共查询到20条相似文献,搜索用时 31 毫秒
1.
P. A. Stunzhas 《Oceanology》2016,56(6):782-788
The Aral Sea is an important water area both for monitoring and oceanological studies, because its salinity and salt composition strongly differ from the oceanic. We offer a semiempiric calculation method of electric conductivity and the coefficient of its temperature dependence k judging from the ionic composition of water. The properties of the solution are considered as the sum of properties of seven binary salts taken based on the ionic composition of the solution. The MgSO4 concentration is thought to be the highest possible, which makes the salt concentration nearly unambiguous. In a salinity range of 46–120‰ and temperature range of 5–25°C (2002–2009), the standard deviation of the calculated and measured electric conductivity was 2.9%. To refine the calculation of salinity from electric conductivity measurements using the “oceanic” formula, we suggest its preliminary reduction to a constant temperature (20°C) using the measured or calculated coefficient k. 相似文献
2.
From 1979 to 1989, the current Qingshuigou course of the Huanghe River formed a sub - delta which resembles a beak extending into the Laizhou Bay. It covers 618 km2 in area. To meet the needs of developing and constructing the Huanghe River Delta and under the presupposition of keeping the current course for 15-20 a, we forecast mainly by using the OM (1, 1) model that the front border of the sub-delta will be close to 119°30'E and its area will become 923 km2by the end of the year 2000. The Huanghe River will make land 760 km2 in area. 相似文献
3.
Lu Jianghua Xie Shileng
Engineer Planning Design Institute for Water Transportation Ministry of Communications Beijing Professor Senior Engineer First Design Institute of Navigation Engineering Ministry of Communications Tianjin 《中国海洋工程》1996,(4)
- By applying the theory of structural reliability, reliability analyses for the stability of a breast wall on the top of a sloping breakwater are carried out. Based on the analyses, the method for determining partial action / load factors and partial resistance factors of breast walls is expounded, and the design expressions with partial factors are given. The values of partial action / load factors and partial resistance factors are recommended preliminarily according to the computation for breast walls with typical cross-sections. 相似文献
4.
Bao Chenglan 《海洋学报(英文版)》1988,7(1):43-56
There were 8 typhoons over the northwestern Pacific Ocean in August of 1985. Their movement characteristics were mainly northward or recurvature northward. At the same time, a complex movement of 3 typhoons clustering was observed. In this paper, the typhoon movement tendency is studied by using satellite cloud maps. The westward and northward tendencies can be distinguished clearly. Based on this rule, typhoon movement can be forecasted 12-48 h before. Some characteristics models of the typhoon moving northward or recurving northward on the satellite cloud maps are also given in this paper. 相似文献
5.
Analysis of characteristics and mechanism of current system on the west coast of Guangdong of China in summer 总被引:1,自引:2,他引:1
On the basis of data of drifting bottles' tracks and the current measured in anchored stations, as well as temperature and salinity observed in cruise investigations and coastal stations, ADCP current data and AVHRR surface sea temperature (SST) data on the western coast of Guangdong, synthetic results of analysis showed that the coastal currents in the west of the mouth of the Zhujiang River were mainly westward in summer, which constituted the north branch of cyclonic gyre in the east of the Qiongzhou Straits. Part of its water flowed westward into the Beibu Gulf through the Qiongzhou Straits. The coastal current pattern was not identical with the traditional current system which flowed westward in the Qiongzhou Straits in winter and eastward in summer. The summertime's coastal current was always westward, maybe temporarily turning northeast only when the southwest wind was strong. The important characteristics of coastal current on the western coast of Guangdong, in the Qiongzhou Straits and in the north of the Beibu Gulf were analyzed and their mechanisms also were explained. 相似文献
6.
O. G. Ignat’eva E. I. Ovsyanyi A. S. Romanov S. K. Konovalov N. A. Orekhova 《Physical Oceanography》2008,18(2):96-105
On the basis of the experimental data accumulated in 1998–2005, we analyzed the space and time variations of the carbonate
system of waters and the content of organic carbon in bottom sediments of the Sevastopol Bay. The intensity of gas exchange
through the water-atmosphere interface was quantitatively estimated. It was shown that the partial pressure of carbon dioxide
pCO2 in waters of the bay became much higher for the period of observations. The maximum changes were observed in summer. They
were especially pronounced for the bottom layer of waters. For the entire period of observations, the invasion of carbon dioxide
CO2 was predominant in the major part of the bay, and the content of organic carbon in the bottom sediments increased. The ability
of waters in the bay to absorb CO2 is explained by the synthesis of organic substances, which becomes possible due to the presence of the equivalent load of
nutrients.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 57–67, March–April, 2008. 相似文献
7.
Suppression of Wave-Excited Vibration of Offshore Platform by Use of Tuned Liquid Dampers 总被引:3,自引:0,他引:3
This paper describes experimenlal and theoretical investigations of Tuned Liquid Damper (TLD) characteristics tor suppressing the wave-excited structural vibration. The structural model lor the experiments is scaled according to a full size offshore platform by matching their dynamic properties. Rectangular TLDs of different sizes with partially filled liquid are examined. By observing the performance and behavior of TLDs through laboratory experiments, the study investigates the influence of a number of parameters, including container size, container shape, frequency ratio, and incident wave characteristics. In an analytical study, a mathematical model that describes the nonlinear behavior of liquid in TLD and the interaction of TLD and structure is prerequisite. The validity of the model is evaluated and simulating results can reasonably match the corresponding experimental results. 相似文献
8.
FAN Zhisong 《海洋学报(英文版)》2005,24(5):50-60
1 IntroductionThe study of SAR remote sensing of surface wake of a semi-elliptical submerged body is of great importance actually in the ocean. The dynamics and the SAR remote sensing mechanism of this wake are very complicated. Numerous researches (Bergmann et al., 1958; Miles, 1968a,b; Huppert and Miles, 1969; Bon-neton et al., 1993) indicate that in the ocean the imagery and dynamics of this wake are quite different when a semi-elliptical submerged body moves horizontally at high speed … 相似文献
9.
Measurement of nuclides of uranium and thorium series of disequilibrium using γ-spectroscopy 总被引:3,自引:0,他引:3
INTRODUCTIONTheradionuclidesofnaturaluraniumandthoriumseriescanbeusedtotracemarinepro cessofvarioustemporalandspatialscaleandpropertiesthatprovideplentifulinformationaboutphysics,chemistry ,geoscienceandbiologyofoceanbecausetheyhavedifferentchemicalpro… 相似文献
10.
Geomorphological features (derived from 16,000 lkm of echo‐sounding and bathymetric data) and deep‐seated tectonic structures of the continental margin off NW India are presented. The shelf break over the entire region occurs between 80 to 154 m water depth, and adjacent to Saurashtra and Bombay High the depth and orientation of the shelf edge show marked variations. The boundary of the slope is shallower in the northern portion (about 1450 m in the vicinity of the Indus) than in the southern region (2900 m off Bombay). The steep slope off the Gulf of Kachchh has relatively smooth physiography due to higher input of fluvial sediment and burial of structures. The gentler slope off Saurashtra and the Bombay High area has numerous complex features, the most prominent among them being benches at depths of 180–230 m (width 2–10 km) and 650–780 m and a series of bathymetric highs and lows. Slope breaks are also observed between 400 and 600 m off Bombay and between 560 and 960 m off Saurashtra. These features are surface manifestations of the anticlinal features extending along the shelf in this region. Unevenness (order of 100–300 m) due to slumping is also observed at the base of the slope. Based on the correlation between tectonic structures of this area and these subphysiographic features, extension of the Saurashtra Anticline onto the slope, a new strike slip fault (the southern boundary fault of Narmada graben) and an along‐shelf anticlinal structure off Saurashtra are delineated. 相似文献
11.
Beta Distribution of Surface Elevation of Random Waves 总被引:2,自引:0,他引:2
A probability density function (PDF) is derived of beta distribution with both λ3 (skewness) and λ4 (kurtosis) as parameters for weakly nonlinear wave surface elevation by use of a method recently proposed by Srokosz. This PDF not only has a simpler form than the well-known Gram-Charlier Series PDF derived by Longuet-Higgins. but also overcomes an obvious shortcoming of the latter that when the series is unsuitably truncated, the resulting PDF is locally negative. To test the derived beta PDF, laboratorial experiments of wind waves are conducted. The experimental data indicate that the theoretical requirements of the parameters in the beta PDF are fulfilled. The experimental results show that the present PDF is in better agreement with the measured data than the beta PDF only including parameter λ3, and also than the Gram-Charlier Series PDF truncated up to the term of H6. 相似文献
12.
Simulation of the Whole Process of Ship-Bridge Collision 总被引:6,自引:0,他引:6
13.
Milovsky G. A. Ishmukhametova V. T. Shemyakina E. M. 《Izvestiya Atmospheric and Oceanic Physics》2017,53(9):1101-1111
Izvestiya, Atmospheric and Oceanic Physics - The methods of a complex analysis of materials of space, gravimetric, and magnetometric surveys were developed on the basis of a study of reference... 相似文献
14.
-At present, it is still difficult to obtain an accurate maximum wind speed of typhoon with modern means,such as satellite survey , radar tracing and airplane reconnaissance. The performance of statistical equation established with observational maximum wind speed and the central pressure of typhoon is unstable ,and it is unreliable in operational use. Therefore a general pressure field model of typhoon is introduced in this paper based on atmospheric motion equations and formulas are derived for computing the maximum wind speed around typhoon center over sea surface . The theoretical curves derived from these formulas are in good agreement with those using the statistic empirical curves of typhoon pressure-wind relations over the western Pacific. Tests were conducted for typhoons which occurred in 1973 and in 1983 and the strongest typhoons selected each year during 1970 and 1978,the results were satisfactory. Meanwhile the analyses of computing results showed that the effect of Coriolis force could be 相似文献
15.
In this paper,the dynamic response of undersea -+towed systems is numerically simulated.Atwo body towed system is especially considered in detail.The factors influencing the heave oftowed-bodies,such as the weight of the towed-body(in sea water),the length and the weight(in sea water)per unit length of the cable between towed-bodies and towing ship,are investigated in detail.Calculationsshow that the two-body towed system can greatly increases the stability of the towed system. 相似文献
16.
A numerical model is developed by use of the boundary integral equation method to investigate the responses of a two-dimensional floating structure.The structure under consideration consisting of two pontoons,is connected by a rigid framework,and linked to the sea floor by a mooring system.The theoretical conception is based on potential theory with linear external forces,and applied to an arbitrarily shaped body and water depth.The discussion includes the influence of draft and space between pontoons on the responses of the floating structure.Finally,the validity of the method is adequately verified by experimental results. 相似文献
17.
徐立论 《海洋学报(英文版)》1986,5(1):147-147
The development of the offshore industry on a world-wide basis has given rise to thegrowing demand for a good knowledge and understanding of the ocean wave environment.In addition to the accepted probabilistic and spectral methods of defining wave climate,attention has recently focussed on wave groups-a series of waves on enhanced amplitudeoccurring in close sequence. Such an occurrence is important in a range of offshore andcoastal engineering problems, particularly in the dynamic response of compliant offshore sys-tems and the stability of breakwaters. The paper presents a brief review of the previous work on wave groups, followed by 相似文献
18.
- Studies on the erosion processes and protective measures at the downcoast of the Friendship Port in Mauritania have been successfully conducted by means of 3-D movable-bed model using light model-sand. The headland control was accepted for the stability of the beach. This paper mainly deals with the shape, orientation, size and erosion depth of the artificial headland. Various forms of headland projects, such as the normal groin, arch groins bending to upcoast ancj to downcoast, offshore breakwater, and T-shaped dike, have been experimentally investigated. Through a comparison of effects of these works on the beach processes, optimized headlands have been obtained, that is, unsymmetrical T-shaped dike or arch groin bending to the downcoast, which has been practically and successfully applied for the stability of beaches. 相似文献
19.
1 .Introduction Owing to the decline of capture fisheries andsaturation of traditional inshorefarms ,sea cage cul-ture as a newtype of aquaculture is developingrapidlyin China .However ,cage culture is a highriskoperation.The practice is vulnerable to natural hazards ,such as strong tides ,storms and typhoons .So,it is necessaryto assess the behavior of a sea cage exposedto waves and current before the designandinstallation of the structure . Computer simulation,due to its many advantages ,ha… 相似文献
20.
Li Runpei Chen Weigang Gu Yongning
Professor Shanghai Jiao Tong University Shanghai Assistant Shanghai Jiao Tong University Shanghai 《中国海洋工程》1996,(1)
In this paper a numerical analysis method combining FEM incemental technique with limit analysis concept is proposed for the study of the static strength of offshore platform in collision. Large deformation and plasticity are accounted for and the limit yield surface expressed by generalized stress for a tubular section is derived. The modified stiffness matrix of space beam element is formulated by Plastic Node Method. The buckling behavior of beam columns can also be taken into account. It can trace the generation of plastic hinges during loading and finally the ultimate strength of offshore platform against collision is obtained. 相似文献