Brief Communication: Earthquake–cloud coupling through the global atmospheric electric circuit

Harrison, Giles; Aplin, Karen; Rycroft, M.J.

doi:10.5194/nhess-14-773-2014

Cited by 31 publications

(10 citation statements)

References 19 publications

(28 reference statements)

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“…Our theoretical analysis favours the view [e.g., Harrison et al 2010Harrison et al , 2013Harrison et al , 2014 that the variations of atmospheric radon concentration may affect the columnar resistance of the atmosphere. For example, according to our estimate the pre-seismic increase in the radon activity concentration by two times can result in the local lowering of the standard atmosphere resistance by 10-20% and approximately the same relative increase in the fair-weather/background conduction current.…”

Section: Discussionsupporting

confidence: 66%

Pre-seismic variations of atmospheric radon activity as a possible reason for abnormal atmospheric effects

Сурков

2015

Annals of Geophysics

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Possible atmospheric effects associated with pre-seismic variations of atmospheric radon concentration occasionally observed prior to earthquake occurrence are subjected to theoretical study in order to assess their potential effectiveness. Altitude distribution of atmospheric conductivity is examined as a function of radon and aerosol concentrations. Horizontal components of atmospheric electric fields and currents, which can arise near a boundary of seismo-active region, are estimated. We speculated that changes in radon-induced air ionization can have an impact on fair-weather spectra of ULF electric pulsations. Particular emphasis has been placed on hypothesis for correlation between variations of pre-seismic radon activity and upward thermal radiation measured by satellite over the high seismicity regions. This hypothesis is based on assumption that the radon-induced ionization of atmospheric surface layer can trigger water vapor condensation which in turn results in release of the vaporization heat. Our analysis has shown that the upward thermal flux has to be many orders of magnitude lower than that predicted on the basis of this hypothesis.

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Section: Discussionsupporting

confidence: 66%

Pre-seismic variations of atmospheric radon activity as a possible reason for abnormal atmospheric effects

Сурков

2015

Annals of Geophysics

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“…The column conductance of the atmosphere can be varied much because of different reasons. Dust clouds and radon emanation are analyzed in Harrison et al (2010) and Harrison et al (2014). One more important reduction in conductivity is made by non-electric clouds.…”

Section: Discussion Of the Numerical Resultsmentioning

confidence: 99%

Mathematical Simulation of the Ionospheric Electric Field as a Part of the Global Electric Circuit

2018

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Electric currents flowing in the global electric circuit are closed by ionospheric currents. A model for the distribution of the ionospheric potential which drives these currents is constructed. Only the internal electric fields and currents generated by thunderstorms are studied, and without any magnetospheric current sources or generators. The atmospheric conductivity profiles with altitude are empirically determined, and the topography of the Earth's surface is taken into account. A two-dimensional approximation of the ionospheric conductor is based on high conductivities along the geomagnetic field; the Pedersen and Hall conductivity distributions are calculated using empirical models. The values of the potential in the E-and F-layers of the ionosphere are not varied along a magnetic field line in such a model and the electric field strength is only slightly varied because the segments of neighboring magnetic field lines are not strictly parallel. It is shown that the longitudinal and latitudinal components of the ionospheric electric field of the global electric circuit under typical conditions for July, under high solar activity, at the considered point in time, 19:00 UT, do not exceed 9 μV/m , and in the sunlit ionosphere they are less than 2 μV/m. The calculated maximum potential difference in the E-and F-layers is 42 V ; the maximum of the potential occurs above African thunderstorms that are near the terminator at that time. A weak local maximum also exists above the thunderstorm area in Central America. The minimum potential occurs near midnight above the Himalayas. The potential has identical values at ionospheric conjugate points. The voltage increases to 55 V at 23:00 UT and up to 72 V at 06:00 UT, when local midnight comes, respectively, for the African and Central American thunderstorm areas. These voltages are about twice as large at solar minimum. With our more realistic ionospheric model, the electric fields are an order of magnitude smaller than those found in the well-known model of Roble and Hays (J Geophys Res 84(A12):7247-7256, 1979). Our simulations quantitatively support the traditional presentation of the ionosphere as an ideal conductor in models of the global electric circuit, so that our model can be used to investigate UT variations of the global electric circuit.

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“…Rycroft et al [2008] described the mechanism through which the air conductivity at the Earth's surface is modified and the consequent change for the ionospheric potential due to the apparition of electrical charges. Harrison et al [2010Harrison et al [ , 2014 presented an application of this mechanism to earthquake processes. Pulinets and Ouzounov [2011] presented a Lithosphere-Atmosphere-Ionosphere Coupling model that explains the precursory phenomena of earthquakes.…”

Section: 318mentioning

confidence: 99%

Suspected seismo‐ionospheric coupling observed by satellite measurements and GPS TEC related to the M7.9 Wenchuan earthquake of 12 May 2008

et al. 2014

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Anomalous changes in the ionospheric conditions related to the Wenchuan earthquake of 12 May 2008 are investigated using electron density (Ne) from Detection of Electro‐Magnetic Emissions Transmitted from Earthquake Regions (DEMETER) and CHAMP satellites, electric field from DEMETER, and GPS‐total electron content (TEC) maps. The normalized Ne from the DEMETER satellite reveal that the previously reported TEC increments before the earthquake can be considered as fragments of the gradual equatorial ionization anomaly (EIA) enhancements near the epicenter longitude that began approximately 1 month before the earthquake and reached its maximum with an exceptionally large strength index 8 days prior to the main shock. This feature is indirectly confirmed through the CHAMP Ne and GPS TEC data. Following the EIA intensity peak, disturbances in the Ne and O+ density were observed in the nightside. Based on the concurrent electric field and Ne changes, it is suggested that EIA intensification could be triggered by the E field disturbances over the epicenter.

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Brief Communication: Earthquake–cloud coupling through the global atmospheric electric circuit

Cited by 31 publications

References 19 publications

Pre-seismic variations of atmospheric radon activity as a possible reason for abnormal atmospheric effects

Pre-seismic variations of atmospheric radon activity as a possible reason for abnormal atmospheric effects

Mathematical Simulation of the Ionospheric Electric Field as a Part of the Global Electric Circuit

Suspected seismo‐ionospheric coupling observed by satellite measurements and GPS TEC related to the M7.9 Wenchuan earthquake of 12 May 2008

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