A Multiscale Asymptotic Theory of Extratropical Wave–Mean Flow Interaction
A Multiscale Asymptotic Theory of Extratropical Wave–Mean Flow Interaction
复制标题
温带波与平均流相互作用的多尺度渐近理论
DOI：
10.1175/jas-d-17-0307.1
复制
发表时间：
2018
影响因子：
3.1
通讯作者：
T. Shepherd
中科院分区：
文献类型：
--
作者：
Lina Boljka;T. Shepherd
本文用多尺度渐近方法导出了行星尺度和天气尺度涡旋的波动活动方程及其与纬向平均气流的相互作用。假设涡旋的幅度较小，并假定天气尺度的纬向和经向长度尺度相等。在这些假设下，纬向平均和行星尺度的动力学是行星地转的(即，以涡旋伸展为主)，行星尺度和天气尺度的涡旋之间的相互作用仅通过纬向平均气流或非绝热过程发生。结果表明，行星尺度的热通量通过经向质量重分布进入角动量收支。在天气尺度和时间尺度上平均后，动量通量从天气尺度波动活动方程中消失，天气尺度热通量从斜压性方程中消失，使得行星尺度热通量成为耦合纬向平均斜压和正压分量的唯一绝热项。
Abstract Multiscale asymptotic methods are used to derive wave activity equations for planetary- and synoptic-scale eddies and their interactions with a zonal mean flow. The eddies are assumed to be of small amplitude, and the synoptic-scale zonal and meridional length scales are taken to be equal. Under these assumptions, the zonal-mean and planetary-scale dynamics are planetary geostrophic (i.e., dominated by vortex stretching), and the interaction between planetary- and synoptic-scale eddies occurs only through the zonal mean flow or through diabatic processes. Planetary-scale heat fluxes are shown to enter the angular momentum budget through meridional mass redistribution. After averaging over synoptic length and time scales, momentum fluxes disappear from the synoptic-scale wave activity equation while synoptic-scale heat fluxes disappear from the baroclinicity equation, leaving planetary-scale heat fluxes as the only adiabatic term coupling the baroclinic and barotropic components of the zonal mean ...