GPS radio interferometry of travelling ionospheric disturbances

Afraimovich, É. L.; Palamartchouk, Kirill; Перевалова, Н. П.

doi:10.1016/s1364-6826(98)00074-1

Cited by 97 publications

(128 citation statements)

References 28 publications

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“…The orientation α of the wave vector K, which is coincident with the propagation azimuth of the SAW phase front, is calculated unambiguously in the range 0-360 • , subject to the condition that arctan(V y /V x ) is calculated with regard to the sign of the numerator and denominator. The above method for determining the SAW phase velocity neglects the correction for orbital motion of the satellite because the estimates of V h , obtained below, exceed an order of magnitude, as a minimum, of the velocity of the subionospheric point at the height of the ionosphere for elevations θ s > 30 • (Afraimovich et al, 1998).…”

Section: E a R T H Q U A K E O F F C O A St O F C E N T R A L A M E Rmentioning

confidence: 99%

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The shock-acoustic waves generated by earthquakes

et al. 2001

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Abstract. We investigate the form and dynamics of shockacoustic waves generated by earthquakes. We use the method for detecting and locating the sources of ionospheric impulsive disturbances, based on using data from a global network of receivers of the GPS navigation system, and require no a priori information about the place and time of the associated effects. The practical implementation of the method is illustrated by a case study of earthquake effects in Turkey (17 August and 12 November 1999), in Southern Sumatra (4 June 2000), and off the coast of Central America (13 January 2001). It was found that in all instances the time period of the ionospheric response is 180-390 s, and the amplitude exceeds, by a factor of two as a minimum, the standard deviation of background fluctuations in total electron content in this range of periods under quiet and moderate geomagnetic conditions. The elevation of the wave vector varies through a range of 20-44 • , and the phase velocity (1100-1300 m/s) approaches the sound velocity at the heights of the ionospheric F-region maximum. The calculated (by neglecting refraction corrections) location of the source roughly corresponds to the earthquake epicenter. Our data are consistent with the present views that shock-acoustic waves are caused by a piston-like movement of the Earth's surface in the zone of an earthquake epicenter.

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Section: E a R T H Q U A K E O F F C O A St O F C E N T R A L A M E Rmentioning

confidence: 99%

“…On the other hand, formula (3) can be used to determine the elevation θ of the wave vector K t of the shock wave at the known value of the azimuth α (Afraimovich et al, 1998). Hence, the phase velocity modulus V t can be defined as…”

Section: T U R K E Y E a R T H Q U A K E Smentioning

confidence: 99%

The shock-acoustic waves generated by earthquakes

et al. 2001

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“…The standard GPS technology provides a means for wave disturbance detection based on phase measurements of TEC at each of the spaced two-frequency GPS receivers. A method of reconstructing TEC variations from measurements of the ionosphere-induced additional increment of the group and phase delay of the satellite radio signal was detailed and validated in a series of publications (Hofmann-Wellenhof et al, 1992;Afraimovich et al, 1998Afraimovich et al, , 2000b. We reproduce here only the final formula for phase measurements…”

Section: Determining the Mean (Global) Power Spectrum Of Tec Variatiomentioning

confidence: 99%

“…It should be noted that the spectrum that is calculated directly from dI (t) variations is a distorted spectrum of irregularities as a consequence of the Doppler shift effect of the TID angular frequency (Afraimovich et al, 1998) …”

Section: Determining the Mean (Global) Power Spectrum Of Tec Variatiomentioning

confidence: 99%

Geomagnetic control of the spectrum of traveling ionospheric disturbances based on data from a global GPS network

et al. 2001

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Abstract.In this paper an attempt is made to verify the hypothesis of the role of geomagnetic disturbances as a factor in determining the intensity of traveling ionospheric disturbances (TIDs). To improve the statistical validity of the data, we have used the method involving a global spatial averaging of disturbance spectra of the total electron content (TEC). To characterize the TID intensity quantitatively, we suggest that a new global index of the degree of disturbance should be used, which is equal to the mean value of the rms variations in TEC within the selected range of spectral periods (of 20-60 min, in the present case). The analysis has been made for a set of 100 to 300 GPS stations for 10 days with a different level of geomagnetic activity (Dst from 0 to −350 nT; the Kp index from 3 to 9).It was found that power spectra of daytime TEC variations in the range of 20-60 min periods under quiet conditions have a power-law form with the slope index k = −2.5. With an increase in the level of magnetic disturbance, there is an increase in the total intensity of TIDs, with a concurrent kink of the spectrum caused by an increase in oscillation intensity in the range of 20-60 min. The TEC variation amplitude is found to be smaller at night than during the daytime, and the spectrum decreases in slope, which is indicative of a disproportionate increase in the amplitude of the small-scale part of the spectrum.It was found that an increase in the level of geomagnetic activity is accompanied by an increase in the total intensity of TEC; however, it does not correlate with the absolute level of Dst, but rather with the value of the time derivative of Dst (a maximum correlation coefficient reaches −0.94). The delay of the TID response of the order of 2 hours is consistent with the view that TIDs are generated in auroral regions, and propagate equatorward with the velocity of about 300-400 m/s.Correspondence to: E. L. Afraimovich (afra@iszf.irk.ru)

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“…Over the past two decades, studies of ionospheric disturbances and its monitoring have caught the attention of the scientific community (Pi et al, 1997;Afraimovich et al, 1998;Tsugawa et al, 2004;Hernández-Pajares et al, 2006;Ding et al, 2007;Trichtchenko et al, 2007;Bergeot et al, 2011;Tang et al, 2016;Yao et al, 2017;Zolotukhina at al., 2017). Stankov et al (2006) presented several case and statistical studies of ionospheric storm, which were clearly showing the generation and propagation of ionospheric disturbances.…”

Section: Introductionmentioning

confidence: 99%

Study of ionospheric disturbances over the China mid- and low-latitude region with GPS observations

Ning

Tanida

2018

Ann. Geophys.

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Abstract. Ionospheric disturbances constitute the main restriction factor for precise positioning techniques based on global positioning system (GPS) measurements. Simultaneously, GPS observations are widely used to determine ionospheric disturbances with total electron content (TEC). In this paper, we present an analysis of ionospheric disturbances over China mid-and low-latitude area before and during the magnetic storm on 17 March 2015. The work analyses the variation of magnetic indices, the amplitude of ionospheric irregularities observed with four arrays of GPS stations and the influence of geomagnetic storm on GPS positioning. The results show that significant ionospheric TEC disturbances occurred between 10:30 and 12:00 UT during the main phase of the large storm, and the static position reliability for this period are little affected by these disturbances. It is observed that the positive and negative disturbances propagate southward along the meridian from mid-latitude to low-latitude regions. The propagation velocity is from about 200 to 700 m s −1 and the amplitude of ionospheric disturbances is from about 0.2 to 0.9 TECU min −1 . Moreover, the position dilution of precession (PDOP) with static precise point positioning (PPP) on storm and quiet days is 1.8 and 0.9 cm, respectively. This study is based on the analysis of ionospheric variability with differential rate of vertical TEC (DROVT) and impact of ionospheric storm on positioning with technique of GPS PPP.

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GPS radio interferometry of travelling ionospheric disturbances

Cited by 97 publications

References 28 publications

The shock-acoustic waves generated by earthquakes

The shock-acoustic waves generated by earthquakes

Geomagnetic control of the spectrum of traveling ionospheric disturbances based on data from a global GPS network

Study of ionospheric disturbances over the China mid- and low-latitude region with GPS observations

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