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Ionospheric Response to the 2020 South American Total Solar Eclipse: Observing Atmospheric Gravity Waves and Total Electron Content Interactions

2020 年南美日全食的电离层响应：观测大气重力波和总电子含量相互作用

基本信息

批准号：
2029804
负责人：
Demian Gomez
金额：
$ 14.42万
依托单位：
Ohio State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-11-01 至 2022-10-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2029804&HistoricalAwards=false
关键词：
Ionospheric Response 2020 South American

项目摘要

Total solar eclipse has always been the most visible celestial phenomenon that attracts public attention. It is also a unique opportunity for a broad range of scientific research. The sudden shutdown of solar radiation can create disturbances throughout the atmosphere, from the surface to the ionosphere, a region of atmosphere with a high concentration of ions and free electrons from about 50 to 600 miles above the Earth's surface. Observation of such disturbances during a solar eclipse provides a unique opportunity to understand ionospheric dynamics and energy transportation in the atmosphere. This 2020 South America solar eclipse is of particular interest because it will occur in a region where atmospheric gravity waves (AGWs) are being generated by the Andes below, which create perturbations in the total electron content (TEC) in the ionosphere. In this project the team will observe and model the interaction between the total electron content (TEC) in the ionosphere and AGWs during the December 2020 total solar eclipse in southern Chile and Argentina. It will focus on AGWs known as “mountain waves” that are associated with and anchored by the topographic front of the Andes. The team will collect geodetic data at about 35 Global Navigation Satellite System (GNSS) sites and weather observations at 6 sites before, during, and after the 2020 eclipse so as to examine the mechanisms by which TEC is perturbed by eclipse-generated AGWs. The sites of the existing sparse GNSS continuous network will be complemented with temporary sites installed to observe the eclipse. Through the development and application of novel techniques, the team will analyze the resulting dataset to address unresolved questions about interactions between the ionospheric TEC variations and the eclipse’s umbra. These new observations will allow the team to build on observational data collected during the 2017 and the 2019 eclipses. New observations will also help to perfect the data processing techniques and interpretation of future eclipses, such as the 2024 North American eclipse. This project will address specific scientific questions: does the passage of the eclipse, through changes in atmospheric conditions, trigger mountain waves or other troposphere-level AGW associated with topographic features? Do these triggered AGWs propagate up to ionospheric heights, perturbing the ionospheric TEC? Does the eclipse trigger AGWs not associated with topography, as predicted by earlier theoretical studies? The team will use a dynamic 3D model of the ionosphere (SAMI3) and singular spectrum analysis (SSA), a non-parametric modeling technique, to separate TEC perturbations from the background TEC affected by the obscuration of the Sun. Eclipses generate two sets of distinct TEC changes within and around the totality zone: a direct effect due to the reduction and shutoff of ionizing radiation, and a set of more complex indirect effects, associated with both cooling of the atmosphere and the weather, that propagate into the ionosphere from the underlying atmospheric behavior. Perturbations related to the complex interaction between eclipse-induced AGWs and the ionospheric TEC are poorly understood due to limitations in current TEC analysis techniques. This project will address both topics by collecting new data, applying new techniques such as SSA to TEC time series, and modeling the AGW-TEC interactions.The project will help to produce accurate background TEC models to reliably detect anomalies in ionospheric time series due to AGWs (and also acoustic waves) triggered by tsunamis and nuclear explosions. It will also enhance the reliability of systems that depend on the real-time state of the ionosphere, including telecommunications and real-time positioning services. The project will be led by an early career Argentine-American faculty member and further promote diversity in geosciences by including a female Latin American geodesist in fieldwork and subsequent data analysis. A graduate student from Ohio State University (OSU) will participate in the field campaign and the analysis of the TEC data.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

日全食一直是最受公众关注的可见天体现象。这也是进行广泛科学研究的独特机会。太阳辐射的突然停止可以在整个大气层中产生扰动，从表面到电离层，电离层是一个在地球表面上方约50至600英里处具有高浓度离子和自由电子的大气区域。在日食期间观测这种扰动为了解电离层动力学和大气中的能量传输提供了一个独特的机会。 2020年南美洲日食特别令人感兴趣，因为它将发生在下面的安第斯山脉产生大气重力波（AGW）的区域，这会对电离层中的总电子含量（TEC）产生扰动。在这个项目中，该团队将观察和模拟2020年12月智利南部和阿根廷日全食期间电离层总电子含量（TEC）与AGW之间的相互作用。它将侧重于与安第斯山脉的地形前沿有关并由其固定的被称为“山波”的AGW。该团队将在2020年日食之前，期间和之后收集大约35个全球导航卫星系统（GNSS）站点的大地测量数据和6个站点的天气观测数据，以研究TEC受到日食产生的AGW扰动的机制。将安装临时观测点，以补充现有稀疏的全球导航卫星系统连续网络的观测点。通过开发和应用新技术，该团队将分析由此产生的数据集，以解决有关电离层TEC变化和日食本影之间相互作用的未解决问题。这些新的观测将使团队能够建立在2017年和2019年日食期间收集的观测数据的基础上。新的观测也将有助于完善数据处理技术和对未来日食的解释，例如2024年北美日食。该项目将解决具体的科学问题：日食的通过，通过大气条件的变化，触发山波或其他对流层级AGW与地形特征？这些触发的AGW传播到电离层高度，扰动电离层TEC？日食触发的AGW是否与早期理论研究预测的地形无关？该团队将使用电离层的动态3D模型（SAMI 3）和奇异谱分析（SSA），一种非参数建模技术，将TEC扰动与受太阳遮蔽影响的背景TEC分离。日全食在全食带内和周围产生两组不同的TEC变化：由于电离辐射的减少和关闭而产生的直接影响，以及一组更复杂的间接影响，与大气和天气的冷却有关，从底层大气行为传播到电离层。由于目前TEC分析技术的局限性，人们对日食引起的AGW和电离层TEC之间复杂相互作用的扰动知之甚少。该项目将通过收集新数据、将SSA等新技术应用于TEC时间序列以及建立AGW-TEC相互作用模型来解决这两个问题。该项目将有助于制作准确的本底TEC模型，以可靠地探测海啸和核爆炸引发的AGWs（以及声波）引起的电离层时间序列异常。它还将提高依赖电离层实时状态的系统的可靠性，包括电信和实时定位服务。该项目将由一名早期职业的阿根廷裔美国教师领导，并通过在实地工作和随后的数据分析中包括一名拉丁美洲女性大地测量师来进一步促进地球科学的多样性。来自俄亥俄州州立大学（OSU）的一名研究生将参与实地活动和TEC数据分析。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。