Collaborative Research: CEDAR: Large Amplitude Variations & Instabilities due to Strong Interactions between Tides & Planetary Waves in the Upper Mesosphere and Lower Therm

该项目旨在说明潮汐与行波和定常行星波之间的非线性相互作用，包括不稳定性在中间层上层和热层下层(MLT)产生可变性方面的作用。这项工作将特别集中在夏季南半球的两天波(TDW)，包括研究由于与日潮汐的亚谐共振而导致的TDW放大以及由此产生的参数亚谐不稳定(PSI)，以及锁相TWW与气辉发射亮度显著增强之间的明显联系。此外，该项目将研究调节潮汐幅度和/或产生非迁移性潮汐的非线性强迫机制，特别是在高纬度中间层上层占主导地位的向西的半日潮。这项工作将利用一种系统科学方法，将地面风和气辉强度测量、NASA定时卫星的温度测量、Time-GCM大气环流模型和全球数据同化模型结合起来。这项工作将作为国际和美国教育、研究和小企业机构之间的合作进行。

This project is to characterize the role of nonlinear interactions, including instability, between tides and traveling and stationary planetary waves in generating variability in the upper mesosphere and lower thermosphere (MLT). The work will focus particularly on the two day wave (TDW) in the summertime southern hemisphere, including studies on its amplification due to resonance with a subharmonic of the diurnal tide and consequent generation of a parametric subharmonic instability (PSI) as well as on the apparent association between phase-locked TDWs and pronounced enhancements of airglow emission brightness. In addition, this project will investigate nonlinear forcing mechanisms which modulate tidal amplitude and/or produce non-migrating tides, particularly the westward semidiurnal tide which is dominant in the high-latitude upper mesosphere. This effort will utilize a systems science methodology which combines ground-based wind and airglow intensity measurements, temperature measurements from the NASA TIMED satellite, the TIME-GCM general circulation model, and a global data assimilation model. This work will be conducted as a collaboration between international and U.S. educational, research, and small business institutions.