Bimodal Behavior in the Zonal Mean Flow of a Baroclinic β-Channel Model
Bimodal Behavior in the Zonal Mean Flow of a Baroclinic β-Channel Model
复制标题
斜压 β 通道模型的分区平均流中的双峰行为
DOI：
--
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
M. Ghil
中科院分区：
文献类型：
--
作者：
S. Kravtsov;A. Robertson;M. Ghil
本文用一个β平面上的热强迫准地转两层通道模式研究了中纬度纬向急流变率的动力学起源。该模型的行为进行了研究作为一个功能的底部摩擦强度。两个不同的带状流状态存在于现实的，低的，和中间值的底部阻力，这两个国家是由涡旋和不同的主要是在其气候急流的纬向位置。该系统的低频演化的特点是两个状态之间的不规则的过渡。对于一个给定的分支的模式解决方案，领先的固定和传播的经验正交函数相关的模式的动力算子的本征模，线性化的气候状态在这个分支。这些模式之间的非线性相互作用有助于确定它们的相对能级。特别地，稳态模式的自相互作用被证明是消失的。因此，这些模式不与…
Abstract The dynamical origin of midlatitude zonal-jet variability is examined in a thermally forced, quasigeostrophic, two-layer channel model on a β plane. The model’s behavior is studied as a function of the bottom-friction strength. Two distinct zonal-flow states exist at realistic, low, and intermediate values of the bottom drag; these two states are maintained by the eddies and differ mainly in terms of the meridional position of their climatological jets. The system’s low-frequency evolution is characterized by irregular transitions between the two states. For a given branch of model solutions, the leading stationary and propagating empirical orthogonal functions are related to eigenmodes of the model’s dynamical operator, linearized about the climatological state on this branch. Nonlinear interactions between these modes are instrumental in determining their relative energy level. In particular, the stationary modes’ self-interaction is shown to vanish. Thus, these modes do not exchange energy wit...