Noise-Induced Transitions in a Barotropic β-Plane Channel
Noise-Induced Transitions in a Barotropic β-Plane Channel
复制标题
正压 β 平面通道中噪声引起的跃迁
DOI：
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发表时间：
2002
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影响因子：
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通讯作者：
P. Sura
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文献类型：
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作者：
P. Sura
本文将乘性随机扰动和噪声诱导转捩的概念应用于一个准地转b平面地形正压气流模式。这个组态的光谱三分量低阶表示产生了Charney-DeVore（CDV）模型。允许系统的外部规定阻尼分散在平均值附近。阻尼项的随机表示导致乘法随机强迫。数值求解了低阶CDV模型的Fokker-Planck方程和随机微分方程。研究发现，系统的定性行为是乘性噪声水平的函数。特别是，乘性噪声的影响不仅仅是概率密度函数的平滑，就像它对于纯加性噪声一样。相反，乘性噪声导致高折射率状态优于低折射率状态。噪声诱导跃迁的概念解释了这种行为。噪声引起的随机低阶模型的过渡证实了相应的网格点模型与更多的自由度比谱模型的数值积分。这表明，未解决的物理过程的统计可能是一个重要的因素，在了解中纬度大尺度大气动力学的行为。
The concepts of multiplicative stochastic perturbations and noise-induced transitions are applied to a quasigeostrophic b-plane model of barotropic flow over topography. The spectral three-component low-order representation of this configuration yields the Charney‐DeVore (CDV) model. The externally prescribed damping of the system is allowed to scatter around a mean value. The stochastic representation of the damping term leads to a multiplicative stochastic forcing. The Fokker‐Planck equation and the stochastic differential equation of the low-order CDV model are solved numerically. It is found that the qualitative behavior of the system is a function of the multiplicative noise level. In particular, the effect of multiplicative noise is not simply a smoothing of the probability density function, as it would be for pure additive noise. Rather, multiplicative noise leads to the high-index state being favored over the low-index state. The concept of noise-induced transitions explains this behavior. The noise-induced transition of the stochastic low-order model is confirmed by numerical integrations of a corresponding gridpoint model with many more degrees of freedom than the spectral model. It is suggested that the statistics of the unresolved physical processes could be an important factor in understanding the behavior of midlatitude large-scale atmospheric dynamics.