APOD mission status and preliminary results

Tang, Geshi; Xie, Li; Cao, Jianfeng; Liu, Shushi; Chen, Guangming; Man, Haijun; Zhang, Xiaomin; Shi, Sihan; Ji, Sun; Li, Yongping; Calabia, Andrés

doi:10.1007/s11430-018-9362-6

Cited by 13 publications

(8 citation statements)

References 24 publications

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“…The satellites fly in a near‐polar circular orbit with an inclination of about 97°. After calibrated with the precise orbit determination of drag‐derived density, the standard deviation of the estimated density is about 10% of the background density (Tang et al., 2020). The accuracy of the in‐situ densities can reach the same level compared with representative empirical models, e.g., MSISE00 and JB2008 model (Li et al., 2018).…”

Section: Methodsmentioning

confidence: 99%

“…Since the spectrometer for gas composition was not included as the satellites payloads, the averaged molecular mass has to be computed from empirical models such as MSISE00. The detail data processing scheme has been provided by Li et al (2018) and Tang et al (2020).…”

Section: In-situ Density Data From Space-borne Atmospheric Density De...mentioning

confidence: 99%

“…Basically, the space-borne sensor performs in-situ pressure and temperature estimates along the orbit through voltage observations. The atmosphere mass density (ρ) can be deduced from the following equation: ρ = N a .m 2 , where N a denotes the number density in terms of atmosphere temperature and pressure measurements (Clemmons et al, 2009;Li et al, 2018;Tang et al, 2020), and m 2 is the corresponding averaged molecular mass of the atmosphere. Since the spectrometer for gas composition was not included as the satellites payloads, the averaged molecular mass has to be computed from empirical models such as MSISE00.…”

Section: In-situ Density Data From Space-borne Atmospheric Density De...mentioning

confidence: 99%

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Seasonal Oscillations of Thermosphere Neutral Density at Dusk/Dawn as Measured by Three Satellite Missions

et al. 2022

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The thermosphere undergoes intra-annual oscillations in the mass density, composition and plasma density. The first (12-month period) and second (6-month period) harmonic components of these oscillations are considered as ''annual/semiannual'' or ''seasonal '' variation (Guo et al., 2008;Qian et al., 2009). The global average intra-annual oscillation is characterized by maxima near the equinoxes, a primary minimum spanning the boreal summer months and a secondary minimum spanning the boreal winter months. Ever since the intra-annual variation was first reported by Paetzold and Zschörner (1961) using satellite drag data, the annual and semiannual density oscillations of the thermosphere mass density, have been widely studied through observations and numerical simulations (e.g., Bowman et al., 2008;Fuller-Rowell, 1998;Picone et al., 2002). The amplitude of typical global annual oscillation (residual density relative to the mean density) at 400 km in solar minimum is ∼10% (Emmert & Picone, 2010), while the amplitude of the global semiannual oscillations in thermospheric mass density at 400 km (e.g., Emmert, 2015a;Jones et al., 2017) and ionospheric TEC (e.g., Jones et al., 2017;Lean et al., 2011) are typically ∼15%. The annual oscillation shows a strong hemispherically asymmetric latitude dependence with a higher annual amplitude at high latitudes in the southern hemisphere than that in the northern hemisphere (e.g., Lean et al., 2016;Lei et al., 2012). The neutral density data from satellite missions such as GOCE, the Challenging Minisatellite Payload (CHAMP), Gravity Recovery and Climate Experiment (GRACE) have been used to derive intra-annual variations of the thermosphere (e.g., Guo et al., 2008;Weng et al., 2018). The seasonal variation of thermospheric composition, such as the column density ratio ∑O/N 2 , the ratio of O/ N 2 at single pressure level and carbon dioxide emissions observed by the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) spacecraft (e.g., Weimer et al., 2018;Yu et al., 2020;Yue et al., 2019), and the ∑O/N 2 derived from the NASA Global Observations of Limb and Disk (GOLD) mission (Qian et al., 2022), have also been studied. The seasonal variation also exists in the ionosphere. The intra-annual variations in the ionosphere, such as those in the maximum electron density of the F 2 layer N m F 2 , the F 2 -layer height h m F 2 , and the total electron content were reported (e.g.

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Section: Methodsmentioning

confidence: 99%

Section: In-situ Density Data From Space-borne Atmospheric Density De...mentioning

confidence: 99%

Section: In-situ Density Data From Space-borne Atmospheric Density De...mentioning

confidence: 99%

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Seasonal Oscillations of Thermosphere Neutral Density at Dusk/Dawn as Measured by Three Satellite Missions

et al. 2022

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“…Direct measurements of atmospheric density at high altitudes, especially above 100 km, using sounding rocket methods are difficult because of the short duration of rocket flights and their high cost (Watanabe, 1958). China completed the atmospheric density detection and precise orbit determination (APOD) mission with four CubeSats, which was designed to estimate atmospheric density near orbit using in-situ sounding and precision orbit products and to demonstrate the link between geomagnetic storms and density enhancements (Tang et al, 2020). In order to obtain the spatiotemporal variation characteristics of atmospheric density on a global scale, the remote sensing by satellites is gradually developed.…”

Section: Introductionmentioning

confidence: 99%

Measurement of vertical atmospheric density profile from the X-ray Earth occultation of the Crab Nebula with Insight-HXMT

et al. 2022

Preprint

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Abstract. The X-ray Earth occultation sounding (XEOS) is an emerging method for measuring the neutral density in the lower thermosphere. In this paper, the X-ray Earth occultation (XEO) of the Crab Nebula is investigated by using the Insight-HXMT. The pointing observation data on the 30th September, 2018 recorded by the Low Energy X-ray telescope (LE) of Insight-HXMT are selected and analyzed. The extinction lightcurves and spectra during the X-ray Earth occultation process are extracted. A forward model for the XEO lightcurve is established and the theoretical observational signal for lightcurve is predicted. A Bayesian data analysis method is developed for the XEO lightcurve modeling and the atmospheric density retrieval. The posterior probability distribution of the model parameters is derived through the Markov Chain Monte Carlo (MCMC) algorithm with the NRLMSISE-00 model and the NRLMSIS 2.0 model as basis functions and the best-fit density profiles are retrieved respectively. It is found that in the altitude range of 105–200 km, the retrieved density profile is 88.8 % of the density of NRLMSISE-00 and 109.7 % of the density of NRLMSIS 2.0 by fitting the lightcurve in the energy range of 1.0–2.5 keV based on XEOS method. In the altitude range of 95–125 km, the retrieved density profile is 81.0 % of the density of NRLMSISE-00 and 92.3 % of the density of NRLMSIS 2.0 by fitting the lightcurve in the energy range of 2.5–6.0 keV based on XEOS method. In the altitude range of 85–110 km, the retrieved density profile is 87.7 % of the density of NRLMSISE-00 and 101.4 % of the density of NRLMSIS 2.0 by fitting the lightcurve in the energy range of 6.0–10.0 keV based on XEOS method. The measurements of density profiles are compared with the NRLMSISE-00/NRLMSIS 2.0 model simulations and the previous retrieval results with RXTE satellite. Finally, we find that the retrieved density profile from Insight-HXMT based on the NRLMSISE-00/NRLMSIS 2.0 models is qualitatively consistent with the previous retrieved results from RXTE. This study demonstrate that the XEOS from the X-ray astronomical satellite Insight-HXMT can provide an approach for the study of the upper atmosphere. The Insight-HXMT satellite can join the family of the XEOS. The Insight-HXMT satellite with other X-ray astronomical satellites in orbit can form a space observation network for XEOS in the future.

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“…Direct measurements of atmospheric density at high altitudes, especially above 100 km, using sounding rocket methods are difficult because of the short duration of rocket flights and their high cost (Watanabe, 1958). China completed the atmospheric density detection and precise orbit determination (APOD) mission with four CubeSats, which was designed to estimate atmospheric density below 520 km using in-situ sounding and precision orbit products and to demonstrate the link between geomagnetic storms and density enhancements (Tang et al, 2020). In order to obtain the spatiotemporal variation characteristics of atmospheric density on a global scale, the remote sensing by satellites is gradually developed.…”

Section: Introductionmentioning

confidence: 99%

Measurement of the vertical atmospheric density profile from the X-ray Earth occultation of the Crab Nebula with Insight-HXMT

Yu¹,

Li²,

Li³

et al. 2022

Preprint

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The X-ray Earth occultation sounding (XEOS) is an emerging method for measuring the neutral density in the lower thermosphere. In this paper, the X-ray Earth occultation (XEO) of the Crab Nebula is investigated by using the Hard X-ray Modulation Telescope (Insight-HXMT). The pointing observation data on the 30th September, 2018 recorded by the Low Energy X-ray telescope (LE) of Insight-HXMT are selected and analyzed. The extinction lightcurves and spectra during the X-ray Earth occultation process are extracted. A forward model for the XEO lightcurve is established and the theoretical observational signal for lightcurve is predicted. The atmospheric density model is built with a scale factor to the commonly used MSIS density profile within a certain altitude range. A Bayesian data analysis method is developed for the XEO lightcurve modeling and the atmospheric density retrieval. The posterior probability distribution of the model parameters is derived through the Markov Chain Monte Carlo (MCMC) algorithm with the NRLMSISE-00 model and the NRLMSIS 2.0 model as basis functions and the best-fit density profiles are retrieved respectively. It is found that in the altitude range of 105-200 km, the retrieved density profile is 88.8% of the density of NRLMSISE-00 and 109.7% of the density of NRLMSIS 2.0 by fitting the lightcurve in the energy range of 1.0-2.5 keV based on XEOS method. In the altitude range of 95-125 km, the retrieved density profile is 81.0% of the density of NRLMSISE-00 and 92.3% of the density of NRLMSIS 2.0 by fitting the lightcurve in the energy range of 2.5-6.0 keV based on XEOS method. In the altitude range of 85-110 km, the retrieved density profile is 87.7% of the density of NRLMSISE-00 and 101.4% of the density of NRLMSIS 2.0 by fitting the lightcurve in the energy range of 6.0-10.0 keV based on XEOS method. Goodness-of-fit testing is carried out for the validation of the results.The measurements of density profiles are compared to the NRLMSISE-00/NRLMSIS 2.0 model simulations and the previous retrieval results with NASA's Rossi X-ray Timing Explorer (RXTE) satellite. For further confirmation, we also compare the measured density profile to the ones by a standard spectrum retrieval method with an iterative inversion technique. Finally, we find that the retrieved density profile from Insight-HXMT based on the NRLMSISE-00/NRLMSIS 2.0 models is qualitatively

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APOD mission status and preliminary results

Cited by 13 publications

References 24 publications

Seasonal Oscillations of Thermosphere Neutral Density at Dusk/Dawn as Measured by Three Satellite Missions

Seasonal Oscillations of Thermosphere Neutral Density at Dusk/Dawn as Measured by Three Satellite Missions

Measurement of vertical atmospheric density profile from the X-ray Earth occultation of the Crab Nebula with Insight-HXMT

Measurement of the vertical atmospheric density profile from the X-ray Earth occultation of the Crab Nebula with Insight-HXMT

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