Seeing the Northern Lights at the equator? Predicting the next reversal of Earth's magnetic field

在赤道看到北极光？

• 批准号: 2743366
• 金额: --
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2743366
• 关键词: Seeing; Northern; Lights; equator; Predicting

The geomagnetic field is a fundamental part of planet Earth, existing for at least 3.5 billion years. Yet far from being a constant, the field is very dynamic, exhibiting slow fluctuations and wandering magnetic poles which occasionally fully reverse in polarity. During a global magnetic field reversal, the usually strong dipolar field of the Earth fragments into multiple magnetic poles each of which drift across the planet's surface. It is likely that around every one a local auroral oval forms allowing the 'northern lights' to appear anywhere a pole was close by - even at the equator.The magnetic field wraps around our planet as an invisible force-field, providing long-term protection to life on the surface and modern technological infrastructure from harmful solar radiation. Although the current rate of reversals is about 2-3 times per million years, the last global reversal took place some 780,000 years ago, meaning that planet Earth is now well "overdue" a reversal. True or not, it is certainly the case that change is afoot: a patch of weak field in the south Atlantic (the south Atlantic anomaly) is spreading; the global field (expressed by the dipole strength) is weakening at a rate of 5% per century; and very recent measurements over the last few decades have shown that the magnetic North Pole has begun a sprint away from its historical position over northern Canada towards Siberia. Does this indicate that a period of significant change for the global field is upon us?Predicting the magnetic field is challenging, not the least because we do not yet have a complete representation that describes how the magnetic field changes. Although the basic physics is understood, the complexities and extreme conditions within the Earth's core make it computationally difficult to model. The novel aspect of this project is to apply recent advances in Machine Learning or Deep Learning to the prediction of Earth's magnetic field. The key idea behind the project is that a trained neural network may be able to spot patterns in the data that have so far either not been noticed or have been too complex to interpret; such networks may be able to supply accurate short-time forecasts of the internally generated magnetic field. One of the goals of the project is to assess the evidence for whether the geomagnetic field is likely to reverse and how fast it might do so.

地磁场是地球的基本组成部分，至少存在了35亿年。然而，磁场远不是恒定的，而是非常动态的，表现出缓慢的波动和徘徊的磁极，偶尔完全颠倒极性。在全球磁场反转期间，通常很强的地球偶极磁场分裂成多个磁极，每个磁极都在地球表面漂移。很可能在每个地方都有一个局部的椭圆形极光，使得北极光出现在任何靠近极点的地方——甚至在赤道。磁场作为一个看不见的力场包裹着我们的星球，为地球表面的生命和现代技术基础设施提供长期保护，使其免受有害的太阳辐射。虽然目前的倒转率大约是每百万年2-3次，但上一次全球倒转发生在大约78万年前，这意味着地球现在已经“逾期”了一次倒转。无论真假，变化确实正在发生：南大西洋的一块弱磁场（南大西洋异常）正在扩散；全球磁场（用偶极子强度表示）正在以每世纪5%的速度减弱；最近几十年的测量表明，磁北极已经开始从它在加拿大北部上空的历史位置向西伯利亚冲刺。这是否表明全球领域的一个重大变化时期即将到来？预测磁场是具有挑战性的，尤其是因为我们还没有一个完整的表示来描述磁场如何变化。尽管我们已经了解了基本的物理原理，但地核内部的复杂性和极端条件使得在计算上很难建立模型。这个项目的新颖之处在于将机器学习或深度学习的最新进展应用于地球磁场的预测。该项目背后的关键思想是，经过训练的神经网络可能能够发现数据中的模式，这些模式到目前为止要么没有被注意到，要么太复杂而无法解释；这种网络也许能够提供对内部产生的磁场的准确的短期预报。该项目的目标之一是评估地磁场是否可能逆转以及逆转速度的证据。