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.

垂直传播的重力波是连接低层大气与热层/电离层系统的主要耦合机制。全球变暖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，并在传播和耗散时在大气层之间重新分配能量和动量。在TI中，分子粘性和离子拖曳是GWs的主要耗散机制。TI中磁场的变化改变了大气的折射特性（大尺度温度和风分布），并改变了离子阻力的耗散。本研究的主要目的是调查和量化的影响，地磁场的变化的传播和低层大气起源的GW的耗散，并对他们的动态反馈的TI。特别是，全球Ws的作用将被测试在连接的趋势减弱的地磁场，和无法解释的强烈观察到的冷却的热层。这项研究将使用一个全面的耦合中层大气-热层-2（CMAT 2）大气环流模式，该模式利用我们最先进的光谱非线性GW参数化。将进行新的数值模拟，并将结果与现有和未来的观测数据集（包括来自SWARM卫星的数据集）进行测试。除了推进和测试我们对GW耦合的基本理解外，这些结果还可能改善空间天气预测。