WIND INDUCED CURRENT AND ITS IMPACT ON TIDALLY FORCED WATER CIRCULATION PATTERN IN A CORAL REEF AREA OF SOUTHWEST JAPAN

S.M.B.  Rahaman; Eizo  Nakaza; Yasushi  Kitamura; Seikoh  Tsukayama

doi:10.53808/KUS.2008.9.2.0826-L

Authors

S.M.B. Rahaman Fisheries and Marine Resource Technology Discipline, Khulna University, Khulna 9208, Bangladesh
Eizo Nakaza Department of Civil Engineering and Architecture, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan
Yasushi Kitamura Department of Civil Engineering and Architecture, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan
Seikoh Tsukayama Department of Civil Engineering and Architecture, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan

DOI:

https://doi.org/10.53808/KUS.2008.9.2.0826-L

Keywords:

Ishigaki Island, Shiraho coral reef, tidal current, wind, water circulation

Abstract

Present study was conducted in the coastal region of Ishigaki Island, southwest Japan to analyze possible driving forces of water circulation which is crucial to the understanding of coastal ecosystems. Data were collected through the deployment of oceanographic instruments in and outside the reef. The time series of current velocities indicates that Shiraho coral reef is characterized by an almost regular and controlled water circulation under calm wind condition. Tidally forced oceanic water entered the reef through prominent channel and finally drained out through the southern part of the study area. In the offshore area, tidal currents during flood tide and ebb tide were nearly parallel to the north-south stretch of the reef. Data from Ishigaki Meteorological Observatory indicated that local wind can be an important factor in driving currents both in and outside the reef area. Though the wind field of the region was characterized by both north and south wind, the current field was more strongly influenced by north wind than the south wind. North wind developed a dominant south current inside the reef with a significant temperature drop during winter. During summer, northerly wind contributed to the development of south current in the offshore area as north-south component of wind and current showed the existence of low frequency density peaks. As dominant force came from north wind, no strong peak was seen in the east-west (cross-shore) component of wind and current.

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References

Andrews, J.C. and Pickard, G.L. 1990. The physical oceanography of coral-reef systems. In: Coral Reefs: Ecosystems of the World Vol. 25 (Z. Dubinsky, ed.). Elsevier Scientific Publishing Co. Inc. New York, 11-48.

Atkinson, M.; Smith, S.V. and Stroup, E.D. 1981. Circulation in Enewetak Atoll lagoon. Limnological Oceanography, 26(6):1074-1083.

Atkinson, M.J. and Bilger, R.W. 1992. Effects of water velocity on phosphate uptake in coral reef-flat communities. Limnological Oceanography, 37:273-279.

Bilger, R.W. and Atkinson, M.J. 1992. Anomalous mass transfer of phosphate in coral reef flats. Limnological Oceanography, 37:262-272.

Bilger, R.W. and Atkinson, M.J. 1995. Effects of nutrient loading on mass transfer rates to a coral reef community. Limnological Oceanography, 40:279-289.

Chandrakanth, G.; Raganna, G. and James, E.J. 1987. Mixing and circulation process-Pavenje estuary (Karnataka). Proceedings of the National Seminars in Estuarine Management, pp. 67-69.

Davis, R.A. and Fox, W.T. 1972. Coastal processes and nearshore sand bars. Sedimentary Petrology, 42(2): 401-412.

Denes, T.A. and Caffrey, J.M. 1988. Changes in seasonal water transport in a Louisiana estuary, Fourleaque Bay, Louisiana. Estuaries, II:184-190.

Frith, C.A. 1981. Circulation in a platform reef lagoon, One Tree Reef, southern Great Barrier Reef. Proceedings of 4th International Coral Reef Symposium held in Manila, Philippines during May 2001, 1:347-354.

Frith, C.A. and Manson, L.B. 1986. Modeling wind driven circulation, One Tree Reef, southern Great Barrier Reef. Coral Reefs, 4:201-211.

Hamner, W.M. and Wolanski, E. 1988. Hydrodynamic forcing functions and biological processes on coral reefs: a status review. Proceedings of 6th International Coral Reef Symposium held in Australia during 1988, 1:103-113.

Hansen, D.V. and Rattray, M. 1965. Gravitational circulation in estuaries. Journal of Marine Research, 23:104-123.

Hansen, D.V. and Rattray, M. 1967. New dimensions in estuary classification. Limnology and oceanography, 11: 319-326.

Harrison, W. and Krumbein, W.C. 1964. Interactions of the beach-ocean-atmosphere systems at Virginia beach, Virginia. TM-7; U.S. Army Corporations of Engineers Coastal Engineering Research Center, Washington, D.C.

Joseph, J. and Kurup, P.G. 1987. Tidal response and circulation of Cochin estuary. Proceeding of the National Seminars in Estuarine Management, Trivandrum, pp. 88-92.

Kraines, SB.; Yanagi, T.; Isobe, M. and Komiyama, H. 1998. Wind-wave driven circulation on the coral reef at Bora Bay, Miyako Island. Coral Reefs, 17:133-143.

Kruyt, N.M. and van der Berg, J.H. 1993. Hydrography of Gazi Bay. In: Dynamics and Assessment of Kenyan Mangrove Ecosystems, Project Contract No. TS2-0240-C (GDF), Final Report, pp.221-236.

Le, H.P.; Roberts, W.; Cazaillet, O.; Christie, M.; Bassoullet, P. and Bacher, C. 2000. Characterization of intertidal flat hydrodynamics. Continental Shelf Research, 20:1433-1459.

Nadaoka, K.; Nihei, Y.; Kumano, R.; Yokobori, T. Omija, T. and Wakai, K. 2001. A field observation on hydrodynamic and thermal environments of a fringing reef at Ishigaki Island under typhoon and normal atmospheric conditions. Coral Reefs, 20:387-398.

Nakamori, T.; Suzuki, A. and Iryu, Y, 1992. Water circulation and carbon flux on Shiraho coral reef of the Ryukyu Islands, Japan. Continental Shelf Research, 12(7/8):951-970.

Nummedal, D. and Finley, R.J. 1978. Wind generated longshore currents. Proceedings of 16th Conference of Coastal Engineering, American Society of Civil Engineers, held in Hamburg, Germany during September, 1978, 2:1428-1438.

Pickard, G.L. 1986. Effects of wind and tide on upper layer currents at Davis Reef, Great Barrier Reef, during MECOR (July-August 1984). Australian Journal of Marine and Freshwater Research, 37:545-65.

Pylee, A.; Varma, P.U. and Revichandran, C. 1990. Some aspects of circulation and mixing in the lower reaches of the Periyar estuary, west coast of India. Indian Journal of Marine Sciences, 9:32-35.

Shepard, F.P. and Inman, D.L. 1950. Nearshore water circulation related to bottom topography and wave refraction. Trans American Geophys Union 31:196-212.

Smith, S.V. 1984. Phosphorus versus nitrogen limitation in the marine environment. Limnological Oceanography, 29:1149-1160.

Sonu, C.J. and Johannes, L.V. 1971. Systematic beach changes on the outer North Carolina. Geology, 79(4): 416-425.

Sverdrup, H.U.; Johnson, M.W. and Fleming, R.H. 1942. The oceans: their physics, chemistry and biology. Prentice-Hall, New York.

Swenson, E.M. and Chuang, W.S. 1983. Tidal and subtidal water volume exchange in an estuarine system. Estuarine, Coastal and Shelf Science, 16:229-240.

Tyler, R.H. and Sanderson, B.G. 1996. Wind-driven pressure and flow around an island. Continental Shelf Research, 16(4):469-488.

Wolanski, E.M. 1986. An evaporation driven salinity maximum in Australian tropical estuaries. Estuarine, Coastal and Shelf Science, 22:415-424.

Wolanski, E.M. 1994. Physical oceanographic processes in the Great Barrier Reef. C.R.C. Press, Boca Raton, Florida, pp 144.

Wong, K.C. 1999. The wind driven currents on the middle Atlantic Bight inner shelf. Continental Shelf Research, 19: 757-773.

Yamano, H.; Kayanne, H.; Yonekura, N. Nakamura, H. and Kudo, K. 1998. Water circulation in a fringing reef located in a monsoon area: Kabira Reef, Ishigaki Island, southwest Japan. Coral Reefs, 17:89-99.