Weakening of the mid-latitude summer nighttime anomaly during geomagnetic storms

Liu, Huixin; Yamamoto, M.

doi:10.5047/eps.2010.11.012

Cited by 7 publications

(4 citation statements)

References 15 publications

(28 reference statements)

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“…In 1989and 2000, strong geomagnetic storms caused the problem that northern midlatitudes in Russian and Gorky electrification railway section were observed much operation abnormity in the track signal system. These phenomena were found by Liu [2], Wik et al [3], and Beloa et al [4]. Molinski [5] and Gummow and Eng [6] found geomagnetic storms can influence long conductors on the ground surface.…”

Section: Introductionmentioning

confidence: 82%

Geomagnetic Storms’ Influence on Intercity Railway Track Circuit

et al. 2016

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Geomagnetic storms can cause earth surface potentials (ESPs) in the ground. ESP produces geomagnetically induced current (GIC) in a loop which is made up by rails and ground. If GIC flows into intercity railway track circuit, it will threaten the normal operation of track circuit. The reason that geomagnetic storms invade the track circuit was analyzed, and then how GIC affects the characteristics of choke transformers, was found. The calculation method of GIC according to a simulation based on the GIC flow path in the track circuit was built. Electromagnetic system model of choke transformer and track relay were designed in Maxwell software to get the magnetic flux density distribution of them. The results show that GIC values of 2.4 A can bring about serious direct current bias of choke transformers and cause the terminal voltage of track relay to decrease, resulting in relay malfunction. The numerical calculation results show that geomagnetic storms will interfere with intercity railway track circuit, which is in accordance with some phenomenon happened in some rail tracks. This method proves geomagnetic storms' influence on intercity railway track circuit and attentions should be paid to this influence.

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Section: Introductionmentioning

confidence: 82%

Geomagnetic Storms’ Influence on Intercity Railway Track Circuit

et al. 2016

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“…They reported mass density enhancements, a density bulge propagating as a traveling atmospheric disturbance (TAD), and wind variations during a substorm event. Liu and Yamamoto (2011) reported geomagnetic storm effects on the formation and characteristics of the mid-latitude summer nighttime anomaly (MSNA), which is a phenomenon during which the diurnal variation of the plasma density maximizes at night instead of day. They pointed out the role of the effective neutral wind in the formation of MSNA.…”

Section: Upper Thermospherementioning

confidence: 99%

The geospace response to variable inputs from the lower atmosphere: a review of the progress made by Task Group 4 of CAWSES-II

Oberheide

Shiokawa

Gurubaran

et al. 2015

Prog. in Earth and Planet. Sci.

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The advent of new satellite missions, ground-based instrumentation networks, and the development of whole atmosphere models over the past decade resulted in a paradigm shift in understanding the variability of geospace, that is, the region of the atmosphere between the stratosphere and several thousand kilometers above ground where atmosphere-ionosphere-magnetosphere interactions occur. It has now been realized that conditions in geospace are linked strongly to terrestrial weather and climate below, contradicting previous textbook knowledge that the space weather of Earth's near space environment is driven by energy injections at high latitudes connected with magnetosphere-ionosphere coupling and solar radiation variation at extreme ultraviolet wavelengths alone. The primary mechanism through which energy and momentum are transferred from the lower atmosphere is through the generation, propagation, and dissipation of atmospheric waves over a wide range of spatial and temporal scales including electrodynamic coupling through dynamo processes and plasma bubble seeding. The main task of Task Group 4 of SCOSTEP's CAWSES-II program, 2009 to 2013, was to study the geospace response to waves generated by meteorological events, their interaction with the mean flow, and their impact on the ionosphere and their relation to competing thermospheric disturbances generated by energy inputs from above, such as auroral processes at high latitudes. This paper reviews the progress made during the CAWSES-II time period, emphasizing the role of gravity waves, planetary waves and tides, and their ionospheric impacts. Specific campaign contributions from Task Group 4 are highlighted, and future research directions are discussed.

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“…As part of this experiment, it was shown for 2007 that the effect appears at 22:00 LT from November to February, but is most intense in December and January (Lin et al, 2010). Liu and Yamamoto (2011) showed a weakening of the mid-latitude summer nighttime anomaly during geomagnetic storms.…”

Section: Introductionmentioning

confidence: 94%

Variability of Weddell Sea ionospheric anomaly as deduced from observations at the Akademik Vernadsky station

Galushko

Stanisławska

Lisachenko

et al. 2021

UAJ

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Ionospheric Weddell Sea anomaly is an inversion of diurnal variation of the electron density in the ionosphere over Antarctic Peninsula, Weddell Sea, and neighbor territories observed during Antarctic summer. This paper aims at analyzing the reaction of the ionosphere during the Weddell Sea anomaly to changes in solar and geomagnetic activity as deduced from the data of vertical sounding of the ionosphere conducted at the Akademik Vernadsky station. The aim is achieved by comparing the monthly median values of the critical frequencies of the ionosphere (foF2) during Weddell Sea anomaly for the years of high and low solar activity; as well as by comparison of median December height-time diagrams (HT-diagrams) of foF2 calculated separately for the time intervals characterized by low or high levels of F10.7 and K indices for the period from 2007 till 2016. It was experimentally demonstrated that the Weddell Sea anomaly depends on the levels of solar ultraviolet flux and local K indices. The biggest nighttime maximum of ionization corresponds to low K indices and high values of F10.7. The most accurate inversion of diurnal variation of electron density in the F region is observed under the low values of K index and low F10.7 flux. The growth of geomagnetic activity decreases the nighttime ionization under both low and high levels of F10.7 fluxes and leads to a blur of the night maximum. Visible virtual heights of maximums increase together with F10.7 independently of the K index level. Blurring of the night maximum can be explained by destruction of the field of thermospheric winds supporting the nighttime anomaly, and/or by increasing role of plasma drifts in comparison with wind impact. The growth of visible virtual height of the nighttime maximum with increasing solar F10.7 flux could be explained by the gain of equatorward thermospheric wind with increasing solar ultraviolet flux that leads to growth of plasma upwelling effect. The Doppler frequency shift of the signals reflected from the ionosphere during nighttime in presence of the Weddell Sea anomaly is close to zero which could be explained by a stable F2 layer formed as a result of dynamic equilibrium between photochemical processes and upward plasma transport.

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Weakening of the mid-latitude summer nighttime anomaly during geomagnetic storms

Cited by 7 publications

References 15 publications

Geomagnetic Storms’ Influence on Intercity Railway Track Circuit

Geomagnetic Storms’ Influence on Intercity Railway Track Circuit

The geospace response to variable inputs from the lower atmosphere: a review of the progress made by Task Group 4 of CAWSES-II

Variability of Weddell Sea ionospheric anomaly as deduced from observations at the Akademik Vernadsky station

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