内灘海岸における離岸流の連続観測  [in Japanese] CONTINUAL OBSERVATION OF RIP CURRENT WITH X-BAND RADAR AT UCHINADA BEACH, KANAZAWA, JAPAN  [in Japanese]

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Abstract

金沢港に隣接する内灘海岸では,離岸流による海難事故がたびたび発生しているため,現地観測を実施し,離岸流の発生状況を把握することが安全管理上重要である.そこで,本研究ではXバンドレーダにより水際と砕波帯を連続観測した結果を解析し,離岸流の発生,これと海岸地形,海象等の関係を調べた.レーダ画像には,離岸流発生に伴う沖向きの流れが捉えられる.さらに,レーダ画像には沿岸の水際付近の海底地形において水深が局所的に大きくなる箇所(リップチャンネル)が砕波帯の途切れとして捉えられる.この研究では,離岸流の諸元,リップチャンネルの位置,入射波浪等の関連性を検討した.

 Detection of rip current occurrence is important for safety management of swimming beach. In this study, an X-band radar is employed to observe locations of rip-channels and occurrences of rip current at Uchinada Beach, Kanazawa, Japan. The radar was installed on the back-shore, and the effective coverage of the radar was approximately 1,000 m. In the time averaged radar images, which were processed for every 2 minutes, rip channel locations and rip heads were tracked for 40 days in August and September of 2015. The validity of the results was verified from results of morphological surveys and buoy releases. Rip heads were connected with rip channels, and this was evident when the wave height of the area was more than 0.3 m. Rip channels migrated in a complex manner during the observation.

Journal

  • Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering)

    Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering) 72(2), I_307-I_311, 2016

    Japan Society of Civil Engineers

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