A comprehensive study on hydraulic environments to clarify nutrient transport in land-ocean interconnecting zones

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With various field measurements, satellite remote sensing and numerical simulations, in the present study, it has been attempted to clarify the current field and the associated sediment and nutrient transports in coastal areas as land-ocean interconnecting zones, with the influence of terrestrial and ocean water on them. The measurements and analyses have been done for Kashima-nada and Tokyo Bay as typical open and semi-enclosed coastal zones, respectively, and Okinawa coasts as typical coral reef areas. The field measurements have been done by means of, 1) in situ sensor systems with buoy-mounted thermo- and salino-meters and Chlorophyl-a and turbidity meters and bottom-mounted ADCPs and EMCs with pressure-type wave gauges, 2) ship-borne sensors of similar items, and 3) a HF-radar system to detect spatial distribution of sea-surface velocities.In Kashima-nada, it has been succeeded, with the data analysis and the corresponding 3-D numerical simulation of the current field, in clarifyi … More ng the dynamical behavior of the river plume from Naka river on the occasion of the big flood in late August of 1998. The rapid growth of phyto-plankton in a near-shore zone was observed just after the flooding, in which appreciable amount of nutrients may be transported with the river plume. Besides, the dynamic behavior of the coastal water during a typhoon was investigated, with the change of the coastal water quality due to the approach of the Kuroshio water, and the generation of internal tidal waves at the shelf edge and their subsequent deformation and damping on the shelf. In Tokyo Bay, the analysis of the field data obtained both in winter and late summer elucidated highly unsteady characteristics of the approach of the Kuroshio water to the bay mouth and the subsequent exchange with the bay water. Further,. by developing an advanced numerical model for 3-D current computation coupled with a regional atmospheric model, a computation of oil spill dispersion with high accuracy was performed. In Okinawa coral reefs, the current, sediment and thermal environments with influence from river and ocean on them were clarified by field observations. A coastal current field was investigated with field measurements and a numerical simulation to analyze possible long-distance transport of coral eggs. Less