;增加验船技术手段等。为进一步提高海洋钻修井装置检验质量及海上钻修井作业保驾护航。     

Lethality of increasing CO2 levels on deep-sea copepods in the western North Pacific

The first CO₂ exposure experiments on several species of pelagic copepods inhabiting surface and deep layers in the western North Pacific were conducted. Living organisms were collected from two layers between the surface and 1,500 m between latitudes of 11 and 44°N, and they were exposed aboard ship to various pCO₂ up to about 98,000 μatm. Mortality of copepods from both shallow and deep layers in subarctic to subtropical regions increased with increasing pCO₂ and exposure time. Deep-living copepods showed higher tolerance to pCO₂ than shallow-living copepods. Furthermore, deep-living copepods from subarctic and transitional regions had higher tolerances than the subtropical copepods. The higher tolerances of the deep-living copepods from subarctic and transitional regions may be due to the adaptation to the natural pCO₂ conditions in the subarctic ocean.     

Do abyssal scavengers use phytodetritus as a food resource? Video and biochemical evidence from the Atlantic and Mediterranean

Deep-sea benthic communities derive their energetic requirements from overlying surface water production, which is deposited at the seafloor as phytodetritus. Benthic invertebrates are the primary consumers of this food source, with deep-sea fish at the top of the trophic hierarchy. Recently, we demonstrated with the use of baited cameras that macrourid fish rapidly respond to and feed vigorously on large plant food falls mimicked by spinach (Jeffreys et al., 2010). Since higher plant remains are scarce in the deep-sea, with the exception of canyons, where terrestrial material has been observed, these results led us to ask if a more commonly documented plant material i.e. phytodetritus might form a food source for deep-sea fish and mobile scavenging megafauna. We simulated a phytodetritus dump at the seafloor in two contrasting environments (1) the NE Atlantic where carpets of phytodetritus have been previously observed and (2) the oligotrophic western Mediterranean, where the deposition of phytodetritus at the seafloor is a rare occurrence. We recorded the response of the scavenging fauna using an in situ benthic lander equipped with baited time-lapse cameras. In the NE Atlantic at 3000 m, abyssal macrourids and cusk-eels were observed ingesting the phytodetritus. The phytodetrital patch was significantly diminished within 2 h. Abundance estimates calculated from first arrival times of macrourids at the phytodetrital patch in the Atlantic corresponded with abundance estimates from video-transect indicating that fish were attracted to the scent of phytodetrital bait. In contrast to this, in the western Mediterranean at 2800 m a single macrourid was observed investigating the phytodetrital patch but did not feed from it. The phytodetrital patch was significantly diminished within 6.5 h as a result of mainly invertebrate activity. At 1900 m, Lepidion lepidion was observed near the lander and the bait, but did not feed. The phytodetrital patch remained intact until the end of the experiment. In the deployments in the Mediterranean abundance estimates from first arrival times at the bait, corrected for their body size, were lower than estimates obtained from video-transects and trawl catches. This suggests that the Mediterranean fish were not readily attracted to this food source. In contrast, invertebrates in the Balearic Sea were observed ingesting the phytodetritus bait despite the rare occurrence of phytodetritus dumps in the Mediterranean. Stable isotope values of the fish at both study sites, set within the context of the benthic food web, did not demonstrate a strong trophic link to phytodetritus. Fatty acid profiles of these fish indicated a strong link between their lipid pool and primary producers i.e. phytoplankton, which may be attributed to trophic transfer. The usefulness of fatty acid biomarkers in ascertaining deep-sea fish diets is discussed. Our study suggests that the abyssal grenadier C. armatus on the Atlantic Iberian margin is attracted to phytodetritus. However the exact contribution of this food source to the diet of macrourids in this area remains unresolved.     

基于视觉显著性的高分辨率遥感影像舰船检测

通过研究、分析现有基于遥感影像的舰船检测算法,提出了基于Itti视觉显著度模型改进的高分辨率遥感影像海面舰船检测方法,该方法利用海面舰船相对于海面背景信息视觉关注高的特点,参考视觉显著度模型计算原理,对高分辨率遥感影像中的颜色、亮度、方向、纹理等特征进行有效提取,然后利用归一化方法将不同特征融合,形成有利于舰船目标提取得视觉显著度图,最后对生成的视觉显著度图进行阈值分割和精细化处理获得最终的舰船检测结果。与传统舰船检测算法相比,本文算法能够有效检测复杂海面背景下的舰船目标,减少了单一特征变化对检测精度的影响,提高了检测准确率,具有较好的抗噪性和较强的鲁棒性。