太湖沉积物空间分布的风生流输送机制分析

Analysis of conveying mechanism of wind-driven current forming the sediment distribution in Taihu Lake

基于无锡、宜兴和东山3个气象站1997—2007年10年风速的平均值,及太湖站1997—2001年风向统计频率权重,利用非结构有限元的近海海洋环流模型,计算了太湖湖流的辐合区及垂直速度的空间分布。结果表明:太湖流场的主要辐合区集中在北部湾区、西部沿岸、东太湖湾区的北部及平台山以南的区域。东部沿岸福合区相对比较分散;该分布与中下层的下沉运动分布基本一致。流场辐合区及下沉区的分布与太湖沉积物厚度分布非常吻合,表明风场驱动下的流场辐合及下沉运动是决定太湖沉积物空间分布的关键因子。

Based on the data of average wind speed in meteorological stations of Dongshan,Wuxi and Yixing from 1997 to 2007,and wind direction and frequency weight of wind direction in Taihu Station from 1997 to 2001,the spatial distribution of convergence of lake current and subsidence velocity were calculated by Finite Volume Coastal Ocean Model （FVCOM）.The results show that the regions of lake current are distributed in bays in north,western coastwise,the north of bays in east of lake Taihu as well as the south region of mountain Pingtai-shan.The distribution of convergence in east coastwise is relatively scattered.It consistents with the distribution of subsidence region.The distribution of convergence and subsidence regions agreed with that of sediment in the Taihu Lake,so it is one of the key factors affecting the distribution of sediment that convergence and subsidence region of lake current driven by wind fields.The result is helpful to research on the mechanism of the effect of sediment on spatial distribution of nutrient and underwater light climate in the Taihu Lake.