Modern swathe sounding and sub-bottom profiling technology for research applications: The Atlas Hydrosweep and Parasound Systems     

J. A. Grant  R. Schreiber 《Marine Geophysical Researches》1990,12(1-2):9-19

This chapter describes two separate but complementary research echosounder systems originally developed by Krupp Atlas Elektronik GmbH for the new German oceanographic research vessel Meteor.The Hydrosweep is a Hydrographic wide-swathe sweep survey echosounder for both shallow and deep water applications providing accurate bathymetric surveys and terrain-following navigation capabilities.The Parasound system is a hull-mounted dual channel parametric narrow-beam deep sea survey and sub-bottom profiling echosounder enabling particularly high vertical and horizontal resolution of seabed features.  相似文献   

Three-dimensional visualization of mission planning and control forthe NPS autonomous underwater vehicle   总被引：1，自引：0，他引：1  

Zyda  M.J. McGhee  R.B. Kwak  S. Nordman  D.B. Rogers  R.C. Marco  D. 《Oceanic Engineering, IEEE Journal of》1990,15(3):217-221

The Naval Postgraduate School (NPS) is constructing a small autonomous underwater vehicle (AUV) with an onboard mission control computer. The mission controller software for this vehicle is a knowledge-based artificial intelligence (AI) system requiring thorough analysis and testing before the AUV is operational. The manner in which rapid prototyping of this software has been demonstrated by developing a controller code on a LISP machine and using an Ethernet link with a graphics workstation to simulate the controller's environment is discussed. The development of a testing simulator using a knowledge engineering environment (KEE) expert system shell that examines AUV controller subsystems and vehicle models before integrating them with the full AUV for its test environment missions is discussed. This AUV simulator utilizes an interactive mission planning control console and is fully autonomous once initial parameters are selected  相似文献   

Numerical simulation of unsteady free-surface motions using a boundary integral formulation     

D. Sen  M. J. Hinchey  J. H. Lever 《Ocean Engineering》1988,15(4)

A numerical time simulation method is described to solve fluid flow problems including unsteady free surface motion. The method is based on potential flow theory. At every time step, the problem is solved using a boundary integral formulation of the fluid domain. The linearized free surface conditions are integrated in time and the solution is marched forward. Computational results simulating the free surface motion for the cases of a linear progressive wave, wave propagating into a region of calm water and the wave maker motion are presented. Comparison with theoretical results demonstrate the feasibility of the proposed simulation scheme.  相似文献   

Bacterial sulphate reduction in sediments of a european salt marsh: Acid-volatile and tin-reducible products     

D. B. Nedwell  S. Takii 《Estuarine, Coastal and Shelf Science》1988,26(6)

The products of ³⁵S-sulphate reduction by sedimentary bacteria were measured at two sites in a salt marsh on the east coast of England. Non-acid-volatile products were measured, after acid-volatile sulphide was removed, by their reduction to sulphide by digestion with tin. The proportion of the sulphate reduced to tin-reducible products varied between 25% in a salt marsh pan and 61% in creek sediment, over a 0–25 cm depth profile. There were also variations with depth at each site in the proportions of sulphate reduced to tin-reducible products. Further examination revealed differences in the proportions of sulphate which were reduced to free sulphide, acid-volatile sulphide, sulphur or pyrite at the two sites. The data suggest that previous work which did not measure non-acid-volatile products underestimated sulphate reduction rates by three-fold in the creek site, but by only one third in the pan.  相似文献   

Trace metal concentrations in sediments of the Eastern Mississippi Bight   总被引：7，自引：0，他引：7  

B.J. Presley  R.J. Taylor  P.N. Boothe 《Marine environmental research》1992,33(4)

Sediments collected from 3 onshore-offshore transects (12 stations total) in the Eastern Mississippi Bight at 5 different times during 1987–1988 have been analyzed for total Ag, As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Se, Sn, Th and Zn. The data show considerable variation both spatially and temporally, largely as a result of natural variability in grain size and mineralogy. Clay-rich samples from deep water were always more metal-rich than sandy samples from shallow areas. Many samples from near the Mississippi River Delta appeared to be enriched in Ba by about a factor of two, probably as a result of contamination from oil well drilling mud, but there were few other indications of pollution influences. Many samples from throughout the area gave Mn/Fe and Cd/Fe ratios a factor of two or more lower than their Mississippi River source material. This shows that biochemical activity in the sediment is capable of solubilizing reducible and adsorbed metals.  相似文献   

The depletion of oil     

C.J. Campbell 《Marine and Petroleum Geology》1992,9(6)

The trend of previous estimates of the world's ultimate recovery of oil suggests a figure of 1650 BBO, of which 1438 BBO have been discovered and 978 BBO remain to be produced. Some large reported reserve figures are questioned. Importance is attached to the mid-point of depletion when rising production tends to give way to decline. The share of the world's supply coming from six Middle East countries is set to continue to rise from its 1986 low of 16% to as much as 50% by 2010, with the likely consequence of higher oil prices and serious political implications. The world is rapidly approaching a turning point when it has to face the consequences of an irreversible decline in oil production.  相似文献   

Species composition and biomasses of fishes in tropical seagrasses at Groote Eylandt, northern Australia     

S.J.M. Blaber  D.T. Brewer  J.P. Salini  J.D. Kerr  C. Conacher 《Estuarine, Coastal and Shelf Science》1992,35(6)

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The distributions of particulate atmospheric trace metals and mineral aerosols over the Indian Ocean     

R. Chester  A. S. Berry  K. J. T. Murphy 《Marine Chemistry》1991,34(3-4)

Data are presented for the concentrations of Al, Fe, Mn, Ni, Co, Cr, V, Cu, Zn, Pb and Cd in aerosols collected over two contrasting regions of the Indian Ocean. These are: (1) the northern Arabian Sea (AS), from which samples were collected in the northeast monsoon, during which the region receives an input of crustal material from the surrounding arid land masses; and (2) the Tropical Southern Indian Ocean (TSIO), a remote region from which samples were collected from air masses for which there were no large-scale up-wind continental aerosol sources. The TSIO samples can be divided into two populations: Population I aerosols, collected from air masses which have probably impinged on Madagascar, and Population II aerosols, which have been confined to open-ocean regions to the south of the area.The data indicate that there are strong latitudinal variations in the chemical signatures of aerosols over the Indian Ocean. The input of crustal material to the Arabian Sea gives rise to an average Al concentration of about 1000 ng m⁻³ of air in the northeast monsoon regime. As a result, the concentrations of all trace metals are relatively high, and the values of crustal enrichment factors are less than 10 for most metals, in the AS aerosols. In contrast, TSIO Population II ‘open-ocean southern air’ sampled during the southwest monsoon season, has an average Al concentration of only about 10 ng m⁻³ of air. Trace metal concentrations in the TSIO ‘open-ocean southern air’ during the southwest monsoon season are representative of ‘clean’ remote marine air and are generally similar to those reported over the central North Pacific.Mineral dust concentrations over the Indian Ocean decrease in a north to south direction, from about 15–20 μg m⁻³ of air in the extreme north to about 0.01–0.25 μg m⁻³ of air in the far south. The deposition of mineral dust over the northern Arabian Sea can account for approximately 75% of the non-carbonate material incorporated into the underlying sediments.In the Arabian Sea the dissolved atmospheric inputs of all the trace metals, with the exception of Cu and Co, exceed those from fluvial run-off by factors which range from 9.6 for Pb to 1.6 for Cr.  相似文献   

南海囊糠虾亚科的初步研究   总被引：1，自引：0，他引：1  

王绍武  刘瑞玉 《海洋科学集刊》1987,(28):205-231

囊糠虾亚科Gastrosaccinae 包括的种数并不很多，但有些种数量相当大，是经济鱼虾的天然饵料，在海洋食物链中占较重要的地位。例如黄海的漂浮囊糠虾Gastrosaccus pelagicus Ii 数量很大，普遍发现于底层鱼类胃含物中；此种及其他一些量大的种又可用作养殖鱼虾的饵料。这一亚科迄今已知共7属69种。本文根据中国科学院海洋研究所1958-60年在南海北部所采的底层浮游生物标本和中国科学院南海海洋研究所1974-81年采自西沙群岛、中沙群岛的标本写成，共发现4属12种，其中6种为中国近海的首次记录。  相似文献   

A review of the biology and ecology of Calanus agulhensis off South Africa     

Huggett  J. A.; Richardson  A. J. 《ICES Journal of Marine Science》2000,57(6):1834-1849

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