A new algorithm has been developed to determine the position of a Data Collection Platform (DCP) that is used for the ARGOS Localization and Data Collection System. The algorithm uses an estimation scheme to correct the orbital parameters to achieve accurate positioning of the NOAA meteorological satellite. It is proved that the positioning accuracy of a DCP by the method of orbital Paramater correction is superior to the translocation method.
Positioning of a moving DCP was also attempted by installing a DCP on board a vessel.

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This paper gives a description of the egg and larval distribution of the Japanese sardine, Sardinops melanosticta (T. & S.), in the surface water of Sagami Bay in connectionwith the water circulation. This circulation is characterized by a frontal zone, with a marked current shear between the offshore water flowing into the bay and the comparatively sluggish coastal water. The sardine larvae were most abundant in the frontal zone, while the egg distribution was mainly confined to the offshore water. The majority of the eggs were in the middle and late developmental stages, and tended to spread out towards the east following the water movement in the outer area of the front. The average size of the sardine larvae distributed in the frontal zone was appreciably larger than that in the surrounding areas. This suggests that the sardine larvae, which were transported from the offshore spawning grounds to Sagami Bay, were concentrated and retained in the frontal zone.

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Current measurements made with a Doppler Current Profiler were taken along cross sections in the Obatake Seto Strait, a small strait in the western part of the Seto Inland Sea.
The energy loss between two cross sections of the strait was estimated using the control volume analysis of the stationary one-dimensional energy equation. The large energy loss observed in the strait cannot be explained in terms of general bottom friction in the coastal region. The loss is attributed to the form loss, which is accompanied by internal turbulence and vortices generated by the specific topography of the strait, in addition to the loss by friction. This is supported by the fact that the energy loss in the strait differs, depending upon the current direction.

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Matsuno and Nagata (1987) showed numerically that the spreading characteristics of the discharged heated water from power plants of existing scale is significantly influenced by the earth's rotation effect. Although the effect of the enhancement of the Coriolis parameter on the spreading characteristics of the formed warm water mass was discussed in order todemonstrate the rotation effect, other parameters such as the density difference between the discharged heated water and ambient water and the vertical eddy viscosity and diffusivity were fixed. In this paper, the dependence of the spreading characteristics on these parameters is examined. Then, it is shown that the overall shape of the formed warm water mass and density and velocity structure strongly depend on these parameters. Also, it is indicated that the behavior of the warm water mass under the rotation effects is too complicated to be described with a few parameters. For example, the internal radius of deformation seems to be one of the determinative parameters, and the increase of the density difference between discharged water and ambient water has a similar effect on the shape of the formed warm water mass as a decrease of the Coriolis parameter. However, a change of the two values has different effects on the detailed density structure and current structure of thewarm water mass. The Prandtl number seems to determine some aspects of the velocity field such as velocity magnitude and width of the southward flowing current zone. However, otherfeatures such as the thickness of the warm water mass are not determined by the Prandtl number.

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Wind-wave spectra measured in a wind-flume are analyzed according to the hypothesis of local equilibrium. The gross relation between the wave height and the frequency is reexaminedto yield the basic validity of the 3/2-power law of Toba orE-uin the range of 0.4≤u≤1, where u is the wave-wind parameter defined byu=ω_pu/g;ωpdenotes the peak frequency of the wind-wave spectra, uthe friction velocity andgthe gravitational acceleration. Noticeable deviationis found, however, foru<0.4 oru>1. In particular, the data forlargeusuggest the existence of an upper limit of the wave nonlinearityEat about 5×10^-2, whereE=Eω_p⁴/g²withEthe total power of the wind wave spectrum. Then, the spectralform is investigated in detail. Asudecreases, the normalized spectrum becomes more gradual as a whole, but its forward (low frequency) part tends to show a steeper profile. In the high frequency region (ω>2.6), the spectrum is found to have a functional form likeu²ω^-3, which differs from the usualω-dependence asω-5 orω-4. It suggests weak dependence of the high-frequency spectra on the gravitational accelerationgand on the peak frequencyωp;spectraldensity at high frequencies may be saturated, so that its magnitude may be dominated by the frequencyω, the friction velocityu, the surface tension and the viscosity.

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Tides and tidal currents in the Tusima Strait are described, and cotidal charts are re-edited on the basis of intensive analysis of observed data. Some remarkable features are revealed as follows;
(a) The amphidromic points of the K1 and O1 tides are remarkably shifted toward the Korean coast compared to Ogura's traditional charts.
(b) The amphidromic point of the O1 tide is detected at a position further southwest than that of the K1 tide.
(c) The anti-amphidromic areas for the semidiurnal tides are located in the southwestern region of the strait and they are close to the Korean coast.
(d) Remarkable amplitude gaps are found between the east and west coasts of the Tusima Islands; the amplitude on the west coast is larger than that on the east coast.
Close examination of each term inthe momentum equation reveals that the M2 and S2 tides are standing waves which have phases of tides about 90 degrees different from those of the tidal current, and the K1 and O1 tides are understood with a composite of the incident and reflected Kelvin waves.

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I am deeply honored to have been awarded the 1988 Okada Prize of the Oceanographical Society of Japan. The present paper reviews my previous works regarding the ecology of deep-seameiobenthos in the western Pacific area.
The outline cen be summarized as follows:
1) On the basis of multivariate analyses, it was found that the rate of the organicmatter flux to the sea bed and the amount of the interstitial space within the sediment are the main factors regulating the abundance of meiofauna in the deep sea.
2) Two indices were proposed to characterize the vertical distribution of meiofauna in the sediment profile, i.e.their maximum depth in the sediment and the degree of their concentration in the surface layer of the sediment. The index of maximum depth was closely related to the oxygenconcentration in the interstitial water. On the other hand, the index of degree of concentration in the surface of the sediment tended to be higher where the supply of food seemed lower.
3) Some taxonomically important species were found from the axis of the Izu-Ogasawara Trench. They arePliciloricus hadalis, the first species of the newest phylum Loricifera from the Pacific area, from the hadal deep sea and the fine clay sediment, andOccultammina profunda, the first infaunal species of Xenophyophorea, a group of rhizopod Protozoa.
4) The vertical distribution ofOccultammina profundacoincided well with the unusual distribution of 210Pb in the sediment profile. The organisms concentratedas high as 500 dpm of 210Pb in their stercomare and granellare. The steady state model confirmed that the species made the peculiar subsurface peak of 210Pb in the sediment.
5) The depth in the sediment profile where the distinct peak of Mn0₂can be seen showed strong correlation with the vertical distribution of meiofauna. This relationship suggests that oxygen concentration in the interstitial water regulates the structure of the characteristic three layers of the calcareous ooze in the deep sea. This idea was proven bythe vertical distribution of free oxygen in the sediment calculated on the basis of respiration rate of deep-sea meiofauna measured using the cartesian diver technique.
6) Radio-isotope techniques used to measure the rates at which particulated organic matter was ingested and dissolved organic matter was absorbed, suggested that deep-sea meiofauna obtained a significant fraction of their energy by absorption.
7) The work carried out so far has revealed the important role of meiofauna in the benthic ecosystem, and emphasized the necessity for intensive research from various points of views on these microscopic organisms.

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