GRAvity wave short term Variability In the Thermosphere/Ionosphere induced by GLObalscale Waves (GRAVITIGLOW)

全球尺度波引起的热层/电离层中的重力波短期变化 (GRAVITIGLOW)

• 批准号: 403244968
• 负责人: Dr. Thai Trinh
• 金额: --
• 依托单位: Institut für Energie- und Klimaforschung (IEK)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/403244968?language=en
• 关键词: GRAvity; wave; short; term; Variability

Vertical coupling between middle atmosphere and thermosphere/ionosphere (T/I) by atmospheric waves plays an important role in the energy and momentum balance of the T/I. These atmospheric waves include global scale waves (planetary waves (PWs), tides) and mesoscale gravity waves (GWs). It has been modeled and observed that during upward propagation, GWs can interact with global scale waves. The modulation of GWs by global scale waves alters the magnitude of GW momentum fluxes, breaking location and saturation altitudes of GWs. This will affect not only the global distribution of GWs in the T/I but also the wave driving of the global circulation in the T/I. Further, by interaction with GWs, global scale waves are themselves affected. Also, global scale waves can be excited in the T/I due to the non-uniformities of the GW distribution that resulted from GW filtering at lower altitudes. Moreover, selective filtering of GWs by background variations, in particular by global scale waves, influences the wave forcing in the T/I during sudden stratospheric warmings (SSWs). Therefore, simultaneous global observations of GWs and global scale waves in the T/I, together with global observations in the middle atmosphere, are needed to better understand these processes in more detail.In this project, we will analyze the short term variability of GWs induced by global scale waves using different satellite measurements, including CHAMP, GOCE, GRACE, SWARM (in the T/I) and SABER, HIRDLS (in the middle atmosphere). In the T/I, in addition to the global distributions of GW, which were successfully derived from CHAMP and GOCE, we will apply the same method to derive GW distributions from mass density, winds and plasma density from SWARM, CHAMP, and GRACE. Further, tidal amplitudes and tidal phases will be derived from mass density, winds, and plasma density from SWARM, CHAMP, GOCE, and GRACE. These simultaneous observations of GWs and tides will be analyzed to estimate the modulation of GWs by tides. Another focus is the variability of GW distribution in the T/I around central date of each SSW event. Further, we will investigate how the modulation of GWs by background variations, in particular by global scale waves, influences the vertical coupling by GWs during SSWs. For these SSWs, observations both in the middle atmosphere and in the T/I will be analyzed with high temporal resolution. Ray tracing will be performed to investigate filtering of GW spectrum in the middle atmosphere during SSWs. Long-term SABER data and combination of SWARM, CHAMP, GOCE, GRACE data provide a comprehensive collection of study cases. Observations of GWs and tides derived by our project are also important for direct comparison with corresponding quantities simulated by general circulation models.

大气波动引起的中层大气与热层/电离层的垂直耦合对热层/电离层的能量和动量平衡起着重要作用。这些大气波包括全球尺度波（行星波（PW），潮汐）和中尺度重力波（GW）。它已被建模和观察到，在向上传播，GWs可以与全球尺度波相互作用。全球尺度波对全球Ws的调制作用改变了全球Ws动量通量的大小、破裂位置和饱和高度。这不仅会影响T/I中GWs的全球分布，而且会影响T/I中全球环流的波浪驱动。此外，通过与GW的相互作用，全球尺度波本身也受到影响。此外，全球尺度波可以激发在T/I由于GW分布的不均匀性，导致GW过滤在较低的海拔。此外，选择性过滤的背景变化，特别是全球尺度波，影响波强迫的T/I在平流层突然变暖（SSW）。因此，需要对全球大气中的全球尺度波和全球尺度波进行同步观测，并结合中层大气的全球观测，以更详细地了解这些过程。（在T/I中）和SABER、HIRDLS（在中层大气中）。在T/I中，除了从CHAMP和GOCE成功导出的全球GW分布之外，我们将应用相同的方法从SWARM，CHAMP和GRACE的质量密度，风和等离子体密度导出GW分布。此外，潮汐振幅和潮汐相位将来自SWARM、CHAMP、GOCE和GRACE的质量密度、风和等离子体密度。这些同时观测的全球Ws和潮汐将进行分析，以估计调制的全球Ws的潮汐。另一个焦点是在每个SSW事件的中心日期周围T/I中GW分布的变化。此外，我们将研究如何调制的背景变化，特别是全球尺度波，影响的垂直耦合的全球Ws在SSWs。对于这些SSW，在中层大气和在T/I的观测将进行高时间分辨率的分析。将进行射线追踪以研究SSW期间中层大气GW光谱的滤波。长期的SABER数据和SWARM、CHAMP、GOCE、GRACE数据的组合提供了一个全面的研究案例集合。由我们的项目得出的全球变暖和潮汐观测也很重要，可以直接与大气环流模式模拟的相应数量进行比较。