10 YEARS CROSS-SHORE AND ALONGSHORE SHORELINE VARIABILITIES OBSERVED AT HASAKI COAST, JAPAN
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- TAKEWAKA Satoshi
- University of Tsukuba
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- GALAL Elsayed M.
- Port Said University
Bibliographic Information
- Other Title
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- 波崎海岸で観測された10年間の汀線分布の変動特性
- ハサキ カイガン デ カンソク サレタ 10ネンカン ノ テイセン ブンプ ノ ヘンドウ トクセイ
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Abstract
Distribution of shoreline positions from year 2005 to 2014 was observed with an X-band radar at Hasaki Coast, Japan. The observation covers an extent of approximately 5 km in the longshore with 10 m resolution. The spatial and temporal variability of the shoreline positions is split by Empirical Orthogonal Functions decomposition. The dominant mode accounted for 36% of the observed variance in the shoreline position which is cross-shore and seasonal shifts of the spatial mean of shoreline positions. The rest of the modes are alongshore variability which can be explained by longshore migrations of beach cusps and other topographic features within the intertidal region. They have longshore scales of 102-103 meters and a temporal scale of days to months. The dominant modes of shoreline variability were correlated with the wave energy flux components estimated by SWAN model. The cross-shore wave energy fluxes were well correlated to the seasonal variation of the mean shoreline position, or the most prevailing mode of the EOF analysis. Speeds of the longshore movements of shoreline features have been estimated from cross-correlation analyses. The migration speeds showed a reasonable association with longshore wave energy flux and longshore wind component. This result supports the supposition that the longshore migration of the shoreline features is forced by the wave- and wind-driven longshore current.
Journal
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- Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering)
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Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) 71 (2), I_673-I_678, 2015
Japan Society of Civil Engineers
