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1.
The temperature measurement system of the standard Woods Hole Oceanographic Institution/Neil Brown Instrument Systems conductivity-temperature-depth microprofiler consists of a platinum thermometer, which has stable calibration characteristics but response time of order 200 ms combined with a fast response thermistor designed to sample the higher frequency temperature fluctuations. The calibration characteristics and temporal response of the individual sensors relative to the conductivity cell were studied using a modified instrument which digitized these data channels separately. The relative responses of the individual sensors were found to be fairly well modeled by a single pole filter, but the response of the standard temperature signal, which is an analog combination of the two temperature sensor outputs, exhibited a complicated behavior. Several methods for obtaining a well-calibrated fast-responding temperature signal from the digitized platinum thermometer and thermistor records are discussed. Preliminary results suggest that thermohaline features on scales of less than a meter in the vertical are resolvable. 相似文献
2.
Optical backscatterance (OBS, D&A Instruments, Inc.1) sensors for measuring suspended-solids concentrations have been deployed in Tampa Bay to monitor resuspension of bottom sediments. This paper describes biological factors that affected the OBS sensors deployed in Tampa Bay and discusses deployment strategies that minimize biological interference. Phytoplankton may interfere with the OBS sensors when the suspended-solids concentration is near or below the sensor response threshold. Fish swimming in front of the OBS sensors caused spikes in the OBS sensor output, so the median average was more appropriate than the mean average. An algal slime on the OBS sensors caused excessive backscatterance that dominated the backscatterance from suspended material. Because of the fouling problem, deployments were limited to less than a week, and OBS sensors were cleaned daily, if possible. Calibration of OBS sensors with water samples collected from Tampa Bay was satisfactory when biological interference was not significant. When properly deployed, the OBS sensors can successfully monitor sediment resuspension in Tampa Bay and similar subtropical estuaries. 相似文献
3.
Definitive studies on the response of marine mammals to anthropogenic sound are hampered by the short surface time and deep-diving lifestyle of many species. A novel archival tag, called the DTAG, has been developed to monitor the behavior of marine mammals, and their response to sound, continuously throughout the dive cycle. The tag contains a large array of solid-state memory and records continuously from a built-in hydrophone and suite of sensors. The sensors sample the orientation of the animal in three dimensions with sufficient speed and resolution to capture individual fluke strokes. Audio and sensor recording is synchronous so the relative timing of sounds and motion can be determined precisely. The DTAG has been attached to more than 30 northern right whales (Eubalaena glacialis) and 20 sperm whales (Physeter macrocephalus) with recording duration of up to 12 h per deployment. Several deployments have included sound playbacks to the tagged whale and a transient response to at least one playback is evident in the tag data. 相似文献
4.
The response of an array of sensors to coherent undesired noise interfering with the measurement of a desired signal can be optimized if special filters are applied to the outputs of the sensors. In this paper, we derive analytic expressions for filters which minimize the power spectrum of the array response to the undesired coherent signal while simultaneously providing an all-pass condition for the desired signal. These filters are shown to yield an array rejection response which has zero-width main lobes and no sidelobes. An example illustrating the results is also presented. 相似文献
5.
This paper proposes a high-speed iterative procedure for estimating the ocean wave directional spectrum from vessel motion data. It uses as input data, the measurements from motion sensors that are commonly available on dynamically positioned vessels and which may easily be installed on any ship. Because the necessary sensors are relatively inexpensive or may already be installed, it becomes an ideal solution to provide initial estimates to offline estimation procedures and to give spectral updates under quickly changing weather conditions. The Kalman filtering algorithm, for iterative harmonic detection, and frequency domain vessel response data are used in the estimation procedure. The results and conclusions are still based on synthesized data, but very promising. 相似文献
6.
走航式海洋多参数剖面测量系统(MVP)是一种集成程度和自动化程度都较高的海洋调查设备,能对多要素进行同时观测,获得高水平空间分辨率的数据资料。MVP由于温度和电导率传感器响应时间的不匹配,下放速度过快(峰值速度4m/s)而造成非常严重的盐度尖峰现象。本研究通过结合F法、GM法和Grose法提出的盐度尖峰订正方案,提出了一种新的方法Match conductivity and temperature response times法,对压力、温度和电导率传感器三者进行响应时间的匹配来减弱盐度尖峰。与SBE-9型CTD资料进行对比发现订正后的资料误差比订正前减小80%,与CTD盐度曲线互相关程度为0.917。对比35N断面修正前后的盐度资料发现订正后温盐跃层处出现的低盐区域消失,与CTD断面资料对比结果显示MVP资料比CTD资料在细结构上更具有优势。 相似文献
7.
The response characteristics of conductivity-temperature-depth (CTD) sensors used for the derivation of ocean properties from profiling instruments are discussed. The influence of design and operating conditions on the impulse response is explored with examples drawn from commercially produced cells in common use. The speed dependence of both temperature and conductivity sensor response is discussed with reference to sensor matching to reduce salinity spiking. A brief discussion is included on data processing and filtering techniques 相似文献
8.
走航式海洋多参数剖面测量系统(moving vessel profiler,MVP)是一种集成程度和自动化程度都较高的海洋调查设备,能对海洋多要素进行同时观测,获得水平方向的高分辨率数据资料。由于温度和电导率传感器响应时间的不匹配,MVP下放速度过快(峰值速度4 m/s)而造成非常明显的盐度尖峰现象。本研究结合Fofonoff(F)法、时间常数指数递归数字滤波(Giles and McDougall,GM)法和Grose提出的盐度尖峰订正方案,提出了一种新的方法,即MCT(match conductivity and temperature response time)法,通过对压力、温度和电导率传感器进行响应时间的匹配来减弱盐度尖峰。将SBE-9型CTD资料作为标准,发现订正后的资料与CTD盐度曲线的互相关系数为0.917,误差比订正前减小80%。对比35°N断面修正前后的盐度资料,订正后温盐跃层处出现的低盐区域消失。MVP的应用比常规海洋调查仪器CTD对于海洋现象的观测更有优势。 相似文献
9.
T. J. P. Gwilliam 《Ocean Engineering》1976,3(6):391-401
With ever increasing information being collected by the offshore continental shelf tide gauges, it became inevitable that researches into ocean tides would require instrumentation to collect tidal data in the deep oceans.This paper briefly describes the temperature and pressure sensors developed, and used by the Institute of Oceanographic Sciences (Wormley), in response to this requirement. Also described are the techniques and equipment used to calibrate these sensors.The deep sea tide gauges, each of which include two pressure and one temperature sensor, have now been operationally deployed on four occasions at pressures up to 300 bars (3000 m) providing well over 100 days of tidal data. In an international exercise to evaluate the performance of existing deep sea pressure sensors, results show that the unit described in this paper compares favourably with the other sensors. For example, the amplitude of the semi-diurnal components were within 1% of the average value, determined by all the sensors. The temperature sensor has an operational range within the limits — 1° and + 40°C and exhibiting a stability of the order 8 milli°C/month. 相似文献
10.
中高空间分辨率宽波段光学卫星已成为赤潮监测的主要数据源,但与水色卫星传感器不同,中高空间分辨率卫星传感器主要面向陆地应用,其波段数量少、宽度大,由此对赤潮探测带来的影响尚待研究。为此,本文基于不同优势种赤潮实测高光谱数据、时空同步的GF-1 WFV2、GF-1 WFV3传感器影像、Sentinel-2A MSI传感器影像及GF-6 WFV传感器影像,探究了波段设置、光谱响应函数、信噪比及空间分辨率对赤潮探测的影响,并分析了红边波段赤潮探测优势。结果表明:波段设置对赤潮探测影响大,特别是红光波段和红边波段的中心波长和波段宽度;波段设置相同的情况下,赤潮探测精度受光谱响应函数的影响大,受信噪比的影响较小;空间分辨率对赤潮探测的影响较大,空间分辨率的提升有助于提高赤潮探测的精度。红边波段赤潮探测实验表明,较之红光波段,基于红边波段的赤潮探测具有明显的优势,平均F1-Score提高了11%。本文的研究结果一方面可为赤潮中高空间分辨率卫星探测的数据选取提供理论依据,另一方面可为中高空间分辨率卫星传感器的设计提供参考。 相似文献
11.
The BIO Mark 8 thrust anemometer measures the drag of the wind on a perforated table tennis ball mounted on a vertical beam. The tri-axial displacement of the beam is sensed by eddy current proximity sensors. This anemometer has a flat frequency response from 0 to 10 Hz and can measure wind from 0 to 28 m s−1 at temperature from − 19 to + 28°C. It is designed for remote operation for extended periods of time such as on stable towers at sea. 相似文献
12.
Electric potential due to a ring electrode 总被引：2，自引：0，他引：2
Electrical sensors utilizing ring electrodes mounted on cylindrical rods have been used by several workers to measure the resistivity of marine sediments. As the resistivity of sediment is dependent upon the water content of the sediment, such measurements are extremely valuable for determining the density of sediments. Recently, ring electrodes have also been used in instrumentation to determine fluctuations in the marine sediment-seawater interface due to erosion or deposition. In the past, approximate formulas have been used to evaluate the response of the sensors. In this work, an exact formula is derived, and it is shown that the previous formulas are in error by up to 5%. Although this is not serious for most borehole logging applications, it is essential to use the exact formulas to interpret data from electromagnetic sediment level sensors 相似文献
13.
Sarah E. Zedler Guido Kanschat Robert Korty Ibrahim Hoteit 《Journal of Oceanography》2012,68(2):227-241
We seek to determine if a small number of measurements of upper ocean temperature and currents can be used to make estimates
of the drag coefficient that have a smaller range of uncertainty than previously found. We adopt a numerical approach using
forward models of the ocean’s response to a tropical cyclone, whereby the probability density function of drag coefficient
values as a function of wind speed that results from adding realistic levels of noise to the simulated ocean response variables
is sought. Allowing the drag coefficient two parameters of freedom, namely the values at 35 and at 45 m/s, we found that the
uncertainty in the optimal value is about 20% for levels of instrument noise up to 1 K for a misfit function based on temperature,
or 1.0 m/s for a misfit function based on 15 m velocity components. This is within tolerable limits considering the spread
of measurement-based drag coefficient estimates. The results are robust for several different instrument arrays; the noise
levels do not decrease by much for arrays with more than 40 sensors when the sensor positions are random. Our results suggest
that for an ideal case, having a small number of sensors (20–40) in a data assimilation problem would provide sufficient accuracy
in the estimated drag coefficient. 相似文献
14.
Kose E. Gosine R.G. Dunwoody A.B. Calisal S.M. 《Oceanic Engineering, IEEE Journal of》1995,20(1):13-22
This paper describes an intelligent monitoring and advisory system for vessel safety. This system uses environmental information obtained from a number of sensors and proposes corrective action based on a rule-base derived from human expertise, experiments, and theoretical research. The architecture of the monitoring and advisory system is described. Capsizing modes of a ship at sea are explained, and the fuzzy expert system used in the decision-making process is detailed. Simulations of various sea conditions leading to capsize are presented, and the vessel response to the corrective action suggested by the advisory system is illustrated 相似文献
15.
A new method is introduced for calibrating optical backscatter sensors for suspended quartz sand concentrations of up to 200 kg m−3. Due to the high settling velocity of quartz sand in water, considerable difficulties have arisen in the past to maintain a spatially and temporally homogeneous suspension suitable for calibration. Traditional methods are clumsy and prone to errors. Here, the sediment is calibrated in glycerol, a clear fluid with a higher viscosity than water. The settling velocity is reduced by three orders of magnitude. An empirical relationship is obtained which is used to correct for any optical differences in response of the sensors in the two fluids. Any extra errors introduced by calibrating with a different fluid from that found in the field are outweighed by the simplicity and reliability of this method. 相似文献
16.
The often poor quality of ocean bottom seismic data, particularly that observed on horizontal seismometers, is shown to be the result of instruments responding to motions in ways not intended. Instruments designed to obtain the particle motion of the ocean bottom are found to also respond to motions of the water. The shear discontinuity across the ocean floor boundary results in torques that cause package rotation, rather than rectilinear motion, in response to horizontal ground or water motion. The problems are exacerbated by bottom currents and soft sediments. The theory and data presented in this paper suggest that the only reliable way of obtaining high fidelity particle motion data from the ocean floor is to bury the sensors below the bottom in a package with density close to that of the sediment. Long period signals couple well to ocean bottom seismometers, but torques generated by bottom currents can cause noise at both long and short periods. The predicted effects are illustrated using parameters appropriate for the operational OBS developed for the U. S. Office of Naval Research. Examples of data from ocean bottom and buried sensors are also presented. 相似文献
17.
光纤化学/生物传感技术在海洋环境监测中的应用 总被引：3，自引：0，他引：3
本文通过光纤溶解氧、 p H、湿度等化学传感探头及发光菌水质毒性监测生物传感探头的研制 ,开发出了一类能用于环境监测的新型传感器。本文的创新之处在于传感探头的设计与包装 ,以及数种可逆性、选择性、稳定性、使用寿命、响应时间、灵敏度等响应特性具佳的化学及生物传感膜的配方和制作技术。利用这些技术 ,通过对光纤探头的设计与包装 ,可以实现在现场及实验室模拟条件下对样品的选择性检测。研制的传感器能广泛应用于海洋污染调查、内河水质评价、水产养殖、工矿企业水气排污自检等诸多方面。 相似文献
18.
海洋化学传感器研制的动态评述 总被引：5，自引：0，他引：5
化学海洋学研究数据的获得要方便、经济、高效的分析测试手段,化学传感器则是海洋调查和监测ＤＯ、ｐＨ、ＣＯ２、ＮＨ３－Ｎ和Ｓ（－ＩＩ）等的理想手段和工具。本文评述了６０年代末以来用于天然水体中ＣＯ２、ＮＨ３－Ｎ和Ｓ（－ＩＩ）检测的化学传感器的研制情况,进一步讨论了海洋化学传感器研制所需解决的问题和发展方面,并分析了海洋化学传感器研制进展缓慢的原因。 相似文献
19.
20.
The performance of various directional instruments for practical oceanographic and coastal engineering applications is examined. The emphasis is put on the application of conventional current meters equipped with high resolution pressure sensors and three element arrays. Two simulation techniques have been used to produce input data with known frequency spectrum and known directional spreading. The directional spreading is determined by the maximum likelihood method and the resulting spreading is compared with the input spreading. The performance of a conventional current meter equipped with a high resolution pressure sensor depends on the width of the directional spreading of surface waves and on the frequencies under consideration. Even for very narrow directional spreading, the current meter response is acceptable for practical applications and for shallow water deployment. In general, the current meter directional response does not depend on the direction of the incident waves. The spatial array of three wave staffs deployed in shallow water shows a similar performance to that of the current meters when the dimension of the spatial array is of the order of 1 m. This performance also does not depend on the direction of the incident waves. 相似文献