Experimental Investigation of Wave Heights in A Directional Wave Field Through Image Sequences     

Chung-RenCHOU Teng-WeiLIN Ruey-SyanSHIH JohnZ.YIM 《中国海洋工程》2005,19(1):37-48

Measurements of wave heights with image sequences from a Charged Coupled Device(CCD) camera were made. Sinusoidal, as well as unidirectional and directional, waves were used for the experiments. A transfer function was obtained by calibration of the magnitudes of the gray values of the images against the results of wave gauge measurements for directional waves. With this transfer function, wave heights for regular waves were deduced. It is shown that the average relative errors are smaller than 16% for both unidirectional and directional waves.  相似文献   

Field tests of seasat bathymetric detections     

B. Keating  N. Z. Cherkis  P. W. Fell  D. Handschmacher  R. N. Hey  A. Lazarewicz  D. F. Naar  R. K. Perry  D. Sandwell  D. C. Schwank  P. Vogt  B. Zondek 《Marine Geophysical Researches》1984,7(1-2):69-71

Knowledge of the locations and sizes of seamounts is of great importance in applications such as inertial navigation and ocean mining. The quality and density of bathymetry data in the equatorial regions and the southern hemisphere are, unifortunately, highly variable. Our present knowledge of bathymetry, and in particular of seamount locations and characteristics, is based upon ship surveys, which are both time-consuming and expensive. It is likely that a significant number of uncharted seamounts exist throughout the oceans, and remote-sensing techniques may be the most effective means of locating them.  相似文献   

海带综合利用的进一步研究     

纪明侯  史升耀  蒲淑珠  张燕霞 《海洋科学集刊》1963,(3):77-101

海带类的工业利用在国外从17世纪末就开始,19世纪中叶起陆续出现了一些综合利用的方法。近20年来在这方面进行研究工作较多的国家有日本、英国、苏联等。 近几年来,我国由于大力开展了海带的人工养殖,产量猛增,为工业利用提供了必要的基础。我们在研究了海带综合利用中的两个关键性问题一一原料处理和主产品褐藻酸的提取条件——之后,接着开始了综合利用方法的研究。 国外所研究的海带综合利用要点和缺点大致是： 1. 从同一份海带中综合考虑的产品大多是褐藻酸、碘和甘露醇,而很少同时考虑氯化鉀、褐藻淀粉等其他产品; 2. 水溶性成分是用稀酸提取,这不仅消耗酸和中和用碱,而且对褐藻酸会带来很不利的影响; 3. 甘露醇和碘的分离也各有不同：高桥等推荐用铜沉淀法;英国则直接用酒精从海藻中提取甘露醇,或从稀酸提取液中加有机药品制成水不溶性甘露醇衍生物。前者所需铜盐量相当大,且对于氯化鉀、褐藻淀粉的分离研究不利;后者直接以酒精煮沸海藻,必将显著减低褐藻酸粘度,而水不溶性甘露醇沉淀的制备则成本太高,无多大实用价值。 我们认为,要寻求一个较全面、合理、轻济、简易的综合利用流程,首先应考虑： 1. 各种成分如褐藻酸、甘露醇、碘、氯化鉀、褐藻淀粉等的全面利用的流程; 2. 以水代替稀酸作提取剂;同时确定各种产品的适宜分离条件等。 综合利用流程的初步轮廓和结果已于1959年初提出。其后至1960年初这段时间内,我们对于各产品的分离条件和在各步骤中的产率等方面作了比较系统的进一步实验,并且对于先前提出的流程作了部分修正、补充。  相似文献   

Investigations of the East Greenland continental margin between 70° and 72° N by deep seismic sounding and gravity studies     

W. Weigel  E. R. Flüh  H. Miller  A. Butzke  G. A. Dehghani  V. Gebhardt  I. Harder  J. Hepper  W. Jokat  D. Kläschen  S. Kreymann  S. Schüβler  Z. Zhao 《Marine Geophysical Researches》1995,17(2):167-199

Results are presented from a deep seismic sounding experiment with the research vessel POLARSTERN in the Scoresby Sund area, East Greenland. For this continental margin study 9 seismic recording landstations were placed in Scoresby Sund and at the southeast end of Kong Oscars Fjord, and ocean bottom seismographs (OBS) were deployed at 26 positions in and out of Scoresby Sund offshore East Greenland between 70° and 72° N and on the west flank of the Kolbeinsey Ridge. The landstations were established using helicopters from RV POLARSTERN. Explosives, a 321 airgun and 81 airguns were used as seismic sources in the open sea. Gravity data were recorded in addition to the seismic measurements. A free-air gravity map is presented. The sea operations — shooting and OBS recording — were strongly influenced by varying ice conditions. Crustal structure 2-D models have been calculated from the deep seismic sounding results. Free-air gravity anomalies have been calculated from these models and compared to the observed gravity. In the inner Scoresby Sund — the Caledonian fold belt region — the crustal thickness is about 35 km, and thins seaward to 10 km. Sediments more than 10 km thick on Jameson Land are of mainly Mesozoic age. In the outer shelf region and deep sea a ‘Moho’ cannot clearly be identified by our data. There are only weak indications for the existence of a ‘Moho’ west of the Kolbeinsey Ridge. Inside and offshore Scoresby Sund there is clear evidence for a lower crust refractor characterised byp-velocities of 6.8–7.3 km s^?1 at depths between 6 and 10 km. We believe these velocities are related to magmatic processes of rifting and first drifting controlled by different scale mantle updoming during Paleocene to Eocene and Late Oligocene to Miocene times: the separation of Greenland/Norway and the separation of the Jan Mayen Ridge/Greenland, respectively. A thin igneous upper crust, interpreted to be of oceanic origin, begins about 50 km seaward of the Liverpool Land Escarpment and thickens oceanward. In the escarpment zone the crustal composition is not clear. Probably it is stretched and attenuated continental crust interspersed with basaltic intrusions. The great depth of the basement (about 5000 m) points to a high subsidence rate of about 0.25 mm yr^?1 due to sediment loading and cooling of the crust and upper mantle, mainly since Miocene time. The igneous upper crust thickens eastward under the Kolbeinsey Ridge to about 2.5 km; the thickening is likely caused by higher production of extrusives. The basementp-velocity of 5.8–6.0 km s^?1 is rather high. Such velocities are associated with young basalts and may also be caused by a higher percentage of dykes. Tertiary to recent sediments, about 5000 m thick, form most of the shelf east of Scoresby Sund, Liverpool Land and Kong Oscars Fjord. This points to a high sedimentation rate mainly since the Miocene. The deeper sediments have a rather high meanp-velocity of 4.5 km s^?1, perhaps due to pre-Cambrian to Caledonian deposits of continental origin. The upper sediments offshore Scoresby Sund are thick and have a rather low velocity. They are interpreted as eroded material transported from inside the Sund into the shelf region. Offshore Kong Oscars Fjord the upper sediments, likely Jurassic to Devonian deposits, are thin in the shelf region but thicken to more than 3000 m in the slope area. The crust and upper mantle structure in the ocean-continent transition zone is interpreted to be the result of the superposition of the activities of three rifting phases related to mantle plumes of different dimensions:

1. the ‘Greenland/Norway separation phase’ of high volcanic activity,
2. the ‘Jan Mayen Ridge/Greenland separation phase’ and
3. the ‘Kolbeinsey Ridge phase’ of ‘normal’ volcanic activity related to a more or less normal mantle temperature.

During period 2 and 3 only a few masses of extrusives were produced, but large volumes of intrusives were emplaced. So the margin between Scoresby Sund and Jan Mayen Fracture Zone is interpreted to be a stretched margin with low volcanic activity.  相似文献   

Mathematical simulation of the bio-optical state of water in application to the passive probing problem     

V. E. Shemshura  Z. Z. Finenko  Z. P. Burlakova  L. V. Eremeeva 《Physical Oceanography》1995,6(6):421-434

The method of bio-optical modelling of seawater is discussed in application to the passive remote sensing of an ocean within the optical wavelength range. The model implies the presence of two hydrobiological characteristics in the algorithm for the spectral composition of upward radiation, namely the phytoplankton pigment concentration and the total particulate organic matter. The method has been thoroughly tested. The data provided byin situ measurements in the areas accommodating waters of different types (from Case 1 and Case 2) and the modelling results, with the errors being considered, are in good agreement.Translated by Vladimir A. Puchkin.  相似文献   

Sedimentary framework of the modern Huanghe (Yellow River) delta   总被引：12，自引：0，他引：12  

B. D. Bornhold  Z. -S. Yang  G. H. Keller  D. B. Prior  W. J. Wiseman Jr.  Q. Wang  L. D. Wright  W. D. Xu  Z. Y. Zhuang 《Geo-Marine Letters》1986,6(2):77-83

The geometry, stratigraphy, and structure of recently deposited Huanghe (Yellow River) Delta sediments were examined by high resolution subbottom profiles and medium-penetration boomer profiles. The results indicate that the active (post-1976) subaqueous delta advances as a single thin localized lobe with a maximum thickness of only 15 m. Calculations of sediment volumes indicate that 90% or more of the sediment supplied by the Huanghe remains within 30 km of the mouth. Sediment on the delta platform near the mouth is fine sand; elsewhere silts and clays prevail.[/p]  相似文献   

Dynamics of dissolved organic carbon in the northwestern Indian Ocean     

M. Dileep Kumar  A. Rajendran  K. Somasundar  B. Haake  A. Jenisch  Z. Shuo  V. Ittekkot  B.N. Desai 《Marine Chemistry》1990,31(1-3)

We report here the non-conservative behaviour of DOC in the northwestern Indian Ocean by studying this parameter together with other carbon and nitrogen components. This contrasts with earlier reports of conservative behaviour. Concentrations of DOC, 3–4 times higher than those reported earlier, were found to decrease northward from the equator. Total carbon dioxide (TCO₂) increases in proportion of the oxygen utilized, thus revealing the dominant biological role in the carbon turnover. The CO₂ added through dissolution of biogenic debris is found to decrease southward, in general. Decomposition of organic material contributes at least 64% to the CO₂ addition that increases southward, the rest being from dissolution of skeletal material. Evidence is provided for the utilization of oxygen and nitrate for DOC oxidative decomposition. Accumulation of DOC without its complete oxidation to CO₂ could be the main reason for the TCO₂ decrease in southern Arabian Sea. Relationships of DOC with nitrification and denitrification processes show that the microbial population plays a major role in regulating the DOC contents in the seawater of this region. Consumption/decomposition by denitrifying bacteria and other micro-organisms responsible for nitrogen cycling in the sea are found to be intimately related to the DOC dynamics and are responsible for decreased DOC concentrations in the north. DOC accumulation in the southern Arabian Sea seems to facilitate bacterio-particulate aggregate formation and consequent nitrification, which results in excess nitrate. Application of a one-dimensional advection-diffusion model to the present data set provides evidence for the non-conservative nature of DOC in the Arabian Sea.  相似文献   

Estimation of phytoplankton pigments,total suspended matter and the concentration of its components by Secchi depth in Guinea's coastal zone     

Z. P. Burlakova  L. V. Eremeeva  V. E. Shemshura 《Physical Oceanography》1994,5(5):383-393

Relationships between the surface concentrations of phytoplankton pigments (C _ph), total suspended matter (C _sm), particulate organic carbon (C _poc), and total suspended phosphorus (C _sp), on the one hand, and the relative water transparency determined through the Secchi disc depth (z _d), on the other, are analysed using the data compiled in the Guinean coastal waters (Tabunsu and Tonkima river estuaries) during November–December 1990. The functions ofC _ph,C _sm=f(z _d) are matched up with the experimentally derived data, as well as with the model bio-optical state of seawater. The general regression equation has been calculated using the data characteristic of various types of water.Translated by Vladimir A. Puchkin.  相似文献   

Paleoecological Relations of Foraminifera in a Desert-Enclosed Sea -The Gulf of Aqaba (Elat), Red Sea     

E. Halicz  Z. Reiss 《Marine Ecology》1981,2(1):15-34

Abstract. Planktonic and benthonic foraminifera live in the desert-enclosed, hypersaline and oligotrophic Gulf of Aqaba and northernmost Red Sea near the edge of their ecological tolerance. Marked changes in foraminiferal abundance patterns in the past, resulting from hydrological shifts related to global climatic fluctuations, facilitate a high-resolution ecostratigraphic subdivision of deep-sea records covering the last 150,000 years. Of particular significance are the foraminiferal plankton/benthos ratios, the presence/absence pattern of such species as Globigerinoides sacculifer , as well as the frequency variation of Globigerina bulloules-falconensis, Buliminacea, Miiiolacea and various "rotaliform" species. Paleoceanographic interpretation of the shifts in assemblage composition and of stable oxygen isotope data obtained on planktonic foraminifera and pteropods indicates that during glacial intervals - because of global cooling, lowered sea-level and reduced water exchange at the straits of Bab-el-Mandeb - the temperature of the upper waters fell by about 4–6 ^oC (to 15–17 ^oC), salinity rose by about 10%o to more than 50%₀ while residence time of the water became longer and the input/output ratio of nutrients became higher. As a consequence, fertility of the photic zone was higher, the organic content of the sediments increased and oxygen levels in the deep basin became reduced. Thus, sea level-oscillations and strait-dynamics played a major role in the foraminiferal paleoecology of the Red Sea.  相似文献   

Irregular wave kinematics from a kinematic boundary condition fit (KBCF)     

George Z. Forristall 《Applied Ocean Research》1985,7(4):202-212

Calculation of the kinematics of random waves above the mean water line presents great difficulties. The kinematic boundary condition fit (KBCF) method approximates the solution through the numerical calculation of a potential function which fits the kinematic boundary condition on a specified surface. Comparisons with a high order regular wave show that the method converges to the true solution when the surface is accurately specified. Tests of the method for irregular waves were made with measurements from a laser-Doppler current meter in the Delft wave tank. These tests showed good agreement between theory and measurement when the surface evolution was calculated correct to second order. Stretched linear theory was also compared to the measurements. The stretched velocities were reasonably good when the phases of the component wavelets were measured but somewhat low when the phases were selected from a uniform distribution.  相似文献