A Simple Dynamical Model with Features of Convective Momentum Transport
A Simple Dynamical Model with Features of Convective Momentum Transport
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DOI：
10.1175/2008jas2805.1
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发表时间：
2009-02
影响因子：
3.1
通讯作者：
A. Majda;S. Stechmann
中科院分区：
文献类型：
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作者：
A. Majda;S. Stechmann
摘要对流动量输运（CMT）在多时空尺度相互作用中起着核心作用。然而，由于CMT的多尺度特性，量化和参数化其影响往往是一个挑战。本文系统地推导和研究了具有CMT特征的简单动态模型。该模式包括大尺度纬向平均流与对流耦合重力波之间的相互作用，对流采用多云模式进行参数化。这里显示的湿对流波-平均流相互作用有几个有趣的特征，使它们与其他经典波-平均流设置区别开来。首先描述了平均气流和对流耦合波（CCWs）的季节内振荡。高尺度和低尺度CMT均引起平均流量振荡，随平均流量振荡，CCWs减弱、改变传播方向、增强。用线性稳定性理论证实了这种振荡的基本机理。
Abstract Convective momentum transport (CMT) plays a central role in interactions across multiple space and time scales. However, because of the multiscale nature of CMT, quantifying and parameterizing its effects is often a challenge. Here a simple dynamic model with features of CMT is systematically derived and studied. The model includes interactions between a large-scale zonal mean flow and convectively coupled gravity waves, and convection is parameterized using a multicloud model. The moist convective wave–mean flow interactions shown here have several interesting features that distinguish them from other classical wave–mean flow settings. First an intraseasonal oscillation of the mean flow and convectively coupled waves (CCWs) is described. The mean flow oscillates due to both upscale and downscale CMT, and the CCWs weaken, change their propagation direction, and strengthen as the mean flow oscillates. The basic mechanisms of this oscillation are corroborated by linear stability theory with differe...