Observatories_and_Data_Analysis: Recent submissions

Now showing items 61-80 of 185

On the performance of the IRI-2012 and NeQuick2 models during the increasing phase of the unusual 24th solar cycle in the Brazilian equatorial and low-latitude sectors

Venkatesh, K.; Fagundes, P.R.; Seemala, Gopi K.; Jesus, R. de; Abreu, A.J. de; Pillat, V.G. (2014)

It is known that the equatorial and low-latitude ionosphere is characterized with typical dynamical phenomena namely, the equatorial ionization anomaly (EIA). Accurate modeling of the characteristic variations of the EIA ...
Study of simultaneous presence of DD and PP electric fields during the geomagnetic storm of November 7–8, 2004 and resultant TEC variation over the Indian Region

Galav, P.; Sharma, Shweta; Rao, S.S.; Veenadhari, B.; Nagatsuma, T.; Pandey, R. (2014)

During very intense geomagnetic storm of November 7–8, 2004 simultaneous presence of storm time disturbance dynamo and eastward and westward directed prompt penetration electric fields inferred from the ground based ...
Signatures of moderate (M-class) and low (C and B class) intensity solar flares on the equatorial electrojet current: Case studies

Chakrabarty, D.; Bagiya, Mala S.; Thampi, Smitha V.; Pathan, B.M.; Sekar, R. (2013)

The present investigation brings out, in contrast to the earlier works, the changes in the equatorial electrojet (EEJ) current in response to a few moderate (M-class) and low (C and B class) intensity solar flares during ...
One-to-one relationship between low latitude whistlers and conjugate source lightning discharges and their propagation characteristics

Srivastava, Prateek R.; Gokani, Sneha A.; Maurya, A.K.; Singh, Rajesh; Kumar, Sushil; Veenadhari, B.; Selvakumaran, R.; Singh, Abhay K.; Siingh, Devendraa; Lichtenberger, Janos (2013)

One-to-one relation with its causative lightning discharges and propagation features of night-time whistlers recorded at low-latitude station, Allahabad (geomag. lat. 16.05°N, L = 1.08), India, from continuous observations ...
Three-dimensional GPS ionospheric tomography over Japan using constrained least squares

Seemala, Gopi K.; Yamamoto, Mamoru; Saito, Akinori; Chen, Chia-Hung (2014)

A new three-dimensional GPS ionospheric tomography technique is developed that uses total electron content (TEC) data from the dense Global Position System (GPS) receiver network, GPS Earth Observation Network (GEONET) in ...
A study on ionospheric scintillation near the EIA crest in relation to equatorial electrodynamics

Chatterjee, S.; Chakraborty, S.K.; Veenadhari, B.; Banola, S. (2014)

Equatorial electrojet (EEJ) data, which are considered as a proxy index of equatorial electric field, are analyzed in conjunction with equatorial ionosonde, total electron content (TEC) and scintillation data near the ...
Secular trend of geomagnetic elements in the Indian region

Bhardwaj, S.K.; Subbarao, P.B.V. (2013)

In the present study, secular trends and jerks in the geomagnetic elements D, H and Z are investigated at the six Indian magnetic observatories using annual and monthly mean values for all days, quiet days and night base ...
Sub-ionospheric very low frequency perturbations associated with the 12 May 2008 M = 7.9 Wenchuan earthquake

Maurya, A.K.; Singh, Rajesh; Veenadhari, B.; Kumar, S.; Singh, A.K. (2013)

The present study reports the VLF (very low frequency) sub-ionospheric perturbations observed on transmitter JJI (22.1 kHz), Japan, received at the Indian low-latitude station, Allahabad ( geographic lat. 25.41° N, long ...
Analysis of vertical drifts in the post sunset equatorial F-region during geomagnetically quiet and disturbed periods

Simi, K.G.; Vineeth, C.; Pant, T.K.; Alex, S. (2013)

This paper reports the HF Doppler Radar measured post sunset F-region vertical drift (Vd) over Trivandrum (8.5°N, 77°E, 0.5°N dip latitude) during quiet and disturbed periods. In general, Vd showed significant day-to-day ...
Investigations on vertical coupling of atmospheric regions using combined multiwavelength optical dayglow, magnetic and radio measurements

Laskar, Fazlul I.; Pallamraju, Duggirala; Lakshmi, T. Vijaya; Reddy, M. Anji; Pathan, B.M.; Chakrabarti, Supriya (2013)

Systematic investigations of optical dayglow emissions at OI 557.7, OI 630.0, and OI 777.4 nm have been carried out simultaneously over a large field of view (~140°). These emission intensities are obtained during January–March ...
The activities at world data center for geomagnetism Mumbai, India

Doiphode, M.G.; Nimje, R.; Alex, S. (2013)

The World Data Centre for Geomagnetism, Mumbai has functioned as a division of the Indian Institute of Geomagnetism, Navi Mumbai since its full fledged activities commenced in 1991 in coordination with the International ...
Diurnal and semi-diurnal tidal structures due to O2, O3 and H2O heating

Vichare, Geeta; Rajaram, R. (2013)

Today with increased availability of data of middle atmospheric winds and temperature, modelling of middle atmospheric tides has acquired greater importance. The theory of atmospheric tides has two main parts: (i) Investigation ...
Characteristics of penetration electric fields to the equatorial ionosphere during southward and northward IMF turnings

Bhaskar, Ankush; Vichare, Geeta (2013)

The signatures of abrupt turnings of the vertical component of the interplanetary magnetic field (IMF), Bz, can be seen at equatorial latitudes through the prompt transmission of high-latitude electric fields to the lower ...
Can a nightside geomagnetic Delta H observed at the equator manifest a penetration electric field?

Wei, Y.; Fraenz, M.; Dubinin, E.; He, M.; Ren, Z.; Zhao, B.; Liu, J.; Wan, W.; Yumoto, K.; Watari, S.; Alex, S. (2013)

A prompt penetration electric field (PPEF) usually manifests itself in the form of an equatorial ionospheric electric field being in correlation with a solar wind electric field. Due to the strong Cowling conductivity, a ...
Ionospheric response to a geomagnetic storm during November 8–10, 2004

Simi, K.G.; Manju, G.; Haridas, M. K. Madhav; Nayar, S. R. Prabhakaran; Pant, Tarun Kumar; Alex, S. (2013)

This paper investigates the response of the equatorial, and near equatorial, ionosphere to geomagnetic disturbances during the period November 8–10, 2004. Ionosonde data from Trivandrum (8.5°N 77°E and dip 0.5°N) and SHAR ...
Absence of streaming plasma waves around noontime over Thumba in recent times: Is it related to the movement of the dip equator?

Sekar, R.; Gupta, S.P.; Acharya, Y.B.; Chakrabarty, D.; Pallamraju, D.; Pathan, B.M.; Tiwari, D.; Choudhary, R.K. (2013)

Systematic ground-based magnetometer measurements from Thumba (8.47°N, 76.6°E) and Tirunelveli (8.73°N, 77.8°E), India, revealed a movement of the magnetic dip equator towards the south. The magnetic dip angle measured ...
Magnetic Observatory Data and Metadata: Types and Availability

Reay, S.; Herzog, D.; Alex, S.; Kharin, E.; McLean, S.; Nosé, M.; Sergeyeva, N. (2011)

The availability of magnetic observatory data has evolved rapidly with the transition of observatories from analogue photographic magnetograms to digital electronic recordings, and the advent of the internet for instant ...
Application of lightning discharge generated radio atmospherics/tweeks in lower ionospheric plasma diagnostics

Maurya, A.K.; Singh, Rajesh; Veenadhari, B.; Pant, P.; Singh, A.K. (2010)

Lightning discharges during thunderstorm are the significant natural source of electromagnetic waves. They generate electromagnetic pulses, which vary from few Hz to tens of MHz, but the maximum radiated energy is confined ...
Investigation of the response time of the equatorial ionosphere in context of the equatorial electrojet and equatorial ionization anomaly

Jose, L.; Ravindran, S.; Vineeth, C.; Pant, T.K.; Alex, S. (2011)

Equatorial Electrojet (EEJ) and Equatorial Ionization Anomaly (EIA) are two large-scale processes in the equatorial/low latitude ionosphere, driven primarily by the eastward electric field during daytime. In the present ...
On the significant impact of the moderate geomagnetic disturbance of March 2008 on the equatorial ionization anomaly region over Indian longitudes

Mridula, N.; Manju, G.; Pant, Tarun Kumar; Ravindran, Sudha; Jose, Lijo; Alex, S. (2011)

The response of the equatorial and low‐latitude ionosphere plasmasphere system to the moderate geomagnetic disturbance of March 2008 is the subject of this paper. This study for the first time reports large plasmaspheric ...

Now showing items 61-80 of 185

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