Nonlinear symmetric instability and intraseasonal oscillations in the tropical atmosphere
Nonlinear symmetric instability and intraseasonal oscillations in the tropical atmosphere
复制标题
热带大气中的非线性对称不稳定性和季节内振荡
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
M. Ghil
中科院分区：
文献类型：
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作者：
J.;M. Ghil
本文研究了赤道地区平流层和对流层对称惯性不稳定（SII）现象的一种机制。我们调查的线性和非线性动力学的SII在两层，纬向对称模型的赤道β平面上，在存在的基本流与水平和垂直剪切，有和没有耗散效应。根据之前发表的结果，线性对称不稳定性是纯指数的，即非振荡的。非线性SII，在这里研究的第一次在行星尺度上，可以产生有限振幅的振荡行为，周期或混乱。在无粘情况下的振荡周期取决于初始数据。当存在耗散效应时，所有解都趋向于极限环或奇异吸引子。在这种情况下，在一个广泛的参数范围内，无论垂直切变是否存在，主要的周期是在季节内，20-30天的范围。因此，非线性…
Abstract Symmetric inertial instability (SII) is studied here as a mechanism for stratospheric and tropospheric phenomena in the equatorial regions. We investigate the linear and nonlinear dynamics of SII in a two-layer, zonally symmetric model on an equatorial beta plane, in the presence of a basic flow with horizontal and vertical shear, with and without dissipative effects. Linear symmetric instabilities are, in accordance with previously published results, purely exponential, that is, nonoscillatory. Nonlinear SII, studied here for the first time on a planetary scale, can produce finite-amplitude oscillatory behavior, periodic or chaotic. The period of oscillations in the inviscid case depends on the initial data. In the presence of dissipative effects, all solutions tend to a limit cycle or to a strange attractor. The dominant period in this case, over a wide range of parameters and whether vertical shear is present or not, is in the intraseasonal, 20–30-day range. It appears therefore that nonlinear...