Understanding the Geospace Phenomena Connected to Localized Perturbations in Earth’s Magnetic Field

在地磁活动增强的时间间隔内，地球空间中电流的增加会在地面或人造长导体(如电线)中感应电流。这些地磁感应电流(GIC)可能导致停电并损坏电力部件，同时还会影响管道和列车系统。发展预测GIC的能力对于保护基础设施和限制地磁风暴对公共安全和经济的影响非常重要。该项目致力于通过了解磁场测量的局部时间变化(分贝/dt)与引起这些变化的磁层和电离层现象之间的联系来进行GIC预测。这项工作将支持培训两名准备进入空间科学、空间气象和机器学习知识的STEM工作人员的研究生，并支持领导该项目的一名女性PI的职业生涯。该项目由磁层物理计划、已建立的激励竞争研究计划(EPSCoR)和空气动力学计划共同资助。几项研究表明，分贝/分贝/分贝的峰值可以非常局部化，在数百公里的尺度上。因此，需要在本地化的水平上进行预测，以向电力公司提供可行的警告。空间天气预报中心目前使用的以物理为基础的模型缺乏必要的分辨率，无法在分贝/分贝峰值的空间尺度上包括物理现象。更高分辨率的模型正被用于科学研究，但计算成本很高，运行时间也更长，这使得它们更难用于及时预测。机器学习(ML)模型的一个优势是，一旦经过训练，进行预测的时间明显低于基于物理的直接建模。ML网络对数据集中的非线性关系进行建模的能力使我们能够通过使用模型可解释性技术更好地理解导致局部分贝/dt的现象。将讨论下列科学问题：(1)局域磁扰动的空间特征是什么？(2)磁层和电离层现象与局域磁扰动有什么关系？为什么？第一个问题将使用两种方法来解决，这两种方法利用了NSF资助的SuperMAG数据库：通过将区域表征为特定差异(将一个位置的值与定义区域内的平均值进行比较的参数)和通过使用球面初级电流系统进行内插，然后比较结果。第二个问题将利用可解释的机器学习技术，结合来自卫星(例如DMSP、安培、TWINS和THEMIS)的数据集，探索与空间局部扰动相关的磁层和电离层现象。这项工作的结果将提高我们对地磁活动间隔、磁层-电离层耦合以及地面磁场局部扰动的原因的理解。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

During intervals of increased geomagnetic activity, increased currents in geospace can induce currents in the ground or in long, manmade conductors, such as power lines. These geomagnetically induced currents (GICs) can drive power outages and damage power components while also affecting pipelines and train systems. Developing the ability to predict GICs is important to protecting infrastructure and limiting the impact of geomagnetic storms on public safety and the economy. This project addresses GIC prediction by seeking to understand the connection between localized temporal changes in magnetic field measurements (dB/dt) and the magnetospheric and ionospheric phenomena causing them. This work will support the training of two graduate students that will be prepared to enter the STEM workforce with knowledge of space science, space weather, and machine learning and support the career of a woman PI leading the project. This project is jointly funded by the Magnetospheric Physics program, the Established Program to Stimulate Competitive Research (EPSCoR), and the Aeronomy program.Several studies have shown that peaks in dB/dt can be very localized, on the scales of hundreds of km. Thus, forecasting is needed at a localized level to provide power companies with actionable warnings. The current physics-based models used by the Space Weather Prediction Center lack the resolution needed to include physical phenomena at the spatial scales of the dB/dt peaks. Higher resolution models are being used for scientific studies, but are computationally expensive and take longer to run, making them more challenging to use for timely forecasting. An advantage of machine learning (ML) models is that once trained, the runtime to make predictions is significantly lower than physics based direct modeling. ML networks’ ability to model nonlinear relationships in datasets can allow us to better understand the phenomena that result in localized dB/dt through the use of model explainability techniques. The following science questions will be addressed: (1) What are the spatial characteristics of localized magnetic perturbations? (2) What magnetosphere and ionosphere phenomena correlate with localized magnetic perturbations and why? The first question will be tackled using two methods that take advantage of the NSF-funded SuperMAG database: by characterizing the Region to Specific Difference (a parameter that compares the value at one location to the average values within a defined region) and by interpolation with spherical elementary current systems, and then comparing the results. The second question will utilize explainable machine learning techniques to explore magnetosphere and ionosphere phenomena that correlate with the spatially localized perturbations, incorporating datasets from satellites (e.g., DMSP, AMPERE, TWINS, and THEMIS). The results of this work will improve our understanding of geomagnetically active intervals, magnetosphere-ionosphere coupling, and the causes of localized perturbations in the ground magnetic field.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.