Collaborative Research: NSWP--Investigation of Global E-region Conductivities Relevant to the Seeding and Variability of Equatorial Spread F Using Measurements from COSMIC

合作研究：NSWP——利用 COSMIC 的测量结果调查与赤道传播 F 的播种和变异相关的全球 E 区电导率

• 批准号: 0719968
• 负责人: Gary Bust
• 金额: $ 11.25万
• 依托单位: ATMOSPHERIC & SPACE TECHNOLOGY RESEARCH ASSOCIATES, L.L.C.
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0719968&HistoricalAwards=false
• 关键词: Collaborative; Research; NSWP; Investigation; Global

Low-latitude severe space weather is typified by the phenomenon of equatorial spread F (ESF), which is an explosive release of stored gravitational energy, usually occurring in the post-sunset period. The occurrence and severity of an ESF event depends on the condition of the local equatorial ionosphere, as well as that of the plasma in electrical contact with it (namely, the off-equatorial E region) through coupling within the appropriate magnetic flux tube. Convective plumes of turbulent plasma that develop during strong ESF events can degrade communications from high frequencies to the L-band and can last for several hours as the plumes drift with the background plasma. A major current area of interest relates to the causal mechanisms that drive the day-to-day variability of ESF. ESF has been convincingly linked to variations in the strength of the pre-reversal enhancement (PRE), which is an increase in the vertical drift velocity during the post-sunset period that drives equatorial plasma to higher altitudes where conditions are more conducive to instability. This project focuses on global measurements of E-region densities and applies them to understand the day-to-day and longer-term variability of ESF. The global measurements will come from instruments onboard the COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) satellites and will include high-resolution Global Positioning System occultation measurements of the total electron content (TEC), ultra-violet photometer measurements related to the integrated ionospheric electron density, and tri-band TEC measurements along the trajectory of the satellite. The measurements will be combined using tomographic inversion and data assimilative techniques to estimate the two-dimensional distribution of electron density, including the horizontal plasma density gradients of the E region densities. Results will be validated and errors and resolutions quantified using ground-truth measurements from the Arecibo and Jicamarca radars. One of the project's broader impacts lies in the database of E region densities that will be assembled which could be useful for global assimilation models and perhaps important in reproducing equatorial ionospheric variability, particularly in terms of prediction. A graduate student will be involved in the projectas well as a new young investigator for whom this is the first proposal as principal investigator

低纬度的严重空间天气是赤道扩散f（ESF）的现象，这是储存的重力能量的爆炸性释放，通常发生在产后期间。 ESF事件的发生和严重程度取决于局部赤道电离层的状况，以及与IT电气接触中的血浆（即外旁E区域）通过适当的磁磁管中的耦合。在强烈的ESF事件期间发育的湍流血浆的对流羽可以使从高频到L波段的通信降低通信，并且随着羽流随背景等离子体的漂移而持续几个小时。当前的主要目标领域与驱动ESF日常变异性的因果机制有关。 ESF令人信服地与反转前增强强度的变化相关，这是垂直漂移速度在降低后期的增加，该垂直漂移速度将赤道等离子体驱动到更高的高度，而条件更有助于不稳定。 该项目着重于电子区域密度的全球测量，并将其应用于了解ESF的日常和长期变异性。 The global measurements will come from instruments onboard the COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) satellites and will include high-resolution Global Positioning System occultation measurements of the total electron content (TEC), ultra-violet photometer measurements related to the integrated ionospheric electron density, and tri-band TEC measurements along the trajectory of the satellite.测量结果将使用层析成像倒置和数据同化技术组合，以估计电子密度的二维分布，包括E区域密度的水平等离子体密度梯度。结果将得到验证，并使用Arecibo和Jicamarca雷达的地面真相测量来量化错误和决议。 该项目的更广泛的影响之一在于将组装E区域密度的数据库，该数据库将用于全球同化模型，并且对于再现赤道电离层变异性，尤其是在预测方面。 研究生将参与Projectas以及新的年轻调查员，这是首先作为首席研究员的建议