Artificial plasma cave in the low‐latitude ionosphere results from the radio occultation inversion of the FORMOSAT‐3/COSMIC

Liu, J. Y.; Lin, Chia Ying; Lin, Chien Hung; Tsai, Heng; Solomon, Stanley C.; Sun, Yihe; Lee, I. T.; Schreiner, William S.; Kuo, Ying Hwa

doi:10.1029/2009ja015079

Cited by 75 publications

(95 citation statements)

References 22 publications

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“…The RMS increases with increasing altitude over 300 km and reaches about 45% around 500 km. Below 250 km, the estimation error of the N e profile is very large due to the fundamental issue of the Abel inversion (Liu et al, 2010), and the data used in the construction have inherent errors. Such errors might produce a high dispersion and show high RMS.…”

Section: Resultsmentioning

confidence: 99%

“…Observed N e profiles are accumulated under geomagnetically quiet conditions (K p < 4) from 29 June, 2006, to 17 October, 2009. Since N e profiles are calculated using the Abel inversion with an assumption of spherical symmetry, the errors mainly appear below 250 km around the equatorial ionization anomaly region (Liu et al, 2010), which leads to a negative value of the N e profile in some cases. Therefore, observed N e profiles showing a negative value are not used in the model construction.…”

Section: Methodology Of the Construction Of An Empirical Modelmentioning

confidence: 99%

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A comparison of a model using the FORMOSAT-3/COSMIC data with the IRI model

2012

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In this study, an empirical model constructed using data of FORMOSAT3/COSMIC (F3/C) from 29 June, 2006, to 17 October, 2009, retrieves altitude profiles of electron density (N e ). The model derives global N e profiles from 150 to 590 km altitude as functions of the solar EUV flux, day of year, local time and location under geomagnetically quiet conditions (K p < 4). N e profiles derived by the model are further compared with those of the International Reference Ionosphere (IRI). Results show that the F 2 peak altitude h m F 2 and the electron density N m F 2 , as well as the electron density above, derived by the model are lower than those of the IRI model. The F3/C model reproduces observations of F3/C well at 410-km altitude while the IRI model overestimates them. The overestimation of the IRI model becomes large with decrease of EUV flux. It is found that the topside vertical scale height of the F3/C model shows high values not only magnetic dip equator but also middle latitude. The results differ significantly from those of IRI, but agree with those observed by topside sounders, Alouette and ISIS satellites.

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Section: Resultsmentioning

confidence: 99%

Section: Methodology Of the Construction Of An Empirical Modelmentioning

confidence: 99%

A comparison of a model using the FORMOSAT-3/COSMIC data with the IRI model

2012

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“…The quality of COSMIC occultation measurements was validated by comparing the data of incoherent scatter radar with those of ionosondes (Lei et al, 2007;Kelley et al, 2009;Sun et al, 2014), which revealed good agreement. Liu et al (2010) and Yue et al (2010) showed that the Abel retrieval provided a accurate ionospheric NmF2 and F2 layer peak height (HmF2) from radio occultation measurements. Hence, COSMIC is a powerful system for global or regional mapping of the ionospheric NmF2 and slab thickness because of its global coverage and high vertical resolution.…”

Section: Introductionmentioning

confidence: 99%

Climatology of the ionospheric slab thickness along the longitude of 120° E in China and its adjacent region during the solar minimum years of 2007–2009

Huang

Yuan

2015

Ann. Geophys.

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Abstract. The ionospheric slab thickness is defined as the ratio of the total electron content (TEC) to the ionospheric F2 layer peak electron density (NmF2). In this study, the slab thickness is determined by measuring the ionospheric TEC from dual-frequency Global Positioning System (GPS) data and the NmF2 from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC). A statistical analysis of the diurnal, seasonal and spatial variation in the ionospheric slab thickness is presented along the longitude of 120 • E in China and its adjacent region during the recent solar minimum phase (2007)(2008)(2009). The diurnal ratio, defined as the maximum slab thickness to the minimum slab thickness, and the night-to-day ratio, defined as the slab thickness during daytime to the slab thickness during night-time, are both analysed. The results show that the TEC of the northern crest is greater in winter than in summer, whereas NmF2 is greater in summer than in winter. A pronounced peak of slab thickness occurs during the postmidnight (00:00-04:00 LT) period, when the peak electron density is at the lowest level. A large diurnal ratio exists at the equatorial ionization anomaly, and a large night-to-day ratio occurs near the equatorial latitudes and mid-to high latitudes. It is found that the behaviours of the slab thickness and the F2 peak altitude are well correlated at the latitudes of 30-50 • N and during the period of 10:00-16:00 LT. This current study is useful for improvement of the regional model and accurate calculation of the signal delay of radio waves propagating through the ionosphere.

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“…Scientists find that the local spherical symmetry assumption in the standard (Abel) RO inversion processes results in systemic biases, especially the EIA (equatorial ionization anomaly) at low latitudes, where the horizontal gradient is most significant (cf. Liu et al, 2010b). Lei et al (2007) indicated that to conduct the Abel inversion, the electron density at the satellite altitude should be assumed.…”

Section: Introductionmentioning

confidence: 99%

Electron density profiles probed by radio occultation of FORMOSAT-7/COSMIC-2 at 520 and 800 km altitude

2015

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Abstract. The FORMOSAT-7/COSMIC-2 (F7/C2) will ultimately place 12 satellites in orbit with two launches with 24-28.5 • inclination and 520-550 km altitude in 2016 and with 72 • inclination and 720-750 km altitude in 2018. It would be very useful for the community to construct the global three-dimensional electron density structure by simultaneously combining the two launch observations for studying ionospheric structure and dynamics. However, to properly construct the global electron density structure, it is essential to know and evaluate differences between the ionospheric electron densities probed by the two launches. To mimic the F7/C2 observations, we examine the electron density probed at the two satellite altitudes 500 and 800 km by means of FORMOSAT-3/COSMIC (F3/C) observations at the parking orbit 500 km altitude and mission orbit 800 km altitude, as well as a corresponding observing system simulation experiment (OSSE). Observation and OSSE results show that the sounding geometries by satellite orbiting at 500 and 800 km altitudes can cause the overall differences in the electron density, the F2 peak electron density, and the F2 peak height of about 18-24, 12-28 %, and 7-19 km, respectively. Results confirm that the discrepancies mainly result from the sounding geometry and the grid (contour) bias of the electron density.

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Artificial plasma cave in the low‐latitude ionosphere results from the radio occultation inversion of the FORMOSAT‐3/COSMIC

Cited by 75 publications

References 22 publications

A comparison of a model using the FORMOSAT-3/COSMIC data with the IRI model

A comparison of a model using the FORMOSAT-3/COSMIC data with the IRI model

Climatology of the ionospheric slab thickness along the longitude of 120° E in China and its adjacent region during the solar minimum years of 2007–2009

Electron density profiles probed by radio occultation of FORMOSAT-7/COSMIC-2 at 520 and 800 km altitude

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