Bibliography

Sounding Rocket Observation of Nitric Oxide in the Polar Night

An altitude profile of Nitric Oxide (NO) in the 80–110 km altitude range was measured in the polar night from a sounding rocket on 27 January 2020. The observations were made using the technique of stellar occultation with a UV spectrograph observing the γ (1,0) band of NO near 215 nm. The tangent point for the altitude profile was at 74° latitude, a location that had been in darkness for 80 days. The retrieved slant column density profile is interpreted using an assumed four-parameter analytic profile shape. Retrievals of the fitting parameters yield a profile with a peak NO concentration of 2.2 ± 0.7 × 108 cm−3 at 93.5 ± 4.1 km. The observations were made during a time of minimum solar and geomagnetic activity. The NO maximum retrieved from the rocket profile is significantly larger in abundance and lower in altitude than other observations on the same day at nearby latitudes just outside the polar night. These rocket-borne results are consistent with NO that is created over the course over the polar winter and is confined to high latitudes in the polar night by the mesospheric polar vortex. During the course of that confinement the abundance increases due to the lack of photodissociation, allowing the NO to descend. We show that the observed descent can be explained by eddy diffusion-driven transport, though vertical advection cannot be ruled out.

Bailey, Scott; McClintock, William; Carstens, Justin; Thurairajah, Brentha; Das, Saswati; Randall, Cora; Harvey, Lynn; Siskind, David; Stevens, Michael; Venkataramani, Karthik;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2022     DOI: 10.1029/2021JA030257

Lower thermosphere; mesosphere; nitric oxide; polar night; sounding rocket; stellar occultation

Spatial and temporal confinement of the ionospheric responses during the St. Patrick s Day storm of March 2015

The present study provides a multi‐instrument analysis of the ionospheric response to the effects of the St. Patrick s Day storm of 17–18 March 2015. Simultaneous observations from 85

Kader, Sk; Dashora, N; Niranjan, K;

Published by: Space Weather      Published on:

YEAR: 2022     DOI: 10.1029/2022SW003157

Understanding the role of exospheric density in the ring current recovery rate

Atomic Hydrogen (H) is the most abundant constituent of the terrestrial exosphere. Its charge exchange interaction with ring current ions (H+ and O+) serves to dissipate magnetospheric energy during geomagnetic storms, resulting in the generation of energetic neutral atoms (ENAs). Determination of ring current ion distributions through modeling depends critically on the specification of the exospheric H density distribution. Furthermore, theoretical studies have demonstrated that ring current recovery rate after the storm onset directly correlates with the H density. Although measurements of H airglow emission at altitudes [3,6] Re exhibit storm-time variations, the H density distributions used in ring current modeling are typically assumed to be temporally static during storms. In this presentation, we will describe the temporal and spatial evolution of ring current ion densities in response to a realistically dynamic exospheric H density distribution using the Comprehensive Inner Magnetosphere-Ionosphere Model (CIMI). The exospheric densities used as input to the model are fully data-driven, derived as global, 3D, and time-dependent tomographic reconstructions of H emission data acquired from Lyman-alpha detectors onboard the NASA TWINS satellites during the geomagnetic storm that occurred on March 17, 2013. We will examine modeled ring current recovery rates using both dynamic and static reconstructions and evaluate the impact of realistic storm-time exospheric variability on the simulations.

Cucho-Padin, Gonzalo; site, this; Ferradas, Cristian; Waldrop, Lara; Fok, Mei-Ching; site, this;

Published by: Earth and Space Science Open Archive ESSOAr      Published on: jan

YEAR: 2021     DOI: 10.1002/essoar.10505770.1

Atmospheric Sciences; Atmospheric Sciences / Magnetospheric Particles

Space Physics and Aeronomy: Space Physics and Aeronomy, Solar Physics and Solar Wind

Raouafi, Nour; Vourlidas, Angelos; Zhang, Yongliang; Paxton, Larry;

Published by:       Published on:

YEAR: 2021     DOI:

Diffuse and Pulsating Aurora

This chapter reviews fundamental properties and recent advances of diffuse and pulsating aurora. Diffuse and pulsating aurora often occurs on closed field lines and involves energetic electron precipitation by wave-particle interaction. After summarizing the definition, large-scale morphology, types of pulsation, and driving processes, we review observation techniques, occurrence, duration, altitude, evolution, small-scale structures, fast modulation, relation to high-energy precipitation, the role of ECH waves, reflected and secondary electrons, ionosphere dynamics, and simulation of wave-particle interaction. Finally we discuss open questions of diffuse and pulsating aurora.

Nishimura, Yukitoshi; Lessard, Marc; Katoh, Yuto; Miyoshi, Yoshizumi; Grono, Eric; Partamies, Noora; Sivadas, Nithin; Hosokawa, Keisuke; Fukizawa, Mizuki; Samara, Marilia; Michell, Robert; Kataoka, Ryuho; Sakanoi, Takeshi; Whiter, Daniel; Oyama, Shin-ichiro; Ogawa, Yasunobu; Kurita, Satoshi;

Published by: Space Science Reviews      Published on: 01/2020

YEAR: 2020     DOI: 10.1007/s11214-019-0629-3

Consequences of a solar wind stream interaction region on the low latitude ionosphere: event of 7 October 2015

In this article, we present a study of the perturbations occurring in the Earth’s environment on 7 October 2015. We use a multi-instrument approach, including space and ground

Molina, Maria; Dasso, S; Mansilla, G; Namour, Jorge; Cabrera, Miguel; Zuccheretti, Enrico;

Published by: Solar Physics      Published on:

YEAR: 2020     DOI: 10.1007/s11207-020-01728-7

Solar activity variations of equatorial spread F occurrence and sustenance during different seasons over Indian longitudes: Empirical model and causative mechanisms

Haridas, M.K.; Manju, G.; Arunamani, T.;

Published by: Advances in Space Research      Published on: 05/2018

YEAR: 2018     DOI: 10.1016/j.asr.2018.02.040

On the equinoctial asymmetry in the threshold height for the occurrence of equatorial spread F

In the present study, the threshold height (h F_c) for ESF occurrence irrespective of the polarity of the meridional winds during vernal and autumnal equinoxes is investigated using a large database spread over 1993\textendash2008. The characteristics of the thermosphere during the two equinoxes have also been examined using TIMED/GUVI O/N2 data. The major aspects that have emerged are (i) presence of significant equinoctial asymmetry inh F_c\ for the years examined, (ii) increase in the equinoctial asymmetry of\ h F_c\ with solar activity, (iii) presence of significant asymmetry in O/N₂\ and TIEGCM simulations of normalized atomic oxygen mass density, between the two equinoxes.

Manju, G.; Haridas, M.K.;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: 03/2015

YEAR: 2015     DOI: 10.1016/j.jastp.2015.01.008

Threshold height; O/N2; Equinoctial asymmetry; Solar flux

Effects of transionospheric signal decorrelation on Global Navigation Satellite Systems (GNSS) performance studied from irregularity dynamics around the northern crest of the EIA

Transionospheric satellite navigation links operate primarily at L band and are frequently subject to severe degradation of performances arising out of ionospheric irregularities. Various characteristic features of equatorial ionospheric irregularity bubbles like the drift velocity, characteristic velocity, decorrelation time, and decorrelation distance can be determined using spaced aerial measurements at VHF. These parameters measured at VHF from a station Calcutta situated near the northern crest of the Equatorial Ionization Anomaly (EIA) in the geophysically sensitive Indian longitude sector have been correlated with L band scintillation indices and GPS position accuracy parameters for identifying possible proxies to L band scintillations. Good correspondences have been observed between decorrelation times and distances at VHF with GPS S₄ and Position Dilution of Precision during periods of GPS scintillations (S₄ \> 0.3) for February\textendashApril 2011, August\textendashOctober 2011, and February\textendashApril 2012. A functional relation has been developed between irregularity drift velocity measured at VHF and S₄ at L band during February\textendashApril 2011, and validation of measured S₄ and predicted values performed during August\textendashOctober 2011 and February\textendashApril 2012. Significant improvement in L band scintillation prediction and consequent navigational accuracy will result using such relations derived from VHF irregularity measurements which are much simpler and inexpensive.

Das, T.; Roy, B.; Paul, A.;

Published by: Radio Science      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/rds.v49.1010.1002/2014RS005406

GNSS position determination accuracy under adverse ionospheric conditions; GUVI; irregularity dynamics at VHF

First observational evidence of the modulation of the threshold height h'Fc for the occurrence of equatorial spread F by neutral composition changes

[1]\ In the present study, the seasonal and solar activity variations of the threshold height for equatorial spread F occurrence irrespective of the polarity of the meridional winds during magnetically disturbed period are presented for the first time. The modulation of the seasonal pattern of the threshold height by the seasonal mean O/N₂ values is also examined. The Ionosonde data of magnetic equatorial location Trivandrum (8.5\textdegreeN, 76.5\textdegreeE) and low latitude station SHAR (13.7\textdegreeN, 80.2\textdegreeE) in the Indian longitude sector during equinoxes, winter, and summer seasons of 2002 to 2006 and the corresponding Thermosphere Ionosphere Mesosphere Energetics and Dynamics/GUVI (Global Ultra Violet Imager) O/N₂ data are used for the study. The important findings that have emerged from this study are (i) the substantial increase of threshold height with magnetic activity for all the seasons and (ii) the modulation of h\textquoterightF_c by neutral density changes, irrespective of season, solar, or magnetic activity.

Haridas, M.; Manju, G.; Pant, Tarun;

Published by: Journal of Geophysical Research: Space Physics      Published on: 06/2013

YEAR: 2013     DOI: 10.1002/jgra.50331

Equatorial Spread F; O/N2; solar activity; Threshold height

Ionospheric response to a geomagnetic storm during November 8--10, 2004

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\textdegreeN 77\textdegreeE and dip 0.5\textdegreeN) and SHAR (13.5\textdegreeN, 80.2\textdegreeE, dip \~5.5\textdegreeN), magnetic field data from Tirunelveli (8.7\textdegreeN, 76.9\textdegreeE, dip latitude 0.5\textdegreeS) and Alibag (18.64\textdegreeN, 72.87\textdegreeE), and GUVI O/N₂ data in the Indian longitude sector, are used for the study. The behavior of interplanetary parameters is also examined in conjunction with the ionospheric data. On 8 November, the EIA around noontime is not fully inhibited even though the electrojet strength an indicates inhibition of EIA due to a disturbance dynamo electric field effect. It is the enhanced O/N₂ over TRV and SHAR, with a larger increase over SHAR, which results in a larger (than expected) value of the EIA proxy parameter. On 9 November, the comparable values of f_oF₂ at TRV and SHAR around noon time is due to the combined effect of a weakened anomaly in the presence disturbance dynamo electric field effects leading to the EIA crest being near SHAR, and increased O/N₂ values at TRV and SHAR with a larger increase at TRV. On 10 November, the very strong values of the EIA proxy-SHAR parameter is attributed to the combined effects of prompt penetration electric field related modulations of EIA, and significant O/N₂ changes at the equatorial, and near equatorial, latitude. Thus, the study reveals the important role of storm-induced O/N₂ changes, along with prompt penetration electric fields and disturbance dynamo electric fields in modulating the ionization distribution in the equatorial ionization anomaly (EIA) region during this period.

Simi, K.; Manju, G.; Haridas, M.; Nayar, S.; Pant, Tarun; Alex, S.;

Published by: Earth, Planets and Space      Published on: 05/2013

YEAR: 2013     DOI: 10.5047/eps.2012.09.005

Equatorial Electrojet; Equatorial ionization anomaly; geomagnetic storm; O/N2 ratio

Large-scale ionospheric disturbances due to the dissipation of convectively-generated gravity waves over Brazil

In a companion paper, we show that large-scale secondary gravity waves and circulation cells are created by the body forces generated by the dissipation of convectively generated gravity waves over Brazil on 01 October 2005. In this paper, we show that these fluid perturbations cause large-scale perturbations of the plasma drift and plasma density in the ionosphere by changing the wind dynamo and transport. These fluid perturbations modify both the amplitude and direction of the plasma drifts. Near the geomagnetic equator, the magnitude of the pre-reversal enhancement can be increased or weakened, depending on the location and local time. Because the circulation cells persist from late afternoon through midnight, the modulation of the vertical drift near the geomagnetic equator persists until midnight. The largest changes of the wind-driven currents can occur either in the E or F region and are determined by the magnitudes of the wind perturbations, conductivities, and conductivity perturbations. The contributions to the plasma transport changes are from advection by the neutral winds along field lines, plasma drifts, and ambipolar diffusion, in the order of their relative significance in the numerical results.

Liu, H.-L.; Vadas, S.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2013

YEAR: 2013     DOI: 10.1002/jgra.50244

atmosphere coupling; atmosphere gravity wave; ionospheric variability; tropospheric convection

Longitudinal study of the ionospheric response to the geomagnetic storm of 15 May 2005 and manifestation of TADs

Sharma, S.; Galav, P.; Dashora, N.; Pandey, R.;

Published by: Annales Geophysicae      Published on: Jan-01-2011

YEAR: 2011     DOI: 10.5194/angeo-29-1063-2011

Periodic spacing between consecutive equatorial plasma bubbles

Makela, Jonathan; Vadas, SL; Muryanto, R; Duly, T; Crowley, G;

Published by: Geophysical Research Letters      Published on:

YEAR: 2010     DOI:

Overview and summary of the Spread F Experiment (SpreadFEx)

We provide here an overview of, and a summary of results arising from, an extensive experimental campaign (the Spread F Experiment, or SpreadFEx) performed from September to November 2005, with primary measurements in Brazil. The motivation was to define the potential role of neutral atmosphere dynamics, specifically gravity wave motions propagating upward from the lower atmosphere, in seeding Rayleigh-Taylor instability (RTI) and plasma bubbles extending to higher altitudes. Campaign measurements focused on the Brazilian sector and included ground-based optical, radar, digisonde, and GPS measurements at a number of fixed and temporary sites. Related data on convection and plasma bubble structures were also collected by GOES 12, and the GUVI instrument aboard the TIMED satellite.\ 

Initial results of our SpreadFEx analyses are described separately by Fritts et al. (2009). Further analyses of these data provide additional evidence of 1) gravity wave (GW) activity near the mesopause apparently linked to deep convection predominantly to the west of our measurement sites, 2) small-scale GWs largely confined to lower altitudes, 3) larger-scale GWs apparently penetrating to much higher altitudes, 4) substantial GW amplitudes implied by digisonde electron densities, and 5) apparent influences of these perturbations in the lower F-region on the formation of equatorial spread F, RTI, and plasma bubbles extending to much higher altitudes. Other efforts with SpreadFEx data have also yielded 6) the occurrence, locations, and scales of deep convection, 7) the spatial and temporal evolutions of plasma bubbles, 8) 2-D (height-resolved) structures in electron density fluctuations and equatorial spread F at lower altitudes and plasma bubbles above, and 9) the occurrence of substantial tidal perturbations to the large-scale wind and temperature fields extending to bottomside F-layer and higher altitudes. Collectively, our various SpreadFEx analyses suggest direct links between deep tropical convection and large GW perturbations at large spatial scales at the bottomside F-layer and their likely contributions to the excitation of RTI and plasma bubbles extending to much higher altitudes.

Fritts, D.; Abdu, M.; Batista, B.; Batista, I.; Batista, P.; Buriti, R.; Clemesha, B.; Dautermann, T.; de Paula, E.; Fechine, B.; Fejer, B.; Gobbi, D.; Haase, J.; Kamalabadi, F.; Kherani, E.; Laughman, B.; Lima, P.; Liu, H.-L.; Medeiros, A.; Pautet, P.-D.; Riggin, D.; Rodrigues, F.; Sabbas, F.; Sobral, J.; Stamus, P.; Takahashi, H.; Taylor, M.; Vadas, S.; Vargas, F.; Wrasse, C.;

Published by: Annales Geophysicae      Published on: Jan-01-2009

YEAR: 2009     DOI: 10.5194/angeo-27-2141-2009

Reconstruction of the gravity wave field from convective plumes via ray tracing

We implement gravity wave (GW) phases into our convective plume and anelastic ray trace models. This allows us to successfully reconstruct the GW velocity, temperature, and density perturbation amplitudes and phases in the Mesosphere-Lower-Thermosphere (MLT) via ray tracing (in real space) those GWs that are excited from a deep convective plume. We find that the ray trace solutions agree very well with the exact, isothermal, zero-wind, Fourier-Laplace solutions in the Boussinesq limit. This comparison also allows us to determine the normalization factor which converts the GW spectral amplitudes to real-space amplitudes in the ray trace model. This normalization factor can then be used for ray tracing GWs through varying temperature and wind profiles. We show that by adding GW reflection off the Earth\textquoterights surface, the resulting GW spectrum has more power at larger vertical and horizontal wavelengths. We determine the form of the momentum flux and velocity spectra which allows for easy calculation of GW amplitudes in the MLT and thermosphere. Finally, we find that the reconstructed (ray traced) solution for a deep, convective plume with a duration much shorter than the buoyancy period does not equal the Fourier-Laplace Boussinesq solution; this is likely due to errors in the Boussinesq dispersion relation for very high frequency GWs.

Vadas, S.; Fritts, D.;

Published by: Annales Geophysicae      Published on: Jan-01-2009

YEAR: 2009     DOI: 10.5194/angeo-27-147-2009

Simultaneous observation of ionospheric plasma bubbles and mesospheric gravity waves during the SpreadFEx Campaign

Takahashi, H.; Taylor, M.; Pautet, P.-D.; Medeiros, A.; Gobbi, D.; Wrasse, C.; Fechine, J.; Abdu, M.; Batista, I.; Paula, E.; Sobral, J.; Arruda, D.; Vadas, S.; Sabbas, F.; Fritts, D.;

Published by: Annales Geophysicae      Published on: Jan-01-2009

YEAR: 2009     DOI: 10.5194/angeo-27-1477-2009

The Spread F Experiment (SpreadFEx): Program overview and first results

Fritts, D.; Abdu, M.; Batista, B.; Batista, I.; Batista, P.; Buriti, R.; Clemesha, B.; Dautermann, T.; de Paula, E.; Fechine, B.; Fejer, B.; Gobbi, D.; Haase, J.; Kamalabadi, F.; Kherani, E.; Laughman, B.; Lima, J.; Liu, H.-L.; Medeiros, A.; Pautet, P.-D.; Riggin, D.; Rodrigues, F.; Sabbas, Sao; Sobral, J.; Stamus, P.; Takahasi, H.; Taylor, M.; Vadas, S.; Vargas, F.; Wrasse, C.;

Published by: Earth Planets Space      Published on:

YEAR: 2009     DOI:

Gravity wave and tidal influences on equatorial spread F based on observations during the Spread F Experiment (SpreadFEx)

The Spread F Experiment, or SpreadFEx, was performed from September to November 2005 to define the potential role of neutral atmosphere dynamics, primarily gravity waves propagating upward from the lower atmosphere, in seeding equatorial spread F (ESF) and plasma bubbles extending to higher altitudes. A description of the SpreadFEx campaign motivations, goals, instrumentation, and structure, and an overview of the results presented in this special issue, are provided by Fritts et al. (2008a). The various analyses of neutral atmosphere and ionosphere dynamics and structure described in this special issue provide enticing evidence of gravity waves arising from deep convection in plasma bubble seeding at the bottomside F layer. Our purpose here is to employ these results to estimate gravity wave characteristics at the bottomside F layer, and to assess their possible contributions to optimal seeding conditions for ESF and plasma instability growth rates. We also assess expected tidal influences on the environment in which plasma bubble seeding occurs, given their apparent large wind and temperature amplitudes at these altitudes. We conclude 1) that gravity waves can achieve large amplitudes at the bottomside F layer, 2) that tidal winds likely control the orientations of the gravity waves that attain the highest altitudes and have the greatest effects, 3) that the favored gravity wave orientations enhance most or all of the parameters influencing plasma instability growth rates, and 4) that gravity wave and tidal structures acting together have an even greater potential impact on plasma instability growth rates and plasma bubble seeding.

Fritts, D.; Vadas, S.; Riggin, D.; Abdu, M.; Batista, I.; Takahashi, H.; Medeiros, A.; Kamalabadi, F.; Liu, H.-L.; Fejer, B.; Taylor, M.;

Published by: Annales Geophysicae      Published on: 10/2008

YEAR: 2008     DOI: 10.5194/angeo-26-3235-2008

Equatorial anomaly development mapped by TIMED/GUVI: Occurrence/suppression of scintillations at low latitudes and their modeling

Basu, S; Basu, S; Makela, J; Miller, E; Dasgupta, A; Roy, S; Huba, J; Groves, K; Rich, F;

Published by: Eos Trans. AGU      Published on:

YEAR: 2006     DOI:

Comparison of the Equatorial Anomaly Development Mapped by TIMED/GUVI and Occurrence of Scintillations at low Latitudes

Basu, S; Makela, J; Miller, E; Dasgupta, AK; Ray, S; Groves, K; Rich, FJ;

Published by:       Published on:

YEAR: 2006     DOI:

Space-Time Variabilty of Ionospheric Scintillaion in the Equatorial Region

Basu, S; Makela, J; Christensen, A; Groves, K; Dasgupta, A;

Published by:       Published on:

YEAR: 2004     DOI: