Variability of nonlinear internal waves in the South China Sea affected by tidal forcing, the Kuroshio and mesoscale eddies
Variability of nonlinear internal waves in the South China Sea affected by tidal forcing, the Kuroshio and mesoscale eddies
复制标题
受潮汐强迫、黑潮和中尺度涡影响的南海非线性内波变化
DOI：
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发表时间：
2016
影响因子：
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通讯作者：
Jae-Hun Park
中科院分区：
文献类型：
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作者：
Li Q.;Bing Wang;Xu Chen;Xueen Chen;Jae-Hun Park
对南中国海区非线性内波的长期观测揭示了季节变化和年际变化。在吕宋海峡选择的两个测深仪观测段中，潮汐强迫基本相同，但在南海观测到的非线性内波的振幅却有很大的不同。在此基础上，研究了混合Cooridnate.Ocean模式(HYCOM)再分析模拟再现的黑潮和中尺度涡的影响。黑潮可以增强温跃层的纬向倾斜，并在吕宋海峡诱发侵入流。在所选的两个区段中，不同的温跃层斜率对内潮的产生没有明显的影响，但侵入流可能导致M2内潮的幅度相差11%。在所选的两个节段中，内波传播路径上出现了中尺度涡旋，一种是冷涡，另一种是暖涡。这些涡旋改变了局地层结，并诱发了额外的背景流，从而影响了内潮的非线性演化。此外，由于中尺度涡旋的波前转向显著地影响了观测到的非线性内波的幅度变化：非线性内波前的边缘而不是中心穿过观测站，导致观测的幅度减小。
Long-term observations of nonlinear internal waves in the South China Sea reveal seasonal to.interannual variability. During two selected segments of inverted echo sounder observations, tidal forcing.in Luzon Strait is almost identical, but the observed amplitudes of nonlinear internal waves in the South.China Sea are very different. The effects of the Kuroshio and mesoscale eddies, reproduced by HYbrid Cooridnate.Ocean Model (HYCOM) reanalysis simulation, are then investigated. The Kuroshio can enhance the.zonal tilt of the thermocline and induce intruding flow in Luzon Strait. During the two selected segments,.different thermocline slopes did not significantly change the internal tide generation, but the intruding flow.may result in a 11% difference in the amplitude of generated M2 internal tides. During the two selected segments,.mesoscale eddies appeared on the path of internal wave propagation, a cold eddy in one case and a.warm one in the other. The eddies changed local stratification and induced additional background currents,.thus affecting the nonlinear evolution of internal tides. In addition, wave front steering due to the mesoscale.eddies dramatically affected the observed amplitude changes of the nonlinear internal waves: the.edge, rather than the center, of the nonlinear internal wave front passed through the observational stations,.resulting in reduced amplitude in the observations.