Investigation of geomagnetic influences on the vertical coupling by gravity waves in the thermosphere/ionosphere

研究地磁对热层/电离层重力波垂直耦合的影响

• 批准号: 273419358
• 负责人: Dr. Paul Hartogh
• 金额: --
• 依托单位: Max-Planck-Institut für Sonnensystemforschung (MPS)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/273419358?language=en
• 关键词: Investigation; geomagnetic; influences; vertical; coupling

Vertically propagating gravity waves (GWs) represent a major coupling mechanism that provides connections between the lower atmosphere and thermosphere/ionosphere (TI) system. GWs are an essential component of the climate of Earth. A large portion of them originate in the troposphere, and redistribute energy and momentum between the atmospheric layers upon propagation and dissipation. In the TI, molecular viscosity and ion drag are the major dissipation mechanism of GWs. Variations of the magnetic field in the TI change the refractive properties of the atmosphere (large-scale temperature and wind distributions), and alter dissipation by ion drag. The primary objective of this study is to investigate and quantify the influence of variations of the geomagnetic field on propagation and dissipation of GWs of lower atmospheric origin, and on their dynamical feedback on the TI. In particular, the role of GWs will be tested in linking a trend of weakening the geomagnetic field, and the unexplainably strong observed cooling of the thermosphere. The study will be performed using a comprehensive Coupled Middle Atmosphere-Thermosphere-2 (CMAT2) general circulation model that utilizes our state-of-the-art spectral nonlinear GW parameterization. Novel numerical simulations will be performed, and the results tested against existing and future observational datasets, including those from the SWARM satellites. Besides advancing and testing our fundamental understanding of the GW coupling, the results can potentially improve space weather predictions.

垂直传播的重力波（GWS）代表了一种主要的耦合机制，该机制提供了低大气与热层/电离层（TI）系统之间的连接。 GWS是地球气候的重要组成部分。它们中的很大一部分起源于对流层，在传播和耗散时大气层之间的能量和动量。在Ti中，分子粘度和离子阻力是GWS的主要耗散机制。 Ti中磁场的变化改变了大气的折射率（大规模温度和风分布），并通过离子阻力改变耗散。这项研究的主要目的是研究和量化地磁场对较低大气来源GW的传播和耗散以及对Ti的动态反馈的影响。特别是，GWS的作用将在连接削弱地磁场的趋势中的作用，以及无法明确观察到的热层冷却。这项研究将使用使用我们最新的光谱非线性GW参数化的综合耦合中间大气 - 热球2（CMAT2）通用循环模型进行。将进行新颖的数值模拟，并针对现有和将来的观察数据集进行了测试，包括群体卫星。除了促进和测试我们对GW耦合的基本理解外，结果还可以改善空间天气的预测。