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1.
Spectral characteristics of rapid-changing random data in the ocean are discussed. Analysis shows that, if records are approximated by saw-toothed random series 1 and step series 2, 1 and 2 generally have spectral ranges of the –4th power and –2nd power, respectively, with respect to frequency (or wave number).  相似文献   

2.
Calcium-alkalinity relationship in the North Pacific   总被引：3，自引：0，他引：3  
The dissolution of calcium carbonate in deep ocean water causes variation in calcium concentration (Ca) and alkalinity (TA) in the ratio of one to two. The decomposition of organic matter generates nitric acid, phosphoric acid and sulfuric acid. A proton flux which is derived from this process also changes alkalinity. Using the variation in nitrate concentration (NO3) as an index of the proton flux, the relationship betweenCa,TA andNO3 is expressed asCa=0.5TA+0.63NO3 The values of Ca obtained from direct measurements in the North Pacific are in good agreement with the values estimated from this equation.  相似文献   

3.
Values of root mean square slope 0 and its variations -0 are estimated using the brightness field of an image of the surface of the sea near a speck of light. When 0 and -0 are defined it is highly important to take into account direct as well as dissipated solar radiation.The space-time analysis of the structure of the image brightness field is performed. This gives an opportunity to estimate dispersion relationship and the running effect of a brightness contrast packet. Comparison of the parameters obtained with the theoretical dispersion ratio of internal waves (IW) allows one to make a conclusion that IW surface manifestations are recorded in a frame.UDK 551.463.5  相似文献   

4.
The formation of the spun up region by the withdrawal of water from a watergate located in the eastern boundary in a homogeneous ocean on a beta-plane at low Rossby number is presented. The spun up region penetrates only westward from the Watergate because of the special character of the generated Rossby waves. The growth rate and the final longitudinal length of the spun up region in the dissipative system is much affected by the watergate scale in the north-south direction.The relation with the experiment ofLong (1952) and the geophysical application are presented.  相似文献   

5.
Assessment was made of residual ratio of North Pacific Intermediate Water (NPIW) produced in subpolar region of the North Pacific using chlorofluorocarbons, CFC-11 and CFC-12 (CCl3F and CCl2F2), along 175°E. NPIW on density horizons less than 26.80 remained more than 80% north of 30°N. It was suggested that new NPIW laterally spreads over the northern North Pacific without hardly being diluted by the surroundings. For density horizons greater than 26.80 north of 30°N, NPIW remained less than 60%. The difference in the residual ratio between <26.80 and >26.80 north of 30°N suggests that NPIW is produced on density horizons less than 26.80, which contacts the atmosphere in the subpolar region, and that NPIW is diluted by upwelling deep water on density horizons greater than 26.80 in high latitude of the North Pacific. NPIW on a density horizon of 26.80 remained about 50% south of 30°N. The decrease in the horizontal distribution of the residual ratio of NPIW suggests that half the new NPIW produced in the subpolar region is laterally spread over the North Pacific with the southward movement of NPIW.  相似文献   

6.
The amount of penetration of a western boundary current into a marginal sea which is connected to an open ocean by two narrow straits is estimated from a linear, steady and barotropic theoretical model. In this model the western boundary current in the open ocean is driven by a wind stress imposed at the sea surface. The inflow of the water of the open ocean into the marginal sea is caused by the pressure difference between two straits produced by the wind-driven circulation in the open ocean.Main external parameters are combined into two non-dimensional parameters; and (the ratio of the depth of the marginal sea to that of the open ocean), whereb is the distance between north and south boundaries of the ocean,D 0 is the depth of the open ocean, is the latitudinal variation of the Coriolis parameter andR is the coefficient of friction. The friction is assumed to be proportional to the flow velocity.In the limit of infinite the volume transport into the marginal sea is not affected by the width of two straits and . It is mainly controlled by the wind stress and the positions of two straits. For finite values of , however, the volume transport depends considerably on and the width of the straits.Guided by both this model and physical considerations, we obtained a relation between the volume transport into the marginal sea and the external parameters. This relation predicts that about 2 % of the volume transport of the Kuroshio penetrates into the Japan Sea.  相似文献   

7.
We compare the results obtained by using theoretical and semiempirical models developed for the evaluation of the dissipation rate of turbulent energy in a stratified ocean with independent distribution of this quantity established by the authors for the active layer of the Black Sea (50–300 m) by using a one-dimensional model taking into account the balance of heat, salt, and fluid inside the layer. It is shown that, in a layer with gradual variation of the Väisälä–Brunt frequency N as a function of depth, the predominant sink of the energy of motion into dissipation N 2 is ensured by the flow of energy through the spectrum of internal waves toward low frequencies and small vertical scales. On the contrary, in layers with abrupt drops of density as a function of depth (layers with jumps of density), an important role is played by the interface-type waves and the dependence of on N transforms into N .  相似文献   

8.
Regeneration of silicate in the Japan Sea, an example of semi-closed sea, was studied. In the Japan Sea Proper Water the apparent regenerative ratio of the nutrients was determined to be:O C N P Si=–289 (116)14.3181.It was assumed that the dissolved silicate present in sea water is grouped into three fractions; 1)preformed silicate of conservative nature, 2)oxidative silicate which dissolves in oxidation process of organisms with consumption of oxygen, and 3)non-oxidative silicate which dissolves without oxygen consumption. The dissolution rate ofnon-oxidative silicate in the Japan Sea Proper Water was estimated to be 0.07g-at. Si/l/yr from the data ofAOU values and assumed rates of oxygen consumption. This dissolution rate ofnon-oxidative silicate agreed with that obtained in the deep Pacific by the vertical advection diffusion model byKido andNishimura (1972).  相似文献   

9.
The downward short- and long-wave radiation fluxes at the sea surface (S, L) were measured aboard the R/VHakuho Maru, University of Tokyo, for the period of 117 days on six cruises from 1981 to 1985 in the western North Pacific near Japan. The upward fluxes of short- and long-wave radiation (S, L) were calculated by Payne's (1972) table and the Stefan-Boltzmann's law, respectively. The sensible and laten heat fluxes (Q h ,Q e ) were also estimated from an aerodynamic bulk method.From April to August, the daily mean value ofS varied with the amplitude of 100200 Wm–2. The value ofS was estimated approximately 6% ofS in all seasons. The difference betweenL andL was so small that the net radiation flux (Q n ) was dominated byS. In addition, the net heat flux at the sea surface was also dominated byS due to small values ofQ h andQ e , and then the ocean was warmed at the rate of 111 Wm–2 in April and 63 Wm–2 in August in the Oyashio Area, and 132 Wm–2 in May and 164 Wm–2 in June in the Kuroshio Area, respectively.From September to March, a remarkable negative correlation between the day to day variation ofS and that ofL was observed except when an intense cold air outbreak occurred. It was found that the correlation was caused by the cloud climatological feature of the western North Pacific in this period.S was not a dominant factor in the net heat flux. The value ofQ h +Q e in the Kuroshio Area ranged from 260 Wm–2 to 630 Wm–2, much larger thanQ n which ranged from –8 Wm–2 to 92 Wm–2 in the leg mean values (each leg period was about 10 days). Then the ocean was cooled at the rate of –160–620 Wm–2 during this period. The net heat flux in the Kuroshio Area averaged over five legs from late November to February was –473 Wm–2. This value is 50100% larger than the climatological values reported so far.The temporal and spatial variability of radiation fluxes and heat fluxes during each leg was also discussed.  相似文献   

10.
Various wind velocitiesu *,U /2,U andU 10 are correlated to the measured growth rate of water waves , whereu * is the friction velocity of the wind, andU /2,U andU 10 are the wind speeds respectively at the heights /2, and 10m above sea surface (: wave length). It is shown that within a range of the dimensionless wind speed, 0.1<u * /C<0.6, there are no appreciable differences in the correlations, whereC is the phase velocity of water waves. The present relation between andU shows qualitatively similar properties as the one obtained by Al'Zanaidi and Hui (1984); the growth rate for waves with rough surface is larger than that with smooth surface. However, our present relations give, for the both waves with different surface roughness, larger values by factors 1.71.8 than those given by Al'Zanaidi and Hui's relation.  相似文献   

11.
The vertical distribution of salts brought by the Bosphorus undercurrent is numerically evaluated. By multiplying the average vertical salinity gradient by the diffusion coefficient,K z , and the cross-section of the sea at the appropriate depth, we can determine the total vertical salt flux,Q(z). The derivative ofQ with respect toz depicts the salt source intensity distribution over depth. The highest intensity, Q/z, matches the 200 m depth level, i.e. the shelf edge. Below 1500 m, Q/z equals merely 0.1% of the value observed at a depth of 200 m. Above 37 m, salts are noted to sink, which corresponds to their outflow with the Bosphorus current. The distribution of Q/z and the respective values of mineral phosphorus and hydrogen sulphide are matched up.Translated by Vladimir A. Puchkin.  相似文献   

12.
Chlorofluorocarbons (CFC-11 and CFC-12) in the intermediate water having between 26.4 and 27.2 were determined at 75 stations in the western North Pacific north of 20°N and west of 175.5°E in 1993. The intermediate water of 26.4–26.6 was almost saturated with respect to the present atmospheric CFC-11 in the zone between 35 and 45°N around the subarctic front. Furthermore, the ratios of CFC-11/CFC-12 of the water were also of those formed after 1975. These suggest that the upper intermediate water (26.4–26.6) was recently formed by cooling and sinking of the surface water not by mixing with old waters. The water below the isopycnal surface of 26.8 contained less CFCs and the area containing higher CFCs around the subarctic front was greatly reduced. However, the CFC age of the lower intermediate water (26.8–27.2) in the zone around the subarctic front was not old, suggesting that the water was formed by diapycnal mixing of the water ventilated with the atmosphere with old waters not containing appreciable CFCs, probably the Pacific Deep Water. The southward spreading rate decreased with depth and it was one sixth of its eastward spreading rate of the North Pacific Intermediate Water (NPIW).  相似文献   

13.
In deep ocean settings where water depth greatly exceeds the source-to-receiver length, the geometry is insufficient for accurate determinations of velocity from reflection-moveout. However, velocities are crucial for estimates of physical properties and image processing. Focusing analyses with conventional post-stack two-dimensional migration improves images, but does not produce geologically meaningful velocities except in the special case of a two-dimensional earth. For the more general case of the three-dimensional earth there is no a priori method to determine the degree of geometrical complexity. We present a technique using a short-offset three-dimensional (3-D) data set over the 5 km deep trench west of the Lesser Antilles. These data illustrate highly sensitive post-stack 3-D focusing analyses (± 20 m s–1 interval velocities), and the relationship of these seismically derived velocities to rock velocities. In our Barbados example we were able to establish the presence of a widespread 80-160 m thick low-velocity zone at and above the main low-angle fault. This observation suggests the water-rich décollement leaks water into the overlying sections. Also evident is a low-velocity section associated with turbidite sands. These results are confirmed with sparse logging data and well samples. Deep-water short offset 3-D experiments provide a potentially effective approach for velocity estimation, replacing the operational complexity of long-offsets with simpler short-offset techniques. In areas of structural complications and abundant diffracted energy, it is a surprisingly accurate method, utilizing the high fidelity 3-D wavefield and the information carried in zero-offset diffraction ellipsoids. The velocity used to properly collapse a diffraction ellipsoid is explicitly the velocity of propagation in the media since the travel path is known exactly. Thus, the derived velocities should closely represent rock velocities, unlike the 2-D case where the propagation geometry is not known.  相似文献   

14.
Barotolerant bacterium was isolated from sediment sample which was obtained from the depth of 4033 m in the Izu-Ogasawara Trench. The physiological property, growth characteristics and fatty acid composition were examined. The strain was a psychrotrophic and barotolerant bacterium, and was identified as species in the genusAlteromonas. The fatty acids of the strain were from C12 to C18. As the growth pressure increased, the portion of unsaturated fatty acid in membrane fraction increased due to an increase in the portion of C171 and C181, while the relative portion of C160 and C161 decreased. On the other hand, as the growth temperature decreased, the portion of unsaturated fatty acid increased due to the increase in the portion of C161 and C181.  相似文献   

15.
Detailed bathymetric data from a Hydrosweep multibeam sonar survey of a 250 km-long portion of the superfast-spreading southern East Pacific Rise crest and flanks show that the along-axis variation in morphology and axial depth differs significantly from that observed at the fast-spreading northern East Pacific Rise. While the deep mantle upwelling pattern is similar under the northern and southern East Pacific Rise, our observations require that the connectivity of the shallow, subcrestal plumbing system be more efficient beneath the super-fast spreading southern East Pacific Rise than beneath the slower spreading northern East Pacific Rise.  相似文献   

16.
The design and use of a marine heat probe with capability for measuring thermal conductivity insitu with high accuracy, and providing digital acoustic transmission of data to the ship, is described. The instrument employs the violin bow strength member and parallel sensor string configuration suggested by C. R. B. Lister. Several hundred measurements have been made in the deep ocean on multipenetration or pogostick profiles using a 3 m probe and in deep inlets of western Canada using a 7 m probe. The insitu thermal conductivity technique using a calibrated heat pulse has been studied in detail through laboratory calibration of the probe in materials of known conductivity, through numerical models, and through comparison of insitu measurements with needle probe measurements on sediment cores taken from the same sites. The insitu technique permits a conductivity accuracy of better than ±5% with a recording time of 7 minutes following 7 minutes in the bottom to establish the geothermal gradient. The pulse heating is also more energy efficient than the conventional continuous heating technique.Contribution from the Earth Physics Branch No. 807.  相似文献   

17.
An analytical study is made of linearized internal wave dispersion relation in a density-stratified deep ocean with aN(z) profile which contains turning points. Principal emphasis is placed on obtaining the-k relationship for all frequencies. Taking advantage of the largeness of the nondimensional wavenumber (kS1), the mathematical tool to attack the governing Sturm-Liouville equation is a combination of the two-variable expansion (valid far away from the turning point) and the limit-process expansion (valid in the neighborhood of the turning point). The matching conditions for these two expansion schemes provide the desired-k relationship. A numerical example of this method demonstrates satisfactory agreement with the results obtained by the strict analytical solution and the multi-layered matrix numerical model.  相似文献   

18.
Cysts ofChattonella antiqua (Raphidophyceae) were obtained in laboratory cultures for the first time. They were formed on the surface of glass coverslips added to both P- and N- depleted mediums. The yield was 50–250 cysts cm–2. Crossing experiments showed the highest cyst production in mixed cultures, although cysts were observed in clonal cultures as well. Cysts had approximately double the DNA content of synchronously growing vegetative cells (G1 phase). The encystment process was also monitored: Under P-depleted conditions, small cells were formed that fused to become a triangle-shaped cell which in turn changed into a cyst.These results strongly suggest that cysts are the products of fusion and are diploid. Small cells, triangle-shaped cells, and cysts are considered to be gametes, planozygotes, and hypnozygotes, respectively. Significant mortality was observed in laboratory cysts stored in the cold and dark for five months, although those remaining were capable of germination to reestablish a motile, vegetative population.  相似文献   

19.
Ishiwatari  R.  Hirakawa  Y.  Uzaki  M.  Yamada  K.  Yada  T. 《Journal of Oceanography》1994,50(2):179-195
Organic geochemical study of bulk organic matter (OM), hopanoid hydrocarbon and normal hydrocarbon (C23C35) was conducted for a 936-cm-long sediment core sample from the Oki Ridge of the Japan Sea (Core KH-79-3, C-3; 37°03.5 N, 134°42.6E, water depth 935 m). Stable carbon isotopic ratios were also measured for both bulk OM and individual hydrocarbons. The following results were obtained: (1) The weight ratios of total organic carbon to total nitrogen range from 6.2 to 9.4 in the core. The 13C values of bulk OM range from –25.1–20.7%.. The 13C values of OM in the sections of 140190 cm are lower (–25–24) than those in the other sections (–23–21). This result indicates that OM in the core except for the 140190 cm sections is essentially of marine origin. (2) The 13C value of diploptene (a hopanoid hydrocarbon) in the last glacial maximum (LGM), is –66.3 (vs. PDB), which indicates it originating in methanotrophic bacteria. This result provides evidence to support for the previous ideas (Oba et al., 1980, 1984; Masuzawa and Kitano, 1984) that the bottom waters in the Japan Sea were anoxic in LGM. (3) Long chain (C23C35) n-alkanes of higher-plant wax origin were found throughout the core. Their concentration is high in 140190 cm in depth, suggesting that eolian dust load was high in LGM. (4) The n-alkane/TOC ratio increases with decreasing 13C values of bulk OM. This result indicates that the load of terrestrial (probably eolian dust-derived) OM to the Japan Sea became higher in colder climates. (5) The CPI values of long-chain n-alkanes are different in different 13O stages of paleoclimate, probably reflecting variations in species of terrestrial higher plants as a result of climatological adaptations.  相似文献   

20.
We have investigated the fundamental processes of deep convection in a lake at high latitudes triggered by wind during spring or autumn and the associated deep water formation, executing vertically two-dimensional numerical experiments with a nonhydrostatic model. The water column in which a relatively cold mixed layer overlies a relatively warm layer becomes unstable, when the Ekman convergence on the shore due to along-shore wind deepens the mixed layer below the compensation depth, where water densities in both layers becomes equal to each other because of the thermobaric effect. At the onset of deep convection, the critical Rayleigh number agrees with that predicted by the linear theory. The onset time of deep convection is inversely proportional to the magnitude of wind stress. On the other hand, the onset time is minimal when water temperature in the mixed layer m is 3.1°C because a change of m has two effects oppositely acting on the stability of the water column. After the first onset, deep convection occurs intermittently for a few days. The sinking of the mixed layer water occurs in a thermal-like shape, and its amount is 4184% of the time-integrated Ekman transport when m 3°C while it decreases to less than 10% for m lower than 1.5°C. The present process can explain 30% of the amount of deep water renewal which is expected from the observation in Lake Baikal.  相似文献   

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