南海东北部全日非相干内潮的特征及其成因

本文利用南海东北部的潜标资料研究了南海东北部全日非相干内潮的特征。潜标数据的结果表明,在2010年7月下旬和8月上旬,全日非相干内潮的能量显著增强,同时全日内潮的总能量强度达到了预期(相干部分)的两倍;从能量的垂向分布上来看,非相干内潮的能量最大值出现在120 m深度附近。射线追踪模型的结果表明,此次强非相干内潮能量主要来自吕宋海峡的中部,黑潮入侵是导致非相干内潮信号增强的主要原因,全日内潮在吕宋海峡中部生成后向西传播进入南海,而黑潮改变了全日内潮的传播路径,将西向传播的内潮向北折射,导致来自多源地的内潮在潜标处叠加,引起全日非相干内潮能量的增强。本文的结果将有助于加深对非相干内潮的特征的认识和促进对其生成机制的了解。

Characteristics and Cause Analysis of Diurnal Incoherent Internal Tides in the Northeastern South China Sea

Characteristics of the incoherent internal tides(ITs)in the Northeastern South China Sea(SCS)were examined using mooring data.In late July and early August 2010,energetic diurnal incoherent IT was observed in the deep basin near the Luzon Strait(LS),leading to the enhanced diurnal IT with magnitudes about twice than expected.The maximum kinematic energy density of incoherent ITs appeared around 120 m depth.By means of a ray-tracing method,we found that the Kuroshio currents refracted strong ITs emitting from the middle portion of the LS northward,resulting in the superposition of internal tides originated from multiple sites and giving rise to strong incoherent signals at the observation site.The observation results presented here is helpful to understand the characteristics and generation mechanisms of incoherent ITs.