变系数EKdV模型在模拟南海北部大振幅内孤立波传播和裂变中的应用

Application of Variable-Coefficient Extended KdV Model on the Simulation of Propagation and Disintegration of Internal Solitary Waves in the Northern South China Sea

利用垂向连续分层变系数EKdV模型,模拟了南海北部海域大振幅内孤立波的传播和裂变过程,并与观测数据进行比较。结果表明:连续分层变系数EKdV模型能够较好地反映振幅小于100m的内孤立波的振幅和波宽,对于更大振幅的强非线性内波,该模型模拟的振幅和波宽均较实测较小;非线性模态函数能够较准确地反映温度振荡的垂直结构,而水平流速的大小和垂直结构则与线性模态较符合。研究结果表明,变系数EKdV模型能够为研究和理解大振幅内孤立波的传播和裂变过程提供较好的理论支持。

A vertical continuously stratified variable-coefficient extended Korteweg-deVries（vEKdV）model is applied to simulate the propagation and disintegration of the large-amplitude internal solitary waves（ISWs）in the northern South China Sea（NSCS）,and the results are compared with the observational data.It is found that the vEKdV model fits the wave profile of the observed large amplitude ISWs with amplitude lower than 100 m,pretty well,as both the wave amplitude and wave width are consistent with the observed results.However,for the larger ISWs,either wave amplitude or wave width predicted by theoretical model is smaller than in-situ data.The nonlinear modal function can accurately show the vertical structure of temperature fluctuation,while the magnitude and vertical structure of horizontal current are consistent with the linear modal function.The results indicate that the vEKdV model can provide agood theoretical support on the study of propagation and disintegration of large-amplitude ISWs.