新型船载气象卫星接收系统

新型船载气象卫星接收系统为南极考察船的航海气象保障和在南大洋冰区中航行导航专门研制.该系统能够适应高温、高湿和低温超饱和的气候环境,在12级以上大风和船在破冰时剧烈摇摆和振动以及有雷达等强磁场信号干扰的情况下,具有自我保护能力.有极轨高分辨和静止低分辨卫星的双套接收和图像处理系统.该系统的关键创新之处:(1)采用了有源陀螺仪稳定平台.利用惯性测量和三轴伺服机构控制天线和隔离船摇.解决极轨卫星低仰角和过顶轨道高仰角跟踪丢线的矛盾,解决了船在运动状态下,不断改变位置、方向以及摇摆的状态下,准确地跟踪和捕捉到卫星,接收到清晰的卫星云图.(2)图像处理系统用了最新的BORLAND-DELPHI语言编程,采用两行元素的轨道模式计算动态定位套网格系统.利用电子地图网格数据,用迭代法画出地形海岸线.计算出每一像元素的位置;能够在图上显示任意一点的经纬度,标出任意目标物.解决了在海洋中航行找不到参照物时的困惑.能够监测云和温度、林火、海洋及陆地的异常变化.能够输出24位真彩色的高清晰度的卫星云图.该系统整体结构技术先进,体积小,重量轻,适应恶劣气候和海洋环境,图像处理系统功能齐全、分辨率高,操作方便.既适用于各种船只,也适用于陆地.     

基于漂流浮标的南大洋卫星高度计有效波高研究

随着技术的进步和数据处理方法的完善,经过修正的卫星高度计数据已获得普遍认可.但在南大洋缺少波浪现场数据,卫星高度计在极端恶劣气候条件下获得数据的准确度仍受到一定程度的质疑.中国于2020年第36次南极考察中,在南大洋布放了一套感应耦合漂流浮标,可提供可靠的南大洋现场波浪数据.本文利用该漂流浮标2020年1月27日至9月...     

基于浮标数据的卫星雷达高度计海浪波高数据评价与校正

卫星雷达高度计是海浪有效波高（significant wave height,SWH）观测的重要手段之一,本文利用时空匹配方法对T/P、Jason-1、Envisat、Jason-2、Cryosat-2和HY-2A共6颗卫星雷达高度计SWH数据与NDBC（National Data Buoy Center,NDBC）浮标SWH数据进行对比验证,并对雷达高度计SWH数据进行校正。全部卫星雷达高度计SWH数据时间跨度为1992年9月25日到2015年9月1日,对比验证NDBC浮标共53个,包括7个大洋浮标。精度评价发现除T/P外,各卫星雷达高度计SWH的RMSE都在0.4~0.5 m之间,经过校正后,RMSE都有显著下降,下降程度最大为13.82%;对于大洋浮标,评价结果RMSE在0.20~0.28 m之间,结果明显优于全部NDBC浮标的精度评价结果;HY-2A卫星雷达高度计SWH在经过校正后数据质量与国外其他5颗卫星雷达高度计SWH数据质量差异较小。     

基于Linux的气象水文浮标采集系统设计及实现

为了获取海洋连续稳定的气象和水文数据,作者设计了基于Linux的气象水文浮标采集系统,多线程同时测量海面的气象参数(温度、湿度、气压和风速、风向)和海下的水文参数(不同深度的水温和盐度),监控浮标的电压、漏水和开舱状态,测量和监控原始数据自动备份到系统的数据库,通过CDMA/GPRS或卫星与岸站接收系统通信,实现采集数...     

利用FY-4A气象卫星观测海洋内波

随着遥感技术的迅猛发展,可用于观测海洋内波的数据源越来越丰富.本文基于静止轨道气象卫星连续观测的优势,开展了FY-4A气象卫星海洋内波观测研究.首先计算得到了FY-4A遥感影像耀斑区位置,并基于遥感影像对结果进行了验证;然后,以此为依据选择了适用于内波观测的FY-4A数据,对比了FY-4A与MODIS遥感影像成像的差异...     

Comparison of Kuroshio surface velocities derived from satellite altimeter and drifting buoy data

Sea-surface geostrophic velocities for the Kuroshio region calculated from TOPEX/POSEIDON altimetry data together within situ oceanographic data are compared with surface velocities derived from drifting buoy trajectories. The geostrophic velocities agree well with the observed velocities, suggesting that the Kuroshio surface layer is essentially in geostrophic balance, within measurement error. The comparison is improved a little when the centrifugal acceleration is taken into account. The observed velocities are divided into the temporal mean and fluctuation components, and the partitioning of velocities between these two components is examined. For the Kuroshio region, most of the fluctuation components of the velocities derived from drifting buoys are found to be positive. This result suggests that Eulerian mean velocities for the Kuroshio region estimated from drifting buoy data tend to be larger than actual means, due to the buoy’s tendency to sample preferentially in the high-velocity Kuroshio.     

A submarine-launched wave measuring buoy

A wave buoy, the Submarine Deployed Sea State Sensor (SUDSS), was developed to directly measure surface waves from a submerged moving submarine. The SUDSS is adapted from the Submarine Launched Expendable Bathythermograph (SSXBT) by replacing its temperature probe with a vertical sensing accelerometer. The SUDSS, launched from the aft signal ejector, utilizes the SSXBT cylinder, its lifting body, and filament wire spool-out mechanisms. Upon surfacing it oscillates vertically in phase with waves of frequencies below 0.5 Hz producing a voltage signal that is conducted via the filament wire back to the submarine and processed to produce a 10–12 minute wave record. On-board data analysis determines spectra, sea state, and the partial variance of spectral energy which between 0.2–0.5 Hz estimates the local wind speed.An accelerometer calibrator for wave frequencies was assembled consisting of a computer-controlled motor-driven swing arm which rotates an accelerometer as a simple harmonic oscillator; different rotation rates providing a variety of frequencies. Absolute accelerations are determined from the arm radius and its angular velocity. Wilcoxen accelerometers were chosen, providing a linear output of 1 v/g₀ (sensitivity) for simulated waves from 0.09–0.25 Hz (4–11 s periods).The SUDSS fitted with a buoyant tether signal cable, can be deployed from a surface ship for rapid wave/sea state measurements.     

A discus-hulled wave measuring buoy

Described herein is a self-contained, discus-hulled buoy 1.5 m dia., weighing 150 kg, which uses inertial instruments to measure wave height and tilt. Wave tank calibration and the theory of shallow draft buoys demonstrate such a hull accurately follows waves with length greater than twice the buoy diameter. The non-linear response of the buoy determines its sensitivity to low-frequency waves in a sea. And the ratio of wave signal to instrument “noise” is constant over the energetic part of the ocean-wave spectrum for measurements of wave acceleration and slope.     

WindSat近海岸风场与美国沿岸浮标对比分析

利用美国近海岸2004-2014年的固定浮标数据,本文对比分析了WindSat的近海岸风速产品。匹配时空窗口分别为30分钟和25公里。对比分析结果表明：WindSat反演的美国近海岸风速产品的均方根误差优于1.44 m/s,并且东海岸风速反演结果优于西海岸。WindSat下降轨道的风速反演结果优于上升轨道的结果。通过浮标相互间的对比分析发现,WindSat近海岸的风速反演结果与近岸海水深度、经度及距岸距离等因素并无明显的相关性。此外,利用2007-2008年的固定浮标数据,本文还对比分析了WindSat和QuikSCAT的近海岸风速反演结果,结果表明：相对于浮标数据,WindSat的风速反演值偏低,而QuikSCAT的风速反演值偏高;总体上来看,WindSat的近岸风速反演结果略优于QuikSCAT的近海岸风速反演结果。以上风速反演的精度均达到了传感器设定的指标,其为进一步的科学研究提供了良好的数据支撑。     

基于DINEOF的风云极轨气象卫星海表温度重构方法研究

海表温度是表征海洋表层热力状况的重要海洋参数,日均全天候覆盖的海温观测数据可为服务台风监测及其他海洋灾害时空演变的精细化预报提供数据支撑。可见光红外扫描辐射计和中分辨率光谱成像仪反演的海温产品具有较高的空间分辨率,但是红外遥感反演的海温产品受到云、雾和霾的影响,在云下存在大面积、无规律的缺值;微波辐射计反演的海温产品空间分辨率低,但可穿透云层,实现全天候海温观测。本文基于风云三号B、C、D三颗极轨气象卫星红外和微波遥感仪器反演的海温资料,利用经验正交函数插值法(DINEOF)重构得到全球海表温度产品。与全球分析场日平均海温OISST数据进行比较可知：原始海温资料的均方根误差为0.59~0.70℃,DINEOF重构后海温资料均方根误差降至0.10~0.34℃;相关系数从0.33~0.48提升到0.78~0.98。多传感器重构海温数据空间分布上连续可信,能够监测不同季节的海温变化特征及暖池空间模态。风云三号气象卫星微波遥感的加入显著提升了重构海温的空间连续覆盖率和时间分辨率。     

A study of spar buoy floating breakwater

A floating breakwater produces less environmental impact, but is easily destroyed by large waves. In this paper, the spar buoy floating breakwater is introduced with a study on the wave reflection and transmission characteristics and mooring line tension induced by the waves. Mei (The Applied Dynamics of Ocean Surface Waves, Wiley, New York (1983) 740 p) proposed a theoretical solution for the reflection and transmission coefficients as the wave propagates through a one-layer slotted barrier. For a multiple-layer fence system, the analytical solution is proposed linearly. The results show that the theoretical computations agree well with the experimental trends. For a multiple-layer fence system, the transmission coefficients become maximal as the layer spacing to wavelength ratio moves to 1/2. Conversely, the coefficients become minimal, as the ratio moves to 0.3. To estimate the maximum tension of the mooring line, both numerical calculations and laboratory experiments were executed. The numerical calculation results were similar to the experimental results.     

Comparing satellite and meteorological data on wind velocity over the Black Sea

Wind-velocity data obtained from in situ measurements at the Golitsyno-4 marine stationary platform have been compared with QuikSCAT scatterometer data; NCEP, MERRA, and ERA-Interim global reanalyses and MM5 regional atmospheric reanalysis. In order to adjust wind velocity measured at a height of 37 m above the sea surface to a standard height of 10 m with stratification taken into account, the Monin–Obukhov theory and regional atmospheric reanalysis data are used. Data obtained with the QuikSCAT scatterometer most adequately describe the real variability of wind over the Black Sea. Errors in reanalysis data are not high either: the regression coefficient varies from 0.98 to 1.06, the rms deviation of the velocity amplitude varies from 1.90 to 2.24 m/s, and the rms deviation of the direction angle varies from 26° to 36°. Errors in determining the velocity and direction of wind depend on its amplitude: under weak winds (<3 m/s), the velocity of wind is overestimated and errors significantly increase in determining its direction; under strong winds (>12 m/s), its velocity is underestimated. The influence of these errors on both spatial and temporal estimates of the characteristics of wind over the Black Sea is briefly considered.     

Question of the pitch-roll buoy response to ocean waves as a simple harmonic oscillator?

The assumption that the East and North deck slopes of a pitch–roll buoy respond to East and North sea slopes as simple harmonic oscillators is routinely made by the National Data Buoy Center (NDBC) and others producing directional wave data. Although directional wave data derived with this assumption usually appear to be of good quality, the validity of the assumption has not previously been more directly demonstrated. In this paper, a method is proposed to judge the validity of the assumption for any set of time series records of buoy angular motion. The proposed method is applied to 200 record sets taken by an NDBC buoy located at ocean station 46024, and to five record sets taken by another NDBC buoy at 46051. For the 46024 data, it was demonstrated that the simple harmonic oscillator assumption was near perfectly valid. For the smaller 46051 data set, the simple harmonic oscillator assumption was shown to be slightly less valid.     

一种简易的潜标辅助寻标定位系统

介绍一种自主研发的、结合GPS定位和水声测距于一体的潜标自动搜寻定位系统。系统由安装于搜索船只上的全球定位系统GPS接收机、水声释放器甲板单元、综合信号接收处理单元(由计算机组成),以及集成于潜标系统水声释放器上的水声应答系统组成。利用GPS定位原理,将GPS测得的定位信息,与水声测距技术相结合,实现潜标系统的空间定位,为潜标系统的可靠回收提供技术保障。     

A modified linear analysis of a wave-energy conversion buoy

The analysis of a pneumatic-type wave-energy conversion buoy is developed assuming independence of the buoy heaving motion and the motion of the water column within the center pipe. Results of the analysis are then compared with experimental data in a study of the relative air velocity within the turbine passage. The results compare very well. The effect of the variation of the center pipe length is found to be significant for periods about the surge chamber resonance but is negligible in the neighborhood of the heaving resonance period. Further, the theory is applied to a prototype buoy study of the U.S. Coast Guard, and a dimensionless design curve is developed from the results of the prototype analysis.     

A simple waterline approach for tidelands using multi-temporal satellite images: A case study in the Yangtze Delta

Waterline technique based on satellite remote sensing is potentially one of the most effective tools for studying changes in tidal flat environment and coastlines. However, multi-temporal waterlines obtained from satellite images are often difficult to compare directly because fluctuant tidal conditions may produce different elevation of waterlines. To overcome the difficulty, this study developed a comparable waterline solution to estimate active lateral evolutions using TM satellite images at different tide conditions. Owing to the dynamic properties, the Yangtze River mouth was selected as the case example to test the suitability of the approach, and totally four time slices were partitioned during 1987–2004 for investigating coastline changes. The first step of this technique is to digitize waterlines with various elevations labeling in a time slice. In the second step, the waterlines were merged to generate DEMs and contour maps using the linear gridding interpolation method. In the last step, any interested contour line may be extracted from DEMs and used for comparison of tideland changes. To evaluate the errors in digitizing and interpolation process, quantitative checks were examined after the DEMs were constructed. In order to monitoring the rate of coastline spread, a proposed approach for estimating mean coastline spread distance between two time spans is developed in this paper. To conclude, this work demonstrates the importance of TM/ETM images to provide high-frequency historical topography and morphodynamics information for coastal monitoring and evaluation.     

A microprocessor-based acoustic telemetry system for tide measurement

This paper describes the ocean bottom unit and surface ship deck unit of a multi-microprocessor-based underwater acoustic telemetry system designed primarily to address the application of tidal data gathering during the course of a hydrographic survey. The problems of tidal data collection are highlighted and the objectives of the acoustic telemetry system are stated. A shallow-water environmental model is used to obtain accurate estimates of parameters such as propagation loss, band-level noise, frequency dispersion, and time dispersion. The environmental model in conjunction with in situ measurements dictates the guidelines used in the system design. A breakdown of the units into subsystems is given and each subsystem is described. The results of tests performed with the system on June 12 and 13, 1982, in the Bedford Basin, Dartmouth, Nova Scotia, are summarized. Finally, other potential applications of the system are mentioned.     

一种用于海洋综合观测浮标的多种通信方式集成系统

为了优化海洋综合观测浮标的通信系统,设计了一种通信方式集成系统,将多种通信模块进行集成管理,并在每个数据发送周期进行通信信号检测,经过比较选择最优的通信方式进行数据传输。该系统具有采集数据完整、数据冗余小、运行功耗低等优点,有效增强了浮标的通信能力,完善了原有通信系统的功能,并且后期还具备较强的可扩展性功能,如浮标舱内环境监测和独立定位等,进一步增强浮标的安全性。该系统已经完成12个月的海上试运行,系统运行稳定,功能达到预期,可满足海洋综合观测浮标对多种通信方式进行优化管理的需求。     

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