Comparison of seasonal and longitudinal variation of daytime MSTID activity using GPS observation and GAIA simulations

AbstractThe total electron content (TEC) data derived from the GAIA (Ground-to-topside model of Atmosphere Ionosphere for Aeronomy) is used to study the seasonal and longitudinal variation of occurrence of medium-scale traveling ionospheric disturbances (MSTIDs) during daytime (09:00–15:00 LT) for the year 2011 at eight locations in northern and southern hemispheres, and the results are compared with ground-based Global Positioning System (GPS)-TEC. To derive TEC variations caused by MSTIDs from the GAIA (GPS) data, we obtained detrended TEC by subtracting 2-h (1-h) running average from the TEC, and calculated standard deviation of the detrended TEC in 2 h (1 h). MSTID activity was defined as a ratio of the standard deviation to the averaged TEC. Both GAIA simulation and GPS observations data show that daytime MSTID activities in the northern and southern hemisphere (NH and SH) are higher in winter than in other seasons. From the GAIA simulation, the amplitude of the meridional wind variations, which could be representative of gravity waves (GWs), shows two peaks in winter and summer. The winter peak in the amplitude of the meridional wind variations coincides with the winter peak of the daytime MSTIDs, indicating that the high GW activity is responsible for the high MSTID activity. On the other hand, the MSTID activity does not increase in summer. This is because the GWs in the thermosphere propagate poleward in summer, and equatorward in winter, and the equatorward-propagating GWs cause large plasma density perturbations compared to the poleward-propagating GWs. Longitudinal variation of daytime MSTID activity in winter is seen in both hemispheres. The MSTID activity during winter in the NH is higher over Japan than USA, and the MSTID activity during winter in the SH is the highest in South America. In a nutshell, GAIA can successfully reproduce the seasonal and longitudinal variation of the daytime MSTIDs. This study confirms that GWs cause the daytime MSTIDs in GAIA and amplitude and propagation direction of the GWs control the noted seasonal variation. GW activities in the middle and lower atmosphere cause the longitudinal variation.

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Analisis Total Electron Content (TEC) Menggunakan Continous Wavelet Transform Sebagai Indikator Prekursor Gempa Bumi Di Wilayah Provinsi Bengkulu

JURNAL AMPLIFIER : JURNAL ILMIAH BIDANG TEKNIK ELEKTRO DAN KOMPUTER ◽

10.33369/jamplifier.v9i2.15380 ◽

2019 ◽

Vol 9 (2) ◽

pp. 27-33

Author(s):

Laksamana Agung Aprillo ◽

Hendy Santosa ◽

Faisal Hadi

Keyword(s):

Wavelet Transform ◽

Standard Deviation ◽

Total Electron Content ◽

Electromagnetic Waves ◽

Electron Content ◽

Observation Data ◽

Dual Frequency ◽

Total Electron ◽

Gps Observation ◽

Large Earthquakes

ABSTRACT Bengkulu is one of 34 provinces in Indonesia which is a megathrust region. So Bengkulu province is often hit by many large earthquakes with shallow depth. TEC anomaly was analyzed based on three electromagnetic waves radiated by an earthquake. The total electron content (TEC) anomaly is seen through the global positioning system (GPS) dual-frequency radio signal data. The continuous wavelet transform (CWT) method is used to divide the signal analysis into several sections according to the electromagnetic wave frequency range of acoustic (2.5 mHz) -3 mHz), gravity waves (1 mHz-2.8 mHz) and rayleigh waves (5 mHz-33 mHz). GPS observation data for 9 days is calculated using the Standard deviation (2?) method to see trends in data changes. The analysis shows anomalies in the September 12 2007 earthquake (7.9 Mw), the March 5 2010 earthquake (6.3 Mw) and the August 4 2011 earthquake (6.0 Mw). Anomalies are detected 1 to 5 hours before an earthquake occurs. TEC anomalies that occur may be related to the process of preseismic before the earthquake and may be an early sign of an earthquake.Keyword: earthquake, total electron content, continous wavelet transform, standard deviation

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Modification of the low-latitude ionosphere before the 26 December 2004 Indonesian earthquake

Natural Hazards and Earth System Science ◽

10.5194/nhess-6-817-2006 ◽

2006 ◽

Vol 6 (5) ◽

pp. 817-823 ◽

Cited By ~ 42

Author(s):

I. E. Zakharenkova ◽

A. Krankowski ◽

I. I. Shagimuratov

Keyword(s):

Electron Content ◽

Equatorial Anomaly ◽

Low Latitude ◽

Total Electron ◽

Ionospheric Effects ◽

Earthquake Preparation ◽

Low Latitude Ionosphere ◽

Positive Effect ◽

Possible Cause ◽

Gps Observations

Abstract. This paper investigates the features of pre-earthquake ionospheric anomalies in the total electron content (TEC) data obtained on the basis of regular GPS observations from the IGS network. For the analysis of the ionospheric effects of the 26 December 2004 Indonesian earthquake, global TEC maps were used. The possible influence of the earthquake preparation processes on the main low-latitude ionosphere peculiarity – the equatorial anomaly – is discussed. Analysis of the TEC maps has shown that modification of the equatorial anomaly occurred a few days before the earthquake. For 2 days prior to the event, a positive effect was observed in the daytime amplification of the equatorial anomaly. Maximal enhancement in the crests reached 20 TECU (50–60%) relative to the non-disturbed state. In previous days, during the evening and night hours (local time), a specific transformation of the TEC distribution had taken place. This modification took the shape of a double-crest structure with a trough near the epicenter, though usually in this time the restored normal latitudinal distribution with a maximum near the magnetic equator is observed. It is assumed that anomalous electric field generated in the earthquake preparation zone could cause a near-natural "fountain-effect" phenomenon and might be a possible cause of the observed ionospheric anomaly.

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Comparison of simultaneous variations of the ionospheric total electron content and geomagnetic field associated with strong earthquakes

Natural Hazards and Earth System Science ◽

10.5194/nhess-1-53-2001 ◽

2001 ◽

Vol 1 (1/2) ◽

pp. 53-59 ◽

Cited By ~ 7

Author(s):

Sh. Naaman ◽

L. S. Alperovich ◽

Sh. Wdowinski ◽

M. Hayakawa ◽

E. Calais

Keyword(s):

Total Electron Content ◽

Vertical Displacement ◽

Temporal Variations ◽

Electron Content ◽

Geomagnetic Disturbances ◽

Total Electron ◽

Strong Earthquakes ◽

Ionospheric Total Electron Content ◽

Geomagnetic Observations ◽

Gps Observations

Abstract. In this paper, perturbations of the ionospheric Total Electron Content (TEC) are compared with geomagnetic oscillations. Comparison is made for a few selected periods, some during earthquakes in California and Japan and others at quiet periods in Israel and California. Anomalies in TEC were extracted using Global Positioning System (GPS) observations collected by GIL (GPS in Israel) and the California permanent GPS networks. Geomagnetic data were collected in some regions where geomagnetic observatories and the GPS network overlaps. Sensitivity of the GPS method and basic wave characteristics of the ionospheric TEC perturbations are discussed. We study temporal variations of ionospheric TEC structures with highest reasonable spatial resolution around 50 km. Our results show no detectable TEC disturbances caused by right-lateral strike-slip earthquakes with minor vertical displacement. However, geomagnetic observations obtained at two observatories located in the epicenter zone of a strong dip-slip earthquake (Kyuchu, M = 6.2, 26 March 1997) revealed geomagnetic disturbances occurred 6–7 h before the earthquake.

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Ionospheric Total Electron Content Derived from GNSS Signals by Double Thin-Shell Model near the Magnetic Equator and Implication in the Meridional Wind

2019 Russian Open Conference on Radio Wave Propagation (RWP) ◽

10.1109/rwp.2019.8810250 ◽

2019 ◽

Author(s):

Takashi Maruyama ◽

Kornyanat Hozumi ◽

Guanyi Ma

Keyword(s):

Shell Model ◽

Total Electron Content ◽

Thin Shell ◽

Meridional Wind ◽

Magnetic Equator ◽

Electron Content ◽

Total Electron ◽

Ionospheric Total Electron Content

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Ionospheric response to total solar eclipse of 22 July 2009 in different Indian regions

Annales Geophysicae ◽

10.5194/angeo-31-1549-2013 ◽

2013 ◽

Vol 31 (9) ◽

pp. 1549-1558 ◽

Cited By ~ 17

Author(s):

S. Kumar ◽

A. K. Singh ◽

R. P. Singh

Keyword(s):

Total Electron Content ◽

Solar Eclipse ◽

Total Solar Eclipse ◽

Lower Atmosphere ◽

Electron Content ◽

Vertical Total Electron Content ◽

Total Electron ◽

Ionospheric Response ◽

Total Electron Content Data ◽

Photoionization Process

Abstract. The variability of ionospheric response to the total solar eclipse of 22 July 2009 has been studied analyzing the GPS data recorded at the four Indian low-latitude stations Varanasi (100% obscuration), Kanpur (95% obscuration), Hyderabad (84% obscuration) and Bangalore (72% obscuration). The retrieved ionospheric vertical total electron content (VTEC) shows a significant reduction (reflected by all PRNs (satellites) at all stations) with a maximum of 48% at Varanasi (PRN 14), which decreases to 30% at Bangalore (PRN 14). Data from PRN 31 show a maximum of 54% at Kanpur and 26% at Hyderabad. The maximum decrement in VTEC occurs some time (2–15 min) after the maximum obscuration. The reduction in VTEC compared to the quiet mean VTEC depends on latitude as well as longitude, which also depends on the location of the satellite with respect to the solar eclipse path. The amount of reduction in VTEC decreases as the present obscuration decreases, which is directly related to the electron production by the photoionization process. The analysis of electron density height profile derived from the COSMIC (Constellation Observing System for Meteorology, Ionosphere & Climate) satellite over the Indian region shows significant reduction from 100 km altitude up to 800 km altitude with a maximum of 48% at 360 km altitude. The oscillatory nature in total electron content data at all stations is observed with different wave periods lying between 40 and 120 min, which are attributed to gravity wave effects generated in the lower atmosphere during the total solar eclipse.

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An opposite response of the low-latitude ionosphere at Asian and American sectors during storm recovery phase: drivers from below and above

10.5194/egusphere-egu2020-5401 ◽

2020 ◽

Author(s):

Chao Xiong ◽

Hermann Luehr ◽

Yosuke Yamazaki

Keyword(s):

Geomagnetic Storms ◽

Recovery Phase ◽

The Philippines ◽

Lower Atmosphere ◽

Electron Content ◽

Early Recovery ◽

Total Electron ◽

Ionospheric Response ◽

Swarm Satellites ◽

Opposite Response

<p>The energy input from the solar wind and magnetosphere is thought to dominate the ionospheric response during geomagnetic storms. However, at the storm recovery phase, the role of forces from lower atmosphere could be as important as that from above. In this study, we focused on the geomagnetic storm happened on 6&#8211;11 September 2017. The ground-based total electron content (TEC) data as well as the F region in situ electron density measured by the Swarm satellites reveals that at low and equatorial latitudes the dayside ionosphere shows as prominent positive and negative responses at the Asian and American longitudinal sectors, respectively. The global distribution of thermospheric O/N2 ratio measured by global ultraviolet imager on board the TIMED satellite cannot well explain such longitudinally opposite response of the ionosphere. Comparison between the equatorial electrojet variations from stations at Huancayo in Peru and Davao in the Philippines suggests that the longitudinally opposite ionospheric response should be closely associated with the interplay of E region electrodynamics. By further applying nonmigrating tidal analysis to the ground&#8208;based TEC data, we find that the diurnal tidal components, D0 and DW2, as well as the semidiurnal component SW1, are clearly enhanced over prestorm days and persist into the early recovery phase, indicating the possibility of lower atmospheric forcing contributing to the longitudinally opposite response of the ionosphere on 9&#8211;11 September 2017.</p>

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Variability of the lunar semidiurnal tidal amplitudes in the ionosphere over Brazil

Annales Geophysicae ◽

10.5194/angeo-39-151-2021 ◽

2021 ◽

Vol 39 (1) ◽

pp. 151-164

Author(s):

Ana Roberta Paulino ◽

Fabiano da Silva Araújo ◽

Igo Paulino ◽

Cristiano Max Wrasse ◽

Lourivaldo Mota Lima ◽

...

Keyword(s):

Lower Atmosphere ◽

Electron Content ◽

Semidiurnal Tide ◽

Large Power ◽

Total Electron ◽

Power Spectral ◽

Temporal And Spatial Variability ◽

Short Period ◽

Main Component ◽

Almost All

Abstract. The variability in the amplitudes of the lunar semidiurnal tide was investigated using maps of total electron content over Brazil from January 2011 to December 2014. Long-period variability showed that the annual variation is always present in all investigated magnetic latitudes, and it represents the main component of the temporal variability. Semiannual and triannual (two and three times a year, respectively) oscillations were the second and third components, respectively, but they presented significant temporal and spatial variability without a well-defined pattern. Among the short-period oscillations in the amplitude of the lunar tide, the most pronounced ones were concentrated between 7–11 d. These oscillations were stronger around the equinoxes, in particular between September and November in almost all latitudes. In some years, as in 2013 and 2014, for instance, they appeared with a large power spectral density in the winter hemisphere. These observed short-period oscillations could be a result of a direct modulation of the lunar semidiurnal tide by planetary waves from the lower atmosphere and/or due to electrodynamic coupling of E and F regions of the ionosphere.

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Winter anomaly in NmF2 and TEC: when and where it can occur

Journal of Space Weather and Space Climate ◽

10.1051/swsc/2018036 ◽

2018 ◽

Vol 8 ◽

pp. A45 ◽

Cited By ~ 11

Author(s):

Yury V. Yasyukevich ◽

Anna S. Yasyukevich ◽

Konstantin G. Ratovsky ◽

Maxim V. Klimenko ◽

Vladimir V. Klimenko ◽

...

Keyword(s):

Solar Activity ◽

Meridional Wind ◽

Global Scale ◽

Activity Level ◽

Electron Content ◽

Intensity Increase ◽

Total Electron ◽

Solar Activity Level ◽

Winter Anomaly ◽

Activity Dependence

For the first time, by using a regression procedure, we analyzed the solar activity dependence of the winter anomaly intensity in the ionospheric F2-layer peak electron density (Nm F2) and in the Total Electron Content (TEC) on a global scale. We used the data from global ionospheric maps for 1998–2015, from GPS radio occultation observations with COSMIC, CHAMP, and GRACE satellites for 2001–2015, and ground-based ionosonde data. The fundamental features of the winter anomaly in Nm F2 and in TEC (spatial distribution and solar activity dependence) are similar for these parameters. We determined the regions, where the winter anomaly may be observed in principle, and the solar activity level, at which the winter anomaly may be recorded in different sectors. A growth in geomagnetic disturbance or in the solar activity level is shown to facilitate the winter anomaly intensity increase. Longitudinal variations in the winter anomaly intensity do not conform partly to the generally accepted Rishbeth theory. We consider the obtained results in the context of spatial and solar cycle variations in O/N2 ratio and thermospheric meridional wind. Additionally, we briefly discuss different definitions of the winter anomaly.

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