Rossby Waves Entering the Equatorial Middle Atmosphere

众所周知，热带外行星的Rossby波从其对流层源区向上并向赤道传播能量。这些波浪活动大部分到达赤道中部大气层，在那里人们对它的命运知之甚少。卫星数据显示，在至日附近，当赤道中部大气惯性不稳定时，赤道上空会出现垂直分层的扰动(所谓的“煎饼结构”)，但只有当Rossby波的爆发活动冲击该地区时才会出现。在这项基本的流体力学研究中，PI将使用高垂直分辨率的国家大气研究中心(NCAR)社区气候模式(CCM)的中层大气版本来检验煎饼结构是由进入惯性不稳定区域的Rossby波引起的假设。将进行一系列实验，其中控制高纬度波的强迫，并依次指定平均气流为惯性稳定、惯性不稳定，最后允许随波场演变。除了深入了解低纬度Rossby波的命运外，这项研究还将提高对半球间示踪剂输送的理解。在CCM中诊断的越赤道输送将在目前用于模拟臭氧分布的二维中层大气评估模式中进行参数化。

Extratropical planetary Rossby waves are known to propagate energy upward and equatorward from their tropospheric source region. Much of this wave activity reaches the equatorial middle atmosphere, where relatively little is known about its fate. Satellite data reveal that, around the solstices, when the equatorial middle atmosphere is inertially unstable, vertically layered disturbances (so-called "pancake structures") appear over the equator, but only when a burst of Rossby wave activity is impinging on the region. In this fundamental hydrodynamic study, the PI will use a high vertical resolution middle atmosphere version of the National Center for Atmospheric Research (NCAR) Community Climate Model (CCM) to test the hypothesis that the pancake structures are caused by Rossby waves entering an inertially unstable region. A hierarchy of experiments will be performed in which high latitude wave forcing is controlled and the mean flow is specified successively to be inertially stable, inertially unstable, and finally allowed to evolve with the wave field. In addition to gaining insight into the fate of Rossby waves at low latitudes, this study will improve understanding of interhemispheric tracer transport. Cross-equatorial transport diagnosed in the CCM will be parameterized in a two-dimensional middle atmosphere assessment model currently used to model ozone distribution.