*********** +++++++++++++++++++++ 122294B.PHY + Source: ONR Asia + *********** +++++++++++++++++++++ Contributory Categories: ENG, GEO, MET, SHP Country: Japan From: Techno-Ocean '94 Proceedings Volumes International Symposium 26-29 October 1994 Kobe, Japan KEYWORDS: With each item Part III/V 3 Items Item 1 V. I, p. 463-467 Text in English STUDY ON CROSS-SHORE PROFILE OF TIDAL FLAT Yasuo KOTAKE(1) Masahiko ISOBE(2) and Yoshiki SAITO(3) (1) Ms. Eng., Graduate Student, Dept. of Civil Eng., Univ. Tokyo (2) Dr. Eng., Professor, Univ. Tokyo, (3) Dr. Sci., Senior Scientist, Marine Geology Dept., Geological Survey of Japan KEY WORDS : tidal flat, sedimentation, mud content ratio, coastal engineering ABSTRACT Tidal flats have many ecological, environmental, and disaster-preventing functions. Since tidal flats exist in very shallow water regions, they can easily be reclaimed or dredged. Many of them have already been vanished with the development of waterfronts. Recently, a few trials of creating tidal flats artificially have been done in Japan to mitigate environmental impacts. The studies on tidal flats can be classified into four types: ecological, fisheries engineering, geographical and coastal engineering studies. Alany results have been obtained but there are few studies on the dynamic beliavior of cross-shore profile of a tidal flat. Though the bed material of most tidal flats in Japan is sand mixed with mud, studies on the transport of the sediment of sand-mud mixture began only recently. To create tidal flats in Japan, it is very important to study details of the dynamic mechanism of sandy tidal flats. In this paper, the dynamics of cross-shore sediment transport. was focused. And mud-sand mixed sediment was discussed as an important factor of the dynamics. A plan of experiment to know the mechanism of mud-sand mixed sediment transport was shown. And necessary improvements were mentioned. FURTHER STUDIES The plan of experiment, which is given above, is only a preliminary one. There are many other physical factors which are not taken into account. For example, the influence of dry and wet cycle by the tide, tidal current, very mild slope, organic surface and so on has not been understood yet. By integrating the results, we construct a numerical model. Fig.4 (Not transmitted) is a flow chart which shonvs the outline of the numerical model. More details will be studied and reported. REFERENCES 1) Uemura M., M. Nakamura , T. Noma , H. Kimura , T. Iikura , S. Sugiura, S. Hagino and R. Oonishi , 1974: Artificial Tidal Flat (1) , Paper of the 21st Coastal Engeneering Conference, Japan Society of Civil Engineers , pp.465-469 (printed in Japanese) 2) Uemura M., M. Nakamura , T. Noma , H. Kimura , T. Iikura , S. Hagino, S. Sugiura and R. Oonishi , 1975 : Artificial Tidal Flat (2) , Paper of the 22st Coastal Engeneering Conference, Japan Society of Civil Engineers , pp.489-493 (printed in Japanese) 3) Ishihara K., 1988 : Solid Dynanmics , Maruzen Co., Ltd., 297p- (printed in Japanese) 4) Kishi S. and Y. Saito , 1992 : Grain Size Analysis of Obitsu Delta in Tokyo Bay , Japan Society of Sedimentology (printed in Japanese) 5) Kishi S. and Y. Saito , 1992 : Holocene Transgression, Regression and Alluvium around Dissected Valley of Obitsu River , Japan Society of Sediinentology (printed in Japanese) 6) Kotake Y., M. Isobe and A. Watanabe , 1992 : Adoption of Fuzzy Theory into Evaluation of Coastal Environment , The 47th Annual Conference of Japan Society of Civil Engineers, Japan Society of Civil Engineers, pp.370-371 7) Kotake Y., M. Isobe and A. Watanabe , 1993 : Studies of Physical Factores in Tidal Flat , The 48th Annuual Conference of Japan Society of Civil Engineers , Japan Society of Civil Engineers p. 972-973 8) Kurihara Y., 1980 Tidal Flats Are Alive: Iwanami Books Co., Ltd., 219p. (printed in Japanese) 9) Kuiharara Y., 1991 Ecology and Ecotecnology In Estuarine- Coastal Area, Tokai University Press, 335p. (printed in Japanese) 10) Saito and S. Kishi, 1992 : Three Dimesional Analysis of Alluvium Sequence around Dissected valley of Obitsu River , Japan Society of Sedimentology (printed in Japanese) 11) Shimizu T., S. Kanayama, S. Inoue, T. Yamada, K. Ueki and T. Sakakiyama , 1992 : Numerical Model of Siltation in a Cooling Water Intake Basin Coastal Engineering in Japan , No. 35 , No.2 Japan Society of Civil Engineers , pp.421-425 12) Tokyo Electric Power Conpany and Tokyo Electric Power Environmental Engineering Co., Ltd. . 1994: Study on Aqucultural Technology around Port Structures of Nuclear Power Plants (printed in Japanese) 13) Tokyo Aviation Enterprise Co., Ltd., 1980: Report of Survey of Sea Environment, The 2nd fundamental Survey of Conservation of Natural Environment, Ministry of Environment, 154p. (Printed in Japanese) 14) Yoshida S., 1984: Studies on the Biology and Aquaculture of a Common Polychaet, Perinereis nuntia (Grube) , Bull Osaka Pref. Fish Exp. Stat.(6) , p. l-63. +++++ Item 2 V. I, p. 469-474 Text in English WAVE OBSERVATION APPARATUS BY MARINE RADAR AND EVALUATION OF ITS ANALYTICAL RESULTS Hiroshi ISHIDA*, Tokujirou INOUE*, Mitsuru HAYASHI**, Shigeaki SHIOTANI#, Ryusuke HOSODA##, Yoshikuni KUNITAKE### *Maritime University of Kobe, **: Nippon Marine Enterprises Co. Ltd., #: Nagasaki University, ##: University of Osaka Prefecture, ###: Mitsui Engineering and Shipbuilding Co. Ltd. KEYWORDS: radar, waves, sea echo, 2-dimension, spectral analysis ABSTRACT The wave observation system by a marine radar has been developed and operated to examine its observational and analytical ability on waves at the west coast of the Awaji Island facing to the Harimanada sea for 30 days in total during 3 years from 1991 to 1993. In 11-run observations when the westerly winds blew relatively strong, the propagating directions and wavelengths of prevailing waves were obtained from the radar sea echo data by directional 1-dimensional (DlD) and 2-dimensional (2D) spectral analyses. The wave directions and wavelengths by the 2D spectral analysis were not different from the visually observed ones by 7 degrees and 6m, relatively. The results by the DlD spectral analysis were not different from the visually observed ones and the ones by the 2D spectral analysis by 270 and 250 in the wave direction and 21m and 16m in the wavelength, respectively. The method of the 2D spectral analysis can provide reliable and accurate wave information from the rgdar sea echo data. The method of the DlD spectral analysis is useful in the automatic selection of the analyzing area on the reproduced PPI radar image for the 2D spectral analysis in this present system, in which the area is selected manually. CONCLUSION The wave observation system by a marine radar has been developed and operated at the west coast of the Awaji Island for 30 days during 3 years from 1991 to 1993. In 11run observations, the westerly winds blew relatively strong, 7-13m/s, and the waves grew up high enough, and the propagating directions and the wave- lengths of prevailing waves were obtained by 2 dimensional (2D) and directional 1-dimensional (DID) spectral analyses of radar sea echo data. At the observatiL,Iial site, the sea was relatively smooth and gentle, and the crest lines of waves were not clear on the radar iniage when the wind speed was less than 7-8 m/s. The wave direction and the wavelength by the 2D spectral analysis (D, and L2) were not different from the visually observed wave direction (Dv) and the estimated wavelength (Le) by 7degrees and 6 m, respectively. The mean of (D2-Dv) was -1.3 degrees and its standard deviation (STD) was 5.10 . The mean of (L2-Le) was 3.5m and its STD was 2.9m. They are fairly well consistent with each other. It is thought that the method of the 2D spectral analysis in this wave observation system can provide reliable and accurate wave information. The DID spectral analysis was made under various conditions varying the beginning distance of analysis from the antenna and the analyzing interval. The distance was changed from 500m to 1000m every 100m, and the interval was changed 320, 640 and 1280m except for 3 combinations, the distances (800, 900, 1000m) and the interval (1280m). The most suitable beginning distances of analysis and the calculating interval were 700m and 640m, respectively, in this study. It corresponds to the grazing angle of the radar beam 0.8 to 1.6 degrees. Therefore, we analyzed the data of which the distance is 700m and the interval is 640m for the DlD spectral analysis. The wave direction and the wavelength by the DlD spectral analysis (D1 and L1) differed with Dv and Le by no more than 27 degrees and 21 m, respectively. The means of (D1-Dv) and (L1-Le) are 14.6 degrees and 6.8m, and their STD are 7.60 and 6.7m, respectively. D1 and L1 were not different from D2 and L2, by 25 degrees and 16m, respectively. The means of (D1-D2) and (L1-L2) are 13.5 degrees and 2.7m, and their STD are 6.2 degres and 6.4m, respectively. The method of DlD spectral analysis cannot be used independently to get wave information from the radar sea echo data because of low accuracy and unstability. This method is, however, useful to select automatically the analyzing area on the reproduced PPI image for the 2D spectral analysis in this wave observation system, in which the area is selected manually. This research was supported by a Grant-in-Aid for Scientific Research, from the Ministry of Education, Science, and Culture, Japan 02302035. REFERENCES 1. Inoue, T. et al., : On the Observations by Using of Navigational Radar, Rev. of Kobe Univ. of Mercantile Marine, Part U, 23, 29-34, 1975. (in Japanese) 2. Inoue, T. and K. Kato, : A Method of Wave Observation and Analysis Using a Shipborn Navigational Radar, J. of Japan Institute of Navigation, 67, 127-135, 1982. (in Japanese) 3. Matsuno T. et al., : Sea Wave Observation by MarineRadar- I ., J. of Japan Institute of Navigation, 69, 107114, 1983. (in Japanese) 4. Inoue, T. et al.,: Wave Observation System by Marine Radar, Rept. of Res. Institute for Marine Cargo Transportation, 5, 161-166, 1991. (in Japanese) 5. Ishida, H. et al., : Outline of the Wave Analysis System of Wave Observation Apparatus Using Navigational Radar, Rev. of Kobe Univ. of Mercantile Marine, Part D, 40, 1-6, 1992. (in Japanese) 6. Ishida, H. et al., : Wave Analysis by Using Navigational Radar and the Simulation Image of Radar Sea Clutter, J. of Japan Institute of Navigation, 87, 217-225, 1982. (in Japanese) 7. Hosoda, R. et al., : Application of Marine Radar for Real- Time Data Acquisition of Sea Condition Around Ships and Marine Structures, Techno-Oceans '92 Inter. Symps, Proc.2, 693-699, 1992. 8. Ishida, H. et al., : Wave Observation and Analysis by Marine Radar- I . -Experiment on the Land Station-, J. of Japan Institute of Navigation, 90, 23-31, 1994. (in Japanese) +++++ Item 3 V. I, p. 475-480 Text in Japanese ON THE DEVELOPMENT OF A GLOBAL WAVE FORECASTING SYSTEM AND THE SHIP ROUTING SERVICE USING GPV DATA Yashusi SUZUKI Michiaki HASHIMOTO Teruhiko TANAHASHI Japan Weather Association 2-9-2, Nishkicho, Kanda, Shiyodaku, Tokyo 101, Japan KEYWORDS : GPV data, wave model, wave forecasting, ship routing ABSTRACT A weather forecasting from Japan Meteorological Agency(JMA) is usually used as FAX charts or teletype messages up to now. In addition to these forecasts, GVP (Grid point Value) products from numerical weather prediction models arte available for producing special value added products. We have developed a global ocean wave forecasting and ship routing service system, in which surface wind GPV from global weather prediction model of JMA is used as a wind forcing term/ GPV wind data is interpolated in 2.5 deg. by 2.5 deg. grid and every 6 hours interval. A third generation global wave model JWA3G which is based on the latest sutdy is used. And then an optimum ship route is decided using routing simulation method. We are planning to extend the forecast time and to improve the routing simulation including the performance of ship using two dimensional wave spectrum from wave models. +++++ END Part III/V ************** END Msg. B.PHY **************