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Found 11 entries in the Bibliography.
Showing entries from 1 through 11
| 2022 |
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Using a suite of instruments, which included a chain of ground-based dual-frequency GPS receivers, and magnetometers, we have studied the importance of thermospheric meridional wind circulation in controlling the distribution of plasma over the Indian low latitude ionospheric regions during the period of a severe geomagnetic storm. The storm on 15 May 2005, which had its onset coinciding with the local noon time sector for the Indian ionospheric zone, was a severe geomagnetic storm with symH ∼ - 305 nT. A steep increase i ... Published by: Advances in Space Research Published on: oct YEAR: 2022 DOI: 10.1016/j.asr.2022.06.027 Compositional disturbances; Equatorial ionosphere; geomagnetic storm; total electron content |
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The hemispherical asymmetry of the low latitude region along 100°E ± 5°E is scrutinized for the year 2015 at magnetically conjugate points on seasonal and intra-seasonal time scales. Two conjugate Ionosonde station pairs are selected- one pair in the inner valley (from SEALION) and the other in the outer edges of the EIA region. The anomaly in the stations is estimated using the difference of low latitude NmF2 from the dip equatorial NmF2 in the same meridian. A monthly average scheme is used instead of a seasonal mean, ... Kalita, B.; Bhuyan, P.; Nath, S.; Choudhury, M.; Chakrabarty, D.; Wang, K.; Hozumi, K.; Supnithi, P.; Komolmis, T.; . Y. Yatini, C; Le Huy, M.; Published by: Advances in Space Research Published on: may YEAR: 2022 DOI: 10.1016/j.asr.2022.02.058 NmF2; asymmetry; Conjugate; EIA; model; Hemisphere; hmF2; Subsolar |
| 2021 |
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Near Real-Time Global Plasma Irregularity Monitoring by FORMOSAT-7/COSMIC-2 This study presents initial results of the ionospheric scintillation in the F layer using the S4 index derived from the radio occultation experiment (RO-S4) on FORMOSAT-7/COSMIC-2 (F7/C2). With the sufficiently dense RO-S4 observations at low latitudes, it is possible to construct hourly, global scintillation maps to monitor equatorial plasma bubbles (EPBs). The preliminary F7/C2 RO-S4 during August 2019 to April 2020 show clear scintillation distributions around American and the Atlantic Ocean longitudes. The RO-S4 near Jic ... Chen, Shih-Ping; Lin, Charles; Rajesh, Panthalingal; Liu, Jann-Yenq; Eastes, Richard; Chou, Min-Yang; Choi, Jong-Min; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2021 DOI: 10.1029/2020JA028339 equatorial plasma bubbles; FORMOSAT-7/COSMIC-2; global observation of limb and disk; GNSS scintillation; radio occultation; S4 index |
| 2020 |
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order to examine if the variations in the TEC were caused by thermospheric composition changes in the southern high-latitude regions, we present O/N 2 maps obtained from the GUVI Shreedevi, PR; Choudhary, RK; Thampi, Smitha; Yadav, Sneha; Pant, TK; Yu, Yiqun; McGranaghan, Ryan; Thomas, Evan; Bhardwaj, Anil; Sinha, AK; Published by: Space Weather Published on: YEAR: 2020 DOI: 10.1029/2019SW002383 |
| 2019 |
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Morphological features of the quiet/disturbed time variations in the Total Electron Content (TEC) at the polar cusp station Bharati (76.69\textdegreeS MLAT) during a period of 5 years starting from February 2013 to December 2017 has been studied using GPS TEC measurements. The TEC at Bharati follows a diurnal pattern with its peak appearing close to local noon/magnetic noon during the summer/winter months. A nighttime enhancement in the TEC is seen around the magnetic midnight during winter. The plasma density at Bharati ... Shreedevi, P.R.; Choudhary, R.K.; Yu, Yiqun; Thomas, Evan; Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: 10/2019 YEAR: 2019 DOI: 10.1016/j.jastp.2019.105058 |
| 2018 |
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Low latitude ionospheric behavior during solar transient disturbances of solar flares and storm time penetrating electric fields comprises an important part of the Earth\textquoterights space weather. The flares enhance the electron density of the sunlit ionosphere by supplying excess solar radiation. However, the degree of these density changes is subjective if a geomagnetic storm persists simultaneously. The present case study addresses the ionospheric variations over the Indian longitudes under the combined effects of ... Bagiya, Mala; Thampi, Smitha; Hui, Debrup; Sunil, A.; Chakrabarty, D.; Choudhary, R.; Published by: Journal of Geophysical Research: Space Physics Published on: 08/2018 YEAR: 2018 DOI: 10.1029/2018JA025496 |
| 2017 |
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The Far Ultra-Violet Imager on the Icon Mission ICON Far UltraViolet (FUV) imager contributes to the ICON science objectives by providing remote sensing measurements of the daytime and nighttime atmosphere/ionosphere. During sunlit atmospheric conditions, ICON FUV images the limb altitude profile in the shortwave (SW) band at 135.6 nm and the longwave (LW) band at 157 nm perpendicular to the satellite motion to retrieve the atmospheric O/N2 ratio. In conditions of atmospheric darkness, ICON FUV measures the 135.6 nm recombination emission of O+ ions used to ... Mende, S.; Frey, H.; Rider, K.; Chou, C.; Harris, S.; Siegmund, O.; England, S.; Wilkins, C.; Craig, W.; Immel, T.; Turin, P.; Darling, N.; Loicq, J.; Blain, P.; Syrstad, E.; Thompson, B.; Burt, R.; Champagne, J.; Sevilla, P.; Ellis, S.; Published by: Space Science Reviews Published on: 10/2017 YEAR: 2017 DOI: 10.1007/s11214-017-0386-0 |
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We show evidence of a positive ionospheric storm occurring simultaneously at the equatorial, low-latitude and mid-latitude ionospheric regions in the Indian sector in response to an intense geomagnetic storm on 17 March 2013. The storm had its onset time coinciding with the local noon. An on-site digisonde at Trivandrum (dip equator) recorded a sharp decrease in the height of F\ region peak in the afternoon, which is a signature of westward electric field associated with a counter electrojet (CEJ). Coupled w ... Published by: Journal of Geophysical Research: Space Physics Published on: 10/2017 YEAR: 2017 DOI: 10.1002/2017JA023980 |
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We show evidence of a positive ionospheric storm occurring simultaneously at the equatorial, low-latitude and mid-latitude ionospheric regions in the Indian sector in response to an intense geomagnetic storm on 17 March 2013. The storm had its onset time coinciding with the local noon. An on-site digisonde at Trivandrum (dip equator) recorded a sharp decrease in the height of F region peak in the afternoon, which is a signature of westward electric field associated with a counter electrojet (CEJ). Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2017 DOI: 10.1002/2017JA023980 |
| 2016 |
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A case of the westward disturbance dynamo (DD) electric field, influencing the daytime equatorial and low-latitude ionosphere, during a geomagnetic storm that occurred on 28\textendash29 June 2013 is presented. The GPS total electron content (TEC) observations from a network of stations in the Indian equatorial, low and middle latitude regions along with the radio beacon TEC, ionosonde, and magnetic field observations are used to study the storm time behavior of the ionosphere. Negative ionospheric storm effects were seen ... Thampi, Smitha; Shreedevi, P.; Choudhary, R.; Pant, Tarun; Chakrabarty, D.; Sunda, S.; Mukherjee, S.; Bhardwaj, Anil; Published by: Journal of Geophysical Research: Space Physics Published on: 09/2016 YEAR: 2016 DOI: 10.1002/2016JA023037 |
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The relative contributions of the composition disturbances and the disturbance electric fields in the redistribution of ionospheric plasma is investigated in detail by taking the case of a long-duration positive ionospheric storm that occurred during 18\textendash21 February 2014. GPS total electron content (TEC) data from the Indian Antarctic station, Bharti (69.4\textdegreeS, 76.2\textdegreeE geographic), the northern midlatitude station Hanle (32.8\textdegreeN, 78.9\textdegreeE geographic), northern low-latitude statio ... Shreedevi, P.; Thampi, Smitha; Chakrabarty, D.; Choudhary, R.; Pant, Tarun; Bhardwaj, Anil; Mukherjee, S.; Published by: Journal of Geophysical Research: Space Physics Published on: 02/2016 YEAR: 2016 DOI: 10.1002/2015JA021841 Geomagnetic storms; High latitude low latitude coupling; Ionosphere; positive ionospheric storm |
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