杭州湾年最大潮差分析

Analysis of annual maximum tidal range in Hangzhou Bay

潮差变化对水沙输移、潮滩演变、涌潮、盐水入侵、潮能开发、港口航运、水产养殖和生态环境均有较大影响。该文基于杭州湾实测潮汐资料,对杭州湾年最大潮差时空变化、成因及增大原因进行了系统分析。结果表明:钱塘江河口最大潮差位置位于澉浦上游;年最大潮差杭州湾北岸出现在8月的次数最多,杭州湾口南岸镇海出现在12月和1月的次数最多;所有年最大潮差均发生在大潮期,乍浦年最大潮差中受台风暴潮影响的占29%;20世纪70年代以来,杭州湾年最大潮差显著增大,增大速率为0.7 cm/a-2.0 cm/a;钱塘江河口治江缩窄是引起杭州湾年最大潮差增大的主要因素;台风暴潮对年最大潮差的影响没有趋势性变化;平均海平面上升加剧了杭州湾年最大潮差的增大。

The change of tidal range has a great influence on water-sediment transport,tidal flat evolution,tidal bore,saline intrusion,tidal energy development,port shipping,aquaculture and ecological environment.Based on the measured tidal data in Hangzhou Bay,the spatiotemporal variations,causes of formation and enlarging causes of the annual maximum tidal range in Hangzhou Bay were systematically analyzed.The results showed that the largest tidal range is located at the upper reaches of Ganpu in the Qiantang estuary.The annual maximum tidal range along the north coast of Hangzhou Bay occurred most often in August,and the most frequently in December and January at Zhenhai on the south bank of Hangzhou Bay mouth.All the annual maximum tidal range occurred at spring tide,and 29%of the annual maximum tidal range at Zhapu was affected by typhoon storm surge.Since the 1970 s,the annual maximum tidal range in Hangzhou Bay has increased significantly,increasing at a rate ranging from 0.7 to 2.0 cm/annual.Contracted river for regulation in the Qiantang estuary is the main factor causing the increase of the annual maximum tidal range in Hangzhou Bay.The influence of typhoon storm surge on annual maximum tidal range has no trend change in Hangzhou Bay.The annual maximum tidal range in Hangzhou Bay is exacerbated by rising mean sea level.