Ionospheric Bow Waves and Perturbations Induced by the 21 August 2017 Solar Eclipse
Ionospheric Bow Waves and Perturbations Induced by the 21 August 2017 Solar Eclipse
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DOI：
10.1002/2017gl076054
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发表时间：
2017-12-28
影响因子：
5.2
通讯作者：
Vierinen, Juha
中科院分区：
文献类型：
--
作者：
Zhang, Shun-Rong;Erickson, Philip J.;Vierinen, Juha
在日食期间，月球的阴影导致大气能量输入的大幅减少，不仅包括平流层，还包括热层和电离层。日食阴影具有超音速运动，理论上预计会产生大气弓形波，类似于快速移动的河船，波从低层大气开始并传播到电离层。然而，以前的地理上有限的观测很难检测到这些弱波的自然背景大气变化，日食引起的电离层波的存在和它们在一个复杂的耦合系统的演变仍然存在争议。在2017年8月21日的日食期间，高保真和广覆盖的电离层观测首次提供了一组过采样的日食数据，使用了北美大约2，000个站点的全球导航卫星系统接收器密集网络。我们首次明确地证明了电离层弓形波是美国中部/东部上空的电子含量扰动，持续时间约为1小时，波长为300- 400公里，相位速度为280米/秒，从全食区发出并尾随全食区。我们还确定了大的电离层扰动的最大太阳遮蔽的超音速移动，这是太快了，与已知的重力波或大规模的旅行电离层扰动过程。这项研究揭示了太阳、月球和地球的中性大气层和电离层之间复杂的相互联系，并展示了地球大气层不同成分之间持续的耦合过程，这是一个重要的社区感兴趣的话题。简明语言摘要在日食期间，月球的阴影导致大气能量输入大幅减少，包括平流层以及热层和电离层（大约100-1，000公里高度）。自20世纪60年代以来的理论研究预测，月球的超音速阴影应该会产生大气弓形波，类似于快速移动的河流船。然而，这些微弱而复杂的波的观测受到地理限制。2017年，使用北美全球导航卫星系统（GNSS）近2，000个接收器网络进行了高保真和广覆盖电离层观测。日食通道产生明确的电离层弓形波的电子内容的干扰，从全食主要是在美国中部/东部。波的特性研究揭示了太阳、月球和地球的中性大气层和电离层之间复杂的相互联系。
During solar eclipses, the Moon's shadow causes a large reduction in atmospheric energy input, including not only the stratosphere but also the thermosphere and ionosphere. The eclipse shadow has a supersonic motion which is theoretically expected to generate atmospheric bow waves, similar to a fast-moving river boat, with waves starting in the lower atmosphere and propagating into the ionosphere. However, previous geographically limited observations have had difficulty detecting these weak waves within the natural background atmospheric variability, and the existence of eclipse-induced ionospheric waves and their evolution in a complex coupling system remain controversial. During the 21 August 2017 eclipse, high fidelity and wide coverage ionospheric observations provided for the first time an oversampled set of eclipse data, using a dense network of Global Navigation Satellite System receivers at approximate to 2,000 sites in North America. We show the first unambiguous evidence of ionospheric bow waves as electron content disturbances over central/eastern United States, with approximate to 1h duration, 300-400km wavelength and 280m/s phase speed emanating from and tailing the totality region. We also identify large ionospheric perturbations moving at the supersonic speed of the maximum solar obscuration which are too fast to be associated with known gravity wave or large-scale traveling ionospheric disturbance processes. This study reveals complex interconnections between the Sun, Moon, and Earth's neutral atmosphere and ionosphere and demonstrates persistent coupling processes between different components of the Earth's atmosphere, a topic of significant community interest.Plain Language Summary During solar eclipses, the Moon's shadow causes a large reduction in atmospheric energy input, including the stratosphere and both the thermosphere and ionosphere (approximate to 100-1,000km altitudes). Theoretical studies since the 1960s have predicted that the Moon's supersonic shadow should generate atmospheric bow waves, similar to a fast-moving river boat. However, observations were geographically limited for these weak and complicated waves. In 2017, high fidelity and wide coverage ionospheric observations were made using a North American Global Navigation Satellite System (GNSS) approximate to 2,000 receiver network. Eclipse passage generated clear ionospheric bow waves in electron content disturbances emanating from totality primarily over central/eastern United States. Study of wave characteristics reveals complex interconnections between the Sun, Moon, and Earth's neutral atmosphere and ionosphere.