风暴潮叠加天文大潮下的沙滩循环与海岸侵蚀

Beach Cycle and Coastal Erosion under the Conditions of a Storm Surge Combined with a Spring Tide

通过比较9914号特大台风前后厦门岛东南部沙滩及地物的变化,探讨了海滩循环在风暴潮叠加天文大潮条件下的运动过程.研究表明,在9914号台风期间,厦门湾海岸水位增高达黄海平均海平面以上4.04 m的条件下,风浪携海滩砂向上冲越可达黄海平均海面以上8.5 m.造成沙滩滩肩消失,沙棱体的砂一部分向上冲越脱离海滩,一部分被回流带到低潮区.原滩肩下伏的基底因沙棱体的消失受波浪的冲刷.台风过后,低潮区的砂又重新回到滨面,但台风期间向上冲越的砂却不能全部返回,沙棱体长时间未能恢复原状,最终导致海滩侵蚀与岸线后退.

The spring tide combined with the storm surge resulted in a high water level of 4.04m above the main sea level（MSL）during No.9914 typhoon.More wave energy was transferred to the coast because of greater water height.The stormy waves washed beach sands away and ran up to 8.5m high above MSL.Under the force of the stormy waves,the beach berm disappeared completely.The sand prism lying in the high tidal zone was scoured and it induced offshore and onshore sediment transport.Some overwash occured and other sediment was brought to the low tidal zone.The bare shoreface without sand prism was scoured directly by waves and currents.Although the sediment which had been brought to the deeper zone by the stormy waves came back to the shoreface,the washover sediment never returned after the storm.It caused irretrievable beach erosion and coastal retreat.