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

2015 ◽  
Vol 8 (2) ◽  
pp. 1615-1627
Author(s):  
J. Y. Liu ◽  
C. Y. Lin ◽  
H. F. Tsai
Keyword(s):  
Electron Density ◽  
Density Profile ◽  
Radio Occultation ◽  
System Simulation ◽  
Electron Density Profile ◽  
Abel Inversion ◽  
Simulation Experiments ◽  
Density Profiles ◽  
Satellite Altitude ◽  
Electron Density Profiles

Abstract. The FORMOSAT-7/COSMIC-2 (F7/C2) will ultimately place 12 satellites in orbit with two launches with 24° inclination and 520 km altitude in 2016 and with 72° inclination and 800 km altitude in 2019. In this study, 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 packing orbit 500 km altitude and mission orbit 800 km altitude, as well as observing system simulation experiments (OSSE). The electron density derived from 500 and 800 km satellite altitude of the F3/C observation and the OSSE confirm that the standard Abel inversion can correctly derive the electron density profile.

scholarly journals Accuracy assessment of the quiet-time ionospheric F2 peak parameters as derived from COSMIC-2 multi-GNSS radio occultation measurements

2021 ◽  
Vol 11 ◽  
pp. 18
Author(s):  
Iurii Cherniak ◽  
Irina Zakharenkova ◽  
John Braun ◽  
Qian Wu ◽  
Nicholas Pedatella ◽  
...  
Keyword(s):  
Electron Density ◽  
Radio Occultation ◽  
Electron Density Profile ◽  
Equatorial Region ◽  
Quality Data ◽  
Quiet Time ◽  
Density Profiles ◽  
Middle Latitudes ◽  
Receiver System ◽  
Electron Density Profiles

The Constellation Observing System for Meteorology, Ionosphere, and Climate 2 (COSMIC-2) mission was launched into a low-inclination (24°) orbit on June 25, 2019. Six satellites, each with an advanced Tri-GNSS Radio-Occultation Receiver System (TGRS), provide a global and uniform data coverage of the equatorial region with several thousand electron density profiles daily. The COSMIC-2 electron density profiles, and specifically the derived ionospheric F2 peak parameters, are properly validated in this study with reliable “truth” observations. For this purpose, we used manually scaled ionograms from 29 ground-based ionosondes located globally at low and middle latitudes. For this validation campaign, we considered only geomagnetically quiet conditions in order to establish benchmark level of the new mission’s ionospheric observation quality and to evaluate the operational capability of the COSMIC-2 Radio Occultation (RO) payload at the background of normal day-to-day variability of the ionosphere. For reliable colocations between two independent techniques, we selected only COSMIC-2 RO profiles whose F2 peak point coordinates were within 5° of the closest ionosonde. Our comparison of the ionospheric F2 peak height (hmF2) derived from COSMIC-2 RO and ground-based ionosonde measurements showed a very good agreement, with a mean of ~5 and ~2 km at low and middle latitudes, respectively, while RMS error was of ~23 and ~14 km, respectively. That range corresponds to a deviation of only 6–9% from the reference, ionosonde observations. Examination of representative collocation events with multiple (2–5) simultaneous RO tracks near the same ionosonde with different RO geometry, multi-satellite and multi-GNSS combination give us observational evidence that COSMIC-2 RO-based EDPs derived from GPS and GLONAS links show good self-consistency in terms of the ionospheric F2 peak values and electron density profile shape. We can conclude that COSMIC-2 provides high quality data for specification the ionospheric electron density at the F2 peak region.

scholarly journals On the determination of ionospheric electron density profiles using multi-frequency riometry

2021 ◽  
Author(s):  
Derek McKay ◽  
Juha Vierinen ◽  
Antti Kero ◽  
Noora Partamies
Keyword(s):  
Radio Wave ◽  
Electron Density ◽  
Density Profile ◽  
Electron Density Profile ◽  
Cosmic Radio ◽  
Density Profiles ◽  
Wave Absorption ◽  
Altitude Profile ◽  
Radio Wave Absorption ◽  
Electron Density Profiles

Abstract. Radio wave absorption in the ionosphere is a function of electron density, collision frequency, radio wave polarisation, magnetic field and radio wave frequency. Several studies have used multi-frequency measurements of cosmic radio noise absorption to determine electron density profiles. Using the framework of statistical inverse problems, we investigated if an electron density altitude profile can be determined by using multi-frequency, dual-polarisation measurements. It was found that the altitude profile cannot be uniquely determined from a complete measurement of radio wave absorption for all frequencies and two polarisation modes. This implies that accurate electron density profile measurements cannot be ascertained using multi-frequency riometer data alone, but that the reconstruction requires a strong additional a priori assumption of the electron density profile, such as a parameterised model for the ionisation source. Nevertheless, the spectral index of the absorption could be used to determine if there is a significant component of hard precipitation that ionises the lower part of the D region, but it is not possible to infer the altitude distribution uniquely with this technique alone.

scholarly journals On the possible use of radio occultation middle latitude electron density profiles to retrieve thermospheric parameters

2014 ◽  
Vol 4 ◽  
pp. A12 ◽  
Author(s):  
Andrei V. Mikhailov ◽  
Anna Belehaki ◽  
Loredanna Perrone ◽  
Bruno Zolesi ◽  
Ioanna Tsagouri
Keyword(s):  
Electron Density ◽  
Radio Occultation ◽  
Middle Latitude ◽  
Density Profiles ◽  
Electron Density Profiles

scholarly journals Comparison of ionospheric radio occultation CHAMP data with IRI 2001

2005 ◽  
Vol 2 ◽  
pp. 275-279 ◽  
Author(s):  
N. Jakowski ◽  
K. Tsybulya
Keyword(s):  
Electron Density ◽  
Radio Occultation ◽  
Satellite Orbit ◽  
High Solar Activity ◽  
Satellite Mission ◽  
Density Profiles ◽  
Champ Satellite ◽  
Ionospheric Models ◽  
Routine Basis ◽  
Electron Density Profiles

Abstract. GPS radio occultation measurements on board low Earth orbiting satellites can provide vertical electron density profiles of the ionosphere from satellite orbit heights down to the bottomside. Ionospheric radio occultation (IRO) measurements carried out onboard the German CHAMP satellite mission since 11 April 2001 were used to derive vertical electron density profiles (EDP’s) on a routine basis. About 150 vertical electron density profiles may be retrieved per day thus providing a huge data basis for testing and developing ionospheric models. Although the validation of the EDP retrievals is not yet completed, the paper addresses a systematic comparison of about 78 000 electron density profiles derived from CHAMP IRO data with the International Reference Ionosphere (IRI 2001). The results are discussed for quite different geophysical conditions, e.g. as a function of latitude, local time and geomagnetic activity. The comparison of IRO data with corresponding IRI data indicates that IRI generally overestimates the upper part of the ionosphere whereas it underestimates the lower part of the ionosphere under high solar activity conditions. In a first order correction this systematic deviation could be compensated by introducing a height dependence correction factor in IRI profiling.

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