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Volume 31, Issue 1
Displaying 1-6 of 6 articles from this issue
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Takashige SUGIMOTO1975 Volume 31 Issue 1 Pages 1-14
Published: February 28, 1975
Released on J-STAGE: June 17, 2011
JOURNAL FREE ACCESSThe effects of the coastal boundary geometries on the tidal currents and the tidal mixing are studied mainly on the basis of hydraulic model experiments. Mizushima-Nada Sea, which is located in the central part of Seto Inland Sea, and the whole Seto Inland Sea were chosen as the prototypes.
Currents and eddies geometrically induced in the tidal currents and in the ocean currents have significant effects on the water exchange, from small scales to meso scales, in the bays and near-shore regions of the ocean.
As to small scale phenomena near irregular coastal boundaries such as river mouths, headlands and harbors, tidal currents produce organized eddy currents of the width scale. They are important to the temporary flushing and the local redistribution of the river water or the waste water.
As to phenomena of larger scales, the tidal currents produce rather steady residual circulations in each part of the Inland Sea, due to the non-linear effects of the oscillating component. They are controlled by the geometry of the sea as separated by a narrow strait. These horizontal circulations of about 20 km in scale become the main mechanism of the water exchange in the Inland Sea. The one-dimensional dispersion coefficient due to these circulations is proportional to the product of the diameter and the current velocity of the circulations. The proportional constant takes the value of 0.4-0.5.View full abstractDownload PDF (2066K) -
Barotropic Circular Currents Induced by the Uniform WindNorihisa IMASATO, Seiichi KANARI, Hideaki KUNISHI1975 Volume 31 Issue 1 Pages 15-24
Published: February 28, 1975
Released on J-STAGE: June 17, 2011
JOURNAL FREE ACCESSSome numerical experiments by the barotropic nonlinear two dimensional models are performed to study the water circulations in Lake Biwa, especially to study the large anticlockwise gyre in the north basin. The wind fields used in the experiments have no rotational component. This gyre is induced by the southerly wind and is approximately on the geostrophic balance. The vorticity of this gyre is contributed from the vertical stretching of the vortex tube by the variable bottom topography and the inertia term. But the latter term does not become effective if the bottom profile of the basin is flat. Therefore the horizontal circulation in the barotropic closed basin is the “topographic gyres”. The bottom stress has a little contribution to the vorticity balance of the gyre.View full abstractDownload PDF (3109K) -
Part II. Field ObservationYukio FUJINAWA1975 Volume 31 Issue 1 Pages 25-42
Published: February 28, 1975
Released on J-STAGE: June 17, 2011
JOURNAL FREE ACCESSThe directional spectrum of wind waves was observed using seven wave gauges at the marine observation tower. Directional spectrum was calculated by the method described in FUJINAWA (1974 a) which assures the high directional resolving power. Under the nearly uniform condition of the wind the process of wave development was studied by the use of the data of the directional spectrum. The analysis revealed that, 1) the mean wave direction does not necessarily coincide with the wind direction, 2) the directional spreading is much narrower than hitherto reported, 3) the growth rate is closely proportional to the square of cosine of the angle between the wave direction and the wind direction, 4) the resonancetype wave-wave interaction plays only minor role in the process of wave development for any wave component in the earlier stage of development and for the most rapidly developing component in the main stage of development.View full abstractDownload PDF (2820K) -
Norio OGURA, Akiyoshi KAMATANI, Nobutada NAKAMOTO, Masaki FUNAKOSHI, S ...1975 Volume 31 Issue 1 Pages 43-47
Published: February 28, 1975
Released on J-STAGE: June 17, 2011
JOURNAL FREE ACCESSFluctuation of dissolved organic carbon (DOC) was studied during 1971-1972 at monthly intervals in surface layers of Sagami Bay. Concentration of DOC varied from 0.8 to 1.7 mgC/l in surface water (0 m). Maximum concentration of 1.7 mgC/l was observed in July 1971 and after then DOC decreased gradually to a minimum of 0.8 mgC/l in May 1972. The fluctuation of DOC during the observation periods seems to have close relations with those of water temperature and salinity. High DOC concentration found in summer months may be associated with bloom of phytoplankton or intrusion of seawater from Tokyo Bay and/or inland water containing high DOC.View full abstractDownload PDF (805K) -
Michio J. KISHI, Nobuo SUGINOHARA1975 Volume 31 Issue 1 Pages 48-50
Published: February 28, 1975
Released on J-STAGE: June 17, 2011
JOURNAL FREE ACCESSEffects of the longshore variation of the coastline geometry and the bottom topography on coastal upwelling are discussed. Longshore variations of the topography cause local enhancing or weakening of upwelling in the process of the generation and propagation of internal Kelvin and the shelf waves.View full abstractDownload PDF (417K) -
Reply to Takano (1974)'s PaperMasahiro ENDOH1975 Volume 31 Issue 1 Pages 51-52
Published: February 28, 1975
Released on J-STAGE: June 17, 2011
JOURNAL FREE ACCESSIt is shown by a numerical experiment with fine grid that the finite difference form of rotation of the Coriolis force used in ENDOH (1973) gives practically the same solution as that obtained by the use of the finite difference form pointed out by TAKANO (1974).View full abstractDownload PDF (261K)
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