翡翠岛沙丘动态变化监测与动力成因探讨
Sand Dune Dynamics and Controlling Factors at Emerald Island
中文摘要：
利用翡翠岛观测站、沙丘流量及影像监测、渤海海冰监测等资料，研究了2008年以来翡翠岛沙丘动态变化特征，探讨了气象与海洋要素对沙丘动态变化的影响。研究结果表明：西部海区入海河流沙源量自然减小下，水动力条件可自动修复海岸带存沙量，沙丘之间在环境风场作用下微循环流动；不同季节的盛行风对沙丘动态变化的贡献值有差异；翡翠岛气象观测站沿岸沙丘整体增高了1.5～1.8 m，沙丘向海坡度和背海坡度平均增幅为20～30°；沙丘高度变化与重冰期相关，冬季海冰外缘线大于20 km时，海陆温差致水平气压梯度加大，海冰摩擦系数小，致偏东风在冰面迅速增强，是流沙量增大的主要动力因素。
中文关键词：
翡翠岛沙丘动态变化监测，海陆沙源循环，风动力因子，海冰因素
KeyWords：
sand dune variation detection at emerald island, sand source cycles between land and sea, wind dynamical factor, sea ice factor
Abstract：
This study examined the temporal variation of sand dune at Emerald Island since 2008. Datasets used in this study include site meteorological observation, Bohai sea ice detection, sand dune flow-meter, and image monitoring. The results indicated that, with the reduction of sand yield from rivers to the western sea, hydrodynamic force automatically restored coastal sand deposit sediment. Sand dunes moved slightly between under the in?uences of environmental wind felds. Prevailing winds in di?erent seasons contributed di?erently to the sand dynamical movement. Compared with the data in 2008, the sand dune height along the coast has increased by 1.5–1.8 m in general, with an average increase of 20–30°in seaward and reverse seaward. Further results showed that sand dune height variation was related to sea ice period. Once the Bohai sea ice edge was extended over 20 km, the horizontal pressure gradient increased as a result of the sea-land air temperature di?erence and the sea ice friction coefcient decreased. This resulted in an increased intensity of easterly wind on the sea ice, which was mainly responsible to the increased sand ?ow.