The 30 cm radio flux as a solar proxy for thermosphere density modelling

Wit, T. Dudok de; Bruinsma, Sean

doi:10.1051/swsc/2017008

Cited by 24 publications

(22 citation statements)

References 31 publications

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“…Solar radio flux measurements can serve as indicators of solar activity and proxies for ultraviolet emissions. As described by White () and Dudok de Wit and Bruinsma (, and references therein), these emissions are due to a combination of thermal bremsstrahlung and gyroresonance emissions in the chromosphere and the corona. The variability of radio emissions depends on both the source location in the solar atmosphere and the transmissivity of the corona.…”

Section: Revised Compositementioning

confidence: 99%

“…The variability of radio emissions depends on both the source location in the solar atmosphere and the transmissivity of the corona. Solar emissions near 10.7‐cm range have similar variability to the extreme ultraviolet emissions (10–120 nm), while emissions in the 20‐ to 30‐cm range correlate better with longer wavelength emissions from bright ultraviolet features from the chromosphere such as plages and faculae and so are better correlated to Lyman α (Dudok de Wit et al, ; Dudok de Wit & Bruinsma, ).…”

Section: Revised Compositementioning

confidence: 99%

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An Improved Lyman‐Alpha Composite

Machol

Snow

Woodraska

et al. 2019

Earth and Space Science

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The hydrogen Lyman-alpha (Lyman α) line at 121.56 nm is the strongest solar vacuum ultraviolet emission line. Especially because of the impacts on planetary atmospheres, long-term data sets of Lyman α are important for understanding solar and atmospheric processes. A revised composite data set of daily Lyman α values beginning in 1947 is constructed using measurements of Lyman α from Atmospheric Explorer E, Solar Mesospheric Explorer, Upper Atmosphere Research Satellite, and Solar Radiation and Climate Experiment. Gaps are filled using proxy models based on the Magnesium II index and the 10.7-and 30-cm solar radio fluxes (F10.7 and F30).Plain Language Summary When ultraviolet light from the Sun is absorbed in the Earth's upper atmosphere above 70 km, it can impact radio communications and satellite orbits. The brightest solar wavelength in the ultraviolet is called the Lyman-alpha line and is emitted by hydrogen in the Sun's atmosphere. Because ultraviolet light is absorbed by the Earth's atmosphere, measurements of the Lyman-alpha line must be made by satellites which are above most the atmosphere. This paper is about the development of a set of daily measurements of Lyman-alpha brightness (irradiance) from 1947 through the present time. This data set will be used to validate other solar irradiance data, models of the Sun's variable intensity, and models of terrestrial atmospheric processes.

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Section: Revised Compositementioning

confidence: 99%

Section: Revised Compositementioning

confidence: 99%

An Improved Lyman‐Alpha Composite

Machol

Snow

Woodraska

et al. 2019

Earth and Space Science

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“…DTM2013 is one of the most commonly used empirical TMD models representing the statistical average status of the atmosphere in the altitude range of 120-1,500 km (Bruinsma, 2015). Based on the spherical harmonic expansion technique, the DTM-2013 model outputs the atmospheric neutral temperature and mass density along with the concentrations of atmospheric components including N 2 , O 2 , He, O, and H. The inputs of DTM2013 include the day of the year (DOY), local time, geodetic coordinates, and the F 10.7 and K p indices.…”

Section: Dtm2013mentioning

confidence: 99%

“…Intradiurnal variations have been considered in many popular empirical TMD models, for example, the DTM-class models (Berger et al, 1998;Bruinsma et al, 2003;Bruinsma, 2015). Analogous to equation (5), first three intradiurnal TMD variations at given location can be expressed as a function of LT (or UT):…”

Section: Intradiurnalmentioning

confidence: 99%

“…Empirical thermospheric mass density (TMD) models can be used for atmospheric drag calculations, for example, NRLMSISE-00 (Naval Research Laboratory Mass Spectrometer Incoherent Scatter Radar Series) (Picone et al, 2002), JB2008 (Jacchia-Bowman) (Bowman et al, 2008), and DTM2013 (Drag Temperature Model) (Bruinsma, 2015). Accurate TMD prediction is critical in the tracking and collision avoidance of LEO satellites.…”

Section: Introductionmentioning

confidence: 99%

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Impact of Thermospheric Mass Density on the Orbit Prediction of LEO Satellites

et al. 2020

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Many thermospheric mass density (TMD) variations have been recognized in observationsand physical simulations; however, their impact on the low-Earth-orbit satellites has not been fully evaluated. The present study investigates the quantitative impact of periodic spatiotemporal TMD variations modulated by the empirical DTM2013 model. Also considered are two small-scale variations, that is, the equatorial mass anomaly and the midnight density maximum, which are reproduced by the Thermosphere-Ionosphere-Electrodynamics General Circulation Model. This investigation is performed through a 1-day orbit prediction (OP) simulation for a 400-km circular orbit. The results show that the impact of TMD variations during solar maximum is 1 order of magnitude larger than that during solar minimum. The dominant impact has been found in the along-track direction. Semiannual and semidiurnal variations in TMD exert the most significant impact on OP among the intra-annual and intradiurnal variations, respectively. The zero mean periodic variations in TMD may not significantly affect the predicted orbit but increase the orbital uncertainty if their periods are shorter than the time span of OP. Additionally, the equatorial mass anomaly creates a mean orbit difference of 50 m (5 m) with a standard deviation of 30 m (3 m) in 1-day OP during high (low) solar activity. The midnight density maximum exhibits a stronger impact in the order of 150 ± 30 and 15 ± 6 m during solar maximum and solar minimum, respectively. This study makes clear that careful selection of TMD variations is of great importance to balance the trade-off between efficiency and accuracy in OP problems.where ⃗ v is the velocity of the satellite and ⃗ v r is the relative velocity of the satellite with respect to the wind ⃗ v w . In the orbit prediction (OP) simulation performed in this study, these equations are evaluated in the Earth-centered inertial frame.Empirical thermospheric mass density (TMD) models can be used for atmospheric drag calculations, for example, NRLMSISE-00 (Naval Research Laboratory Mass Spectrometer Incoherent Scatter Radar Series) (Picone et al., 2002), JB2008 (Jacchia-Bowman) (Bowman et al., 2008), and DTM2013 (Drag Temperature Model) (Bruinsma, 2015). Accurate TMD prediction is critical in the tracking and collision avoidance of LEO satellites. The error of empirical TMD models is one of the largest sources of uncertainty in OP for LEO

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EUV Irradiance Inputs to Thermospheric Density Models: Open Issues and Path Forward

Vourlidas

Bruinsma²

2018

Space Weather

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One of the objectives of the NASA Living With a Star Institute on “Nowcasting of Atmospheric Drag for low Earth orbit (LEO) Spacecraft” was to investigate whether and how to increase the accuracy of atmospheric drag models by improving the quality of the solar forcing inputs, namely, extreme ultraviolet (EUV) irradiance information. In this focused review, we examine the status of and issues with EUV measurements and proxies, discuss recent promising developments, and suggest a number of ways to improve the reliability, availability, and forecast accuracy of EUV measurements in the next solar cycle.

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The 30 cm radio flux as a solar proxy for thermosphere density modelling

Cited by 24 publications

References 31 publications

An Improved Lyman‐Alpha Composite

An Improved Lyman‐Alpha Composite

Impact of Thermospheric Mass Density on the Orbit Prediction of LEO Satellites

EUV Irradiance Inputs to Thermospheric Density Models: Open Issues and Path Forward

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