Radiation balance and heat budget at the ocean/atmosphere interface in the western North Pacific

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.     

Analysis of photographic images of the structure of the surface of the sea near a speck of light

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     

On the relation between the growth rate of water waves and wind speed

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.     

Bispectra of spike-array type time series and their application to the analysis of oceanic microstructures

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.     

Relationship between cadmium and phosphate in the northwest Pacific Ocean

The relationship between Cd and PO₄ in the Kuroshio and Oyashio regions and the Okhotsk Sea was examined. The resultant equations are as follows: Cd (ng l^–1)=37.0 PO₄ (M)+2.6; Cd(ng l^–1)=32.1 PO₄ (M)+1.2 and Cd (ng l^–1)=34.1 PO₄ (M)+7.9, respectively. These results are in good agreement with previously reported studies, and indicate that during removal from surface waters to deeper waters by biological assimilation and regeneration in deeper waters Cd and PO₄ maintain the same ratio in the open ocean. The relationship between Cd and PO₄ in coastal waters, however, differed from that in the open ocean.     

Variation of water system distribution in the Sanriku Coastal Area

We analyzed hydrographic data obtained monthly by the Iwate Prefectural Fisheries Laboratory during 1977–1981. Our attention was focussed on the classification of waters based on the Temperature-Salinity (T-S) scatter diagram analyses, and on the extraction of the mean state of their distribution for each season. The water system was defined as all waters occupying some specific region on the T-S plane, and the mean state for each season was expressed by the distribution of the mode water systems (i.e., the most commonly occuring water system).Because of the coexistence of the Tsugaru Warm Current, the Oyashio and the Kuroshio, and their large seasonal variability, the sea waters had a wide variety of T-S combinations. The detailed T-S scatter diagram analyses allowed us to classify the waters into six water systems. A time-longitude diagram of water systems and the distribution of mode water systems are presented. The latter showed clear seasonal variations of the Tsugaru Warm Current and the Oyashio.Though the water system analysis was successfully able to present the distribution of the various waters in the Sanriku Coastal Area and to clearly extract the mean state of sea conditions, it was found that the classification of water systems on the T-S plane was not complete in all cases for this area.     

Intrusive Stratification of the Gulf-Stream Frontal Zone According to the Results of Investigations Performed during Cruise 43 of the R/V Akademik Vernadskii

We analyze the data of investigation of the intrusive structure of the Gulf-Stream frontal zone obtained in making frequent drift sections with the help of an MGI-8102 probing complex, study the regularities of variation of temperature, salinity, and density along separate intrusions, and present a series of results connected with the specific features of initiation and development of intrusions and the types of exchange processes determining their transformations. It is shown that the T-diagrams of all intrusions are well separated into segments with different slopes. Moreover, by comparing the slopes and locations of these segments with each other and with the T-diagrams of the Gulf Stream and slope waters, we can fairly reliably attribute the corresponding segments of intrusions to one of the following four types: initial dynamic folds of the frontal zone, layers of domestic water separating the intrusive segments of foreign water from each other, intrusive segments characterized by the penetration of ambient water, and segments not intrusive initially but getting the required slope as a result of interaction with upper and lower intrusive segments. For segments of the last two types, it is possible to specify the predominant type of exchange.     

The statistical distributions for the elevation,velocity and acceleration of the surface of wind waves

Water surface elevations(t), vertical surface velocities and vertical surface acceleration of wind-generated waves have been measured in a laboratory wind wave channel by using resistance-type wave gauges combined with an electronic differentiation circuits. Probability distributions of the values of(t), , and have been determined from the wave records.In an initial stage of wave generation,i.e., when wind waves are generated at short fetches and low wind speeds, the observed distributions for(t), and are appreciately good fit to the distributions given by successive sum of a Gram-Charlier series, which has been derived following the formulation ofLonguet-Higgins (1963), by taking the weakly nonlinear effect into account.However, when wind waves develop with increasing wind speeds and fetches, the observed distributions deviate gradually from the Gram-Charlier series. Particularly, the deviations are remarkable for the distribution of .When the wind speed increases, the observed distributions of(t), and show the following characteristics: (i) the skewnesses of the distributions of(t) and decrease slightly, (ii) the skewness of changes, at some wind speed, from positive small values to relatively large negative values, (iii) the kurtosis of the distribution of(t) decreases slightly but that of increases slightly and these characteristics seem to depend not so much on fetches, (iv) the kurtosis of the distribution of increases rapidly.     

Thermolability of dehydrogenases from a psychrophilic marine bacterium

The heat lability of succinic dehydrogenase, malic dehydrogenase and lactate dehydrogenase in cell-free extracts ofVibrio marinus MP-1 grown at 15C was compared for the tris buffer suspended enzymes and the NaCl suspended enzymes. The tris buffer suspended enzymes lost 50 percent activity at low thermal exposure between 5C and 27C. No activity was evident on thermal exposure between 32C and 39C. The enzyme extracts suspended in NaCl at 36 % were more heat stable, losing 50 percent activity after exposure between 16C and 40C. The enzymes lost all activity on thermal exposure between 33C and 42C in the presence of NaCl.     

Some remarks on the spectrum of rapid-changing random data in the ocean

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).     

Field data support of three-seconds power law andgu *σ−4-spectral form for growing wind waves

Observational data on air-sea boundary processes at the Shirahama Oceanographic Tower Station, Kyoto University, obtained in November, 1969, was analyzed and presented as an example representing the structure of growing wind-wave field. The condition was an ideal onshore wind, and the data contained continuous records of the wind speed at four heights, the wind direction, the air and water temperatures, the tides, and the growing wind waves, for more than six hours. The main results are as follows. Firstly, in both of the wind speed and the sea surface wind stress, rather conspicuous variations of about six-minute period were appreciable. Secondly, the three-seconds power law and its lemma expressed byH ^*=BT ^*3/2 and=2BT ^*–1/2, respectively, are very well supported by the data, whereH ^*(gH/u _* ²) andT ^*(gT/u _*) are the dimensionless significant wave height and period, respectively, the wave steepness,u _* the friction velocity of air,g the acceleration of gravity, andB=0.062 is a universal constant. Thirdly, the spectral form for the high-frequency side of the spectral maximum is well expressed by the form of()= _sgu_*^–4, where is the angular frequency and() the spectral density. The value of _s is determined as 0.062±0.010 from the observational data. There is a conspicuous discrepancy between the spectral shape of wind waves obtained in wind-wave tunnels and those in the sea, the former containing well-defined higher harmonics of the spectral peak, and consequently there is an apparent difference in the values of _s also. However, it is shown that the discrepancy of _s may be eliminated by evaluating properly the energy level of the spectral form containing higher harmonics.     

Some characteristics of the development process of the wind-wave spectrum

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.     

Analytically derived wind-wave directional spectrum part 1. Derivation of the spectrum

In contrast with the usual method to obtain the wind-wave directional spectrum by multiplying the frequency spectrum with an empirical directional function, the authors attempt to derive analytically the directional spectrum by adopting proper spectral form and using effective parameters, namely, the zero order momentm ₀ of the wind-wave frequency spectrumS(), its peak frequency ₀ and the so-called peakness factorP=₀ S(₀)/m ₀, where is angular frequency. The directional spectrum is given in a form of frequency spectrum for each direction. The spectral directionality depends on, in addition to frequency, the wind-wave growth status, for the peakness factorP as introduced by the authors previously is a measure of the wave development stage. The salient features of the directional spectrum, comparison with existing formulas and the verification of the spectrum by observational data are to be given in the Part 2 of the paper.Project supported by the National Natural Science Foundation of China.     

A study on the chemical forms of radionuclides in seawater—II chloride and sulfate complexes of60Co

The apparent stability constants for chloride and sulfate ions with Co (II) at ionic strength of 0.67 were determined by the cation exchange method. The value of the stability constant ₁ for chloride ion with Co (II) ion was 0.79±0.055. The stability constants ₁, ₂ and ₃ for sulfate ion with Co (II) ion were 12.0±0.27, 91.5±11.4 and l,110±250, respectively. The chemical species of Co (II) in seawater was estimated at the pH of 8.0 to be present as Co²⁺ (63%), CoCl⁺ (27%) and CoSO₄ ⁰ (8.6%) using the known value of dissociation constant of Co (II), and under the assumption that only major inorganic anions are responsible for the chemical equilibrium of Co (II).     

Calcium-alkalinity relationship in the North Pacific

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.     

Formation of the vertical salinity profile in the Black Sea

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.     

The mechanism of the development of wind-wave spectra

The mechanism of the development of wind-waves will be proposed on the basis of the observed wave spectra in the wind tunnels and at Lake Biwa (Imasato, 1976). It consists of two aspects: One is that the air flow over the wind-waves transfers momentum concentratively to the steepest component waves and the other is that the upper limit of the growth of a wave spectral density is given by the ultimate value in the slope spectral density. The first aspect means that the wave field has the momentum transfer filter on receiving the momentum from the air flow. Wind-waves in the stage of sea-waves receive the necessary amount of momentum by the form drag,e.g. according to the Miles' (1960) inviscid mechanism, through a very narrow frequency region around a dominant spectral peak. On the other hand, wind-waves in the stage of initial-wavelets receive it according to the Miles' (1962a) viscous model through a fairly broad frequency region around the peak. The upper limit ofS _max developing according to viscous mechanism is given byS _max =6.40×10^–4 k _max ^–2cm²s andS _max =2.03C(f _max )^–2cm²s(S _max is the power density of the wave spectral peak with the frequencyf _max ,k _max is the wave number corresponding to the frequencyf _max andC is the phase velocity).From the second aspect, the upper limit of the growth of wave spectral density is given by 33.3f ^–4cm²s in the frequency region of late stage of sea-waves. Therefore, the spectral peak, which has the largest value in the slope spectral density in the component waves of the wave spectrum, rises high over the line 4.15f ^–5cm²s. The energy is transported from the spectral peak to the high frequency part and to the forward face of a wave spectrum by nonlinear wave-wave interaction. This nonlinearity is confirmed by the bispectra calculated from the observed wind-wave data. In the stage of sea-waves, nonlinear rearrangement of the wave energy comes from a narrow momentum transfer filter, and, in the stage of initial-wavelets, it comes mainly from small corrugations and small steepness of the wave field.     

Classification of “siome”, streaks and fronts

Siome, which was firstly defined by Uda (1938); is a line of convergence on the sea surface. There are many kinds of siome in the sea. I propose in this paper that siome should be classified into streak and front. Streak is defined as the convergence within the same water mass and front the convergence between two different water masses. Streaks and fronts are classified into more details on the basis of their mechanisms of generation. The proposed classification will be useful for understanding the dynamics of siome and should help to promote interdisciplinary studies around siome regions.     

The thermal effects of cooling system of a thermal power plant on photosynthesis of marine phytoplankton

The activity of photosynthesis and the contents of chlorophylla and pheo-pigments were compared in the samples of the intake and effluent seawater of Owase-Mita Thermal Power Plant and in the seawater samples in the Yoshimi Bay before and after heat treatment. At Owase-Mita Thermal Power Plant, after passage of sea water through the cooling system chlorophylla content reduced to about a half and pheo-pigment content doubled in August with high temperature (25–27C), but the contents of chlorophylla and pheo-pigments changed little in January with low temperature (16C); whereas the depression of photosynthetic activity after passing through the cooling system was 71–77 % in August and 31–46 % in January. In the laboratory experiments, the heat treatment at 34–43C for 7–8 sec., which resulted in temperature rise of 7–8C, gave the decrease of chlorophylla and an increase of pheo-pigments in August temperature (26.5C), but a slight decrease of chlorophylla and a slight increase of pheo-pigments in November at the initial temperature of 19.2C, while in January and December the samples with low initial temperature (11.6 and 10.8C) showed almost no change in the content of pigments; the decrease in photosynthetic activity was 32 % in August sample,ca. 11 % in November sample,ca. 15% in January and almost no change in December. It is concluded that the photosynthetic carbon assimilation of marine phytoplankton is suppressed by passing through the cooling system of a thermal power plant even at lower water temperature in winter, while the content of chlorophylla is affected very little at a temperature below 20C.     

Transmission and reflection of planetary and topographic Rossby waves in a two-layer ocean

Transmission and reflection problems when kissing≓ occurs among planetary and topographic Rossby waves in a two-layer ocean are studied. The slope parameterS(=dh ₂/dx, whereh ₂is the thickness of the lower layer) is assumed to have constant values in the regionsx 0 andxL and to vary linearly with the increase ofx in the region0xL (refer to Fig. 2 in the text). Furthermore, a wave is entered fromx=– and kissing is assumed to occur in the region (0<)x _axx_b(<L).It is found that a wave of the same type as the incident wave is mainly transmitted when the width of the region in which kissing occurs,L _kiss(=tx _b–x_a), is smaller than _kiss=2/(¦K¦+ _y/2), whereK is a representative wavenumber in the regionx _ab, _y is they-component of , and is the frequency. WhenL _kiss is larger than _kiss, on the other hand, the main wave transmitted is of a different type to the incident wave. As an application, transmission and reflection problems of planetary Rossby waves are considered, and it is shown that when an external (internal) planetary Rossby wave is entered, an internal (external) one can be transmitted due to the effect of kissing.