Bibliography

Investigation of the negative ionospheric response of the 8 September 2017 geomagnetic storm over the European sector

In this study, we investigate the negative ionospheric response over the European sector during two storms that took place on 8 September 2017, primarily, by exploiting observations over ten European locations. The spatial and temporal variations of TEC, foF2 and hmF2 ionospheric characteristics are examined with the aim to explain the physical mechanisms underlying the strong negative ionospheric response. We detected very sharp electron density (in terms of foF2 and TEC) decrease during the main phases of the two storms and we attributed this phenomenon to the large displacement of the Midlatitude Ionospheric Trough (MIT). Our study also revealed that the two storms show different features caused by different processes. In addition, Large Scale Traveling Ionospheric Disturbances (LSTIDs) were observed during both storms, followed by enhanced Spread F conditions over Digisonde stations. The regional dependence of ionospheric storm effects was demonstrated, as the behavior of ionospheric effects over the northern part of Europe differed from that over the southern part.

Oikonomou, Christina; Haralambous, Haris; Paul, Ashik; Ray, Sarbany; Alfonsi, Lucilla; Cesaroni, Claudio; Sur, Dibyendu;

Published by: Advances in Space Research      Published on: aug

YEAR: 2022     DOI: 10.1016/j.asr.2022.05.035

Large-scale traveling ionospheric disturbances; Mid-latitude ionospheric trough; September 2017 geomagnetic storm; Swarm satellite

The Terrestrial Magnetospheric Response to the 28th October 2021 CME

Waters, James; Jackman, Caitriona; Whiter, Daniel; Fogg, Alexandra; Lamy, Laurent; Carter, Jennifer; Fryer, Laura; Louis, Corentin; Carley, Eion; Briand, Carine; , others;

Published by:       Published on:

YEAR: 2022     DOI:

Multi-wavelength coordinated observations of ionospheric irregularity structures from an anomaly crest location during unusual solar minimum of the 24th cycle

The present paper reports coordinated ionospheric irregularity measurements at optical as well as GPS wavelengths. Optical measurements were obtained from Tiny Ionospheric Photometer (TIP) sensors installed onboard the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites. GPS radio signals were obtained from a dual frequency GPS receiver operational at Calcutta (22.58\textdegreeN, 88.38\textdegreeE geographic; geomagnetic dip: 32.96\textdegree; 13.00\textdegreeN, 161.63\textdegreeE geomagnetic) under the SCIntillation Network Decision Aid (SCINDA) program. Calcutta is located near the northern crest of Equatorial Ionization Anomaly (EIA) in the Indian longitude sector. The observations were conducted during the unusually low and prolonged solar minima period of 2008\textendash2010. During this period, four cases of post-sunset GPS scintillation were observed from Calcutta. Among those cases, simultaneous fluctuations in GPS Carrier-to-Noise ratios (C/N_o) and measured radiances from TIP over a common ionospheric volume were observed only on February 2, 2008 and September 25, 2008. Fluctuations observed in measured radiances (maximum 0.95 Rayleigh) from TIP due to ionospheric irregularities were found to correspond well with C/N₀ fluctuations on the GPS links observed from Calcutta, such effects being noted even during late evening hours of 21:00\textendash22:00 LT from locations around 40\textdegree magnetic dip. These measurements indicate the existence of electron density irregularities of scale sizes varying over several decades from 135.6\ nm to 300\textendash400\ m well beyond the northern crest of the EIA in the Indian longitude sector during late evening hours even in the unusually low solar activity conditions.

Paul, Ashik; Sur, Dibyendu; Haralambous, Haris;

Published by: Advances in Space Research      Published on: 03/2020

YEAR: 2020     DOI: 10.1016/j.asr.2019.11.035

GPS radio measurements; ionospheric irregularities; Northern crest of EIA; Optical measurements; solar minimum; TIP

Effect of solar flux versus compositional variations on the variability of daytime oxygen optical emission rates over low-and mid-latitudes

Pallamraju, Duggirala; Karan, Deepak; Laskar, Fazlul; Lakshmi, Vijaya; Chakrabarti, Supriya;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on:

YEAR: 2020     DOI:

Effect of geomagnetic storms on the daytime low-latitude thermospheric wave dynamics

Sparse Hierarchical Nonparametric Bayesian learning for light field representation and denoising

In this paper, we present a sparse hierarchical non-parametric Bayesian (SHNB) model, which is used to represent the data captured by the light field cameras. Specifically, a light field can be represented as a set of sub-aperture views. In order to capture the visual variations of these viewpoints, we propose the so-called \textquotedblleftdepth flow\textquotedblright features. Then based on the depth flow features, we model these views statistically with a sparse representation in a fully unsupervised manner. While local dictionaries are learned based on each sub-aperture view, all the views with different perspectives share one global dictionary. To show the effectiveness of the proposed model, we apply our model to denoise the light field data. In the experiments, we demonstrate that our method outperforms several state-of-the-art light field denoising approaches.

Sun, Xing; Meng, Nan; Xu, Zhimin; Lam, Edmund; So, Hayden;

Published by:       Published on:

YEAR: 2016     DOI: 10.1109/IJCNN.2016.7727617

Characteristics of post-midnight L-band scintillation in the transition region from the equatorial to mid-latitudes over the Indian longitude sector using COSMIC, C/NOFS and GPS measurements

Occurrence of L band scintillations around midnight and postmidnight hours have not been well studied and reported from the higher equatorial latitudes in the transition region from the equatorial to midlatitudes over the Indian longitude sector. The present paper reports cases of postmidnight L band scintillation observations by COSMIC during March 2014 over the Indian longitude sector. GPS\ S₄measurements from the International Global Navigation Satellite Systems Service station at Lucknow (26.91\textdegreeN, 80.96\textdegreeE geographic; magnetic dip: 39.75\textdegreeN) corroborate occurrence of postmidnight scintillations. The\ F\ region vertical upward velocities around the magnetic equator during evening hours have been used to understand the possibility of impact of irregularities generated over the magnetic equator at latitudes north of 30\textdegreeN. Postmidnight L band scintillations at latitudes greater than 30\textdegreeN without corresponding premidnight scintillations present interesting scientific scenario and give rise to suggestions of (1) any coupling mechanism between the equatorial and midlatitudes through which irregularities seeded in the midlatitudes may affect transionospheric satellite links at low latitudes or (2) irregularity generation at midlatitudes not connected with equatorial instabilities. Long-term analysis of\ S₄\ at L band measured by COSMIC over the Indian longitudes during March 2007\textendash2014 exhibits a well-defined longitude swath around 75\textendash83\textdegreeE of reduced (0.2 \< S₄ \< 0.4) or no scintillations which may be attributed to the longitudinal variability of scintillation occurrence following the global four-cell pattern of ionospheric activity.

Paul, A.; Haralambous, H.; Oikonomou, C.;

Published by: Radio Science      Published on: 12/2015

YEAR: 2015     DOI: 10.1002/2015RS005807

postmidnight L band scintillation over Indian longitude sector

Characteristics of postmidnight L band scintillation in the transition region from the equatorial to midlatitudes over the Indian longitude sector using COSMIC, C/NOFS, and GPS measurements

Paul, A; Haralambous, H; Oikonomou, C;

Published by: Radio Science      Published on:

YEAR: 2015     DOI:

Effects of prolonged southward interplanetary magnetic field on low-latitude ionospheric electron density

The present work describes the low-latitude ionospheric variability during an unusually prolonged (~33 h) geomagnetically disturbed condition that prevailed during 15\textendash16 July 2012. The low-latitude electron density in summer hemisphere, investigated using ground- and satellite-based observations, responded to this by generating strong negative ionospheric storm on 16 July. The maximum electron density on 16 July over Indian low latitudes was reduced by more than 50\% compared to that on a geomagnetically quiet day (14 July 2012). In contrast to the extreme reduction in total electron content (TEC) in the Northern Hemisphere, TEC from a winter hemispheric station revealed substantial (~23 total electron content unit, 1 TECU = 10¹⁶ el m^-2) enhancements on the same day. This contrasting hemispherical response in TEC is suggested to be due to the combined effects of strong interhemispheric and solar-driven day-night winds. Further, very weak equatorial electrojet (EEJ) strength on 16 July indicated that the westward electric field perturbations in the low-latitude ionosphere were possibly due to the disturbance dynamo effect associated with meridional circulation from polar to equatorial latitudes. Interestingly, despite reduction in the integrated EEJ strength on 15 July, the low-latitude electron density showed substantial enhancement, highlighting the significant effect of the positive ionospheric storm on the low-latitude ionosphere. The roles of electrodynamical/neutral-dynamical and compositional disturbances are discussed in view of these observations to understand low-latitude ionospheric response when geomagnetic disturbance persists for longer duration.

Bagiya, Mala; Hazarika, Rumajyoti; Laskar, Fazlul; Sunda, Surendra; Gurubaran, S.; Chakrabarty, D.; Bhuyan, P.; Sridharan, R.; Veenadhari, B.; Pallamraju, D.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2014

YEAR: 2014     DOI: 10.1002/2014JA020156

low-latitude ionosphere; neutral winds; prolonged southward IMF Bz; thermospheric neutral composition

Mars Reconnaissance Orbiter observation of Comet C/2013 A1 (Siding Spring)

Tamppari, Leslie; Zurek, Richard; Cantor, Bruce; Delamere, WA; Egan, Anthony; Humm, David; Kass, David; McEwen, Alfred; McGovern, Andy; Phillips, Roger; , others;

Published by:       Published on:

YEAR: 2014     DOI:

On deriving incident auroral particle fluxes in the daytime using combined ground-based optical and radar measurements

Pallamraju, Duggirala; Chakrabarti, Supriya; Solomon, Stanley;

Published by: Journal of Geophysical Research      Published on: Jan-01-2011

YEAR: 2011     DOI: 10.1029/2010JA015934

Observation of the exhaust plume from the space shuttle main engines using the microwave limb sounder

Pumphrey, H.; Lambert, A.; Livesey, N.;

Published by: Atmospheric Measurement Techniques      Published on: Jan-01-2011

YEAR: 2011     DOI: 10.5194/amt-4-89-2011

Observation of the exhaust plume from the space shuttle main engine using the Microwave Limb Sounder

Pumphrey, H.; Lambert, A.; Livesey, N.;

Published by: Atmospheric Measurement Techniques Discussions      Published on: Jan-01-2010

YEAR: 2010     DOI: 10.5194/amtd-3-3971-2010

Compositional changes in thermosphere during a geomagnetic storm inferred using ground-based daytime OI 630.0 nm optical airglow emissions

Pallamraju, D; Chakrabarti, S; Solomon, S; Crowley, G;

Published by:       Published on:

YEAR: 2006     DOI:

Contributions of imaging Echelle spectrographs to daytime optical aeronomy

We present a brief overview of the contributions made by high spectral resolution imaging spectrographs that are capable of obtaining daytime airglow and auroral emissions in the presence of scattered solar background continuum, to the advancement in our understanding of the dynamics in daytime upper atmosphere. By making use of ground-based OI 6300 angstrom daytime emissions from various geomagnetic latitudes this technique has succeeded in demonstrating many interesting and first of their kind results ranging from ionosphere–thermosphere coupling, space weather interactions to magnetosphere–thermosphere–ionosphere coupling. Finally, in view of the promising results by this technique we propose future advancements in both instrumentation and strategic observational planning with optical spectrographs.

Pallamraju, D.; Chakrabarti, S.;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on:

YEAR: 2006     DOI: https://doi.org/10.1016/j.jastp.2005.05.013

dayglow; AURORA; Spectroscopy; Optical techniques; Thermosphere–ionosphere coupling; space weather

A Sun-to-Earth Campaign Joining Observations from the Great Observatory with Worldwide Satellite and Ground-Based Resources to Investigate System Science Frontiers

Kozyra, JU; Shibata, K; Barnes, RJ; Basu, S; Davila, JM; Fox, NJ; Gopalswamy, N; Kuznetsova, MM; Pallamraju, D; Paxton, LJ; , others;

Published by:       Published on:

YEAR: 2006     DOI:

Developing cyber-infrastructure for addressing grand challenge questions in Sun-Earth system science: First results of a testbed worldwide online conference series

Kozyra, JU; Barnes, R; Fox, NJ; Fox, PA; Kuznetsova, MM; Morrison, D; Pallamraju, D; , Papitashvili; Ridley, A; Talaat, ER; , others;

Published by:       Published on:

YEAR: 2006     DOI:

Two components of ionospheric plasma structuring at midlatitudes observed during the large magnetic storm of October 30, 2003

Basu, Su.; Basu, S.; Makela, J.; Sheehan, R.; MacKenzie, E.; Doherty, P.; Wright, J.; Keskinen, M.; Pallamgaju, D.; Paxton, L.; Berkely, F.;

Published by: Geophysical Research Letters      Published on: Jan-01-2005

YEAR: 2005     DOI: 10.1029/2004GL021669

Space Sciences-Special Section: Violent Sun-Earth Connection Events of October-November 2003-L12S06-Two components of ionospheric plasma structuring at midiatitudes observed during the large

Basu, Su; Basu, Su; Makela, JJ; Sheehan, RE; MacKenzie, E; Doherty, P; Wright, JW; Keskinen, MJ; Pallamraju, D; Paxton, LJ; , others;

Published by: Geophysical Research Letters      Published on:

YEAR: 2005     DOI:

First ground-based measurements of OI 6300 \AA daytime aurora over Boston in response to the 30 October 2003 geomagnetic storm

Pallamraju, D; Chakrabarti, S;

Published by: Geophysical Research Letters      Published on:

YEAR: 2005     DOI:

HIRISE observations of daytime aurora over boston from ground in response to the magnetic disturbance of october 30, 2003 as corroborated by the TIMED measurements from space

Pallamraju, D; Chakrabarti, S;

Published by:       Published on:

YEAR: 2004     DOI:

Two Components of Ionospheric Plasma Structuring at Mid-Latitudes during Large Magnetic Storms

Basu, S; Makela, J; Sheehan, R; MacKenzie, E; Keskinen, M; Pallamraju, D; Paxton, L;

Published by:       Published on:

YEAR: 2004     DOI: