Bibliography

The Role of High Energy Photoelectrons on the Dissociation of Molecular Nitrogen in Earth's Ionosphere

Soft x-ray radiation from the sun is responsible for the production of high energy photoelectrons in the D and E regions of the ionosphere, where they deposit most of their ionization

Samaddar, Srimoyee; Venkataramani, Karthik; Yonker, Justin; Bailey, Scott; , others;

Published by: arXiv preprint arXiv:2209.11185      Published on:

YEAR: 2022     DOI: 10.48550/arXiv.2209.11185

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

The Role of Solar Soft X-rays Irradiance in Thermospheric Structure

We use a new Atmospheric Chemistry and Energetics one-dimensional (ACE1D) thermospheric model to show that the energies deposited by the solar soft x-rays in the lower

Samaddar, Srimoyee; Venkataramani, Karthik; Bailey, Scott; , others;

Published by: arXiv preprint arXiv:2209.10543      Published on:

YEAR: 2022     DOI: 10.48550/arXiv.2209.10543

A Model of the Globally-averaged Thermospheric Energy Balance

Similar to the MSIS data, we bin the GUVI temperatures by latitude It should be noted that GUVI observations at high values of While the GUVI observations cannot be compared directly

Venkataramani, Karthik; Bailey, Scott; Samaddar, Srimoyee; Yonker, Justin;

Published by: arXiv preprint arXiv:2211.05301      Published on:

YEAR: 2022     DOI: 10.48550/arXiv.2211.05301

Comparison of the Thermospheric Nitric Oxide Emission Observations and the GITM Simulations: Sensitivity to Solar and Geomagnetic Activities

An accurate estimate of the energy budget (heating and cooling) of the ionosphere and thermosphere, especially during space weather events, has been a challenge. The abundance of Nitric Oxide (NO), a minor species in the thermosphere, is an important component of energy balance here because its production comes from energy sources able to break the strong bond of molecular nitrogen, and infrared emissions from NO play an important role in thermospheric cooling. Recent studies have significantly improved our understanding of NO chemistry and its relationship to energy deposition in the thermospheric photochemical reactions. In this study, the chemical scheme in the Global Ionosphere Thermosphere Model (GITM) is updated to better predict the lower thermospheric NO responses to solar and geomagnetic activity. We investigate the sensitivity of the 5.3-micron NO emission to F10.7 and Ap indices by comparing the global integrated emission from GITM with an empirical proxy derived from the Sounding of the Atmosphere using Broadband Emission Radiometry measurements. GITM\textquoterights total emission agrees well within 20\% of the empirical values. The updated chemistry scheme significantly elevates the level of integrated emission compared to the previous scheme. The inclusion of N2(A)-related production of NO contributes an additional 5-25\% to the emission. Localized enhancement of ~70\% in column density and a factor of three in column emission are simulated at a moderate geomagnetic level.

Lin, Cissi; Deng, Yue; Venkataramani, Karthik; Yonker, Justin; Bailey, Scott;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2018

YEAR: 2018     DOI: 10.1029/2018JA025310

Comparison of the Thermospheric Nitric Oxide Emission Observations and the Global Ionosphere-Thermosphere Model (GITM) Simulations: Sensitivity to Solar and Geomagnetic Activities

The magnitude of enhancement observed in column density agrees well with the cases observed by TIMED/GUVI −8 W/m3) agree well with TIMED/SABER and GUVI measurements.

Lin, Cissi; Deng, Yue; Venkataramani, Karthik; Yonker, Justin; Bailey, Scott;

Published by: arXiv preprint arXiv:1807.01380      Published on:

YEAR: 2018     DOI: https://doi.org/10.48550/arXiv.1807.01380

Parameterization of Nitric Oxide Emissions in the Thermosphere

Lin, CYT; Deng, Yue; Venkataramani, Karthik; Yonker, Justin; Bailey, Scott;

Published by:       Published on:

YEAR: 2016     DOI:

Equatorial ionization anomaly development as studied by GPS TEC and foF2 over Brazil: A comparison of observations with model results from SUPIM and IRI-2012

The equatorial ionization anomaly (EIA) development is studied using the total electron content (TEC) observed by the Global Positioning System (GPS) satellites, the F2-layer critical frequency (foF2) as measured by digisondes operated in the Brazilian sector, and by model simulation using the SUPIM (Sheffield University Plasmasphere Ionosphere Model). We have used two indices based on foF2 and TEC to represent the strength of the EIA Southern Anomaly Crest (SAC), which are denoted, respectively, by SAC(foF2) and SAC(TEC). Significant differences in the local time variations of the EIA intensity, as represented by these two indices, are investigated. The observed SAC indices are compared with their values modeled by the SUPIM and also by the International Reference Ionosphere (IRI)\textemdash2012. The SUPIM simulations that use the standard E\texttimesB plasma drift and neutral air wind models are found to provide acceptable representations of the observed foF2 and TEC, and hence the indices SAC(foF2) and SAC(TEC) during daytime, whereas the IRI-2012 model is not, except during the post-midnight/sunrise hours. It is found that the differences in the local time variations between the SAC(foF2) and SAC(TEC) can be reduced by limiting the TEC integrations in height up to an altitude of 630\ km in the SUPIM calculations. It is also found that when the EIA intensity is calculated for an intermediate dip latitude (12\textdegreeS) the difference between the local time variation patterns of the two corresponding indices in the experimental data and in the SUPIM results is reduced. For the IRI-2012 values, the subequatorial station modification does not appear to have any effect.

Nogueira, P.A.B.; Abdu, M.A.; Souza, J.R.; Batista, I.S.; Bailey, G.J.; Santos, A.M.; Takahashi, H.;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: 11/2013

YEAR: 2013     DOI: 10.1016/j.jastp.2013.08.013

Equatorial anomaly; foF2; Ionospheric modeling; TEC

Physical mechanisms of the ionospheric storms at equatorial and higher latitudes during the recovery phase of geomagnetic storms

The paper studies the physical mechanisms of the ionospheric storms at equatorial and higher latitudes, which are generally opposite both during the main phase (MP) and recovery phase (RP) of geomagnetic storms. The mechanisms are based on the natural tendency of physical systems to occupy minimum energy state which is most stable. The paper first illustrates the recent developments in the understanding of the mechanisms during daytime MPs when generally negative ionospheric storms (in Nmax and TEC) develop at equatorial latitudes and positive storms occur at higher latitudes, including why the storms are severe only in some cases. The paper then investigates the relative importance of the physical mechanisms of the positive ionospheric storms observed at equatorial latitudes (within \textpm15\textdegree) during daytime RPs when negative storms occur at higher latitudes using CHAMP Ne and GPS-TEC data and Sheffield University Plasmasphere Ionosphere Model. The results indicate that the mechanical effect of the storm-time equatorward neutral winds that causes plasma convergence at equatorial F region could be a major source for the positive storms, with the downwelling effect of the winds and zero or westward electric field, if present, acting as minor sources.

Balan, N.; Otsuka, Y.; Nishioka, M.; Liu, J; Bailey, G.;

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

YEAR: 2013     DOI: 10.1002/jgra.50275

Geomagnetic storms; Ionospheric storms; physical mechanisms

Operational specification and forecasting advances for Dst, LEO thermospheric densities, and aviation radiation dose and dose rate

Tobiska, W; Knipp, DJ; Burke, WJ; Bouwer, D; Bailey, JJ; Hagan, MP; Didkovsky, LV; Garrett, HB; Bowman, BR; Gannon, JL; , others;

Published by:       Published on:

YEAR: 2013     DOI:

Bright polar mesospheric clouds formed by main engine exhaust from the space shuttle's final launch

Stevens, Michael; Lossow, Stefan; Fiedler, Jens; Baumgarten, Gerd; übken, Franz-Josef; Hallgren, Kristofer; Hartogh, Paul; Randall, Cora; Lumpe, Jerry; Bailey, Scott; Niciejewski, R.; Meier, R.; Plane, John; Kochenash, Andrew; Murtagh, Donal; Englert, Christoph;

Published by: Journal of Geophysical Research: Atmospheres      Published on: Apr-10-2013

YEAR: 2012     DOI: 10.1029/2012JD017638

Extreme Ultraviolet Variability Experiment (EVE) on~the~Solar Dynamics Observatory (SDO): Overview~of~Science Objectives, Instrument Design, Data~Products, and Model Developments

The highly variable solar extreme ultraviolet (EUV) radiation is the major energy input to the Earth\textquoterights upper atmosphere, strongly impacting the geospace environment, affecting satellite operations, communications, and navigation. The Extreme ultraviolet Variability Experiment (EVE) onboard the NASA Solar Dynamics Observatory (SDO) will measure the solar EUV irradiance from 0.1 to 105\ nm with unprecedented spectral resolution (0.1\ nm), temporal cadence (ten seconds), and accuracy (20\%). EVE includes several irradiance instruments: The Multiple EUV Grating Spectrographs (MEGS)-A is a grazing-incidence spectrograph that measures the solar EUV irradiance in the 5 to 37\ nm range with 0.1-nm resolution, and the MEGS-B is a normal-incidence, dual-pass spectrograph that measures the solar EUV irradiance in the 35 to 105\ nm range with 0.1-nm resolution. To provide MEGS in-flight calibration, the EUV SpectroPhotometer (ESP) measures the solar EUV irradiance in broadbands between 0.1 and 39\ nm, and a MEGS-Photometer measures the Sun\textquoterights bright hydrogen emission at 121.6\ nm. The EVE data products include a near real-time space-weather product (Level\ 0C), which provides the solar EUV irradiance in specific bands and also spectra in 0.1-nm intervals with a cadence of one minute and with a time delay of less than 15\ minutes. The EVE higher-level products are Level\ 2 with the solar EUV irradiance at higher time cadence (0.25\ seconds for photometers and ten seconds for spectrographs) and Level\ 3 with averages of the solar irradiance over a day and over each one-hour period. The EVE team also plans to advance existing models of solar EUV irradiance and to operationally use the EVE measurements in models of Earth\textquoterights ionosphere and thermosphere. Improved understanding of the evolution of solar flares and extending the various models to incorporate solar flare events are high priorities for the EVE team.

Woods, T.; Eparvier, F.; Hock, R.; Jones, A.; Woodraska, D.; Judge, D.; Didkovsky, L.; Lean, J.; Mariska, J.; Warren, H.; McMullin, D.; Chamberlin, P.; Berthiaume, G.; Bailey, S.; Fuller-Rowell, T.; Sojka, J.; Tobiska, W.; Viereck, R.;

Published by: Solar Physics      Published on: 01/2012

YEAR: 2012     DOI: 10.1007/s11207-009-9487-6

EVE; SDO; Solar EUV irradiance; Space weather research

Ultraviolet Remote Sensing of Nitric Oxide in the Thermosphere Using the TIMED/GUVI Instrument

DeMajistre, R; Wolven, BC; Paxton, LJ; Zhang, Y; Schaefer, RK; Bailey, SM; Yonker, JD; Thurairajah, B;

Published by:       Published on:

YEAR: 2012     DOI:

Response of the ionosphere to super geomagnetic storms: Observations and modeling

Lekshmi, Vijaya; Balan, N; Vaidyan, VK; Alleyne, H; Bailey, GJ;

Published by: Advances in Space Research      Published on:

YEAR: 2008     DOI:

Photolysis and Fluorescence in the/delta and/epsilon Bands of Thermospheric NO

Yonker, JD; Bailey, SM; Paxton, LJ;

Published by:       Published on:

YEAR: 2008     DOI:

Comparing the Measured N2 Lyman-Birge-Hopfield (LBH) Band Brightness in the Dayglow With Model Calculations: Investigating the Importance of Cascading as a Source of Excitation.

Aksnes, A; Eastes, R; Budzien, S; Dymond, K; Bailey, S; Jones, A;

Published by:       Published on:

YEAR: 2005     DOI:

Solar EUV Experiment (SEE): Mission overview and first results

[1]\ The Solar EUV Experiment (SEE) is one of four scientific instruments on the NASA Thermosphere Ionosphere Mesosphere Energetics Dynamics (TIMED) spacecraft, which has been simultaneously observing the Sun and Earth\textquoterights upper atmosphere since January 2002. The SEE instrument measures the irradiance of the highly variable, solar extreme ultraviolet (EUV) radiation, one of the major energy sources for the upper atmosphere. The primary SEE data product is the solar spectral irradiances from 0.1 to 194 nm in 1 nm intervals that are fundamental for the TIMED mission\textquoterights investigation of the energetics in the tenuous, but highly variable, layers of the Earth\textquoterights atmosphere above 60 km. The TIMED mission began normal operations on 22 January 2002, a time when the Sun displayed maximum levels of activity for solar cycle 23, and has provided daily measurements as solar activity has declined to moderate levels. Solar irradiance variability observed by SEE during the 2 years of the TIMED prime mission includes a variety of moderate and large flares over periods of seconds to hours and dozens of solar rotational cycles over a typical period of 27 days. The SEE flare measurements provide important, new results because of the simultaneous spectral coverage from 0.1 to 194 nm, albeit limited temporal coverage due to its 3\% duty cycle. In addition, the SEE measurements reveal important, new results concerning phase shifts of 2\textendash7 days in the intermediate-term variations between different UV wavelengths that appear to be related to their different center-to-limb variations. The new solar EUV irradiance time series from SEE are also important in filling the \textquotedblleftEUV Hole,\textquotedblright which is the gap in irradiance measurements in the EUV spectrum since the 1980s. The solar irradiances measured by SEE (Version 7, released July 2004) are compared with other measurements and predictions from models of the solar EUV irradiance. While the measurement comparisons show reasonable agreement, there are significant differences between SEE and some of the models in the EUV range. The data processing algorithms and calibrations are also discussed.

Woods, Thomas; Eparvier, Francis; Bailey, Scott; Chamberlin, Phillip; Lean, Judith; Rottman, Gary; Solomon, Stanley; Tobiska, Kent; Woodraska, Donald;

Published by: Journal of Geophysical Research: Space Physics (1978\textendash2012)      Published on:

YEAR: 2005     DOI: 10.1029/2004JA010765

thermosphere; solar activity cycle; solar irradiance; ultraviolet emissions; solar effects

Thermospheric Response to Solar EUV during Quiet and Flare Conditions

Solomon, SC; Qian, L; Gladstone, GR; Bailey, SM; Rodgers, EM;

Published by:       Published on:

YEAR: 2005     DOI:

New measurements by the TIMED solar extreme-ultraviolet experiment: Implications for thermospheric modeling

Solomon, SC; Bailey, SM; Eparvier, FG; Gladstone, GR; Paxton, LJ; Woods, TN;

Published by:       Published on:

YEAR: 2003     DOI:

The Response of Thermospheric Nitric Oxide to the Geomagnetic Storm of April 2002

Bailey, SM; Crowley, G; Solomon, SC; Baker, DN;

Published by:       Published on:

YEAR: 2002     DOI:

New Solar Extreme-Ultraviolet and Soft X-ray Measurements: Model Comparisons with Thermosphere and Ionosphere Observations

Solomon, SC; Bailey, SM; Christensen, AB; Eparvier, FG; Gladstone, GR; Paxton, LJ; Wolven, BC; Woods, TN;

Published by:       Published on:

YEAR: 2002     DOI: