Thermosphere/Ionosphere Gravity wave Effects Resulting from Upward Coupling (TigerUC)

向上耦合产生的热层/电离层重力波效应 (TigerUC)

• 批准号: 273514132
• 负责人: Dr. Manfred Ern
• 金额: --
• 依托单位: IEK-7: Stratosphäre
• 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 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/273514132?language=en
• 关键词: Thermosphere; Ionosphere; Gravity; wave; Effects

The thermosphere/ionosphere (T/I) system is strongly influenced from above (solar, geomagnetic), as well as from below. One of the most important processes from below are waves (e.g. planetary waves, tides, or gravity waves) that are mostly excited in the troposphere/tropopause region. Due to their vertical propagation, these waves are vertically coupling the T/I and the middle atmosphere. In particular, the contribution of gravity waves (GWs) to this coupling is still poorly understood. One of the reasons is the short horizontal scale of GWs (a few ten km to several thousand km) that challenges both observations and models.We will derive GW distributions in the T/I from multiple in situ data sets (e.g., both neutral and electron densities) observed by several satellites/satellite constellations (SWARM, CHAMP, GOCE, GRACE). Characteristic global distributions will be derived, and we will identify the most relevant temporal variations (e.g. annual cycle, solar cycle). These GW distributions will be compared with observations of the satellite instruments HIRDLS and SABER (GW variances, GW momentum fluxes and GW drag) in the stratosphere and mesosphere. Several of the data sets (CHAMP, GRACE, SABER) cover more than ten years. Spatial and temporal correlations between the GW distributions in the T/I at altitudes 250-500km and GW distributions in the middle atmosphere (stratosphere/mesosphere) over the whole altitude range 20-100km will be investigated. Based on these correlations, information shall be obtained, which altitudes and regions in the middle atmosphere contribute most to temporal and spatial variations observed in the T/I. In particular, the unique observations of GW drag from HIRDLS and SABER can provide further evidence whether secondary GWs presumably emitted from regions of strong GW dissipation contribute significantly to the global GW distributions observed in the T/I.Further, from the in situ observations, we will attempt to derive GW momentum fluxes and GW drag in the T/I region. Such data sets are particularly important for direct comparison with GW distributions that are simulated by general circulation models (GCMs) in the T/I region. These modeled GW distributions are required to properly simulate the drag that GWs exert on the background flow in the T/I. This is still one of the main uncertainties in the modeling of the T/I region as, up to now, validation of these model distributions by observations is still an open issue.

热层/电离层（T/I）系统受到来自上方（太阳、地磁）和下方的强烈影响。来自下面的最重要的过程之一是主要在对流层/对流层顶区域激发的波（例如行星波、潮汐或重力波）。由于它们的垂直传播，这些波垂直耦合T/I和中层大气。特别是，重力波（GW）的贡献，这种耦合仍然知之甚少。其中一个原因是GW的水平尺度很短（几十公里到几千公里），这对观测和模型都构成了挑战。我们将从多个现场数据集（例如，中性密度和电子密度）。将导出特征性的全球分布，我们将确定最相关的时间变化（例如年周期，太阳周期）。这些GW分布将与卫星仪器HIRDLS和SABER在平流层和中间层的观测结果（GW方差、GW动量通量和GW阻力）进行比较。一些数据集（CHAMP、GRACE、SABER）涵盖十多年。将研究250- 500 km高度T/I中的GW分布与整个20- 100 km高度范围中层大气（平流层/中间层）中GW分布之间的时空相关性。根据这些相关性，将获得中层大气中哪些高度和区域对观测到的T/I的时间和空间变化贡献最大的信息。特别是，从HIRDLS和SABER的GW阻力的独特的观察可以提供进一步的证据，是否二次GW大概从强GW耗散的区域发出的贡献显着的全球GW分布中观察到的T/I.此外，从原位观测，我们将试图获得GW动量通量和GW阻力在T/I区域。这些数据集对于与T/I区域大气环流模式模拟的GW分布进行直接比较特别重要。需要这些模拟的GW分布来正确模拟GW对T/I中背景流施加的阻力。这仍然是T/I区域建模的主要不确定性之一，因为到目前为止，通过观测验证这些模型分布仍然是一个悬而未决的问题。