Nonlinear Wave Packet Evolution on a Baroclinicaily Unstable Jet
Nonlinear Wave Packet Evolution on a Baroclinicaily Unstable Jet
复制标题
斜压不稳定射流上的非线性波包演化
DOI：
--
复制
发表时间：
1994
期刊：
影响因子：
--
通讯作者：
R. Pierrehumbert
中科院分区：
文献类型：
--
作者：
K. Swanson;R. Pierrehumbert
摘要本文研究了斜压不稳定急流上由纬向局部初始扰动产生的无粘、非线性波包的生命周期。该研究揭示了以下内容。1)线性波包理论精确地界定了天气扰动在整个非线性演变过程中的上下游发展。2)在波包上游边缘的短、浅、缓慢传播的波以低振幅平衡，并且永远不会主导波包的演化。3)在天气波包附近激发了向上传播的Rossby波，这导致了大部分波包主体上游的强正压急流的产生。这就阻止了正压调节器机制限制波包主体中扰动的增长;主要的平衡机制是波包附近低层位涡的简单均匀化。4)The waves th.
Abstract Numerical simulations of the inviscid, nonlinear life cycle of wave packets emerging from a zonally localized initial disturbance on a baroclinically unstable jet are studied. The study reveals the following. 1) Linear wave packet theory accurately bounds the upstream and downstream development of the synoptic disturbance throughout the nonlinear evolution. 2) The short, shallow, slowly propagating waves at the upstream fringe of the wave packet equilibrate at low amplitudes and never come to dominate the wave packet evolution. 3) Upslxeampropagating Rossby waves are excited in the vicinity of the synoptic wave packet, which cause the generation of strong barotropic jets mostly upstream of the dominant body of the wave packet. This prevents the barotropicgovernor mechanism from limiting the growth Of the disturbances in the main body of the packet; the main equilibration mechanism is a simple homogenization of the lower-layer potential vorticity in the vicinity of the wave packet. 4) The waves th...