摘要
利用2010年4月3日在舟山外海观测的25hLADCP海流数据与CTD连续观测数据,综合利用Thorpe方法、功率谱分析、交叉谱分析等方法对测站所在海域的小尺度湍混合参数进行估计,分析并讨论了其时空分布特征及影响因子。研究结果表明,上混合层湍流所致的垂向翻转尺度普遍大于下混合层,较大尺度翻转均出现在潮位峰值附近,涨潮时段混合明显大于落潮时段且半日周期,1/4周期显著。该站点存在明显的"上强下弱"双密度跃层现象,湍动能耗散率、湍混合率也呈现出"表强底弱"特征。弱跃层中近惯性频率的内波和近半日潮频率的内潮信号最为显著,而强跃层中则是高频内波和近半日潮频率的内潮信号明显,上下跃层及其之间伴有间歇性强湍流发生。上混合层平均的湍混合对风应力的响应要快于对海流的响应,底应力是下混合层水体湍混合的重要因子。
This paper makes use of 25-hour continuous observation LADCP current data and CTD data on April 3,2010 to estimate small scale turbulent mixing parameters and analyze its temporal and spatial distribution characteristics and the influencing factors using Thorpe method,power spectral analysis and cross spectrum analysis method.Results show that Flip Vertical scale resulting from the upper mixed layer is generally greater than that resulting from mixed layer near bottom;the larger-scale appears near the peak of tide levels,turbulent mixing in the ebb tide periods is significantly smaller.The strength of the upper pycnocline is stronger than the lower.Similar to the turbulent kinetic energy dissipation rate,the turbulent mixing rate is smaller at the bottom.Near-inertial wave frequency and near-semidiurnal tide frequency signal in the weak thermocline are evident,well,high frequency internal waves and tidal wave frequency signal are also clear in the strong thermocline.The intermittent strong turbulence is detected between the two layers.The turbulent mixing on average in the upper mixed layer has a faster response to wind than the response to the current.Bottom stress is an important factor for the turbulent mixing in the nether mixed layer.
出处
《中国海洋大学学报（自然科学版）》
CAS
CSCD
北大核心
2015年第3期25-32,共8页
Periodical of Ocean University of China
基金
海洋公益性行业科研专项经费项目"海洋管道探测技术集成及风险评估技术研究与示范应用"(201315026-3)
"小型阵变频高频地波雷达数据的开发和应用"项目(201205032-4)资助
