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1.
The ratiosR_{s,t,o} of electrical conductivity of seawater samples of precisely known salinity to standard seawater at the same temperature have been measured over a wide range of salinities from 0 to42permil S and over the full range of oceanic temperatures from -2 to35deg C. The samples withS<35permil were prepared by accurate weight dilution of standard seawater with distilled water. High salinity samples were prepared by fast evaporation of standard seawater and subsequent weight dilution into the already determined <35permil range. An equation was derived which expresses the S versusR_{s,t,o} relationship very precisely from1-42permil and at all temperatures, i.e.,S = f_{1}(R_{s,t,o}) + f_{2}(R_{s, t,o},t) =Sigma_{n=0}^{5} a_{n}R^{n/2}+ frac{Delta t}{1+kDelta t} Sigma_{n=0}^{5} b_{n}R^{n/2} whereDelta t = t-15deg C,R = R_{s, t.o} ; only the first termf_{1} is required at15deg C. The effeet of temperature on the electrical conductivity of standard seawater was also measured. The ratior_{t} of the conductivity at temperaturet to the conductivity at15deg C (C_{35,t, o}/C_{35,15,o} ) is very aeenrately expressed by a fourth degree equation int . i.e,r_{t}=Sigma_{n=0}^{4} c_{n}t^{n} These two equations are sufficient for all salinity determinations at normal atmospheric pressure. 相似文献
2.
《Oceanic Engineering, IEEE Journal of》1980,5(1):17-21
The ratiosZ_{K,t} of electrical conductivities of potassium chloride (KCI) solutions of known concentration (K ) to standard seawater at the same temperature have been measured at15deg C and24deg C for solutions withZ_{k,15} between 0.96 and 1.04. The "normal" concentration (N or K_{N} ) givingZ_{N,15}= 1 was found to beK_{N} = 32.4356 gKCI/kg solution. The effect of temperature onZ_{N,t} was measured over the range15deg C to30deg C. Equations are given for KCI concentration as a function ofZ_{15} and the inverse function, forZ_{15}/Z_{24} as a function ofZ_{24} (to allow use of a laboratory salinometer for the KCI-seawater comparisons), andZ_{N,t} as a function of temperature. 相似文献
3.
The Practical Salinity Scale (PSS) 1978 is defined only for salinities within the range 2-42. We have investigated the relationship between mass-determined salinity, electrical conductivity, and temperature for salinities between 0 and 2 with the aim of developing an extension to the Practical Salinity Scale 1978. The paper presents our data, on the basis of which the following correction is proposed to extend the validity of the equations defining the scale to the entire 0-42 range:S=summin{i=0}max{5} (a_{i}+b_{i}f(t))R_{t}^{i/2}-frac{a_{0}}{1 + 1.5x + x^{2}}-frac{b_{0}f(t)}{1+y^{1/2} + y + y^{3/2}} wheref(t)=frac{(t-15)}{1 + k(t-15) x=400R_{t} y=100R_{t} and the constanta_{i}, b_{i} , andk are defind by the Practical Salinity Scale 1978. 相似文献
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5.
Systems of identical precisely spaced bubbles or similar monopole scatterers in water-e.g., inflated balloons or thin-walled shells-insonified at frequenciesomega_{SR} dose to their fundamental radial resonanceomega_{0} (bubble) frequency may themselves display resonance modes or superresonances (SR's) [1]. Ordinary single-bubble resonances magnify the local free-field pressure amplitudep_{1} by a factor(ka)^{-1} ,a being the radius andk the wavenumber in water: for air bubbles or balloons in water, this factor is of the order of 70. Under SR conditions each member of the system amplifies the local free-field amplitude by a further factor of order(ka)^{-1} . Depending upon geometry and other constraints, the pressure fieldP_{SR} on the surface and in the interior of each scatterer will then be in the range of10^{3}p_{1} to5 times 10^{3} p_{1} . This paper investigates the sensitivity of this phenomenon to small departures from the ideal model. In particular, it examines the effect of small differences in scatter positioning and volumes in the context of an SR system consisting of two bubbles/balloons close to the boundary of a thin elastic plate overlying a fluid half-space. It is found that, to observe the SR phenomenon, radii and positions should be controlled to within approximately 1/2 percent.P_{SR} is also sensitive to the angle of incidence of the plane wave train. For the simple system examined here, this sensitivity is considerable for either flexural wave trains or volume acoustic waves incident upon the bubble/ balloon pair (doublet). Practical uses of the phenomenon may range from the design of passive high-Q acoustical filter/amplifiers and acoustical lenses to improved source efficiencies. 相似文献
6.
中国系列标准海水制备与质量评价 总被引：1，自引：1，他引：1
中国系列标准海水是国家二级标准物质 [GBW (E) 130 0 11],在盐度或电导率传感器的现场检定 ,实验室盐度计的检定和校准中应用广泛。主要介绍中国系列标准海水的制备和不确定度分析。 相似文献
7.
Forty-three open-ocean observations of drag coefficients observed at Argus Island Tower near Bermuda by the dissipation technique resulted in constant drag coefficients for mean horizontal wind velocities between 7.8 and10.4 m .s^{1} in good agreement with the larger near-neutral data set of DeLeonibus and Simpson [1] and the neutral data of Large and Pond [2], both of whom observed10^{3}C_{10} = 1.2 whereC_{10} is the drag coefficient at l0 m. Ratios of vertical-to-horizontal wind velocity spectral densities averaged over an inertial subrange of 0.8 to 1.6 Hz ranged from 0.7 to 1.07 in agreement with the Busch and Panofsky [3] result that isotropy is approached only when the observation height is much greater than the Nyquist wavelength. 相似文献
8.
A method is described for measuring the sound speed and the sound-speed gradient of surficial sea floor sediment from bottom-reflected signals recorded in marine seismic experiments. The technique makes use of the ocean-bottom impulse responses that are deconvolved from the data by means of a novel curve-fitting algorithm based on thel_{1} norm (least absolute value) criterion. The algorithm constructs the impulse response by extracting spikes one at a time in a manner that causes thel_{1} error to decrease by the maximum amount possible as each spike is chosen. Thel_{1} curve-fitting approach is a completely general strategy for deconvolution, and our algorithm can be used with data obtained from any type of marine seismic source. Since our experiments have been carried out with small explosive charges, we have also developed a method for estimating the bubble-pulse wavelet directly from the recorded bottom-reflected signal. In this paper, thel_{1} algorithm is used to deconvolve impulse responses for data obtained in an experiment in the Alaskan Abyssal Plain. The sediment-sound-speed gradient determined from these results is typical of other values reported for turbidite abyssal plains where the surficial sediments are composed of unconsolidated silty deposits. 相似文献
9.
《Oceanic Engineering, IEEE Journal of》1982,7(2):75-82
A triaxial set of underwater receiving coils was developed and tested. The receiving system was used jointly with an underwater, calibrated, horizontal, electric dipole source in studies of extremely low-frequency electromagnetic propagation. This paper discusses the electromechanical design of the receiver and tethering system and addresses system sensitivity and noise levels. The receiving system was used successfully in a series of measurements, in spite of serious motion noise contamination. A stationary system sensitivity of5 times 10^{-4} gamma/sqrt{Hz} was achieved. 相似文献
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11.
文章依据相关国家标准,结合海洋环境监测站的实际工作需求,针对环境自动观测系统的盐度传感器,提出新的现场校准方法,即直接比较法;根据不确定度来源,分别计算由测量重复性、盐度标准器、测量环境、测量人员和恒温水槽引入的不确定度分量并合成标准不确定度,据此计算扩展不确定度和合成标准不确定度的有效自由度,由此得出盐度传感器现场校准测量结果的不确定度为0.17。本研究提出的盐度传感器现场校准方法更契合海水盐度的变化规律,可实现盐度分量的量值溯源,具有准确度高和溯源途径清晰的特点;不确定度评定方法科学合理,且具有一定的推广价值。 相似文献
12.
Channel capacity in bits per joule 总被引：1，自引：0，他引：1
Underwater acoustic telemetry has a total input energy constraint, since the energy is stored in the transmitter's batteries. This work is primarily rephrasing the work in channel capacity in terms ofC_{J} bit/J as compared toC bit/s, to emphasize the energy efficiency and to deemphasize the speed of the telemetry. The energy channel capacityC_{J} , for any waveform channel with well-defined capacityC bit/s at signal powerS watts, is defined asC/S bit/J. It is shown that for coherent binary frequency shift keying (BFSK) and waveform channels, the supremum ofC_{J} overS is approached asS approaches zero. For the Gaussian channel the best coding uses narrow bands with the highest S/N. 相似文献
13.
Measurements of salinity perturbations in a partially mixed estuary have been used to evaluate the usefulness of an inductive salinometer and to determine some of the characteristics of the salinity perturbations. The salinometer performed satisfactorily under most conditions. Although internal wave like effects were present, the turbulence fluctuations were dominant. The salinity fluctuations and the turbulent fluxes and were found to behave in a manner similar to the density fluctuations in a thermally stratified atmospheric boundary layer and a laboratory open channel flow. A quadrant analysis suggested that the contribution of each quadrant to the turbulent flux changed with Ri. The turbulence parameters ν and cγ were found to decrease and increase respectively as Ri increases. 相似文献
14.
调查了广东红树林区水质的时空变化, 分别采集了红树林区表层水体水样旱季30个样点(2017年10月至2018年1月)和湿季20个样点(2018年7月至8月)进行分析。利用单一营养状态指数(TSI Chl a)评价红树林水质特征和营养状态, 评价标准: 050为富营养, >70为高营养。红树林区环境参数的时空变化为: 盐度(2.15‰~27.14‰)、pH (6.18~8.65)、电导率(10.87~90.52µs·cm-1)、浊度(0.0975~21.61FTU)、硝酸盐(0~127.2mg·L-1)、亚硝酸盐(0~12.0mg·L-1)、磷酸盐(0~34.5mg·L-1)、硅酸盐(1.22~2.88mg·L-1)和叶绿素a (0.19~38.08mg·m-3)。聚类分析表明, 丰水期横跨雷州半岛右侧至广东沿海东部的水质相对较好, 而左侧则处于中营养化状态。同时, 在枯水期, 红树林区水质较差, 从雷州半岛周围的高中营养化状态, 到广东沿海东部的富营养化状态。主成分分析表明, 营养盐、盐度、pH、电导率(electrical conductivity, EC)和浊度对红树林区水质状况贡献显著, 进而影响红树林生态系统中藻类群落的变化。 相似文献
15.
Rationale for the measurement of open-ocean tsunami signatures are presented, and available pertinent data are reviewed. Models for tsunami signature and background noise are proposed in order to synthesize an optimum tsunami receiver. Using these models, the minimum tsunami amplitude (in cm) to yield the probability of correct tsunami detectionP_{D} = 0.999 and probability of false alarmP_{F} = 10^{-3} is found to be0.718/sqrt{f_{0}} , wheref_{0} is the tsunami dominant frequency (in cycles/h). A realizable receiver is proposed and its performance is evaluated using actual tsunami signatures. It is demonstrated that the detection of a tsunami with an average amplitude as small as 0.7 cm is possible for theP_{D} andP_{F} as above. Simulation results using synthesized background noise are shown. Tidal effects on the receiver performance also are considered and are found negligible for a certain range of the receiver parameters, resulting in a considerable reduction of the signal processing required. 相似文献
16.
A mathematical model of attached bacterial dynamics based on microcolonization was devised using data obtained from a bog. Bacterial samples obtained from any natural water body can be examined by this model with the method of non-linear least squares. The model comprises three bacterial processes; i.e., (1) the attachment rate which was dependent on time after submergence by adsorption onto the substratum surface, and both (2) growth and (3) detachment rate which were dependent on the number of bacterial cells in the microcolony. The population dynamics are expressed as $$\frac{{dC_i }}{{dt}} = - g_i C_i + g_{i - 1} C_{i - 1} - b_i C_i + b_{i + 1} C_{i + 1} + a_i F_i ,$$ where suffixi denotes cell number in each microcolony,C i is microcolony number on the substratum,F i is bacterial clump drifting in the water column,a i , g i andb i are the rate coefficients of attachment, growth and detachment. The growth rate was reciprocally proportional to the cell number in the microcolony. The detachment was shown to increase up to a maximum, and then to decrease as the number of bacterial cells increased in each microcolony. 相似文献
17.
The B/Ca ratio of planktonic foraminifer shells has been used as a proxy for reconstructing past ocean carbonate chemistry. However, recent studies have revealed significant uncertainties associated with this proxy, such as whether seawater temperature or [ CO_3~(2-)] is the dominant control on the partition coefficient(K_D) of planktonic foraminiferal B/Ca. To address these uncertainties and thus improve our understanding of the planktonic foraminiferal B/Ca proxy, we analysed B/Ca ratios in the tests of Neogloboquadrina dutertrei(300–355 μm) and Pulleniatina obliquiloculata(355–400 μm) in surface sediment samples from the tropical western Pacific and South China Sea. The relationship between these B/Ca ratios and bottom water calcite saturation states(Δ[ CO_3~(2-)]) is weak, thus suggesting only a small dissolution effect on the B/Ca of the two species. The correlation coefficients(R~2) between the B/Ca ratios of N. dutertrei and P. obliquiloculata and environmental parameters(e.g., temperature, salinity, phosphate, DIC and ALK) in the tropical western Pacific and South China Sea are not high enough to justify using B/Ca ratios as a palaeoenvironmental proxy in the study areas. The significant correlation between K_D values of N. dutertrei and P. obliquiloculata and carbonate system parameters(e.g.,[ CO_3~(2-)], DIC, ALK, pH and [ HCO_3~-]) in the study area reflect chemical links between the K_D denominator and these variables. Based on our surface sediment calibration, an empirical relationship between the K_D of N.dutertrei and temperature is proposed in the tropical western Pacific. We also generated a record of B/Ca ratios in N. dutertrei(300–355 μm) from Core MD06-3052 in the tropical western Pacific over the past 24 ka to evaluate the application of the revised B/Ca proxy method. Based on the reconstructed empirical relationship for B/Ca and subsurface seawater ALK, we estimated subsurface seawater carbonate system parameters in the tropical western Pacific since 24 ka. In general, the estimated subsurface seawater pH and [ CO_3~(2-)] show an increase with time, and the record of subsurface seawater pCO_2 shows a decrease with time, in the tropical western Pacific over the past 24 ka. The consistent trends in subsurface seawater pCO_2 and opal flux during deglaciation may imply that the reported increase in subsurface water pCO_2 in the study area was promoted by enhanced upwelling in the Southern Ocean. 相似文献
18.
海洋科学的发展离不开精确的数据,然而各种海洋观测仪器在复杂的海洋环境中作业难免产生测量误差,导致观测数据需要进行实时(或延时)质量控制。中国Argo计划在搭载多个航次布放剖面浮标的同时,对航次中获取的船载CTD(conductivity, temperature, and depth)仪观测资料、自动剖面浮标观测资料以及实验室高精度盐度计测量数据进行了实时比对。分析结果显示,利用实验室高精度盐度计对现场观测数据尤其是船载CTD仪观测资料进行质量控制,于温盐数据(特别是深层)的实时/延时校正非常重要;如某航次未经标定的船载CTD仪所测1000dbar以深范围内海水盐度,与实验室高精度盐度计的差值达到±0.1左右,远远落后于国内海洋调查规范对盐度准确度±0.02的一级测量要求,该具体实例更加突显了船载CTD仪在航次前后送往权威部门进行检测的必要性和重要性,从而确保每个航次获取的CTD资料的质量。建议有条件的情况下,在进行深海大洋船载CTD仪观测时要进行现场实验室高精度盐度计的质量控制工作及比对试验,以提高我国深海大洋观测数据的质量。 相似文献
19.
《Oceanic Engineering, IEEE Journal of》2009,34(4):407-422
20.
《Deep Sea Research Part I: Oceanographic Research Papers》2005,52(2):389-396
The salinity of seawater has been defined in terms of the ratio of its electrical conductivity to that of a standard potassium chloride solution. The potassium chloride solution is obtained by dissolution of high-purity potassium chloride in ultrapure water. However, even high-purity potassium chloride is not 100% pure, and suppliers do not certify it, as the standard for electrical conductivity. We prepared defined solutions using several kinds of high-purity potassium chloride and examined the difference between the measured electrical conductivity ratio and the value calculated from the experimental equation given in the UNESCO background papers. The differences between the electrical conductivity ratios of the solutions made from the various potassium chloride reagents were equivalent to about 0.0012 in salinity. The solution may not actually become a standard for salinity measurements even if it is prepared exactly according to the present definition. The lot dependency of the electrical conductivity ratio of the potassium chloride solutions may result in a systematic error in the measurement of salinity. 相似文献