This paper gives an overall description of the maximum significant wave height distribution based on shallow water wave hindcasting which was conducted for each of the 12-selected strong typhoons over a long term of 95 years in Tokyo Bay and for each of the 16-selected strong typhoons over a long term of 85 years in Ise Bay. Sea wind distribution is estimated using the land-based SDP measurement data products acquired around each bay. The largest height in the outer area of Tokyo Bay reduces from 10 m in the offshore boundary to 4 m in the entrance and that in the outer area of Ise Bay from 15 m in the offshore to 7-8 m in the entrance. The distributions in the inner area are roughly classified into two patterns. One has a tendency of wave height increasing towards the bottom from the entrance of the bay and the largest height is a little over 4 m in Tokyo Bay and 6.5 m in Ise Bay. The other has a contrary tendency and the largest height in the entrance is over 4 m. The difference is due to the track of individual typhoon.

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 Shallow water wave hindcastings were carried out for many storms in the Seto Inland Sea, Ise Bay and Tokyo Bay, in cases where hourly sea wind distributions based on measurement data at sea and coastal stations were used. Also, either the SDP land winds-based or the MM5 mesoscale meteorological model-based sea wind distributions were applied. A statistical analysis of the error indices for 50 to 100 cases in each sea area suggests the followings: (1)the measurement winds-based run gives the highest accuracy among the 3 kinds of hindcasts; (2)the SDP winds-based run provides comparable or slightly less accuracy than the former run, although the opposite tendency is found in Tokyo Bay run; (3)the MM5 winds-based run yields a poorer score compared to the other 2 runs.

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 The transport and diffusion of drifter litters or spilled oil are affected by surface current dominantly. Therefore, it is very important to predict the surface current in order to solve these problems. By using the HFRs surface current data and sea surface wind data, we analyzed the characteristics of surface current in Tokyo Bay. Focus on the tidal current and wind-driven current, we investigated the influence of sea surface wind on the HFRs surface current. Moreover, the estimation results of the surface currents were compared with the observation results by HFR.
 We applied the Harmonic Analysis for tidal components, and multiple regression analysis for non-tidal components. Thus we predicted the surface current in Tokyo Bay. Then we applied the results to the diffusion pattern of oil spill accident on the “Diamond Grace” which was occurred on July 2, 1997.
 As a result, we obtained the harmonics constants of Tokyo Bay horizontally, and obtained ranged from 2 to 5 % wind coefficient and deviation angle around 20° clockwise of the wind-driven current.

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 In-situ measurements on microstructures are carried out to investigate turbulent energy dissipation rate in coastal oceans. However it is difficult to figure out turbulent energy dissipation rate near pycnocline, because of the measuring principle of a commonly-used velocity shear sensor. We calculated the turbulent energy dissipation rate using temperature shear data in Kagoshima Bay and demonstrated the worth of this method. Future observations of the turbulence structure of shallow coastal areas where estimation of turbulent energy dissipation rate via turbulent shear data is difficult will be possible via a combination of both turbulent shear analysis and temperature shear data.

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 In Abashiri River, it is demonstrated that salt-water intrusion occurs when tidal level becomes more than the lake water level. It is expected that wind driven current enhances or suppresses. It is expected that wind driven current also enhances or suppresses salt-water intrusion. This study, thus, aims to investigate the influence of wind driven current on salt-water inturion in Abashiri River by following the previous study, which reveals that easterly wind more than 4 m/s enhances salt-water intrusion. An objectoriented environmental fluid dynamics model is applied to investigate the effect of wind driven current on salt-water intrusion. As a result, easterly wind is found to suppress salt-water intrusion, which may support that radiation stress plays a great role in salt-water intrusion compared to wind driven current.

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 Lake Komuke is a typical brackish lake, which is located in the northeastern part of Hokkaido. A lot of birds, such as sipes and plovers, are well known to migrate in Lake Komuke. It is thus important to understand ecological system in Lake Komuke in order to conserve such a significant nature. Mass transport and water quality are the key factors which control ecosystem in an enclosed water body. Therefore, this study aims to clarify the characteristics of water quality and flow field. Conceptual water exchange model was applied and it is revealed that oceanic water intrudes into the lake and the change in surface water level is smaller than the tidal amplitude, which may enhance the primary production of phytoplankton in Lake Komuke.

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 This research aims at the elucidation of the developmental pattern of Anoxic water Masses of the Ariake Bay, and generating conditions. However, the generating in the Ariake Bay differs in ocean space distribution according to the weather and oceanographic-phenomena conditions. Moreover, various environmental elements are carrying out the interaction to the generating. Then, high frequency was removed from the time series data of dissolved oxygen and a meteorological element, and the discrete wavelet transform which separates a low frequency wave was used. After searching for autocorrelation and cross correlation from the data, principal component analysis was carried out. As a result, the cycle of the 14th to 60th day was checked by the element from the autocorrelation of the meteorological element.

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 This paper examines the characteristics of water quality environment in the Yatsushiro Sea with water quality data and red tide data of the Yatsushiro Sea, and sea surfice temperature data of the northern East China Sea. Cluster analysis by the water temperature, salinity, transparency, dissolved oxygen, ph, DIN (dissolved inorganic nitrogen), PO₄-P, and Dsi (dissolved silicate) was conducted, and it divided into five groups. Distribution characteristic based on monthly change of PO₄-P, DIN and Dsi, is suggested the relevance marine culture. It was suggested that water temperature variation of the Yatsushiro Sea is being interlocked with water temperature variation of the northern East China Sea, and became clear that red tide is increasing rapidly in response to the rise of water temperature.

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 It is of great significance to consider local mesh refinement for enhancing the efficiency in numerical computation of tide-induced residual currents in an enclosed bay. The objectives of the present study are thus to propose a mesh refinement index that is useful for determining local areas where finer mesh should be adopted. We performed a series of numerical simulation using several types of mesh with different horizontal resolution of 400m, 800m and 1600m, respectively, in Ise Bay. Computational results of all the adopted mesh systems are basically consistent with field measurements. However, computational results of local residual currents around straits were rather sensitive to the adopted horizontal mesh size, which indicated the importance of adopting local mesh refinement. Thus we proposed mesh refinement indexes in terms of the horizontal gradient of depths and residual currents. Through the comparison of estimated errors of residual currents, we concluded that the mesh refinemnt index using the horizontal gradient of residual currents is more appropriate on the basis of statistical analysis with the value of the coefficient of determination being 0.48.

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 Field investigations were performed to examine environmental factors (wind speed, water temperature, salinity, total alkalinity (TA), dissolved inorganic carbon (DIC), and the metabolism associated with DIC) affecting air-sea CO₂ flux at the lake Furen, Japan. We analyzed the time-series variations of the observed data and their correlationships. In addition, we implemented a multivariate analysis (the path analysis) to examine the direct and indirect effects of the environmental factors on the air-sea CO₂ flux. The environmental factors that directly affect the air-sea CO₂ flux were indicated to be DIC, TA, and wind speed. In turn, the metabolism appears to indirectly affect the air-sea CO₂ flux through DIC, i.e., biological processes, including respiration, mineralization, and photosynthesis.

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 The Great East Japan Earthquake generated a huge tsunami and caused devastating disasters to the maritime structures such as breakwaters and seawalls. The tsunami was much larger than that we had considered in the design, and it caused failure of structures with unexpected mechanism. We have to establish the tenacious design that enables to prevent the structures from having fatal damage against the largest tsunami.
 In the special session, the failure of structures by the tsunami were reviewed and the new design concept of maritime structures, required for the reconstruction of damaged structures and the countermeasures against the largest tsunami that expected in other areas, was discussed.

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