Collaborative Research: CEDAR--Quantifying Ion Drifts in the Mid-latitude Ionosphere and Their Coupling to the Neutral Atmosphere

大气区域耦合、能量学和动力学(Cedar)计划是一个基础广泛、社区指导的高层大气研究计划。它的目的是在区域和全球尺度上从耦合、能量学、化学和动力学方面了解从中间大气层向上穿过大气层电离上层并进入外层空间的大气区域的行为。中纬度电离层是极地和赤道地区活跃电离层之间的中介，但对它的研究还不是很深入。这项合作雪松奖涉及德克萨斯大学达拉斯分校、弗吉尼亚理工大学和科罗拉多大学，旨在开发第一个静默时间的电离层电场分布经验模型，以填补产生对电离层全球动态的真正理解所需的必要的基本事实。这项研究工作将使用15年来空军国防气象空间等离子体(DMSP)对中纬度电离层电离层纬向流动速度的测量，以构建中纬度电离层安静时间电场的经验模型。这一数据集将由从中纬度SuperDARN站点获得的离子漂移数据补充。该数据库将向外部用户开放，因此将是一项宝贵的电离层社区资源。在平静时间模型的开发完成后，将把风暴时间的观测结果与应用新的平静时间模型的预测进行比较。将在CTIP(热层电离层等离子体层耦合模式)-RCM模式运行的指导和背景下分析已确定的差异，以了解造成相对于所建立基线模式的观测可变性的根本物理机制，以量化风暴时间扰动的幅度和程度，最后，量化中纬度离子漂移与中性大气的耦合以及极地和赤道区域之间的能量转移。最后，利用近二十年的DMSP数据来理解和开发经验模型是雪松大气计划的一个基本挑战的核心，即量化中纬度电场的基线模型。因此，可以更仔细地评估作为太阳阶段、地磁活动以及与低层大气和磁层区域的动力耦合作用的可变性问题。所取得的成果将引起电离层和热层模型界的极大兴趣和用处，并与CEDAR任务“了解空间-大气相互作用区的基本性质；确定定义空间--大气层相互作用区的全球行为、演变和对日地系统的影响的相互关联的过程”有关。该项目的主要目标是量化电离层相对于定时航天器和SDO航天器对太阳极端紫外线辐射的直接、光谱分离测量的反应。这种方法与以前基于代理的研究相比是一个巨大的改进。在一定高度范围内的C/NOFS和DMSP航天器将提供相应的电离层参数测量。这一数据集跨越不止一个太阳周期，允许使用先进的统计分析技术，并将与SAMI-2模型一起使用，以解决与了解电离层对太阳极光紫外线可变性的反应有关的悬而未决的科学问题。需要研究的有趣问题包括高层大气的中性和电离成分的反应的相对重要性和相互作用。

The Coupling, Energetics, and Dynamics of Atmospheric Regions (CEDAR) program is a broad-based, community-guided, upper atmospheric research program. It is aimed at understanding the behavior of atmospheric regions from the middle atmosphere upward through the ionized upper layers of the atmosphere and into outer space in terms of coupling, energetics, chemistry, and dynamics on regional and global scales. The mid-latitude ionosphere serves as the intermediary between the active ionospheres of the polar and equatorial regions, but it has not been studied very thoroughly. This Collaborative CEDAR award involving University of Texas at Dallas, Virginia Tech University, and the University of Colorado is aimed at developing the first quiet-time empirical model of the ionosphere electric field distribution to fill in the necessary ground truth needed to produce a true understanding of the global dynamics of the ionosphere. The research effort would use 15 years of Air Force Defense Meteorological Space Plasma (DMSP) measurements of ion zonal flow speeds in the mid-latitude ionosphere to construct an empirical model of mid-latitude ionospheric quiet-time electric fields. This data set would be supplemented by ion drift data obtained from the mid-latitude SuperDARN sites. This database would be made available to outside users, and thus, would be a valuable ionospheric community resource. Following the completion of the development of the quiet time model, observations from storm times will be compared to predictions based upon application of the new quiet time model. The determined differences would be analyzed within the guidance and context of the CTIP (Coupled thermosphere ionosphere plasmasphere)-RCM model runs to understand the underlying physical mechanisms causing the observed variability relative to the baseline model established, to quantify the magnitude and extent of storm-time disturbances, and finally, to quantify the coupling of the mid-latitude ion drifts to the neutral atmosphere and the transfer of energy between the polar and equatorial regions. Finally, making use of nearly two decades of DMSP data to understand and develop empirical models goes to the heart of one of the fundamental challenges of the CEDAR Aeronomy program, which is to quantify a baseline model of mid-latitude electric fields. Consequently, the question of variability as a function of solar phase, geomagnetic activity, and dynamical coupling to the lower atmosphere and to the magnetosphere regions can be more carefully assessed. The results achieved would be of great interest and use to the ionosphere and thermospheric modeling community and also relevant to the CEDAR mission of "understanding the fundamental properties of the space-atmosphere interaction region (SAIR); identify the interconnected processes that define the SAIR's global behavior, evolution, and influence on the Sun-Earth system". The main goal of this project is to quantify the response of the ionosphere relative to direct, spectrally separated measurements of solar extreme ultraviolet (EUV) radiation from the TIMED and SDO spacecraft. This approach constitutes an immense improvement over previous studies based on proxies. The C/NOFS and DMSP spacecraft at a range of altitudes will provide corresponding measurements of ionospheric parameters. This dataset, spanning more than a solar cycle, allows for the use of advanced statistical analysis techniques and will be used together with the SAMI-2 model to address outstanding science questions related to understanding the ionospheric response to solar EUV variability. Interesting questions to be investigated include the relative importance of and interaction between the responses in the neutral and ionized components of the upper atmosphere.