海洋内重力惯性波不稳定模态分析  

Analysis of internal inertio-gravity wave in unstable mode

作　　者：邓冰 张翔 张铭[3] 

机构地区：[1]北京应用气象研究所,北京100029 [2]海军海洋水文气象中心,北京100079 [3]解放军理工大学气象海洋学院,江苏南京211101

出　　处：《海洋预报》2014年第1期36-41,共6页Marine Forecasts

基　　金：国家973计划资助项目(2007CB411800)

摘　　要：基于海洋动力方程的内重力惯性波数学模型给出其数值求解方法,并对沿垂直切变背景流传播的海洋内重力惯性波的不稳定做了探讨,得到的结论有:在不考虑海底地形和采用刚盖近似的条件下,在稳定层化海水中,当背景流为常数时,海洋内重力惯性波均是稳定的。在较弱的稳定层结下,具有垂直切变的背景流会导致海洋内重力惯性波的不稳定。该不稳定内波的增长率对其波长具有选择性并可有短波截断。增长率最大处出现在波长为几十公里的范围内。对固定的内波波长,背景流垂直切变越强则其最大增长率越大;若此时有多个不稳定模态,则增长率最大的模态其垂直结构最简单。该不稳定内波流函数的结构在垂直方向大体呈单圈环流形态,环流中心可以是一个,也可以是2个,后者则呈"猫眼"结构。The numerical solution method is described based on the mathematical model of ocean internal inertio-gravity wave instability.The instability of ocean internal inertio-gravity wave along vertical shear background current is discussed.The main conclusions are：the internal inertio-gravity waves are stable in the stable layer of sea water without the topography change and with rigid lid approximation when the background flow is constant.In a weak stable stratification,the vertical shear background current can result in ocean internal inertiogravity wave instability.Unstable wave growth rate is selective on the wavelength and can have a short-wave truncation.The maximum growth rate appears in the wavelength range of tens of kilometers.When wavelength is constant,the stronger vertical shear background current,the bigger maximum growth rate of internal wave.If there are multiple unstable modes,the modal perpendicular structure with largest growth rate of the internal wave is the simplest structure.The stream function structure of unstable mode in the vertical direction is generally a single circulation pattern,the circulation center can be one or two,while the latter appears as ＂ cat＇s eye＂ structure.

关 键 词：海洋内重力惯性波 垂直切变背景流 不稳定模态 

分 类 号：P731[天文地球—海洋科学]