东海岛东北部典型岸段短期冲淤变化及影响因素分析

Short-term Coastal Erosion-deposition Variation Analysis of Northeastern Donghai Island

通过无人机遥感、岸滩监测剖面、监测桩和沉积物粒度分析等手段研究了东海岛东北部典型岸段短期冲淤变化特征。结果表明,研究区岸线在一年半的时间内呈现后退趋势,侵蚀严重区域岸线平均后退约10m;岸滩夏季年度变化以侵蚀为主,侵蚀严重部位主要位于低滩,最大下蚀可达1m以上;半年度剖面监测结果显示,岸滩季节性变化明显,存在冬淤夏冲的特征;受风暴潮的影响,岸滩在2014-06—09发生严重侵蚀,部分区域后滨沙丘后退约20m;沉积物平均粒径分布的区域差异表明,沉积物有沿岸向北和向陆一侧运移的趋势。风暴潮、虾池排污和灯塔是影响东海岛典型岸段冲淤的主要因素。

Based on a combination of UAV remote sensing technique,monitoring profiles,monitoring stakes and grain-size analysis for surface sediment,this study analyzed the spatio-temporal erosion-deposition pattern of the coastline in northern Donghai Island.The results showed that the coastline of the study area retreated significantly during the 1.5-year observation period,with an average of about 10 meters in the most severe erosional section.Coastal erosion mainly occurred in summer,and the most intensive erosion was concentrated in the lower tidal flat where a maximum of 1 m vertical-erosion was observed.A ＂ Winter-deposition,Summer-erosion＂ pattern can be determined from half-year monitoring results.Impacted by the intensive storm surge,the study area experienced dramatic erosion during June-September in2014,during which some back-shore dunes were retreated by about 20 meters.Grain-size distribution of the surface sediment showed that the surface sediments were mainly transported northwards and landwards along the coast.Strong storm surges,pollution releasing from shrimp ponds,and the construction of lighthouse,should be mainly responsible for the erosion-deposition changes in this area.