D-Region Ionosphere Inferred Maps of Electron-density (DRIIME)

授予佐治亚理工大学的该奖项将支持一项倡议，即利用甚低频（VLF, 3-30 kHz， 33-333 μs周期）无线电接收机建立60-90公里高度的长期电离层等离子体空间测绘能力。虽然利用GPS测量总电子含量的遥感方法获得了海拔250公里以上的高层大气等离子体分布的空间图，但目前还没有这种能力用于这一较低电离层等离子体区域。VLF遥感长期以来一直被视为该地区最有前途的遥感技术，但有几个因素使得从VLF测量到电离层地图非常困难。然而，电离层诊断方面的两项最新进展现在使这种绘图得以实现。该奖项将解决工作的三个关键目标：利用两个VLF遥感进展的融合制定统一的地图确定方法，实现时间和空间分辨率的量化，以及通过检查内部自一致性并与外部HF吸收分析结果进行比较来验证。这些地图将被分析，原始和处理过的数据产品将被公开，扩大可能对其他领域的科学影响。该奖项支持的研究将代表朝着实现对航空工业有用的HF吸收精确模型的进展。作为该奖项更广泛的教育推广的一部分，将开发一套教程，使相关领域的科学家能够理解和使用公共数据集，并作为数据公开发布的一部分提供给公众。来自代表性不足群体的暑期本科生实习生将使用乔治亚理工学院旨在实现多样性和包容性的既定项目参与这项奖项研究工作。VLF信号从这个等离子体区域（称为d区）有效地反射，但在距离源的距离上检测到的VLF信号也随着电离层条件的变化而变化。虽然这个原理已经知道了几十年，但将测量结果转化为等离子体密度估计更加困难。有两个主要的VLF波源可以用于这种形式的遥感：VLF发射机和全球闪电发射的无线电大气（sferics）。两项主要的进展，每一种VLF源，解决了许多这样的问题。该奖励研究计划将把甚低频发射机和天线合并为一种技术。本文介绍了一种利用独立测量验证VLF遥感结果的新方法。这一发展将避免VLF遥感长期存在的障碍，即缺乏对等离子体含量的直接测量以与结果进行比较。新的能力不仅可以直接观测电离层环境条件，包括日和季节变化，还可以直接观测电离层干扰的几种类型，如早期VLF事件和与大气重力和声波有关的影响。该奖项反映了美国国家科学基金会的法定使命，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。

The award to Georgia Tech University would support an initiative to establish a long-term ionospheric plasma spatial mapping capability for the altitudes of 60-90 km with Very Low Frequency (VLF, 3-30 kHz, 33-333 μs period) radio receivers. While spatial maps of the upper atmosphere plasma distribution for altitudes above 250 km have been obtained through remote sensing using GPS measurements of total electron content, no such capability currently exists for this lower ionospheric plasma region. VLF remote sensing has long been viewed as the most promising technique for remote sensing in this region, but several factors have made it very difficult to go from VLF measurements to ionospheric maps. However, two recent advances in ionospheric diagnostics have now enabled this mapping to be achieved. This award would address three key goals for the work: the formulation of a unified map determination method using a fusion of two VLF remote sensing advances, quantification of the temporal and spatial resolution achieved, and validation through checking for internal self-consistency combined with comparison with results of external HF absorption analysis. These maps would be analyzed and the raw and processed data products made public expanding the possible scientific impact to other fields. The research supported by this award would represent progress toward achieving an accurate model of HF absorption useful for the aviation industry. As part of this award broader educational outreach, a set of tutorials that would enable scientists in related fields to understand and use the public datasets would be developed and made available as part of the public release of data. Summer undergraduate interns from underrepresented groups would participate in this award research effort using an established Georgia Tech program designed to achieve diversity and inclusion.VLF signals reflect efficiently from this plasma region (known as the D-region) but also VLF signals detected at a distance from a source change as ionospheric conditions change. While this principle has been known for decades, translating measurements to plasma density estimates is more difficult. There are two major sources of VLF waves that can be used for this form of remote sensing: VLF transmitters and radio atmospherics (sferics) emitted by global lightning. Two major advances, one for each type of VLF source, solve many of these problems. The award research plan would merge VLF transmitters and sferics in a single technique. A novel way of validating VLF remote sensing results with independent measurements would be introduced. This development would avoid a longstanding hurdle for VLF remote sensing, which is the lack of direct measurements of plasma content for comparisons with results. The new capability would allow direct observations of not only the ambient ionospheric conditions including diurnal and seasonal changes, but several types of ionospheric disturbances like Early VLF events and effects relating to atmospheric gravity and acoustic waves.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.