Bibliography

Pronounced Suppression and X-Pattern Merging of Equatorial Ionization Anomalies After the 2022 Tonga Volcano Eruption

Following the 2022 Tonga Volcano eruption, dramatic suppression and deformation of the equatorial ionization anomaly (EIA) crests occurred in the American sector ∼14,000 km away from the epicenter. The EIA crests variations and associated ionosphere-thermosphere disturbances were investigated using Global Navigation Satellite System total electron content data, Global-scale Observations of the Limb and Disk ultraviolet images, Ionospheric Connection Explorer wind data, and ionosonde observations. The main results are as follows: (a) Following the eastward passage of expected eruption-induced atmospheric disturbances, daytime EIA crests, especially the southern one, showed severe suppression of more than 10 TEC Unit and collapsed equatorward over 10° latitudes, forming a single band of enhanced density near the geomagnetic equator around 14–17 UT, (b) Evening EIA crests experienced a drastic deformation around 22 UT, forming a unique X-pattern in a limited longitudinal area between 20 and 40°W. (c) Thermospheric horizontal winds, especially the zonal winds, showed long-lasting quasi-periodic fluctuations between ±200 m/s for 7–8 hr after the passage of volcano-induced Lamb waves. The EIA suppression and X-pattern merging was consistent with a westward equatorial zonal dynamo electric field induced by the strong zonal wind oscillation with a westward reversal.

Aa, Ercha; Zhang, Shun-Rong; Wang, Wenbin; Erickson, Philip; Qian, Liying; Eastes, Richard; Harding, Brian; Immel, Thomas; Karan, Deepak; Daniell, Robert; Coster, Anthea; Goncharenko, Larisa; Vierinen, Juha; Cai, Xuguang; Spicher, Andres;

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

YEAR: 2022     DOI: 10.1029/2022JA030527

EIA suppression and X-pattern; Equatorial ionization anomaly; GNSS TEC; GOLD UV images; ICON MIGHTI neutral wind; Tonga volcano eruption

Latitudinal Dependence of Ionospheric Responses to Some Geomagnetic Storms during Low Solar Activity

The Latitudinal dependence in the response of the Ionospheric F2-layer electron density (NmF2) and peak height (hmF2) to three geomagnetic storms of May and August 2010 has been examined. The data-sets used for the study were obtained from Ilorin, Nigeria (1.87° S/76.67° E), San Vito, Italy (34.68° N/90.38° E), Hermanus, South Africa (42.34° S/82.15° E), and Pruhonice, Czech Republic (45.66° N/90.38° E) geomagnetic coordinates. The quiet time result shows that the rise in NmF2 began earlier at San Vito, followed by Pruhonice. The rate of ionization was observed to be highest in Ilorin, while, the rate of decay in NmF2 is faster at Hermanus. For disturbed NmF2 condition, remarkable similarities in the NmF2 responses during geomagnetic storms were recorded from Hermanus in the mid-latitude and Ilorin, an equatorial station. NmF2 enhancements (\textgreater6 hours) that is consistent with the increase in hmF2 were observed at all the mid-latitude stations during the main phase of the 02 May, 2010 storm, without any noticeable change over ILN. Similarly, 12 hours of positive phase was observed at ILN and HMN, with 30 hours of NmF2 depletions at PRN and SVT during the recovery phase. ILN is in the equatorial Trough, so most of the NmF2 produced at this region is lifted to the higher latitudes by the fountain effect during the main phase. The suppression of the zonal electric field at ILN is responsible for the NmF2 enhancement during the recovery phase, while the mid-latitude responses have been attributed to the effect of the thermospheric winds and neutral composition changes.

Joshua, B.; Adeniyi, J.; Olawepo, A.; Rabiu, Babatunde; Daniel, Okoh; Adebiyi, S.; Adebesin, B.; Ikubanni, S.; Abdurahim, B.;

Published by: Geomagnetism and Aeronomy      Published on: may

YEAR: 2021     DOI: 10.1134/S0016793221030063

Electric field; Electron density; Geomagnetic storms; magnetosphere; peak height

Longitudinal Variation of Postsunset Plasma Depletions From the Global-Scale Observations of the Limb and Disk (GOLD) Mission

The Global-scale Observations of the Limb and Disk (GOLD) mission, launched in 2018, aims to investigate the low latitude ionosphere from a geostationary orbit at 47.5°W. It uses two identical spectrometers measuring the wavelength range from 134.0 to 163.0 nm. The configuration of the Earth s magnetic field shows that the largest offset between geographic and geomagnetic equators occurs in the longitude sectors sampled by GOLD. In an attempt to investigate the longitude dependence of the occurrence rate and time of onset of plasma bubbles, or plasma depletions, GOLD data were separated in three sectors: 65°-55°W, 50°-40°W, and 10°W–0°. Observations of the nighttime emissions in 135.6 nm on November 2018 and March 2019 show plasma depletions occurring very frequently at these longitudes. The growth rate of the Rayleigh-Taylor instability was computed at these longitudes under similar low solar activity conditions, assuming an empirical model of upward plasma drifts. The time and value of the maximum growth rates obtained cannot always explain the observations. On average, the observed occurrence rate of plasma depletions is high, with a maximum of 73\% (observed during November 2018 at ∼45°W). Most of the depletions observed in November at 45°W and 60°W occur within 1 h after sunset. When compared with the November 2018 observations, depletions in March 2019 occur at later times.

Martinis, C.; Daniell, R.; Eastes, R.; Norrell, J.; Smith, J.; Klenzing, J.; Solomon, S.; Burns, A.;

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

YEAR: 2021     DOI: 10.1029/2020JA028510

F region; longitude variability; plasma bubbles; Plasma depletions; upward drifts

Thermospheric Composition and Solar EUV Flux From the Global-Scale Observations of the Limb and Disk (GOLD) Mission

Observations of far-ultraviolet (FUV) dayglow by the Global-scale Observations of Limb and Disk (GOLD) mission provide a new opportunity to monitor relative composition changes in the upper atmosphere as well as solar extreme ultraviolet (EUV) variability. Relative composition changes are quantified by ΣO/N2, the column density ratio of atomic oxygen to molecular nitrogen, while QEUV provides a measure of the solar EUV energy flux from 1 to 45 nm into the upper atmosphere. This spectral range provides the ionizing radiation which ultimately results in FUV airglow emission produced by photodissociation and photoelectron impact. The quantities ΣO/N2 and QEUV are derived from GOLD FUV observations through lookup tables that are constructed using a first-principles photoelectron transport model. The two FUV emissions used are O I 135.6 nm and the N2 Lyman-Birge-Hopfield (LBH) bands. We present an overview of the theoretical basis for the algorithms and practical considerations for application to GOLD data. The effects of uncertainties in electron impact cross sections, off-nadir viewing, and instrument artifacts are reviewed. We also discuss GOLD Level 1C DAY, Level 2 data products ON2 and QEUV, and present representative samples of each.

Correira, J.; Evans, J.; Lumpe, J.; Krywonos, A.; Daniell, R.; Veibell, V.; McClintock, W.; Eastes, R.;

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

YEAR: 2021     DOI: 10.1029/2021JA029517

GOLD; neutral composition; ON2; QEUV; radiative recombination; thermosphere

First zonal drift velocity measurement of Equatorial Plasma Bubbles (EPBs) from a geostationary orbit using GOLD data

Karan, Deepak; Daniell, Robert; England, Scott; Martinis, Carlos; Eastes, Richard; Burns, Alan; McClintock, William;

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

YEAR: 2020     DOI:

Comparison of GOLD nighttime measurements with total electron content: Preliminary results

The National Aeronautics and Space Administration (NASA) Global‐scale Observations of the Limb and Disk (GOLD) has been imaging the thermosphere and ionosphere since

Cai, Xuguang; Burns, Alan; Wang, Wenbin; Coster, Anthea; Qian, Liying; Liu, Jing; Solomon, Stanley; Eastes, Richard; Daniell, Robert; McClintock, William;

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

YEAR: 2020     DOI: 10.1029/2019JA027767

Global-scale Observations of the Equatorial Ionization Anomaly

Abstract The National Aeronautics and Space Administration Global-scale Observations of the Limb and Disk ultraviolet spectrograph has been imaging the equatorial ionization anomaly (EIA), regions of the ionosphere with enhanced electron density north and south of the magnetic equator, since October 2018. The initial 3 months of observations was during solar minimum conditions, and they included observations in December solstice of unanticipated variability and depleted regions. Depletions are seen on most nights, in contrast to expectations from previous space-based observations. The variety of scales and morphologies also pose challenges to understanding of the EIA. Abrupt changes in the EIA location, which could be related to in situ measurements of large-scale depletion regions, are observed on some nights. Such synoptic-scale disruptions have not been previously identified.

Eastes, R.; Solomon, S.; Daniell, R.; Anderson, D.; Burns, A.; England, S.; Martinis, C.; McClintock, W.;

Published by: Geophysical Research Letters      Published on:

YEAR: 2019     DOI: https://doi.org/10.1029/2019GL084199

Equatorial ionosphere; ionospheric irregularities; ionospheric dynamics; Ionospheric storms; forecasting; airglow and aurora

Global-scale Observations of the Limb and Disk (GOLD): science implementation

McClintock, William; Eastes, Richard; Andersson, Laila; Burns, Alan; Codrescu, Mihail; Daniell, Robert; England, Scott; Evans, Scott; Krywonos, Andrey; Lumpe, Jerry; , others;

Published by:       Published on:

YEAR: 2018     DOI:

The Global-Scale Observations of the Limb and Disk (GOLD) Mission

The Earth\textquoterights thermosphere and ionosphere constitute a dynamic system that varies daily in response to energy inputs from above and from below. This system can exhibit a significant response within an hour to changes in those inputs, as plasma and fluid processes compete to control its temperature, composition, and structure. Within this system, short wavelength solar radiation and charged particles from the magnetosphere deposit energy, and waves propagating from the lower atmosphere dissipate. Understanding the global-scale response of the thermosphere-ionosphere (T-I) system to these drivers is essential to advancing our physical understanding of coupling between the space environment and the Earth\textquoterights atmosphere. Previous missions have successfully determined how the \textquotedblleftclimate\textquotedblright of the T-I system responds. The Global-scale Observations of the Limb and Disk (GOLD) mission will determine how the \textquotedblleftweather\textquotedblright of the T-I responds, taking the next step in understanding the coupling between the space environment and the Earth\textquoterights atmosphere. Operating in geostationary orbit, the GOLD imaging spectrograph will measure the Earth\textquoterights emissions from 132 to 162 nm. These measurements will be used image two critical variables\textemdashthermospheric temperature and composition, near 160 km\textemdashon the dayside disk at half-hour time scales. At night they will be used to image the evolution of the low latitude ionosphere in the same regions that were observed earlier during the day. Due to the geostationary orbit being used the mission observes the same hemisphere repeatedly, allowing the unambiguous separation of spatial and temporal variability over the Americas.

Eastes, R.; McClintock, W.; Burns, A.; Anderson, D.; Andersson, L.; Codrescu, M.; Correira, J.; Daniell, R.; England, S.; Evans, J.; Harvey, J.; Krywonos, A.; Lumpe, J.; Richmond, A.; Rusch, D.; Siegmund, O.; Solomon, S.; Strickland, D.; Woods, T.; Aksnes, A.; Budzien, S.; Dymond, K.; Eparvier, F.; Martinis, C.; Oberheide, J.;

Published by: Space Science Reviews      Published on: 10/2017

YEAR: 2017     DOI: 10.1007/s11214-017-0392-2

Scanless ultraviolet remote sensor for limb profile measurements from low earth orbit

Krywonos, Andrey; Harvey, James; Daniell, Robert; Eastes, Richard; Peterson, Gary;

Published by: Optical Engineering      Published on: Jan-10-2006

YEAR: 2016     DOI: 10.1117/1.2360200

The GOLD Science Data Center-Algorithm Heritage, Data Product Descriptions and User Services

Lumpe, JD; Foroosh, H; Eastes, R; Krywonos, A; Evans, JS; Burns, AG; Strickland, DJ; Daniell, RE; England, S; Solomon, SC; , others;

Published by:       Published on:

YEAR: 2013     DOI:

The Science of the Global-scale measurements of the Limb and Disk (GOLD) Mission

Burns, AG; Eastes, R; McClintock, WE; Solomon, SC; Anderson, DN; Andersson, L; Codrescu, M; Daniell, RE; Harvey, J; Krywonos, A; , others;

Published by:       Published on:

YEAR: 2013     DOI:

Remote sensing of neutral temperatures in the Earth\textquoterights thermosphere using the Lyman-Birge-Hopfield bands of N ₂ : Comparisons with satellite drag data

This paper presents remotely sensed neutral temperatures obtained from ultraviolet observations and compares them with temperatures from the NRLMSISE-00 version of the Mass Spectrometer and Incoherent Scatter (MSIS) model (unconstrained and constrained to match the total densities from satellite drag). Latitudinal profiles of the temperatures in the Earth\textquoterights thermosphere are obtained by inversion of high-resolution (\~1.3\ \r A) observations of the (1,1) and (5,4) Lyman-Birge-Hopfield (LBH) bands of N₂. The spectra are from the High resolution Ionospheric and Thermospheric Spectrograph (HITS) instrument aboard the Advanced Research and Global Observation Satellite (ARGOS). The results indicate that on each day examined there was consistency between the remotely sensed thermospheric temperatures, the densities from coincident satellite drag measurements at adjacent altitudes, and the NRLMSISE-00 model.

Krywonos, Andrey; Murray, D.; Eastes, R.; Aksnes, A.; Budzien, S.; Daniell, R.;

Published by: Journal of Geophysical Research      Published on: 09/2012

YEAR: 2012     DOI: 10.1029/2011JA017226

airglow; N2; remote sensing; satellite drag; temperature; thermosphere

Global-scale Observations of the Limb and Disk (GOLD)

Eastes, R; McClintock, W; Aksnes, A; Anderson, D; Andersson, L; Burns, A; Budzien, S; Codrescu, M; Daniell, R; Dymond, K; , others;

Published by: AMC      Published on:

YEAR: 2012     DOI:

Modeled and observed N ₂ Lyman-Birge-Hopfield band emissions: A comparison

Eastes, R.; Murray, D.; Aksnes, A.; Budzien, S.; Daniell, R.; Krywonos, A.;

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

YEAR: 2011     DOI: 10.1029/2010JA016417

Modeled and observed N2 Lyman-Birge-Hopfield band emissions: A comparison

Eastes, RW; Murray, DJ; Aksnes, A; Budzien, SA; Daniell, RE; Krywonos, A;

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

YEAR: 2011     DOI:

Global-scale Observations of the Limb and Disk: a key mission for understanding thermosphere-ionosphere forcing

Eastes, R; Burns, AG; McClintock, W; Aksnes, A; Anderson, D; Andersson, L; Budzien, S; Codrescu, M; Daniell, R; England, S; , others;

Published by:       Published on:

YEAR: 2008     DOI:

Low Latitude Ionosphere Measurements by the Global-scale Observations of the Limb and Disk (GOLD) Mission

Eastes, RW; Anderson, DN; McClintock, WE; Aksnes, A; Andersson, L; Burns, AG; Budzien, SA; Codrescu, MV; Daniell, RE; Dymond, KF; , others;

Published by:       Published on:

YEAR: 2008     DOI:

Constraining and validating the Oct/Nov 2003 X-class EUV flare enhancements with observations of FUV dayglow and E -region electron densities

Strickland, D.; Lean, J.; Daniell, R.; Knight, H.; Woo, W.; Meier, R.; Straus, P.; Woods, T.; Eparvier, F.; McMullin, D.; Christensen, A.; Morrison, D.; Paxton, L.;

Published by: Journal of Geophysical Research      Published on: Jan-01-2007

YEAR: 2007     DOI: 10.1029/2006JA012074

Global-scale Observations of the Limb and Disk (GOLD)-New Observing Capabilities for Space Weather Specification and Forecasting

Eastes, R; Codrescu, M; McClintock, W; Aksnes, A; Anderson, D; Andersson, L; Burns, A; Budzien, S; Daniell, R; Dymond, K; , others;

Published by:       Published on:

YEAR: 2007     DOI:

Global Observations of the Limb and Disk (GOLD): Temperature Measurements

Rusch, D; Aksnes, A; Budzien, S; Eastes, R; Anderson, D; Andersson, L; Burns, A; Codrescu, M; Daniell, R; Dymond, K; , others;

Published by:       Published on:

YEAR: 2007     DOI:

Global-scale Observations of the Limb and Disk (GOLD): Mission Implementation

McClintock, W; Lankton, M; Estes, R; Aksens, A; Anderson, D; Andersson, L; Codrescu, M; Burns, A; Daniell, R; Eparvier, F; , others;

Published by:       Published on:

YEAR: 2006     DOI:

Auroral-E electron density profiles to be derived from SESS particle data

Evans, JS; Daniell, RE; Knight, H; Strickland, DJ; Rodriguez, JV;

Published by:       Published on:

YEAR: 2005     DOI:

Vertical Structure of the Thermosphere and Ionosphere During Geomagnetic Storms in May 2002

Daniell, RE; Burns, AG; Strickland, DJ; Meier, RR; Paxton, LJ;

Published by:       Published on:

YEAR: 2005     DOI:

E-Layer Variations During an X-Class Flare Inferred from Far Ultraviolet Dayglow Observations

Strickland, D.; Daniell, R.; Meier, R.; Lean, J.;

Published by:       Published on:

YEAR: 2005     DOI:

E-Layer Variations During X-Class Flares Inferred from Far Ultraviolet Dayglow Observations

A study is reported that addresses dayglow and ionospheric response to X-class flares that occurred on Oct 28 and Nov 4 2003. Data of interest are 1) the dayglow observations by GUVI and solar EUV/X-ray observations by SEE (both on NASA\textquoterights TIMED satellite), 2) E-region measurements made by the EISCAT radar (on Oct 28) located at Troms\o, Norway, and 3) E-region/F-region IOX GPS occultation measurements (on Nov 4). The timing of the flares was fortunate in that TIMED was on the dayside portion of its orbit when activity peaked for both flares. During the Oct 28 flare, the EISCAT measurements were made near local noon under low geomagnetic activity conditions. Key results are the modeled and measured preflare and flare E-region electron densities. The basis of the modeled densities is QEUV, an integrated measure of solar EUV/XUV energy flux from 0 to 45 nm (that portion of the irradiance spectrum responsible for far ultraviolet dayglow). Use is made of spectra from SEE and the NRLEUV model along with GUVI nadir dayglow observations within its 135.6 and LBHS spectral channels to derive preflare and flare QEUV. The GUVI data are used to derive QEUV with the use of lookup tables, each distinguished by solar EUV/X-ray spectral shape, not by magnitude. Lookup tables have been produced using SEE and NRLEUV flare and preflare spectral shapes. The AURIC model is used to calculate the E-layer with the key input being a solar spectrum with a given shape (those discussed above) and magnitude (set by QEUV). The two sets of ionospheric measurements on their respective flare days show increases in NmE (E-layer peak density) by approximately a factor of three. The QEUV-based NmE agrees well with the measurements before and during these flares. NmE based on SEE spectra, on the other hand, exceeds the observed values, especially during the flares. The favorable agreement supports the derived GUVI QEUV values and argues for a significant reduction in SEE energy fluxes during periods of eruptive solar activity.

Strickland, D.~J.; Daniell, R.~E.; Meier, R.~R.; Lean, J.~L.; Straus, P.~R.; Morrison, M.~D.; Paxton, L.;

Published by: AGU Fall Meeting Abstracts      Published on:

YEAR: 2005     DOI:

2479 Solar radiation and cosmic ray effects; 7519 Flares; 7549 Ultraviolet emissions; 7974 Solar effects

Lookup tables for transionospheric effects on signals

Strickland, DJ; Barnes, RP; Kochenash, AJ; Jones, WA; Reilly, MH; Daniell, RE;

Published by: Radio Science      Published on:

YEAR: 2004     DOI:

Negative ionospheric storm coincident with DE 1-observed thermospheric disturbance on October 14, 1981

Strickland, DJ; Daniell, RE; Craven, JD;

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

YEAR: 2001     DOI:

UV observations of extended galaxies with UVISI

Allen, MM; Murthy, J; Daniels, J; Dring, AR; Newcomer, RE; Henry, RC; Paxton, L; Tedesco, E;

Published by:       Published on:

YEAR: 1997     DOI: