A new strategy for ionospheric remote sensing using the 130.4/135.6 nm airglow intensity ratios

Yin, XiaoHan; Qin, JianQi; Paxton, and Larry J.

doi:10.26464/epp2023042

Cited by 4 publications

(4 citation statements)

References 23 publications

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“…Moreover, owing to the presence of two oxygen populations with distinct kinetic energies in the Martian exosphere, a two‐population radiative transfer model is needed (Chaufray et al., 2016). For this purpose we modify the one‐population radiative transfer model that was recently developed by Qin and Harding (2020) and Qin (2020b) for the studies of the cold oxygen coronae in the terrestrial and the Martian atmospheres (e.g., Qin, 2020a; Qin et al., 2023; Yin et al., 2023). That model was developed based on the Monte Carlo algorithm of Meier and Lee (1982), which uses an angle‐dependent partial frequency redistribution function.…”

Section: Modelsmentioning

confidence: 99%

Mars Hot Oxygen Density and Effective Temperature Derived From the MAVEN IUVS Observations

Qin,

Liu,

2024

JGR Planets

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The escape of hot oxygen atoms from Mars is important for the evolution of the planet's H2O and CO2 inventories. Owing to the lack of data constraints prior to the Mars Atmosphere and Volatile Evolution (MAVEN) mission, previous understanding of this key loss channel of the Mars atmosphere relied mostly on physics‐based models. Using the optical observations from the MAVEN Imaging Ultraviolet Spectrograph (IUVS) during 2014–2018, we perform the first inversion analysis of the coronal scans at 130.4 nm to quantify the density and effective temperature of the Mars hot oxygen corona. Our results indicate that the exobase densities of the hot oxygen atoms are ∼6.3–8.0 × 103 and ∼1.2 × 104 cm−3 during low and moderate solar activities, respectively, which agree well with recent empirical estimates using MAVEN's in situ measurements and, however, are about a factor of two higher than previous model predictions. The effective temperature varies only slightly between ∼4100–4500 K. The temperature and density variations with solar, seasonal, and dust conditions are consistent with previous models. Comparison with inversion results from IUVS limb scans indicates that the cold and the hot oxygen populations dominate below ∼200 and above ∼600 km, respectively, between which the kinetic distribution depends on both populations. Our results demonstrate for the first time the feasibility of extracting information about the Mars hot oxygen corona directly from optical observations, opening up a powerful means for monitoring the Mars oxygen escape on a global scale in future missions.

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Section: Modelsmentioning

confidence: 99%

Mars Hot Oxygen Density and Effective Temperature Derived From the MAVEN IUVS Observations

Qin,

Liu,

2024

JGR Planets

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“…For the aforementioned source mechanisms that are considered, the initial volume emission rate, 4πɛ 135.6 , at a given altitude in the nighttime ionosphere can be calculated as (Qin et al, 2015;Yin et al, 2023):…”

Section: Modelsmentioning

confidence: 99%

“…First-principles methods have been developed by Meier (2021) for the retrieval of the daytime column O/N 2 density ratios from the 135.6/LBH intensity ratios and by Yin et al (2023) for the retrieval of the nighttime ionospheric peak height (h m F 2 ) from the 130.4/135.6 nm intensity ratios. Similarly, we can develop a first-principles method for the retrieval of the n m F 2 from the disk observations of the OI 135.6 nm emission.…”

Section: Modelsmentioning

confidence: 99%

Inferring the Ionospheric State With the Far Ultraviolet Imager on the Fengyun‐4C Geostationary Satellite: Retrieval Algorithm and Verification

Qin,

Liu,

Yin

et al. 2023

Earth and Space Science

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The Multiband Ultraviolet Spectrum Imager (MUSI) is an optical remote sensing instrument scheduled to launch on the Fengyun‐4C meteorological satellite in 2024. MUSI is designed to measure the airglow emissions between ∼120 and 160 nm above the East Asia and Pacific region from a geostationary orbit to infer ionospheric parameters. Here we develop a lookup‐table algorithm for retrieving the peak electron density (nmF2) and the Total Electron Content (TEC) from nighttime observations of the OI 135.6 nm emission. The algorithm takes into account the north‐south asymmetry of the equatorial ionization anomaly and the atmospheric variations with solar activity and local time. Analysis of synthetic observations shows that the assumptions made in the algorithm only lead to ∼2%–4% uncertainties in the retrievals under the modeled ionospheric conditions. The algorithm is verified by retrieving nmF2 and TEC from the Global‐Scale Observations of the Limb and Disk (GOLD) mission and comparing with coincided radio measurements. The comparison indicates almost negligible systematic differences (typically less than ∼3%) between the GOLD and the ionosonde nmF2, which are within the error limit of the GOLD retrievals. The accuracy of the GOLD TEC retrievals is shown to be comparable to (or in some sense even better than) that of the measurements from the Global Navigation Satellite System. Several simplified yet robust retrieval methods are also developed, which can be readily implemented for both existing and upcoming missions. Our results promote far ultraviolet (FUV) remote sensing to be a key technology for accurate determination of the ionospheric state.

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“…Solar VUV radiation can be separated into X-ray ultraviolet (XUV, 0.1-10 nm), extreme ultraviolet (EUV, 10-120 nm), and farultraviolet (FUV, 120-200 nm) radiation, which can vary drastically by 1 or more orders of magnitude on timescales of minutes (e.g., due to eruptive solar flares), days (e.g., due to solar rotation with periods of ∼27 days), and years (e.g., due to solar cycle variations with periods of ∼11 yr), as well as on geometric scales (e.g., due to the varying distances of the Sun to Earth, Mars, and other planets) (Woods & Eparvier 2006;Woods 2008). Accurate estimation of solar VUV irradiance at various locations and times in the solar system is of critical importance for the study of planetary aeronomy, such as for the study of thermospheric and ionospheric variations (Haider et al 2002;Liu et al 2011;Zhang et al 2015), for the development of global circulation models (Solomon & Qian 2005;Qian et al 2008;Deng et al 2012), for the modeling of airglow emissions (Meier et al 2015;Solomon 2017;Qin 2020Qin , 2021Wan et al 2022;Qin et al 2023;Yin et al 2023;Qin et al 2024), for the prediction of space weather effects (Lathuillere et al 2002;Lilensten et al 2008), and for the study of climate evolution (Lilensten et al 2008;Persson et al 2020).…”

Section: Introductionmentioning

confidence: 99%

A Comparative Analysis of the Solar Ultraviolet Spectral Irradiance Measured from Earth and Mars: Toward a General Empirical Model for the Study of Planetary Aeronomy

Xu,

Qin

2024

ApJS

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Accurate estimation of the solar vacuum ultraviolet irradiance between 0.1 and 200 nm is critical for the study of planetary aeronomy. Previous empirical models have relied on a limited number of reference spectra, or on multiple data sets with various degrees of uncertainty, and on an empirical selection of solar proxies. Here we propose a novel method for the development of empirical models based on Fourier transform and least-squares fitting of the long-term measurements from the Solar EUV Experiment on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics mission. A Fourier transform analysis is performed to examine a large number of solar proxies, which reveals that the solar radio flux at 10.7 cm and the solar Lyα flux at 121.6 nm are better proxies for solar irradiance below and above ∼120 nm, respectively. Using these two proxies, a nonlinear empirical model is developed through Fourier transform and least-squares fitting of solar irradiance measurements, which can reproduce the solar irradiance with uncertainties of only ∼1%–2% above ∼120 nm, ∼2%–4% within ∼45–120 nm, and ∼4%–8% below ∼45 nm. Comparison with measurements from the Extreme Ultraviolet Monitor on the Mars Atmosphere and Volatile Evolution mission indicates that the solar irradiance at Mars can be predicted with uncertainties of less than ∼8% by geometric extrapolation of the solar irradiance measured from Earth, provided that the measurements from Earth can be calibrated accurately. Our study provides a general method for the development of empirical models using long-term observations in planetary aeronomy.

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A new strategy for ionospheric remote sensing using the 130.4/135.6 nm airglow intensity ratios

Cited by 4 publications

References 23 publications

Mars Hot Oxygen Density and Effective Temperature Derived From the MAVEN IUVS Observations

Mars Hot Oxygen Density and Effective Temperature Derived From the MAVEN IUVS Observations

Inferring the Ionospheric State With the Far Ultraviolet Imager on the Fengyun‐4C Geostationary Satellite: Retrieval Algorithm and Verification

A Comparative Analysis of the Solar Ultraviolet Spectral Irradiance Measured from Earth and Mars: Toward a General Empirical Model for the Study of Planetary Aeronomy

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