ALBERT

Description: Responses obtained in consonant perception experiments typically show a large variability across stimuli of the same phonetic identity. The present study investigated the influence of different potential sources of this response variability. It was distinguished between source-induced variability, referring to perceptual differences caused by acoustical differences in the speech tokens and/or the masking noise tokens, and receiver-related variability, referring to perceptual differences caused by within- and across-listener uncertainty. Consonant-vowel combinations consisting of 15 consonants followed by the vowel /i/ were spoken by two talkers and presented to eight normal-hearing listeners both in quiet and in white noise at six different signal-to-noise ratios. The obtained responses were analyzed with respect to the different sources of variability using a measure of the perceptual distance between responses. The speech-induced variability across and within talkers and the across-listener variability were substantial and of similar magnitude. The noise-induced variability, obtained with time-shifted realizations of the same random process, was smaller but significantly larger than the amount of within-listener variability, which represented the smallest effect. The results have implications for the design of consonant perception experiments and provide constraints for future models of consonant perception.

Description: Seafloor topography is neither spatially homogeneous, nor does it obey Gaussian statistics; deviations from both of these assumptions are important from a geological and acoustic point of view. It has been found that the distribution of topographic slopes can be used as a primary tool for understanding the sources and extent of spatial heterogeneities and patterns on the seafloor. The covariance function has been widely used to characterize seafloor topography, but requires the assumption of Gaussian joint probability statistics to be valid. For heterogeneous topography characterized by large transient signals such as steep scarps and volcanoes, the covariance becomes dominated by the transients; in contrast the family slope distributions can still be used to derive stable descriptors for regions with large transient signals, as well as regions containing asymmetric features, and regions with only limited sampling. Knowledge of slopes is useful because a direct relation exists between the covariance and the slope distributions at different spatial scales. Studies of the slope distribution provide a means of identifying the presence of the non‐Gaussian elements in the topography, and flagging their spatial locations. The methods used here are demonstrated by applying them to three small patches of topography located within 20 km of each other in the Eastern Pacific. It is found that dominant azimuthal directions and dip angles differ widely between the patches. In addition, asymmetries in the cross‐sectional shapes of faulted abyssal hills are documented. [Work supported by ONR.]

Description: The acoustic backscatter of eight well‐curated ferromanganese nodules has been measured in 1 °C seawater at frequencies from 45 to 167 kHz. The nodules have diameters from 37 to 121 mm and are thought to be representative of the Cu–Ni–Co‐rich nodules from the area around 14° 40’ N, 125° 25’ W (DOMES site C). They had been collected in box cores on the Echo 1 expedition and were kept refrigerated and water soaked in air‐tight plastic bags. Acoustic backscatter variations of over 10 dB were observed while the nodule was rotated 10° to 30° about one of its principal axes. The complicated fine structure, as well as the target strength, makes it clear that nodules cannot be modeled as simple spheres.

Description: Additional data from sonobuoys and the Deep Sea Drilling Project (DSDP) justify separating sound‐velocity‐depth functions and velocity gradients (in the first layer of soft marine sediments) into some geographic areas and sediment types. Based on sonobuoy and core measurements (where V is sound velocity in km/s, and h is depth in sediments in km), the following data are obtained: continental shelf basins off Sumatra and Java—V=1.484+0.710h−0.085h2; U. S. Atlantic continental rise—V=1.513+0.828h−0.138h2; deep‐sea terrigenous sediments—V=1.519+1.227h−0.473h2; and siliceous sediments of the Bering Sea— V=1.509+0.869h−0.267h2. Selected DSDP data (through leg 74) in similar areas yield: continental terrace silt–clays—V=1.505+0.712h; deep‐sea terrigenous sediments—V=1.510+1.019h; and deep‐sea siliceous sediments—V=1.533+0.761h. Computed velocity gradients from sonobuoy measurements are generally supported by the DSDP gradients. Only DSDP data give the following: hemipelagic sediments—V=1.501+1.151h; deep‐sea calcareous sediments—V=1.541+0.928h; and deep‐sea pelagic clay—V=1.526+1.046h. Where fast sediment accumulation occurs, there has not been enough time to reduce sediment pore spaces under overburden pressure; areas of slow accumulation may have relatively high sediment structural strength. Both cases have lower velocity gradients because higher porosities and consequent lower velocities persist to deeper depths.

Description: High‐frequency bottom acoustic and geoacoustic data from three well‐characterized sites of different bottom composition are compared with scattering models in order to clarify the roles played by interface roughness and sediment volume inhomogeneities. Model fits to backscattering data from two silty sites lead to the conclusion that scattering from volume inhomogeneities was primarily responsible for the observed backscattering. In contrast, measured bottom roughness was sufficient to explain the backscattering seen at a sandy site. Although the sandy site had directional ripples, the model and data agree in their lack of anisotropy.

Description: A simple equation is presented for the dependence of sound speed on temperature, salinity, and depth of water. The comparison with Del Grosso’s NRL II shows discrepancies of the order of tenths of m/sec for realistic values of the parameters.

Description: The ratio of compressional wavevelocityV p to shear wavevelocityV s , and Poisson’s ratio in marine sediments and rocks are important in modeling the sea floor for underwater acoustics,geophysics, and foundation engineering. V p and V s versus depth information was linked at common depths in terrigenous sediments (to 1000 m) and in sands (to 20 m) to yield data on V p vs V s , and V p /V s and Poisson’s ratios versus depth. Soft, terrigenous sediments usually grade with depth into mudstones and shales; V p /V s ratios vary from about 13 or more at the sea floor to about 2.6 at 1000 m. Poisson’s ratios vary from above 0.49 at the sea floor to about 0.41 at 1000 m. In sands, V p , V s , and V p /V s have very high gradients in the first few meters; below about 5 m, V p /V s ratios decrease from about 9 to about 6 at 20 m; Poisson’s ratios vary from above 0.49 at the surface to above 0.48 at 20 m. The mean value of V p /V s in 30 laboratory samples of chalk and limestone is 1.90 (standard error: 0.03); mean Poisson’s ratio is 0.31. Literature data on basalts from the sea floor are reviewed. Equations relating V p to V s are given for terrigenous sediments, sands, and basalts.

Description: Gas-hydrate accumulations located onshore in Arctic permafrost regions are seen as a potential source of natural gas. Surprisingly, most of the gas hydrate found in the Mackenzie Delta and Beaufort Sea areas was indirectly discovered or inferred from conventional hydrocarbon exploration programs. One of these occurrences, the Mallik gas-hydrate field (Figure 1), has received particular attention over the last 10 years. Two internationally partnered research well programs have intersected three intervals of gas hydrates and have allowed successful extraction of subpermafrost core samples with significant gas hydrates. The gas-hydrate intervals are up to 40 m thick and have high gas-hydrate saturation, sometimes exceeding 80% of pore volume of unconsolidated clastic sediments with average porosities from 25–40%. At Mallik, the gas-hydrate intervals are located at depths of 900–1100 m and are localized on the crest of an anticline.

Description: The definition of noise and signal in seismic data will vary widely with the viewer's perspective and methods to process and visualize the data. Thus we begin with our definition from the perspective of presenting structural subsurface information.

Description: Shallow gas occurs between 0 and 1000 m below the sea floor. It consists mainly of microbial-formed or thermogenic methane or a combination of both, sometimes with a limited admixture of higher hydrocarbons (propane, butane, etc.).

Description: A new equation for the speed of sound in sea water has been developed with validity not only for realistic combinations of the parameters salinity, temperature, and pressure, but with extension to pure water as well. This new equation, referred to as NRL II, has a standard deviation of 0.05 m/sec. Tables are presented comparing calculations using this new model to each of eight earlier equations. Graphs are also included indicating approximate corrections that could be applied to existing sound speed profiles, but it is recommended that such profiles be recalculated and new ones obtained according to NRL II.

Description: Tables for the speed of sound in sea water are presented. These tables have been prepared from an empirical formula which was derived to fit measured sound‐speed data obtained over the temperature range −3°C to 30°C, the pressure range 1.033 kg/cm2 to 1000 kg/cm2, and the salinity range 33‰ to 37‰. The discrepancy of −3.0 m/sec found by Del Grosso at 1 atm., as compared to the tables of Kuwahara, is substantiated. In addition, the pressure coefficient of sound speed observed in the present work differs from that predicted by Kuwahara.

Description: A new equation is proposed for the calculation of sound speed in seawater as a function of temperature, salinity, depth, and latitude in all oceans and open seas, including the Baltic and the Black Sea. The proposed equation agrees to better than ±0.2m∕s with two reference complex equations, each fitting the best available data corresponding to existing waters of different salinities. The only exceptions are isolated hot brine spots that may be found at the bottom of some seas. The equation is of polynomial form, with 14 terms and coefficients of between one and three significant figures. This is a substantial reduction in complexity compared to the more complex equations using pressure that need to be calculated according to depth and location. The equation uses the 1990 universal temperature scale (an elementary transformation is given for data based on the 1968 temperature scale). It is hoped that the equation will be useful to those who need to calculate sound speed in applications of marine acoustics.

Description: In studies in underwater acoustics,geophysics, and geology, the relations between soundvelocity and density allow assignment of approximate values of density to sediment and rock layers of the earth’s crust and mantle, given a seismicmeasurement of velocity. In the past, single curves of velocity versus density represented all sediment and rock types. A large amount of recent data from the Deep Sea Drilling Project (DSDP), and reflection and refraction measurements of soundvelocity, allow construction of separate velocity–density curves for the principal marine sediment and rock types. The paper uses carefully selected data from laboratory and i n s i t umeasurements to present empirical sound velocity–density relations (in the form of regression curves and equations) in terrigenous silt clays, turbidites, and shale, in calcareous materials (sediments, chalk, and limestone), and in siliceous materials (sediments, porcelanite, and chert); a published curve for DSDP basalts is included. Speculative curves are presented for composite sections of basalt and sediments. These velocity–density relations, with seismicmeasurements of velocity, should be useful in assigning approximate densities to sea‐floor sediment and rock layers for studies in marine geophysics, and in forming geoacoustic models of the sea floor for underwater acoustic studies.

Description: Seismic data are usually acquired and processed for imaging reflections. This paper describes a method of processing seismic data for imaging discontinuities (e.g., faults and stratigraphic features). One application of this nontraditional process is a 3-D volume, or cube, of coherence coefficients within which faults are revealed as numerically separated surfaces. Figure 1 compares a traditional 3-D reflection amplitude time slice with the results of the new method. To our knowledge, this is the first published method of revealing fault surfaces within a 3-D volume for which no fault reflections have been recorded.

Description: Two sets of equations, covering all world oceans and seas, are presented to calculate pressure from depth for the computation of sound speed, and depth from pressure for use in ocean engineering. They are based on the algorithm of UNESCO 1983 [N. P. Fofonoff and R. C. Millard, Jr., Unesco Tech. Papers in Mar. Sci. No. 44 (1983)], and on calculations from temperature and salinity profiles. The pressure to depth conversion is presented first. The equations can be used in those cases where the desired accuracy is reduced to ±0.8 m. The equations to convert depth to pressure provide an overall accuracy between ±8000 Pa and ±1000 Pa. This leads to errors in sound speed consistently smaller than ±0.02 m/s. The discussion, and comparisons with results and other formulas, suggest that the new equations are a substantial improvement on the previous simplified ones, which should now be abandoned.

Description: Attributes have proliferated recently with different selections available on different workstations. What do they all mean? When do we use one and when another? The answers to these questions are not easy but the first step is to understand what our options are, and herein lies the purpose of this article.

Description: As offshore petroleum exploration and development move into deeper water, industry must contend increasingly with gas hydrate, a solid compound that binds water and a low-molecular-weight gas (usually methane). Gas hydrate has been long studied in industry from an engineering viewpoint, due to its tendency to clog gas pipelines. However, hydrate also occurs naturally wherever there are high pressures, low temperatures, and sufficient concentrations of gas and water. These conditions prevail in two natural environments, both of which are sites of active exploration: permafrost regions and marine sediments on continental slopes. In this article we discuss seismic detection of gas hydrate in marine sediments. Gas hydrate in deepwater sediments poses both new opportunities and new hazards. An enormous quantity of natural gas, likely far exceeding the global inventory of conventional fossil fuels, is locked up worldwide in hydrates. Ex-traction of this unconventional resource presents unique exploration, engineering, and economic challenges, and several countries, including the United States, Japan, Canada, India, and Korea, have initiated joint industry-academic-governmental programs to begin studying those challenges. Hydrates also constitute a potential drilling hazard. Because hydrates are only stable in a restricted range of pressure and temperature, any activity that sufficiently raises temperature or lowers pressure could destabilize them, releasing potentially large volumes of gas and decreasing the shear strength of the host sediments. Assessment of the opportunities and hazards associated with hydrates requires reliable methods of detecting hydrate and accurate maps of their distribution and concentration. Hydrate may occur only within the upper few hundred meters of deepwater sediment, at any depth between the seafloor and the base of the stability zone, which is controlled by local pressure and temperature. Hydrate is occasionally exposed at the seafloor, where it can be detected either visually or acoustically by strong seismic reflection amplitudes or high backscatter …

Description: The Green's function (GF) for the scalar wave equation is numerically constructed by an advanced geometric ray-tracing method based on the eikonal approximation related to the semiclassical propagator. The underlying theory is first briefly introduced, and then it is applied to acoustics and implemented in a ray-tracing-type numerical simulation. The so constructed numerical method is systematically used to calculate the sound field in a rectangular (cuboid) room, yielding also the acoustic modes of the room. The simulated GF is rigorously compared to its analytic approximation. Good agreement is found, which proves the devised numerical approach potentially useful also for low frequency acoustic modeling, which is in practice not covered by geometrical methods.

Description: The seismic trace is a complex aggregate of reflected and scattered signals from subsurface formation interfaces and heterogeneities. Although many varieties of random noise may also be present in the trace, we know from reacquiring the same seismic survey that seismic data are highly repeatable, indicating that significant information about the subsurface is contained in the trace but not yet used by our standard analysis methods. Seismic scattering is a type of signal contained in the data that is generally not utilized.

Description: High-resolution 3D (HR3D) seismic data are important for hydrocarbon exploration of shallow reservoirs, site characterization, and geohazard assessments. The goal of this contribution is to identify and quantify the parameters to increase the resolution of HR3D seismic data to meter scale. The main acquisition parameters controlling the resolution of the collected data are the spectrum of the seismic source, source-receiver offset range, and trace density. An evolution to one-meter-scale resolution of 3D seismic will rely on combining a reproducible seismic source with high frequencies up to at least 600 Hz, a high uniform trace density of more than 4 million traces per square kilometer, and an offset range shorter than approximately 200 m. The resulting 3D seismic data volume will reach meter-scale resolution for water and target depths of less than 600 m. The proposed HR3D system will be suitable for 3D and 4D characterization of seabed properties and shallow stratigraphy, the identification of geohazards and hydrocarbon leakage, and monitoring the environmental impact of offshore activities. The P-Cable 3D system is an excellent starting point for achieving one-meter-scale resolution due to its flexible and tight meter-scale shot and receiver spacing.

Description: Understanding mechanical interactions between hydrate and hosting sediments is critical for evaluating formation stability and associated environmental impacts of hydrate-bearing sediments during gas production. While core-scale studies of hydrate-bearing sediments are readily available and some explanations of observed results rely on pore-scale behavior of hydrate, actual pore-scale observations supporting the larger-scale phenomena are rarely available for hydrate-bearing sediments, especially with methane as guest molecules. The primary reasons for the scarcity include the challenge of developing tools for small-scale testing apparatus and pore-scale visualization capability. We present a testing assembly that combines pore-scale visualization and triaxial test capability of methane hydrate-bearing sediments. This testing assembly allows temperature regulation and independent control of four pressures: influent and effluent pore pressure, confining pressure, and axial pressure. Axial and lateral effective stresses can be applied independently to a 9.5 mm diameter and 19 mm long specimen while the pore pressure and temperature are controlled to maintain the stability of methane hydrate. The testing assembly also includes an X-ray transparent beryllium core holder so that 3D computed tomography scanning can be conducted during the triaxial loading. This testing assembly permits pore-scale exploration of hydrate-sediment interaction in addition to the traditional stress-strain relationship. Exemplary outcomes are presented to demonstrate applications of the testing assembly on geomechanical property estimations of methane-hydrate bearing sediments.

Description: A bottom-simulating reflection (BSR) is a seismic reflectivity phenomenon that is widely accepted as indicating the base of the gas-hydrate stability zone. The acoustic impedance difference between sediments invaded with gas hydrate above the BSR and sediments without gas hydrate, but commonly with free gas below, are accepted as the conditions that create this reflection. The relationship between BSRs and marine gas hydrate has become so well known since the 1970s that investigators, when asked to define the most important seismic attribute of marine gas-hydrate systems, usually reply, “a BSR event.” Research conducted over the last decade has focused on calibrating seafloor seismic reflectivity across the geology of the northern Gulf of Mexico (GoM) continental slope surface to the seafloor. This research indicates that the presence and character of seafloor bright spots (SBS) can be indicators of gas hydrates in surface and near-surface sediments (Figure 1). It has become apparent that SBSs on the continental slope generally are responses to fluid and gas expulsion processes. Gas-hydrate formation is, in turn, related to these processes. As gas-hydrate research expands around the world, it will be interesting to find if SBS behavior in other deepwater settings is as useful for identifying gas-hydrate sites as in the GoM.

Description: The curves of optimum frequencies versus maximum range for active sonar detection under specific sets of assumptions are presented for the more recent expressions for attenuation given by Lovett [J. Acoust. Soc. Am. 58, 620–625 (1975)] for the eastern North Pacific and Thorp [J. Acoust. Soc. Am. 42, 270 (1967)] for the western North Atlantic as corrected at low frequencies by Kibblewhite et al. [J. Acoust. Soc. Am. 60, 1040–1047 (1976)].

Description: The present volume gives the observed physical and chemical data obtained by R. V. "Meteor" in the Indian Ocean during her cruise 1964/65. The tables are based on the computations made by the National Oceanographic Data Center (NODC) in Washington. In addition to the normally communicated data, the tables contain four chemical parameters: alkalinity, ammonia, fluoride, and calcium.

Description: In this paper the sections for temperature and salinity are presented, which were obtained during the cruise of R. V. "Meteor" in the Indian Ocean (1964/65). The hydrographic observations in the Arabian Sea, had the aim to provide information on the influence of the NE-monsoon on the distribution of salinity and temperature off the east coast of Africa and off the west coast of India. Special attention was given to the spreading of highly saline water from the Red Sea and the Persian Gulf. The track of the expedition was layed out according to these plans and is presented in figure 1. The data were collected by means of hydrographic casts with newly developed water bottles, and by means of "in-situ" measurements with the "bathysonde", an instrument for the continuous recording of electrical conductivity, temperature and pressure. This paper only deals with the data of the casts which are presented in a special publication together with the chemical data. The hydrographic conditions off the east coast of Africa are characterised by a rather complicated distribution of salinity within the first 1000 m of depth with several intermediate maxima and minima (hydrographic sections III-IX). This is due to the spreading of highly saline water mainly from the Red Sea, which can be traced southwards at least as far as 4° N (figure 9). Similar complicated conditions were found off the west coast of India (sections XI-XVI). Here the cause can be traced back to watermasses from the Persian Gulf. In depths below 2 000 m the TS-relation is virtually the same at both sides of the Arabian Sea.

Description: The present investigatioh concerns itself with two problems: First it is investigated with the aid of the hydrographic data available until medio 1965 from the Indian Ocean, whether due to the varying actions of the monsoons a large scale seasonal shift in the distribution of the isohalines occurs at the level of intermediate salinity maxima ( depth range about from 300 to 800 m). Furthermore it is investigated by means of two theoretical models whether advection or horizontal mixing dominates in the large scale distribution of the salinity in the Arabian Sea. In the treatment of the first problem, distribution charts for the water from the Read Sea and the Persian Gulf were made with the aid of the core layer method for both monsoon periods. The core layer of Red Sea water lies at about 600 to 800 m depth. The watermasses from the Persian Gulf sink from 200 to 500 m while moving from north to south. In both seasons the observable limit of extension lies at about 3° N. Seasonal variations occur apparently only in the northern part of the basin and at its margins. The observed distribution of salinity shows at all levels (300, 400, 500, and 600 m) an east-west pattern (fig. 7 to 10). In no case a tongue form appears in the isohalines. The observed distribution is satisfactorily interpreted by means of a model which considers only horizontal mixing and the natural boundary conditions (Dirichlets problem for the rectangle). A further model which includes advective terms does not corroborate the observations. The investigations lead to the conclusion that the existing stationary distribution of salinity in the central part of the Arabian Sea is maintained essentially by large scale mixing processes. Further theoretical considerations, which are based upon observations at the 800 m level, suggest that the distribution of salinity at the margins of the basin strongly influences the salinity of the inner part. A change in the marginal distribution on the other hand, may be caused by means of horizontal movements of relatively small width. In further investigations on the circulation of the Arabian Sea one has therefore to consider especially the processes at the margins of the basin.

Description: Although vertical velocities are very small, they are of great importance with regard to chemical and biological processes in the sea. A study of the circulation phenomena of down- and upward moving watet masses is not possible experimentally. Therefore, the vertical velocities were determined by means of a theoretical model using empirical data obtained by R. V. "Meteor" in the Arabian Sea, during the period of tbe NE-monsoon 1964/65. Based upon the observed data for the density the physical topography of the sea level was calculated by means of the dynamic method. The wind registrations during the hydrographic stations of R. V. "Meteor" show a very constant wind distribution of the NE-monsoon. The data of wind distribution, shapes of sea level and pycnocline were used in a simple two dimensional two layer model with two constant densities and two constant vertical eddy coefficients. The main results are presented in horizontal charts for four levels from O to 300 m for the African and for the Indian coast (plate 6 and 7). The charts show alternative strips of weak upward and downward movements parallel to the coast. The width of the strips varies from 30 to 80 km. There are three areas of intensified vertical velocities: south of the island of Socotra (profile III), south of the equator near the coast of Mombasa (profile VIII), and southerly from Karachi (profile XV). These results of stripwise distribution of upward and downward velocities are compared for one case with the distribution of particulate carbon, which shows a similar alternative distribution of minimum and maximum values (plate 8). Maximum velocities of 2 · 10-4 cm/sec occur in profile XV, in the layers between 100 and 200 m. On the other profiles velocities are less than 10-5 cm/sec. In all cases it was found that the vertical velocities reach a maximum well below the pycnocline, in order to decrease in either direction.

Description: During the expedition of R.V. "Meteor" in the Indian Ocean the following data were observed on a section from 58° E, 3° S to 58 ° E, 2° N during the end of january 1965: Temperature and salinity by hydrographic casts as well as by continuous registrations with the bathysonde. In addition, observations of several chemical parameters, and measurements of the meridional and zonal current distribution down to 250 m depth were obtained. The results indicate no evidence of an eastward directed equatorial undercurrent towards the end of january 1965: On the contrary, we find relatively strong westward directed currents. Chemical data corroborate this fact as there is no similarity with the distribution of oxygen or phosphate on transequatorial sections from the Pacific or the Atlantic Ocean. A weak eastward directed component of current at 3° S indicates the appearance of the equatorial counter-current. The bathysonde-registrations indicate the existence of at least two characteristic watermasses: Water from the Arabian Sea between 50 to 100 m depth and water from the Red Sea at 700 to 800 m depth.

Description: The Red Sea has a special place among the adjacent seas of the world. High evaporation, exclusion of its deep water from contact with the Indian Ocean proper and complete absence of continental drainage may result special conditions of the chemistry of the Red Sea. This paper aims to describe and to explain the peculiarity of the hydrochemical situation. The influence of the topography, of the inflow and outflow through the straights of Bab el Mandeb, of the evaporation, of the stability of the water layers, and of the circulation will be studied. An attempt is made to estimate the apparent oxygen ultilisation in order to obtain an indication of the biological activity. A further attempt is made toward the quantitative estimation of the circulation of the nutrients and also to obtain some information about transport, dissolution, and precipitation of calcium carbonate. The basis of these investigations are mainly observations of R. V. "Meteor" during the International Indian Ocean Expedition 1964/65.

Description: After almost exclusive use in oceanographic research, the R. V. "Meteor" conducted tests in fall 1967 in the Baltic Sea which were devoted to an important problem in ship building research. In order to check the transfer of model test results to prototype conditions, which has become somewhat uncertain in view of the increase in size and speed of modern vessels, a model family of this ship had been tested at scales of 1: 25, 1 : 19 and 1 : 13 .7 5, and full scale tests were to complete the series. The most important measurements included resistance, propeller thrust and propeller power demand. Furthermore, the nomial wake in the absence of the propeller and the effective wake in front of the working propeller, the velocity distribution in the boundary layer at one point of the hull at least and the behaviour of the ship during manoeuvering with and without propeller have been investigated. The most difficult task consisted of the determination of the resistance as a function of speed, because the ship could not be driven by propeller for these tests, but had to be moved, similar to a model on a towing carriage, by a known force exerted above the water surface. Following the historical example of the resistance tests on the ferry boat "Lucy Ashton", the "Meteor" was supplied with 3 jets, which, with a maximum thrust of about 10 Mp at 12 OOO PS, produced a forward speed of 12 kn (Fig. 1, i., 3). The jet thrust was measured by strain gauges on the diagonals in the supporting frame of each jet (Fig. 3). Measurements of thrust and torque of the propeller were also obtained from strain gauges on the propeller shaft (Fig. 7). Wake measurements were performed with pitot tubes and a total head tube fixed on a rake (Fig. 4) which could be turned by 180° on the stem tube. Boundary layer measurements were obtained by two Prandtl tubes which could be moved sideways at the hull (Fig. 6). Rudder forces were indicated by a three component balance on the rudder shaft. Ott current meters and Prandtl tubes, calibrated on the mile distance, gave the ship speed. All measurements were performed electronically with analog and digital registration. The results obtained so far are remarkably accurate. Plotting the resistance values in the system of the model family indicates, that the ITTC 1957 line, presently in use as an extrapolator for frictional resistance, has too small a slope (Fig. 11 ). The total efficiency of model and prototype is about equal (Fig. 14), and the thrust deduction fraction does not seem to depend on the scale either. For the law of the wall of the boundary layer, the values K = 0.41 and C = 5.0 from recent laboratory tests are supported (Fig. 15). The evaluation of all results will probably be finished by the end of 1968.

Description: Serial observations of temperature, salinity, oxygen, alkalinity and pH are presented. They were carried out during an anchor station of R. V. "Meteor" west of Cape Sao Vincente (Portugal) in the area of the maximum Mediterranean water outflow, which follows the continental slope off Portugal. Two observational results are pointed out: The Mediterranean water masses spread out into the Atlantic Ocean, consisting of two distinct layers at depths of 700 m (T = 12.0 °C, S = 36.15‰) and 1250 m (T = 11.3 °C, S = 36.40‰). The salinity proved to be the most significant indicatot of the observed stratification (see figs. 2, 3, 4 and 5). The values of dissolved oxygen content, alkalinity and pH in the very near bottom layer (1 m above the bottom at depths of 3250 m) are different from the values at depths of 15 m to 1000 m above the bottom (see figs. 11, 12 and table 1). As this phenomenon is not observed for the salinity, the changes may be interpreted in terms of chemical and biological processes at the sediment - water interface.

Description: The following tables show physical and chemical data observed by the "Meteor" in the Persian Gulf and the Strait of Hormus. This study was performed in accordance with the general programme of the International Indian Ocean Expedition (IIOE) during the period from March 25 th until April 16th, 1965. The water temperature was measured by reversing thermometers; in most cases two instruments were used simultaneously. The absolute mean temperature difference of this double measurement is 0.0153 °C. The salinity was determined both by salinometer and by titration. In this case the absolute mean difference amounts to 0.0174‰. The computations of the density, the specific volume anomaly, the dynamic depth anomaly, the sound velocity and the interpolation for standard depths were carried out by the National Oceanographic Data Center (NODC), Washington.

Description: Changes in the dissolved oxygen content, the alkalinity, and the pH in sea water near the ocean floor are interpreted in terms of chemical and biochemical processes at the sediment water interface. A simple model provides a plausible explanation of the observed phenomena. Special emphasis is given to the importance of borate corrections in the calculation of the solution effects of calcium carbonate.

Description: Continuous Bathysonde profiles of temperature versus pressure were used to follow the depths of isotherms at a deep sea anchor station northwest of the Great Meteor Seamount (30 ° N, 28 ° W) from 19th to 27th of April 1967. Assuming temperature to be a conservative parameter, vertical velocities can be computed from the vertical displacements of isotherms, according to equations (1) or (7), respectively. Several advective terms of higher order, however, seem to be large compared to lower order terms (see equ. (7) and table 1). In addition, advective velocities are only known approximately for the period of the measurements. Therefore the total vertical velocity for each depth could not be determined. However, it can be assumed that vertical velocities of semi-diurnal tidal period are large compared, to vertical motions of other frequencies (see fig. 2). The vertical velocity of the semi-diurnal tidal motion can therefore be computed from equ. (10) (table 2). A subsequent approximation of the observed distribution of the vertical velocity component by eigenfunctions reveals a reasonable description of the baroclinic semi-diurnal tide by internal gravity wave modes of the order 1-4 (see fig. 5).

Description: Based on measurements during the "Atlantic Seamount Cruises 1967" with the German R. V. Meteor, (see Cwss et al., 1969; HORN et al., 1971), the fluctuations of temperature in the upper 275 meters are investigated. The analysis of 67 time-series yields the following : 1. Within the period range from 124 hours to 10 minutes fundamental oscillations and their harmonics occur permanently with relatively high amplitudes. These oscillations could be attributed to the diurnal (K1) and semidiurnal (M2) surface- and internal tidal waves as well as to their harmonics. It ought to be mentioned that in the surveyed area the K1-tide and the inertial wave have the same periods and could not be separated by spectrum analysis. 2. Interactions between the K1- or M2-waves and their harmonics by single superposition are shown in the observed periods. These two facts possibly can be explained by the perturbative influence of the Great Meteor Seamount on long wave motions. 3. Special investigations of the short period range lead to significant oscillations with periods between 15 and 40 minutes, which correspond to the Brunt-Väisälä-frequency calculated from the mean density distribution. 4. The diurnal variation of tempernture at the sea surface has a mean amplitude of 0.3 °C and a penetration depth of about 55 m. The mean vertical eddy conductivity amounts to 260 g cm-1 sec-1.

Description: Data obtained during the "Atlantic Seamounts Cruises 1967" with the German R.V. "Meteor" in the area of the Great Meteor Seamount (30 ° N, 28 ° W) are presented graphically. Sections of temperature, salinity, oxygen, pH and alkalinity (figs. 2-5) generally show horizontal homogeneity, which is obviously disturbed around the top of the seamount. This is conformed in greater detail by the results of two bathy thermograph-sections (figs. 6, 7). The time dependence of variations in stratification and currents is presented in figs. 8-10 and 12-17. They clearly indicate the presence of tidal motions, which are amplified in the area above the plateauby a factor of 4. The marked differences in the vertical amplitude distribution suggest the occurrence of internal (tidal) waves. Figs. 18 and 19 graph the residual currents, which show significant deviations from a uniform directional behaviour, especially in the bottom layer on top of the seamount. Various aspects of the data will be treated by HoRN (1971), HUSSELS (1971) and MEINCKE (1971).

Description: The first expedition planned for 1970 was conducted in the ocean area between the Iberian and West African coasts (north of 15 ° N and 30 ° W, see map). The first three sections of the expedition were devoted mainly to biological questions. The fourth and last cruise-section was concentrated on geological and geophysical problems relating to the exploration of the Iberian shelf and shelf margin. Since the activation of R.V. "Meteor" in 1964, biological work has predominantly centred round two questions: a) comparative studies on nutrient dynamics in poor and rich areas and b) communities in the open ocean and their diurnal periodic migrations. It was the purpose of the Canaries Basin expedition to supplement the data collected during previous research cruises, particularly the Atlantic Seamount cruises ("Meteor" cruise 8 and 9) in 1967 and the West African expedition ("Meteor" cruise 13) in 1968. Research work in the various disciplines of marine biology was carried out simultaneously with the collecting of chemical and physical data indispensable for the understanding of productivity, transport and decomposition of organic matter as well as affording an opportunity to observe biogenic sedimentation. In planning the cruise, special emphasis was laid on ensuring as close a coordination as possible between the individual working programmes; it was decided that of the vast number of problems presently confronting marine science, particularly in the biological field, only a few should be selected and these approached from diverse sides. Each cruise section was directed at one focal point, around which other investigations were grouped. Cruise section I. Nutrient dynamics in an upwelling water body off the West African coast. Cruise section II. Communities and environmental conditions in the region of the Great Meteor Seamount. Cruise section III. Metabolism and communities on the Iberian deep-sea bed. Cruise section IV. Testing of geophysical gear. Moreover, investigations on two important questions that for a considerable length of time have occupied the attention of planktologists and geologists at various German institutes covered several cruise sections: a) The structure of communities in the oceanic deep scattering layers and at the sea surface; an insight into the feeding migrations of these organisms is essential for an understanding of the vertical transport of organic matter in the open sea. b) The origin of sediments in the deep sea and on the Iberian shelf in relation to organic productivity and climatic and oceanographic fluctuations. The Canaries Basin expedition 1970 inaugurated the "Cooperative Investigations of the Northeastern Central Atlantic" (CINECA), a programme coordinated by the International Council for the Exploration of the Sea (ICES) on the recommendation of the FAO and IOC.

Description: The Persian Gulf situated in the arid climate region of the northern hemisphere shows special conditions in its hydrochemistry. The high evaporation, the lack of large rivers, and the exclusion of deep water from the Indian Ocean governs the nutrient cycle. At 95 stations in the deeper part of the Persian Gulf (Iran side), in the Strait of Hormuz, and in the Gulf of Oman determinations of dissolved oxygen, dissolved inorganic phosphate, silicate, and pH were carried out. The data are compiled in the data report (BRETTSCHNEIDER, GRASSHOFF, KOSKE & v. TREPKA 1970). The ammonia, nitrite and nitrate data from 30 stations are added to this report. On 4 selected transverse profiles for phosphate, and dissolved oxygen and on 1 length profile for phosphate, silicate, oxygen, and pH the distribution of these components is shown and the in- and outflow is characterized. It is also pointed out that the nutrients on their way into the Persian Gulf are diminished and that temporary replenishment supply from a layer of about 100 m depth in the Indian Ocean follows. On one horizontal map the phosphate distribution in the surface and 30 m layer gives reference to biological activity. One diagram where nitrogen components are plotted against phosphate shows that nitrate is a limiting factor for productivity. 02/P04-P and P04-P/S‰ diagrams enable the different waterbodies and mixed layers to be characterized.

Description: In July, August and September 1969 a joint German-Icelandic-Norwegian-Expedition investigated time- and space-dependent oceanographic processes in the Norwegian Sea (fig. 1) and in the waters east of theIcelandic Shelf as weil as the geological and geophysical structure of the Norwegian continental slope, the Norwegian Basin and the Jan-Mayen-Ridge. The participating research vessels were "Hafthor" from Iceland, "Helland-Hansen" from Norway, "Anton Dohrn" and "Planet" from the Federal Republic of Germany (FRG) and as shooting vessel "Nordkapp" from Norway. "Meteor" (FRG) was eliminated from the measuring programme because of engine trouble shortly before begin. Due to the prolonged activity of "Planet" the originally planned investigations were almost entirely able to be carried out. The measuring programme and the preliminary results of the geological and geophysical working groups are dealt with separately (Closs et al. 1972). Systematic sounding from "Planet" in the main working area between 62° and 63° N, and 3° 25' and 4° 50' E forms the basis for a special contour map (see supplement). As a result of improved mooring technique in the course of the expedition's oceanographic measuring programme an almost one hundred percental retrieval of instruments was achieved and herewith 49 current and 55 continuous temperature recordings over 12 to 45 days in depths between 10 and 800 m were obtained. Hydrographie sections, nine anchor- and driftstations as well as one in five days six times successively passed through triangular course gave information over stratification and its periodic changes. The distribution of stations and the position of the moored self-contained instruments in the main working area is found in figure 2. Figure 3 gives insight into the registration period and depth of the instruments of the by "Planet" in cross formation moored systems I to VI. Parallel to the work clone off Norway observations were made as to variability of physical and chemical parameters in east Iceland waters.

Description: During the "Atlantic Expedition" in 1965 (IQSY) a comprehensive bathymetric survey and a few hydrographic stations were made by R.V. "Meteor" in the equatorial region of the Mid-Atlantic Ridge. The survey results are shown in a bathymetric chart covering the western parts of the Romanche- and Chain Fracture Zones. West fo the original Romanche Trench another deep trench with a medium depth of 6000 m was discovered. The maximum sounding obtained was 7028 m. Both trenches apparently belong to the same fracture zone, but are distinctly separated from each other. The western boundary of the trench against the Brasil Basin is formed by a sill rising to a depth of about 4400 m. The serial hydrographic observations give some indications of the flow of the cold Westatlantic deep watet in the fracture zone area and its influence on the hydrographic conditions in the East-Atlantic Basin. The upper limit of the nearly homogenious Westatlantic bottom water with an Antarctic component lies in about 4400 m. The water mass entering the system of trenches of the Romanehe Fracture Zone over the western sill originates from the lower part of the discontinuity layer lying above the bottom watet. Potential temperatures of 0.6 °C were the lowest observed by "Meteor" in the western trench. There seems to be a remarkable tongue of relatively high salinity and a minimum of oxygen in the deep watet of this trench. At present we can only speculate upon the origin of this highly saline deep water tongue underneath the eastward moving relatively thin layer of less saline Westatlantic deep watet. In the range of the sill separating both trenches a lee-wave is indicated by the distribution of salinity and oxygen, which implies a vertical transport of water masses. Caused by this transport it is assumed that relatively cold watet may be lifted temporarily to a depth, where it can pass the northbounding ridge, thus getting directly into the Sierra Leone Basin. In the original Romanche Trench the cold Westatlantic deep water seems to fill the whole trough, but its extension remains limited to the trench itself. The water masses found east of the sill separating the trench from the East-Atlantic Basin originate from the lower part of the discontinuity layer. With potential temperatures of about 1.3 °C they are much warmer than those observed in the Romanche Trench bottom water.

Description: At first a technique is presented to evaluate repeated hydrographic sections. In order to separate the periodic variations and the fluctuations which arise as a result of the horizontal motion of the profiling ship, the data at defined locations are averaged relative to time. The procedure of averaging can be applied successfully to sets of sections repeated at a constant rate under the assumption that the spatial field is approximately stationary during the time of observation and that the energy of the overlapping temporal processes is concentrated over a few spectral bands. In these cases, the mean spatial distribution can be expected as a result. The periodic part is extracted as the deviation of the actual sections from the averaged section. This procedure was applied to a set of observations made at 28 discrete stations along a triangular course at the continental shelf off the coast of Norway during the expedition "Norwegian Sea 1969". Temperature sections were repeated six times at an interval of 18 hours. The average section shows the expected downsloping of the isotherms perpendicular to the continental shelf corresponding to the Norwegian current. lt turns out that the fluctuations with respect to time during the period of observation are probably produced by semidiurnal internal tides. Wavelength and phase velocity are estimated to be A = 22 km and c = 0.5 ms-1 respectively. The waves progress towards the shelf at right angles. For depths of 250-500 m at the continental slope a considerable amplification of wave is noticed.

Description: The seaward extension and vertical structure of the Coastal Current have been studied, on the basis of a repeated hydrographic section across the Norwegian Shelf off Stad. Current measurements were obtained from five anchor stations. The current ellipses do not reveal a consistent picture of the tidal current system, indicating that the observed currents may be influenced by internal tidal waves.