江苏岸外辐射沙脊群东沙稳定性研究

东沙是江苏岸外辐射沙脊群中的第二大沙洲,具有独特的地形地貌和水动力条件,对它进行稳定性研究为揭示整个辐射沙洲及其邻近岸滩的动态演变都非常有益。通过利用多年遥感卫片资料、1998年取得的现场水文泥沙观测资料和东沙滩面表层沉积物资料等,对东沙的地形地貌特征、沉积特征和东沙两侧潮汐通道的水流泥沙特征等进行了详细分析。研究结果表明,东沙的沙脊偏于西侧,西侧滩面较窄、高程较高且岸线较为顺直,东侧滩面较宽、高程较低且岸线较为破碎;西洋和陈家坞槽均处于冲刷状态,净输沙的主要方向为输向槽外或输向条子泥;东沙近三十年来面积有所缩小且有外围向中央收缩的趋势,尤其以向东、向南方向的迁移最为明显。

Stability study on the Dongsha Sandbanks in submarine radial sand ridges field off Jiangsu Coast

Dongsha sandbank is one of the largest sandbanks in the radial submarine sand ridges system off Jiangsu Province.It has special landform characters and hydrodynamic condition.So the stability study of the Dongsha sandbank is very helpful to the analysis of the stability of the whole radial submarine sand ridges system and the neighboring tidal flat.Many years' remote sensing images,the marine hydrodynamic observation data in 1998 and the sediments grain size data are used.Based on the above works,the conclusions drawn are as follows:(1) the sand ridge of the Dongsha sandbank lies on the west.The west tidal flat is narrower and higher and the coastline is straight.The east tidal flat is wider and lower and the coastline is flexuous.(2) the Xiyang and Chenjiawuchao tidal channels are scoured.The orientation of the net transport sand is to the east-south and the Tiaozini sandbank.(3) the area of the Dongsha sandbank has reduced in the past 30 years.