Bibliography

Analytic and numerical methods for the Abel transform of exponential functions for planetary and cometary atmospheres

Line-of-sight integration of emissions from planetary and cometary atmospheres is the Abel transform of the emission rate, under the spherical symmetry assumption. Indefinite integrals constructed from the Abel transform integral are useful for implementing remote sensing data analysis methods, such as the numerical inverse Abel transform. We propose analytical expressions obtained by a suitable, non-alternating, series development to compute those indefinite integrals. We establish expressions allowing absolute accuracy control of the convergence of these series and illustrate how this accuracy depends on the number of terms involved in the series computation. We compare the analytical method with numerical computation techniques, which are found to be sufficiently accurate as well. Inverse Abel transform fitting is then tested in order to establish that the expected emission rate profiles can be retrieved from the observation of both planetary and cometary atmospheres. We show that the method is robust, i.e. that it can be applied even when the properties of the observed atmosphere depart from the assumed ones, especially when Tikhonov regularization is included. A first application is conducted over observation of comet 46P/Wirtanen, showing some variability, possibly attributable to an evolution of the contamination by dust and icy grains.

Hubert, B.; Munhoven, G.; Moulane, Y.; Hutsemekers, D.; Manfroid, J.; Opitom, C.; Jehin, E.;

Published by: Icarus      Published on: jan

YEAR: 2022     DOI: 10.1016/j.icarus.2021.114654

Abel transform; Aeronomy; Coma; Cometary atmospheres; Comets; Data reduction techniques; Planetary atmospheres.

Neutral composition information in ICON EUV dayglow observations

Since the earliest space‐based observations of Earth s atmosphere, ultraviolet (UV) airglow has proven a useful resource for remote sensing of the ionosphere and thermosphere. The

Tuminello, Richard; England, Scott; Sirk, Martin; Meier, Robert; Stephan, Andrew; Korpela, Eric; Immel, Thomas; Mende, Stephen; Frey, Harald;

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

YEAR: 2022     DOI: 10.1029/2022JA030592

The 15 January 2022 Hunga Tonga Eruption History as Inferred From Ionospheric Observations

On 15 January 2022, the Hunga Tonga-Hunga Ha’apai submarine volcano erupted violently and triggered a giant atmospheric shock wave and tsunami. The exact mechanism of this extraordinary eruptive event, its size and magnitude are not well understood yet. In this work, we analyze data from the nearest ground-based receivers of Global Navigation Satellite System to explore the ionospheric total electron content (TEC) response to this event. We show that the ionospheric response consists of a giant TEC increase followed by a strong long-lasting depletion. We observe that the explosive event of 15 January 2022 began at 04:05:54UT and consisted of at least five explosions. Based on the ionospheric TEC data, we estimate the energy released during the main major explosion to be between 9 and 37 Megatons in trinitrotoluene equivalent. This is the first detailed analysis of the eruption sequence scenario and the timeline from ionospheric TEC observations.

Astafyeva, E.; Maletckii, B.; Mikesell, T.; Munaibari, E.; Ravanelli, M.; Coisson, P.; Manta, F.; Rolland, L.;

Published by: Geophysical Research Letters      Published on:

YEAR: 2022     DOI: 10.1029/2022GL098827

co-volcanic ionospheric disturbances; eruption timeline; GNSS; Hunga Tonga eruption; Ionosphere; ionospheric geodesy

Transpolar Arcs: Seasonal Dependence Identified by an Automated Detection Algorithm

Transpolar arcs (TPAs) are auroral features that occur polewards of the main auroral oval suggesting that the magnetosphere has acquired a complicated magnetic topology. They are primarily a northward interplanetary magnetic field (IMF) auroral phenomenon, and their formation and evolution have no single explanation that is unanimously agreed upon. An automated detection algorithm has been developed to detect the occurrence of TPAs in UV images captured from the Special Sensor Ultraviolet Spectrographic Imager (SSUSI) instrument onboard the Defense Meteorological Satellite Program (DMSP) spacecraft, in order to further study their occurrence. Via this detection algorithm TPAs are identified as a peak in the average radiance intensity poleward of 12.5° colatitude, in two or more of the wavelengths/bands sensed by SSUSI. Using the detection algorithm for the years 2010 to 2016, over 5000 images containing TPAs are identified. The occurrence of these TPAs shows a seasonal dependence, with more arcs being visible in the winter hemisphere. The orbital plane of DMSP has been investigated as a possible explanation of the dependences in the results of the detection algorithm. For the spacecraft of interest this leads to a preferential observation of the northern hemisphere with the detection algorithm missing TPAs in the southern hemisphere around 01–06 UT. No seasonal bias has been found for these spacecraft. We discuss the ramifications of these findings in terms of proposed TPA generation mechanisms and suggest reasons for the seasonal dependence including it being a reflection of probability of seeing TPAs due to visibility.

Bower, G.; Milan, S.; Paxton, L.; Imber, S.;

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

YEAR: 2022     DOI: 10.1029/2021JA029743

auroras; magnetosphere; transpolar arc

Occurrence statistics of horse collar aurora

Bower, Gemma; Milan, Stephen; Paxton, Larry; Anderson, Brian;

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

YEAR: 2022     DOI:

Statistics of transpolar arcs identified by an automated detection algorithm

Bower, Gemma; Milan, Steve; Paxton, Larry; Imber, Suzie;

Published by:       Published on:

YEAR: 2022     DOI:

Height-integrated polar cap conductances during an average substorm

Carter, Jennifer; Milan, Steven; Lester, Mark; Forsyth, Colin; Paxton, Larry; Gjerloev, Jesper; Anderson, Brian;

Published by:       Published on:

YEAR: 2022     DOI:

Lobe Reconnection and Cusp-Aligned Auroral Arcs

Abstract Following the St. Patrick s Day (17 March) geomagnetic storm of 2013, the interplanetary magnetic field had near-zero clock angle for almost two days. Throughout this period multiple cusp-aligned auroral arcs formed in the polar regions; we present observations of, and provide a new explanation for, this poorly understood phenomenon. The arcs were observed by auroral imagers onboard satellites of the Defense Meteorological Satellite Program. Ionospheric flow measurements and observations of energetic particles from the same satellites show that the arcs were produced by inverted-V precipitation associated with upward field-aligned currents (FACs) at shears in the convection pattern. The large-scale convection pattern revealed by the Super Dual Auroral Radar Network and the corresponding FAC pattern observed by the Active Magnetosphere and Planetary Electrodynamics Response Experiment suggest that dual-lobe reconnection was ongoing to produce significant closure of the magnetosphere. However, we propose that once the magnetosphere became nearly closed complicated lobe reconnection geometries arose that produced interleaving of regions of open and closed magnetic flux and spatial and temporal structure in the convection pattern that evolved on timescales shorter than the orbital period of the DMSP spacecraft. This new model naturally explains many features of cusp-aligned arcs, including why they focus in from the nightside toward the cusp region.

Milan, S.; Bower, G.; Carter, J.; Paxton, L.; Anderson, B.; Hairston, M.;

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

YEAR: 2022     DOI: https://doi.org/10.1029/2021JA030089

Geomagnetic and Solar Dependencies of Midlatitude E-Region Irregularity Occurrence Rate: A Climatology Based on Wuhan VHF Radar Observations

By using Wuhan VHF radar, we show the morphological features of E-region field-aligned irregularity (FAI) occurrence at Wuhan during 2015–2020. Statistical results present that E-region FAI occurrence reaches a maximum after sunset in summer season. According to Doppler spectrum features, type-2 irregularity is predominantly observed at Wuhan. In addition, we observed a remarkable correlation between E-region FAI occurrence and geomagnetic activity, which includes periods of positive correlation and negative correlation depending on different geomagnetic conditions. The strong negative correlation also exists between E-region FAI occurrence and solar activity. In our observed results, we find that E-region FAI occurrence shows a strong linkage with local sporadic E (ES) layer. A quantitative analysis of linear theory of plasma instability in the E-region at midlatitudes is also presented in our study. The calculated results of linear growth rate indicate the importance of plasma density gradient of local ES layer and field-line-integrated Pedersen conductivity on the generation of E-region FAI. The geomagnetic and solar variations of E-region FAI occurrence are also discussed in this study, which show a dependence on the geomagnetic and solar variations of both meteor rate and medium-scale traveling ionospheric disturbance occurrence.

Liu, Yi; Zhou, Chen; Xu, Tong; Deng, Zhongxin; Du, Zhitao; Lan, Ting; Tang, Qiong; Zhu, Yunzhou; Wang, Zhuangkai; Zhao, Zhengyu;

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

YEAR: 2022     DOI: 10.1029/2021JA029597

Time Delay Integration Imaging of the Nighttime Ionosphere from the ICON Observatory

TIMED GUVI was on a high inclination orbit changing local time relatively slowly and missing a great deal of the equatorward low latitude regions at the wrong local times.

Mende, SB; Frey, HU; England, SL; Immel, TJ; Eastes, RW;

Published by: Space Science Reviews      Published on:

YEAR: 2022     DOI: 10.1007/s11214-022-00928-w

First Results From the Retrieved Column O/N2 Ratio From the Ionospheric Connection Explorer (ICON): Evidence of the Impacts of Nonmigrating Tides

In near-Earth space, variations in thermospheric composition have important implications for thermosphere-ionosphere coupling. The ratio of O to N2 is often measured using far-UV airglow observations. Taking such airglow observations from space, looking below the Earth s limb allows for the total column of O and N2 in the ionosphere to be determined. While these observations have enabled many previous studies, determining the impact of nonmigrating tides on thermospheric composition has proved difficult, owing to a small contamination of the signal by recombination of ionospheric O+. New ICON observations of far-UV are presented here, and their general characteristics are shown. Using these, along with other observations and a global circulation model, we show that during the morning hours and at latitudes away from the peak of the equatorial ionospheric anomaly, the impact of nonmigrating tides on thermospheric composition can be observed. During March–April 2020, the column O/N2 ratio was seen to vary by 3–4\% of the zonal mean. By comparing the amplitude of the variation observed with that in the model, both the utility of these observations and a pathway to enable future studies is shown.

England, Scott; Meier, R.; Frey, Harald; Mende, Stephen; Stephan, Andrew; Krier, Christopher; Cullens, Chihoko; Wu, Yen-Jung; Triplett, Colin; Sirk, Martin; Korpela, Eric; Harding, Brian; Englert, Christoph; Immel, Thomas;

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

YEAR: 2021     DOI: 10.1029/2021JA029575

airglow; atmospheric composition; Atmospheric tides; thermosphere

Conjugate Photoelectron Energy Spectra Derived From Coincident FUV and Radio Measurements

We present a method for estimating incident photoelectrons energy spectra as a function of altitude by combining global scale far-ultraviolet (FUV) and radio-occultation (RO) measurements. This characterization provides timely insights important for accurate interpretation of ionospheric parameters inferred from the recently launched Ionospheric Connection Explorer (ICON) observations. Quantification of photoelectron impact is enabled by the fact that conjugate photoelectrons (CPEs) directly affect FUV airglow emissions but not RO measurements. We demonstrate a technique for estimation of photoelectron fluxes and their spectra by combining coincident ICON and COSMIC2 measurements and show that a significant fraction of ICON-FUV measurements is affected by CPEs during the winter solstice. A comparison of estimated photoelectron fluxes with measured photoelectron spectra is used to gain further insights into the estimation method and reveals consistent values within 10–60 eV.

Urco, J.; Kamalabadi, F.; Kamaci, U.; Harding, B.; Frey, H.; Mende, S.; Huba, J.; England, S.; Immel, T.;

Published by: Geophysical Research Letters      Published on:

YEAR: 2021     DOI: 10.1029/2021GL095839

airglow; conjugate photolectrons; COSMIC2; energy spectra; ICON

Deducing Non-Migrating Diurnal Tides in the Middle Thermosphere With GOLD Observations of the Earth's far Ultraviolet Dayglow From Geostationary Orbit

The global-scale observations of the limb and disk (GOLD) Mission images middle thermosphere temperature and the vertical column density ratio of oxygen to molecular nitrogen (O/N2) using its far ultraviolet imaging spectrographs in geostationary orbit. Since GOLD only measures these quantities during daylight, and only over the ∼140° of longitude visible from geostationary orbit, previously developed tidal analysis techniques cannot be applied to the GOLD data set. This paper presents a novel approach that deduces two specified non-migrating diurnal tides using simultaneous measurements of temperature and O/N2. DE3 (diurnal eastward propagating wave 3) and DE2 (diurnal eastward propagating wave 2) during October 2018 and January 2020 are the focus of this paper. Sensitivity analyses using TIE-GCM simulations reveal that our approach reliably retrieves the true phases, whereas a combination of residual contributions from secondary tides, the restriction in longitude, and random uncertainty can lead to ∼50\% error in the retrieved amplitudes. Application of our approach to GOLD data during these time periods provides the first observations of non-migrating diurnal tides in measurements taken from geostationary orbit. We identify discrepancies between GOLD observations and TIE-GCM modeling. Retrieved tidal amplitudes from GOLD observations exceed their respective TIE-GCM amplitudes by a factor of two in some cases.

Krier, Christopher; England, Scott; Greer, Katelynn; Evans, Scott; Burns, Alan; Eastes, Richard;

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

YEAR: 2021     DOI: 10.1029/2021JA029563

airglow; composition; temperature; thermosphere; tides

Field-Aligned Current During an Interval of BY-Dominated Interplanetary-Field; Modeled-to-Observed Comparisons

Carter, Jennifer; Samsonov, AA; Milan, Stephen; Branduardi-Raymont, Graziella; Ridley, Aaron; Paxton, Larry; Anderson, Brian; Waters, Colin; Edwards, Thomas;

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

YEAR: 2021     DOI:

Field-aligned current during an interval of $$\backslash$rm B\_ $\$Y$\$ $-dominated interplanetary-field; modeled-to-observed comparisons

Carter, Jennifer; Samsonov, Andrey; Milan, Stephen; Branduardi-Raymont, Graziella; Ridley, Aaron; Paxton, Larry; Anderson, Brian; Waters, Colin; Edwards, Thomas;

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

YEAR: 2021     DOI:

Transpolar arcs: Seasonal dependence identified by an automated detection algorithm

Bower, Gemma; Milan, Stephen; Paxton, Larry;

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

YEAR: 2021     DOI:

Dual-lobe reconnection and cusp-aligned auroral arcs

Milan, Stephen; Bower, Gemma; Carter, Jennifer; Paxton, Larry; Anderson, Brian; Hairston, Marc;

Published by:       Published on:

YEAR: 2021     DOI:

First Comparison of Traveling Atmospheric Disturbances Observed in the Middle Thermosphere by Global-Scale Observations of the Limb and Disk to Traveling Ionospheric Disturbances Seen in Ground-Based Total Electron Content Observations

Traveling ionospheric disturbances (TIDs) and their neutral counterparts known as traveling atmospheric disturbances (TADs) are believed to play a role in communicating inputs to other locations in the fluid. While these two phenomena are believed to be connected, they may not have a one-to-one correspondence as the geomagnetic field influences the TID but has no direct impact on the TAD. The relative amplitudes of the perturbations seen in the ionosphere and atmosphere have been observed but rarely together. This study reports results from a 3-day campaign to observe TIDs and TADs simultaneously over a broad latitudinal region over the eastern United States using a combination of Global-scale Observations of the Limb and Disk (GOLD) and a distributed network of ground-based Global Navigation Satellite System (GNSS) receivers. These results demonstrate that GOLD and the ground-based total electron content (TEC) observations can see the atmospheric and ionospheric portions of a large-scale traveling disturbance. The phase difference in the perturbations to the GOLD airglow brightness, O/N2 and thermospheric disk temperature are consistent with an atmospheric gravity wave moving through this region. The ionospheric signatures move at the same rate as those in the atmosphere, but their amplitudes do not have a simple correspondence to the amplitude of the signal seen in the atmosphere. This campaign demonstrates a proof-of-concept that this combination of observations is able to provide information on TIDs and TADs, including quantifying their impact on the temperature and chemical composition of the upper atmosphere.

England, Scott; Greer, Katelynn; Zhang, Shun-Rong; Evans, Scott; Solomon, Stanley; Eastes, Richard; McClintock, William; Burns, Alan;

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

YEAR: 2021     DOI: 10.1029/2021JA029248

Ionosphere; thermosphere; airglow; atmospheric waves

A Synoptic-Scale Wavelike Structure in the Nighttime Equatorial Ionization Anomaly

Both ground- and satellite-based airglow imaging have significantly contributed to understanding the low-latitude ionosphere, especially the morphology and dynamics of the equatorial ionization anomaly (EIA). The NASA Global-scale Observations of the Limb and Disk (GOLD) mission focuses on far-ultraviolet airglow images from a geostationary orbit at 47.5°W. This region is of particular interest at low magnetic latitudes because of the high magnetic declination (i.e., about -20°) and proximity of the South Atlantic magnetic anomaly. In this study, we characterize an exciting feature of the nighttime EIA using GOLD observations from October 5, 2018 to June 30, 2020. It consists of a wavelike structure of a few thousand kilometers seen as poleward and equatorward displacements of the EIA-crests. Initial analyses show that the synoptic-scale structure is symmetric about the dip equator and appears nearly stationary with time over the night. In quasi-dipole coordinates, maxima poleward displacements of the EIA-crests are seen at about ± 12° latitude and around 20 and 60° longitude (i.e., in geographic longitude at the dip equator, about 53°W and 14°W). The wavelike structure presents typical zonal wavelengths of about 6.7 × 103 km and 3.3 × 103 km. The structure s occurrence and wavelength are highly variable on a day-to-day basis with no apparent dependence on geomagnetic activity. In addition, a cluster or quasi-periodic wave train of equatorial plasma depletions (EPDs) is often detected within the synoptic-scale structure. We further outline the difference in observing these EPDs from FUV images and in situ measurements during a GOLD and Swarm mission conjunction.

Rodríguez-Zuluaga, J.; Stolle, C.; Yamazaki, Y.; Xiong, C.; England, S.;

Published by: Earth and Space Science      Published on:

YEAR: 2021     DOI: 10.1029/2020EA001529

equatorial plasma bubbles; Equatorial ionization anomaly; Equatorial ionosphere; forcing from below; wave structure

Aurora in the Polar Cap: A Review

This paper reviews our current understanding of auroral features that appear poleward of the main auroral oval within the polar cap, especially those that are known as Sun-aligned arcs, transpolar arcs, or theta auroras. They tend to appear predominantly during periods of quiet geomagnetic activity or northwards directed interplanetary magnetic field (IMF). We also introduce polar rain aurora which has been considered as a phenomenon on open field lines. We describe the morphology of such auroras, their development and dynamics in response to solar wind-magnetosphere coupling processes, and the models that have been developed to explain them.

Hosokawa, Keisuke; Kullen, Anita; Milan, Steve; Reidy, Jade; Zou, Ying; Frey, Harald; Maggiolo, Romain; Fear, Robert;

Published by: Space Science Reviews      Published on: 02/2020

YEAR: 2020     DOI: 10.1007/s11214-020-0637-3

Bifurcated Region 2 Field-Aligned Currents Associated With Substorms

Sangha, H; Milan, SE; Carter, JA; Fogg, AR; Anderson, BJ; Korth, H; Paxton, LJ;

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

YEAR: 2020     DOI:

Height-Integrated Ionospheric Conductances Parameterized By Interplanetary Magnetic Field and Substorm Phase

Carter, JA; Milan, SE; Paxton, LJ; Anderson, BJ; Gjerloev, J;

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

YEAR: 2020     DOI:

Bifurcated region 2 field-aligned currents associated with substorms

Sangha, H; Milan, SE; Carter, JA; Fogg, AR; Anderson, BJ; Korth, H; Paxton, LJ;

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

YEAR: 2020     DOI:

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:

The evolution of long-duration cusp spot emission during lobe reconnection with respect to field-aligned currents

Carter, Jennifer; Milan, Stephen; Fogg, Alexandra; Sangha, Harneet; Lester, Mark; Paxton, Larry; Anderson, Brian;

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

YEAR: 2020     DOI:

Dataset for Multi-scale observations of two polar cap arcs occuring on different magnetic field topologies

Reidy, Jade; Fear, Robert; Whiter, Daniel; Lanchester, Betty; Kavanagh, AJ; Price, David; Chadney, Joshua; Zhang, Yongliang; Paxton, Larry; , others;

Published by:       Published on:

YEAR: 2020     DOI:

Dual-lobe reconnection and horse-collar auroras

Milan, Stephen; Carter, Jennifer; Bower, Gemma; Imber, Suzanne; Paxton, Larry; Anderson, Brian; Hairston, Marc; Hubert, Benoit;

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

YEAR: 2020     DOI:

Multiscale observation of two polar cap arcs occurring on different magnetic field topologies

Reidy, JA; Fear, RC; Whiter, DK; Lanchester, BS; Kavanagh, AJ; Price, David; Chadney, Joshua; Zhang, Y; Paxton, LJ;

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

YEAR: 2020     DOI:

Hybrid-Vlasov simulation of auroral proton precipitation in the cusps: Comparison of northward and southward interplanetary magnetic field driving

Particle precipitation is a central aspect of space weather, as it strongly couples the magnetosphere and the ionosphere and can be responsible for radio signal disruption at high

Grandin, Maxime; Turc, Lucile; Battarbee, Markus; Ganse, Urs; Johlander, Andreas; Pfau-Kempf, Yann; Dubart, Maxime; Palmroth, Minna;

Published by: Journal of space weather and space climate      Published on:

YEAR: 2020     DOI: 10.1051/swsc/2020053

A mesoscale wave-like structure in the nighttime equatorial ionization anomaly

Both ground-and satellite-based airglow imaging have significantly contributed to our understanding of the low-latitude ionosphere, especially of the morphology and dynamics of the

iguez-Zuluaga, Juan; Stolle, Claudia; Yamazaki, Yosuke; Xiong, Chao; England, Scott;

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

YEAR: 2020     DOI: 10.1002/essoar.10504705.1

Daily Variability in the Terrestrial UV Airglow

New capability for observing conditions in the upper atmosphere comes with the implementation of global ultraviolet (UV) imaging from geosynchronous orbit. Observed by the NASA

Immel, Thomas; Eastes, Richard; McClintock, William; Mende, Steven; Frey, Harald; Triplett, Colin; England, Scott;

Published by: Atmosphere      Published on:

YEAR: 2020     DOI: 10.3390/atmos11101046

A new data set of thermospheric molecular oxygen from the Global-scale Observations of the Limb and Disk (GOLD) mission

The Global-scale Observations of the Limb and Disk (GOLD) instrument was launched on 25 January 2018 onboard the SES-14 commercial communications satellite and began nominal science operations in October 2018. Operating from geostationary orbit at 47.5°W longitude, GOLD images the Earth s thermosphere and ionosphere in the far-ultraviolet (132–162 nm), measuring critical geophysical parameters by continuously scanning the Earth s disk and limb 18 hours per day. GOLD also performs stellar occultation measurements using bright type O and B stars.

Lumpe, JD; McClintock, WE; Evans, JS; Correira, J; , Veibell; Beland, S; Eastes, R;

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

YEAR: 2020     DOI: 10.1029/2020JA027812

Dayside Aurora

Dayside aurora is related to processes in the dayside magnetosphere and especially at the dayside magnetopause. A number of dayside aurora phenomena are driven by reconnection between the solar wind interplanetary magnetic field and the Earth\textquoterights internal magnetic field at the magnetopause. We summarize the properties and origin of aurora at the cusp foot point, High Latitude Dayside Aurora (HiLDA), Poleward Moving Auroral Forms (PMAFs), aurora related to traveling convection vortices (TCV), and throat aurora. Furthermore we discuss dayside diffuse aurora, morning side diffuse aurora spots, and shock aurora.

Frey, Harald; Han, Desheng; Kataoka, Ryuho; Lessard, Marc; Milan, Stephen; Nishimura, Yukitoshi; Strangeway, Robert; Zou, Ying;

Published by: Space Science Reviews      Published on: 11/2019

YEAR: 2019     DOI: 10.1007/s11214-019-0617-7

Understanding the global dynamics of the equatorial ionosphere in Africa for space weather capabilities: A science case for AfrequaMARN

Evaluation of Space Traffic Effects in SBUV Polar Mesospheric Cloud Data

Water-rich rocket exhaust plumes, in particular those emitted by the National Aeronautics and Space Administration Space Shuttle, have been suggested to make a significant contribution to long-term trends in polar mesospheric cloud (PMC) ice water content. We investigate this claim using the combined Solar Backscatter Ultraviolet (SBUV) PMC data record from eight separate instruments, which includes 60 Shuttle launches during PMC seasons between 1985 and 2011. No statistically significant postlaunch signal in PMC total ice is observed based on superposed epoch analysis of the SBUV record. Only a few launches show individual peaks in total ice anomaly above the seasonal background that exceed an empirical threshold, and the maximum cumulative signature from these infrequent cases is typically less than 5\% of the season total in ice mass. Other non-Shuttle launches show circumstantial evidence of possible PMC effects, although supporting evidence for plume transport is not available. We conclude that space traffic effects have been a negligible component of long-term PMC behavior.

DeLand, Matthew; Thomas, Gary;

Published by: Journal of Geophysical Research: Atmospheres      Published on: 03/2019

YEAR: 2019     DOI: 10.1029/2018JD029756

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

Observations of Spatial Variations in O/N ₂ During an Auroral Substorm Using the Multichannel Downlooking Camera on the VISIONS Rocket

At 0821 UT on 7 February 2013, during an auroral substorm, the NASA VISIONS rocket was launched northward from Poker Flat Research Range on a flight to approximately 750-km altitude that terminated in the Arctic Ocean. A subpayload jettisoned on the up leg carried a multichannel optical imager that looked downward and observed the auroral emission through four narrow passband filters. Three of the channels had sufficiently strong signal to allow a measure of the time evolution of the horizontal extent of the electron aurora and changes in the ratio of the column O to the column N₂. These data revealed rather rapid changes in this measure of composition over an area larger than would be expected from the changes expected from particle and Joule heating. Although such rapid large changes have been observed previously, and Christensen et al. (1997, https://doi.org/10.1029/97JA01800) had hypothesized that they were due to enhanced turbulent diffusion, this imaging experiment is the first to show their evolution over a large area. On the down leg the camera was able to see the vertical spatial extent of the auroral emission which is consistent with the decrease in O/N₂ seen in the downlooking data. The change in this ratio with altitude suggests the deposition of an additional number of low-energy electrons that would cause a larger decrease in that ratio at higher altitudes.

Hecht, J.; Clemmons, J.; Conde, M.; Hampton, D.; Michell, R.; Rowland, D.; Pfaff, R.; Walterscheid, R.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2018

YEAR: 2018     DOI: 10.1029/2018JA025288

Daytime O/N2 Retrieval Algorithm for the Ionospheric Connection Explorer (ICON)

The NASA Ionospheric Connection Explorer Far-Ultraviolet spectrometer, ICON FUV, will measure altitude profiles of the daytime far-ultraviolet (FUV) OI 135.6 nm and N₂ Lyman-Birge-Hopfield (LBH) band emissions that are used to determine thermospheric density profiles and state parameters related to thermospheric composition; specifically the thermospheric column O/N₂ ratio (symbolized as ΣO/N₂). This paper describes the algorithm concept that has been adapted and updated from one previously applied with success to limb data from the Global Ultraviolet Imager (GUVI) on the NASA Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) mission. We also describe the requirements that are imposed on the ICON FUV to measure ΣO/N₂ over any 500-km sample in daytime with a precision of better than 8.7\%. We present results from orbit-simulation testing that demonstrates that the ICON FUV and our thermospheric composition retrieval algorithm can meet these requirements and provide the measurements necessary to address ICON science objectives.

Stephan, Andrew; Meier, R.; England, Scott; Mende, Stephen; Frey, Harald; Immel, Thomas;

Published by: Space Science Reviews      Published on: 01/2018

YEAR: 2018     DOI: 10.1007/s11214-018-0477-6

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:

A remote observatory for geocoronal hydrogen emissions

The Investigating Near Space Interaction Regions (INSpIRe) observatory is an adapt-able research facility that is designed to use Fabry-Perot interferometer (FPI) to study the faint Balmer series emissions of the terrestrial upper thermosphere and exosphere, collectively known as the geocorona. This instrumentation is designed to be deployable to a clear-air site, necessitating remote operations of the entire observatory, including control and monitoring.

Gallant, Margaret;

Published by:       Published on:

YEAR: 2018     DOI:

Modeled gravity wave-like perturbations in the brightness of far ultraviolet emissions for the GOLD mission

The NASA Global‐scale Observations of Limb and Disk (GOLD) mission will study the coupling of the thermosphere with the lower atmosphere through an examination of temperature

Greer, KR; England, SL; Becker, E; Rusch, D; Eastes, R;

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

YEAR: 2018     DOI: 10.1029/2018JA025501

AMICal Sat and ATISE: two space missions for auroral monitoring

A lack of observable quantities renders it generally difficult to confront models of Space Weather with experimental data and drastically reduces the forecast accuracy. This is especially

elemy, Mathieu; Kalegaev, Vladimir; Vialatte, Anne; Le Coarer, Etienne; Kerstel, Erik; Basaev, Alexander; Bourdarot, Guillaume; Prugniaux, Melanie; Sequies, Thierry; Rolland, Etienne; , others;

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YEAR: 2018     DOI: 10.1051/swsc/2018035

The ionospheric connection explorer mission: Mission goals and design

The Ionospheric Connection Explorer, or ICON, is a new NASA Explorer mission that will explore the boundary between Earth and space to understand the physical connection

Immel, Thomas; England, SL; Mende, SB; Heelis, RA; Englert, CR; Edelstein, J; Frey, HU; Korpela, EJ; Taylor, ER; Craig, WW; , others;

Published by: Space Science Reviews      Published on:

YEAR: 2018     DOI: 10.1007/s11214-017-0449-2

Inferring nighttime ionospheric parameters with the far ultraviolet imager onboard the ionospheric connection explorer

The Ionospheric Connection Explorer (ICON) Far Ultraviolet (FUV) imager, ICON FUV, will measure altitude profiles of OI 135.6 nm emissions to infer nighttime ionospheric parameters.

Kamalabadi, Farzad; Qin, Jianqi; Harding, Brian; Iliou, Dimitrios; Makela, Jonathan; Meier, RR; England, Scott; Frey, Harald; Mende, Stephen; Immel, Thomas;

Published by: Space science reviews      Published on:

YEAR: 2018     DOI:

Empirical Study of Subauroral Polarization Streams (SAPS) through Decades of Satellite Observations

Subauroral Polarization Streams (SAPS) are a phenomenon characterized by westward ion drifts driven by poleward electric fields in the subauroral ionosphere associated with field-

Landry, Russell;

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YEAR: 2018     DOI:

The association of high-latitude dayside aurora with NBZ field-aligned currents

Carter, JA; Milan, SE; Fogg, AR; Paxton, LJ; Anderson, BJ;

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

YEAR: 2018     DOI:

Interhemispheric survey of polar cap aurora

Reidy, Jade; Fear, RC; Whiter, DK; Lanchester, B; Kavanagh, Andrew; Milan, SE; Carter, JA; Paxton, LJ; Zhang, Y;

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

YEAR: 2018     DOI:

Interhemispheric survey of polar cap aurora

Reidy, Jade; Fear, RC; Whiter, DK; Lanchester, B; Kavanagh, Andrew; Milan, SE; Carter, JA; Paxton, LJ; Zhang, Y;

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

YEAR: 2018     DOI:

Vertical Coupling in the Ionosphere—Thermosphere System I Posters

Heelis, Roderick; Rowland, Douglas; Paxton, Larry;

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YEAR: 2018     DOI:

Daytime Ionosphere Retrieval Algorithm for the Ionospheric Connection Explorer (ICON)

The NASA Ionospheric Connection Explorer Extreme Ultraviolet spectrograph, ICON EUV, will measure altitude profiles of the daytime extreme-ultraviolet (EUV) OII emission near 83.4 and 61.7\ nm that are used to determine density profiles and state parameters of the ionosphere. This paper describes the algorithm concept and approach to inverting these measured OII emission profiles to derive the associated O+ density profile from 150\textendash450\ km as a proxy for the electron content in the F-region of the ionosphere. The algorithm incorporates a bias evaluation and feedback step, developed at the U.S. Naval Research Laboratory using data from the Special Sensor Ultraviolet Limb Imager (SSULI) and the Remote Atmospheric and Ionospheric Detection System (RAIDS) missions, that is able to effectively mitigate the effects of systematic instrument calibration errors and inaccuracies in the original photon source within the forward model. Results are presented from end-to-end simulations that convolved simulated airglow profiles with the expected instrument measurement response to produce profiles that were inverted with the algorithm to return data products for comparison to truth. Simulations of measurements over a representative ICON orbit show the algorithm is able to reproduce hmF2 values to better than 5\ km accuracy, and NmF2 to better than 12\% accuracy over a 12-second integration, and demonstrate that the ICON EUV instrument and daytime ionosphere algorithm can meet the ICON science objectives which require 20\ km vertical resolution in hmF2 and 18\% precision in NmF2.

Stephan, Andrew; Korpela, Eric; Sirk, Martin; England, Scott; Immel, Thomas;

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

YEAR: 2017     DOI: 10.1007/s11214-017-0385-1