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1.
A storm moves with a constant speed parallel to a stationary geostrophic current which flows only in the upper layer of a two-layer, infinite ocean. It is assumed that the lower layer is motionless. The quasi-geostrophic approximation is valid for a moving speed less than 4 ms–1 for a storm radius of 100 km. The primary change of the upper layer thickness is caused by the wind stress divergence and the time integral of the wind stress curl. A cyclonic storm generates upwelling in its wake. The effect of the stationary flow similar to a western boundary current is minor by an order of magnitude and noticeable only on the left edge of the flow. Scaling of equations of motion and continuity for a more general upper geostrophic flow leads to expansion with a parametera 2=gH m(fL)–2, whereg is reduced gravity,H m is the maximum thickness of the upper layer,f is Coriolis' parameter andL is the storm radius. The zeroth order perturbations of transport and thickness do not include the stationary flow which appears only in the first order perturbations ina 2. When there is a coast, the change of the interface near the coast is dependent on the time integral of the wind stress component parallel to the coast, thus leading to upwelling or downwelling according to the center being to the left or right of the coastline.  相似文献   

2.
Local balance in the air-sea boundary processes   总被引：2，自引：0，他引：2  
A combination of the three-second power law, presented in part I for wind waves of simple spectrum, and the similarity of the spectral form of wind waves, leads to a new concept on the energy spectrum of wind waves. It is well substantiated by data from a wind-wave tunnel experiment.In the gravity wave range, the gross form of the high frequency side of the spectrum is proportional tog u * –4, whereg represents the acceleration of gravity,u * the friction velocity, the angular frequency, and the factor of proportionality is 2.0×l0–2. The wind waves grow in such a way that the spectrum slides up, keeping its similar form, along the line of the gross form, on the logarithmic diagram of the spectral density,, versus. Also, the terminal value of, at the peak frequency of the fully developed sea, is along a line of the gradient ofg 2 –5.The fine structure of the spectrum from the wind-wave tunnel experiment shows a characteristic form oscillating around the –4-line. The excess of the energy density concentrates around the peak frequency and the second- and the third-order harmonics, and the deficit occurs in the middle of these frequencies. This form of the fine structure is always similar in the gravity wave range, in purely controlled conditions such as in a wind-wave tunnel. Moving averages of these spectra tend very close to the form proportional to –5.As the wave number becomes large, the effect of surface tension is incorporated, and the –4-line in the gravity wave range gradually continues to a –8/3-line in the capillary wave range, in accordance with the wind-wave tunnel data. Likewise, the –5-line gradually continues to a –7/3-line.Also, through a discussion on these results, is suggested the existence of a kind of general similarity in the structure of wind wave field.  相似文献   

3.
A coupled model of air-wave-sea interaction is modified based on a new roughness formulation and the latest data. The model parameters for aerodynamic roughness from below (ARB) and wave-dependent roughness from above (ARA, z 0a ) are assumed equal. The combined roughness is assumed to be a function of friction velocity, gravity, air and seawater densities, and wave age (c w ). The model is used in a study of wave-enhanced turbulence under breaking waves to predict turbulent dissipation (), ARA, and drag coefficient (C d ). Both waves and shear production are considered as sources of ocean turbulent energy. The atmospheric part of the model is used only to specify a correct condition at the interface. Numerical experiments are performed to study the -distribution, z 0a and C d , and to compare with data. The major achievement is model verification using all available data. The first full application of this model is in conjunction with an ocean circulation model in a coupled circulation-wave system. Simulations show that the -distribution is strongly dependent on local wind-forced wave heights. For each wind and wave state there is a particular wave-dependent depth that is verified by data. The comparison shows that the model predicted agrees well with the observed of the z –4 law distribution of Gargett (1989). Simulations also show that waves have an important role in causing to differ from the classical wall-layer theory and z 0a , with a value of 0.30 for the empirical constant a a . The model-predicted , z 0a , C d and C gd agree well with data.  相似文献   

4.
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   

5.
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   

6.
The strength of the vertical mixing in the bottom mixed layer near the continental shelf break in the East China Sea was directly measured with the Micro-Scale Profiler (MSP). It has been shown that there is no significant statistical relation between the turbulent energy dissipation and the degree of the stratificationN 2. It seems that the vigorous turbulence occurs not constantly but intermittently in the bottom mixed layer so that a large variation of is found depending on the time. In contrast to , the coefficient of the vertical eddy diffusivityK z is mostly determined byN such thatK z is large in the bottom mixed layer and small in the thermocline. Large value ofK z in the bottom mixed layer is also found in the time series ofK z estimated in terms of Richardson number calculated from the data obtained with electromagnetic current meters. The value ofK z more than 10 cm2s–1 frequently occur in the layer of 20–25 m thick just above the bottom.  相似文献   

7.
The development process of wind-waves of which spectral peak distributes from 0.6 cps to 9.3 cps will be discussed on the basis of the wind tunnel experiments and of the field observations performed at Lake Biwa. The characteristics of power and slope spectra are here presented. The development process of these wind-waves is characterized by three stages;i.e. initial-wavelets, transition stage and sea-waves. In the wind tunnel experiments, the transition from the stage of the initial-wavelets to the transition stage occurs when the wave spectral peak arrives at the line 6.40×10–4 k –2cm2·sec (wherek is wave number) or when the slope spectral density at the frequencyf max becomes larger than 6.40×10–4 sec. In the stage of sea-waves, the component wave of a wave-spectral peak is steepest in the component waves. And the wave spectral peak develops along the line 1.02×102 f –6 cm2·sec (wheref is the frequency corresponding to the wave numberk) untill it reaches the line 33.3f –4cm2·sec, and thereafter develops along the latter line, which indicates the constant density of slope spectrum. It is suggested that the nonlinearity of wind-waves must become stronger as wind-waves develop. The effective momentum flux ws from the air flow to wind-waves in this stage is evaluated to be about 49% of the total stress 0.  相似文献   

8.
The respiration rates of copepod larvae and a ciliate (Placus sp.) from a tropical sea were measured with an oxygen electrode method. The general range of body size of these animals was 40–161m (diameter equivalent to a sphere), and the respiration rate measured was 0.00076–0.00176l O2 (animal)–1h–1 (or 2.02–9.05l O2 (mg wet weight)–1h–1) at 25.5–29.2C. There was no marked difference observed between the respiration rates of copepod larvae and the ciliate. The respiration rates obtained here are relatively higher than the rates of other similar sized protozoans found in the literature, but lower than the rate extrapolated from larger planktonic copepods in tropical seas.The present results and other information available on microzooplankton biomass suggest that microzooplankton respiration is of near equal importance to that of net zooplankton in the study of energy flow through tropical, pelagic ecosystems.  相似文献   

9.
Particulate matter was collected in the Bering Sea and the northern North Pacific Ocean during the cruise of R. V. Hakuho-maru, Ocean Research Institute of Tokyo University in summer of 1975. The particulate matter was analyzed for organic carbon and nitrogen, chlorophylla and amino acids.The concentrations of particulate organic carbon and nitrogen were measured with the range of 16–422gC l–1 and 1–85gN l–1, 19–186gC l–1 and 1–26gN l–1, 46–1,038gC l–1 and 6–79gN l–1 and 19–246gC l–1 and 2–25gN l–1 in the Oyashio, the Deep Bering Sea, the continental shelf of Bering Sea and the northern North Pacific, respectively. Particulate organic carbon and nitrogen decreased with depth throughout the areas. The average concentrations of organic carbon and nitrogen in the entire water column tended to decrease in the following order; the continental shelf > Oyashio > northern North Pacific > Deep Bering Sea.C/N of particulate matter varied in the range of 3–15 (7 on average) in surface waters throughout the areas and these values tended to increase with depth to 5–20 (11 on average) in deep waters without significant regional variability.Linear regressions between chlorophylla and particulate organic carbon in the euphotic layers indicate that detrital organic carbon accounted for 34.2, 44.9, 49.1 and 25.2 % of particulate organic carbon in the Oyashio, the Deep Bering Sea, the continental shelf and the northern North Pacific, respectively.Particulate amino acid was determined in the range of 10.3–78.0g l–1, 104–156g l–1 and 10.4–96.4g l–1 in the Deep Bering Sea, the continental shelf and the northern North Pacific, respectively. Aspartic acid, glutamic acid, serine, glycine and alanine were found as dominant species of amino acid of particulate matter.  相似文献   

10.
Bispectral analysis is applied to records of the vertical profile of the vertical temperature gradient in the oceanic thermocline in the San Diego Trough. The bispectra exhibit three notable features; (1) bispectral peaks at the points (0.2 m–1, 0.2 m–1) and (0.2 m–1, 0.1 m–1), (2) bispectral ridges along the lines ( 1= 0, 2= 0 and 1+ 2= 0 corresponding to peak wavenumbers 0 in power spectra, and (3) array of bispectral peaks of interval of 0.2 m–1 The results are compared with the bispectra of several modeled time series of spike-array type. The periodicity of 5 m found in the records seems to have two meanings: spacing of predominant spikes and wavelength of predominant sinusoidal wave. If this indicates the existence of internal waves having a vertical wavelength the same as the scale of homogeneous layers, it would suggest the possible importance of internal waves in the formation and maintenance mechanisms of oceanic microstructure.  相似文献   

11.
From July to November, the thermocline which has strong temperature gradient (0.7C m–1) is formed in the bottom water of Beppu Bay, and it prevents the downward mixing of surface water. This has caused the bottom water of the basin to become depleted in oxygen, and in November the bottom water below about 60 m depth becomes anoxic. Accordingly manganese and iron are reduced and more soluble under the anoxic condition, those concentrations are high relative to surface water, and the maximums are 1,240g l–1 and 80g l–1. Under the anoxic condition, the flux of dissolved manganese from the sediment is about 10g cm–2 day–1.  相似文献   

12.
In situ measurements of the primary productivity of ice algae and phytoplankton were carried out in the fast ice area near Syowa Station (69°00S, 39°35E) during the austral spring and summer of 1983/84. Standing stock of ice algae reached a maximum of 45.1 mg chla m–2 in late October. Phytoplankton standing stock attained a value of 3.57 mg chla m–2 in mid-January. Primary production of ice algae in late October (7.64 mgC m–2 hr–1) was 14 times greater than that in mid-January (0.54 mgC m–2 hr–1). Production in the water column in mid-January (3.46 mgC m–2 hr–1) was 50 times greater than that in late October (0.07 mgC m–2 hr–1). These results indicate a substantial production by ice algae in the spring and by phytoplankton in the summer period.  相似文献   

13.
Analyses of gallium content were made by the fluorometric method on 57 samples of seaweeds which were composed of 30 species. As the result of it, the gallium content was found ranging from 0.02 to 0.64g g–1 and the average was 0.14g g–1 in the dried seaweeds.Generally, the gallium content in seaweeds had a close relationship to the aluminium and iron contents. The average weight ratio of Ga/Al was 3.8×10–4 and one of Ga/Fe was 4.0×10–4. The average Ga/Al weight ratio (3.8×10–4) was very similar to that reported for shallow-water deposits (2.1×10–4), but was definitely lower than that in sea water (1.5×10–2).  相似文献   

14.
A new set of empirical formulas for the production rate and the number concentration of sea-water droplets on the sea surface are proposed, synthesizing past observation data of sea-salt particles in the sea and water droplets in wind-wave tanks. A new levelz c is introduced as the effective wind-sea surface where seawater droplets are produced. The new formulas are expressed in linear functions in logarithmic scales ofu*2/v p , a parameter to describe overall conditions of airsea boundary processes, whereu * is the friction velocity of air,v the kinematic viscosity of air and p the peak angular frequency of wind-wave part of wave spectra. A model of coexistence of spray droplets and suspended particles near the sea surface is proposed. As for the independent parameter, a comparison between the uses ofu*2/v p and ofu * 3 which was the traditional way of parameterization excluding wave measure, shows that the advantage of usingu*2/v p is statistically significant with a confidence limit 89% in F-test.  相似文献   

15.
Benzo(a)pyrene (BP) in the sediment of Osaka Bay were determined. High concentration was found at two stations near the mouth of Shin-Yodo and off Kobe respectively (0.98g g–1 dry mud basis, 1.1g g–1). The concentration decreases regularly from the mouth of the river further into the bay. The other supplemental determination was carried on the sediment and the seawater of Keihin Canal. Notable BP concentration of 89g g–1 was observed in the sediment beneath the effluent outlet of a gasworks. The BP in the sediment near the ironworks was also considerable, while the BP was relatively less in the sediment beneath the effluent outlet of refineries. These data suggest that coke plants working in gasworks or ironworks may be the larger sources of BP than refineries. The results of Osaka Bay coincide with this hypothesis.Cadmium, lead, copper, zinc, nickel, ignition loss and fine sand content were measured from the same sediment samples of Osaka Bay. Cd, Pb, Cu and ignition loss showed the regular distributions which resemble to BP and accordingly, good correlations with BP. No significant correlations were found between BP and Ni, Zn and fine sand content which showed no regular distributions.  相似文献   

16.
The 18O and 13C compositions of glacial- to Holocene-aged benthic foraminifera in a core collected from the eastern Arabian sea (water depth 1230 m) were determined to investigate glacial—interglacial variations in the intermediate depth water chemistry of the North Indian Ocean. In addition, we determined the 13C composition of Holocene benthic foraminifera from seven cores for which the 18O and 13C of benthic foraminifera from last glacial maximum (LGM) were reported by Kallel et al. (1988). The 13CDIC in the intermediate waters was generally depleted by 0.3–0.4 during the last glacial maximum compared to Holocene.  相似文献   

17.
Early diagenetic properties of Amazon shelf muds are dominated by nonsulfidic Fe and Mn cycling, resulting in relatively little S deposition compared to previously studied marine margin environments. Despite abundant potential reactants typical of sulfidic deposits, authigenic sulfides represent only ~ 10% of diagenetically reduced Fe, and DOP (degree of pyritization) is only ~0.02. The average C/S (wt wt–1) ratio of buried sediment below the zone of SO4 2- reduction is ~ 7.4, ~ 2.6 times more than the commonly assumed modern shelf average of ~ 2.8. The deltaic burial rate forS is ~ 0.65 × 106 tons yr–1. Relatively lowS deposition is promoted by terrestrial weathering that delivers reactive oxide debris, but apparently depends most strongly on reoxidation and rapid burial by intense physical reworking and fluid-mud formation. Diagenetic models of S distributions demonstrate rapid sediment reworking (~ 10–100 cm yr–1 as apparent advection), substantialS reoxidation (84–98%), and in one case, massive sediment deposition of up to ~ 5 m of sediment in ~ 1 year. Extremely low DOP coupled with dominance by nonsulfidic reduced-Fe minerals and lack of biogenic sedimentary structures may be an indicator in marine organic-rich muds of intense physical reworking under oxygenated waters.  相似文献   

18.
A high-resolution sediment core (sedimentation rate ~2 mm/year) from the German Bight was analysed for its foraminiferal stable oxygen isotope (18O) composition. These data were correlated with instrumental summer sea-surface temperature and salinity data from the nearby island of Helgoland, reaching back 100 years. Comparing the isotope data with the instrumental records reveals a distinct 18O–salinity relationship (18O=0.34×S–9.36; r=0.86) for the German Bight, where salinity is mainly driven by freshwater input from the Elbe River. Thus, these findings provide the possibility for future regional paleosalinity and paleodischarge reconstructions for times far beyond the instrumental timescale.  相似文献   

19.
Microbial mats were collected from a variety of sites near hydrocarbon vents along the slope in the northern Gulf of Mexico and, for comparison, from Warm Mineral Springs, Florida, USA. A predominant microorganism in each of the mats was the giant bacterium,Beggiatoa. Diameters of the bacterial filaments ranged from about 6 µm to approximately 200 µm. The latter organisms are the largest prokaryotic organisms yet found. All filaments over about 10 µm in diameter contained a large central vacuole, producing a cell with the cytoplasm as a cylindrical tube underlying the cytoplasmic membrane. Sulfur globules were confined to this peripheral layer. Push cores often contained pyrite tubules whose appearance is suggestive of aBeggiatoa origin. Determinations of 13C inBeggiatoa mats from vents along the Louisiana slope yielded values in the range of –26.6 to –27.9 (PDB), suggesting an unusually high degree of isotope fractionation (–24.9) relative to the carbon source in the ambient seawater, which is typical of sulfur-oxidizing chemoautotrophs. The presence of SO (elemental sulfur) within cells ofBeggiatoa resulting from oxidation of H2S supports the importance of bacterial sulfate reduction processes in the underlying vents for the sustenance of theBeggiatoa mats.  相似文献   

20.
The Algal Growth Potential (AGP) of water samples collected off Gamagori in Mikawa Bay was measured from May 1978 through February 1979, and the limiting nutrient was determined using regression analysis and enrichment bioassays. The surface and bottom water samples had AGP that produced increments of chemical oxygen demand (COD) of 2.1 mg l–1 and 3.1 mg l–1, respectively, on average. These values ofCOD correspond to 46% and 97% of the average COD values of the raw water samples at the surface and bottom, respectively. Seasonal changes of AGP showed a close correlation with those of dissolved inorganic nitrogen (DIN) concentration. Enrichment bioassays showed that DIN was the most deficient nutrient. The DIN:phosphate-phosphorus (PO4 3–-P) ratios and DIN: dissolved phosphorus (DP) ratios in the water samples were below the cellular N:P ratios of the natural algal populations. These results suggest that AGP was mainly limited by DIN concentration.  相似文献   

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