The role of MLT dynamics at mid and high latitudes on the Ionosphere/Thermosphere weather II (DYNAMITE2)

中高纬度 MLT 动力学对电离层/热层天气 II (DYNAMITE2) 的作用

• 批准号: 273502374
• 负责人: Professor Dr. Jorge Chau, Ph.D.
• 金额: --
• 依托单位: Max-Planck-Institut für Meteorologie (MPI-M)
• 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 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/273502374?language=en
• 关键词: role; MLT; dynamics; mid; latitudes

The ionosphere/thermosphere (I/T) system is driven by solar and magnetospheric forcing from above and by smaller but important lower atmospheric forcing from below. The latter has been hypothesized for many years, but its identification has been elusive. This forcing has to pass through the mesosphere and lower thermosphere (MLT), where a wide spectrum of waves interacts and couples to the I/T. Such coupling can occur (a) directly via propagation of waves, and/or (b) indirectly via the E region dynamo. Therefore the MLT dynamics is in general important, but at mid and high latitudes have a special appeal: (1) over these latitudes are observed, according to satellite observations, the major gravity wave (GW) hot spots, and (2) recent studies from global atmospheric/ionospheric coupled simulations have shown that it is over these latitudes that the atmospheric dynamics, responsible for most of the electrodynamics effects at low I/T latitudes, is amplified the most during sudden stratospheric warming (SSW) events. As part of our first phase efforts, so far nine papers in peer-reviewed journals have resulted, including one highlighted in EOS. Based on these results, we propose some changes to the methodology and the focus areas. In this second phase, we propose to continue using unique radar and lidar capabilities at mid and high latitudes to characterize the stratosphere and MLT waves, mean flow, and their interactions. We will add radar data from different longitudes and hemispheres, as well as extend our lidar analysis to temperatures and winds over northern Norway. These studies will be complemented by satellite and reanalysis data. The direct coupling will be studied by correlating MLT and stratospheric seasonal and annual tidal and gravity wave signatures with I/T data from Swarm and other satellites with near-polar orbits (like COSMIC), with special emphasis in the northern hemisphere fall transition. Different atmospheric/ionospheric coupled simulations are used to complement these studies. The E region dynamo effects are also studied with the help of atmospheric/ionospheric coupled simulations with the inclusion of lunar tides, during northern hemispheric strong polar jet oscillations (sPJOs) and non-PJOs periods. Our preliminary results indicate that not only the stratospheric but also the MLT dynamics is affected many weeks after the onset PJO conditions, depending on the type of PJOs. Note that strong PJOs are highly correlated with major SSWs. We study their connection and their effects on the I/T system via ground-based and satellite ionospheric data. Among other important questions, we expect to answer: (a) what is the effect of the observed short-term and seasonal, particularly around the fall transition, variability of MLT waves and mean flows on the I/T weather? (b) what are the characteristics of MLT mean flow, tides and gravity waves during different behaviors of PJOs and their corresponding I/T effects?

电离层/热层（I/T）系统由来自上方的太阳和磁层强迫以及来自下方的较小但重要的较低大气强迫驱动。后者多年来一直被假设，但其鉴定一直难以捉摸。这种强迫必须穿过中间层和低层热层 (MLT)，其中广泛的波谱相互作用并耦合到 I/T。这种耦合可以（a）通过波的传播直接发生，和/或（b）通过E区发电机间接发生。因此，MLT动态总体上很重要，但在中高纬度地区具有特殊的吸引力：（1）根据卫星观测，在这些纬度上观察到主要的重力波（GW）热点，以及（2）最近的研究全球大气/电离层耦合模拟的结果表明，在这些纬度上，造成低 I/T 纬度大部分电动力学效应的大气动力学在平流层突然变暖 (SSW) 事件期间被放大最多。作为我们第一阶段工作的一部分，迄今为止，我们已在同行评审期刊上发表了 9 篇论文，其中一篇在 EOS 中得到了重点关注。根据这些结果，我们建议对方法和重点领域进行一些更改。 在第二阶段，我们建议继续在中高纬度地区使用独特的雷达和激光雷达功能来表征平流层和 MLT 波、平均流量及其相互作用。我们将添加来自不同经度和半球的雷达数据，并将我们的激光雷达分析扩展到挪威北部的温度和风。这些研究将得到卫星和再分析数据的补充。将通过将 MLT 和平流层季节性和年度潮汐和重力波特征与来自 Swarm 和其他近极轨道卫星（如 COSMIC）的 I/T 数据相关联来研究直接耦合，特别关注北半球秋季过渡。不同的大气/电离层耦合模拟用于补充这些研究。在北半球强极急流振荡 (sPJO) 和非 PJO 期间，还借助大气/电离层耦合模拟（包括月球潮汐）研究了 E 区发电机效应。我们的初步结果表明，根据 PJO 的类型，在 PJO 条件出现后数周内，不仅平流层而且 MLT 动力学也会受到影响。请注意，强 PJO 与主要 SSW 高度相关。我们通过地面和卫星电离层数据研究它们的连接及其对 I/T 系统的影响。除其他重要问题外，我们期望回答：(a) 观察到的短期和季节性的影响是什么，特别是在秋季过渡期间、MLT 波的变化和平均流量对 I/T 天气的影响是什么？ (b) PJO不同行为期间MLT平均流量、潮汐和重力波的特征及其相应的I/T效应是什么？