Comparison of CSES ionospheric RO data with COSMIC measurements

Abstract. CSES (China Seismo-Electromagnetic Satellite) is a newly launched electric-magnetic satellite in China. A GNSS occultation receiver (GOR) is installed on the satellite to retrieve electron density related parameters. In order to validate the radio occultation (RO) data from the GOR on board CSES, a comparison between CSES RO and the co-located COSMIC RO data is conducted to check the consistency and reliability of the CSES RO data using measurements from 12 February 2018 to 31 March 2019. CSES RO peak values (NmF2), peak heights (hmF2), and electron density profiles (EPDs) are compared with corresponding COSMIC measurements in this study. The results show that (1) NmF2 between CSES and COSMIC is in extremely good agreement, with a correlation coefficient of 0.9898. The near-zero bias between the two sets is 0.005363×105 cm−3 with a RMSE of 0.3638×105 cm−3, and the relative bias is 1.97 % with a relative RMSE of 16.17 %, which are in accordance with previous studies according to error propagation rules. (2) hmF2 between the two missions is also in very good agreement with a correlation coefficient of 0.9385; the mean difference between the two sets is 0.59 km with a RMSE of 12.28 km, which is within the error limits of previous studies. (3) Co-located EDPs between the two sets are generally in good agreement, but with a better agreement for data above 200 km than those below this altitude. Data at the peak height ranges show the best agreement, and then data above the peak regions; data below the peak regions, especially at the altitude of about the E layer, show relatively large fluctuations. It is concluded that CSES RO data are in good agreement with COSMIC measurements, and the CSES RO data are applicable for most ionosphere-related studies considering the wide acceptance and application of COSMIC RO measurements. However, particular attention should be paid to EDP data below peak regions in application as data at the bottom side of the profiles are less reliable than that at the peak and topside regions.

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Comparison of CSES ionospheric RO data with COSMIC measurements

10.5194/angeo-2019-76 ◽

2019 ◽

Author(s):

Xiuying Wang ◽

Wanli Cheng ◽

Zihan Zhou ◽

Song Xu ◽

Dehe Yang ◽

...

Keyword(s):

Correlation Coefficient ◽

Electron Density ◽

Peak Height ◽

Zero Bias ◽

Density Profiles ◽

Large Fluctuations ◽

The Mean ◽

Electron Density Profiles ◽

Propagation Rules ◽

Good Agreement

Abstract. CSES is a newly launched electric-magnetic satellite in China; its main scientific objective is to monitor earthquake related disturbances in ionosphere. A GNSS occultation receiver (GOR) is installed on the satellite to inverse electron density related parameters. In order to validate the radio occultation (RO) data from GOR onboard CSES, a comparison between CSES RO and the co-located COSMIC RO data is conducted to check the consistency and reliability of the CSES RO data using measurements from February 12, 2018 to March 31, 2019. CSES RO peak values (NmF2), peak heights (hmF2), and electron density profiles (EPDs) are compared with corresponding COSMIC measurements in this study. The results show that: (1) NmF2s between CSES and COSMIC are in extremely good agreement with a correlation coefficient of 0.9891. The near zero bias between the two sets is 0.01235 × 105/cm3 with a RMSE of 0.3680 × 105/cm3; and the relative bias is 2.14 % with a relative RMSE of 16.40%, which are in accordance with previous studies according to error propagation rules. (2) hmF2s between the two missions are also in very good agreement with a correlation coefficient of 0.9379; the mean difference between the two sets is 0.73 km with a RMSE of 13.02 km, which is within the error limits of previous studies; (3) Co-located EDPs between the two sets are generally in good agreements, but with a better agreement for data above 200 km than that below this altitude. Data at the peak height ranges show the best agreement, and then data above the peak regions; data below the peak regions, especially at the altitude of about the E layer, show relatively large fluctuations. It is concluded that CSES RO data are in good agreement with COSMIC measurements, and the CSES RO data are applicable for most ionospheric-related studies. However, particular attention should be paid to EDP data below peak regions in application.

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

Atmospheric Measurement Techniques ◽

10.5194/amt-8-3069-2015 ◽

2015 ◽

Vol 8 (8) ◽

pp. 3069-3074 ◽

Cited By ~ 2

Author(s):

J. Y. Liu ◽

C. Y. Lin ◽

H. F. Tsai

Keyword(s):

Electron Density ◽

Simulation Experiment ◽

Three Dimensional ◽

Peak Height ◽

Density Structure ◽

Density Profiles ◽

Structure And Dynamics ◽

Parking Orbit ◽

Electron Density Profiles ◽

Observing System Simulation Experiment

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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Regional representation of F2 Chapman parameters based on electron density profiles

Annales Geophysicae ◽

10.5194/angeo-31-2215-2013 ◽

2013 ◽

Vol 31 (12) ◽

pp. 2215-2227 ◽

Cited By ~ 16

Author(s):

M. Limberger ◽

W. Liang ◽

M. Schmidt ◽

D. Dettmering ◽

U. Hugentobler

Keyword(s):

Electron Density ◽

Real Data ◽

Peak Height ◽

Electron Content ◽

Density Profiles ◽

Total Electron ◽

Maximum Electron Density ◽

Spatio Temporal ◽

Electron Density Profiles ◽

Model Approach

Abstract. Understanding the physical processes within the ionosphere is a key requirement to improve and extend ionospheric modeling approaches. The determination of meaningful parameters to describe the vertical electron density distribution and how they are influenced by the solar activity is an important topic in ionospheric research. In this regard, the F2 layer of the ionosphere plays a key role as it contains the highest concentration of electrons and ions. In this contribution, the maximum electron density NmF2, peak height hmF2 and scale height HF2 of the F2 layer are determined by employing a model approach for regional applications realized by the combination of endpoint-interpolating polynomial B splines with an adapted physics-motivated Chapman layer. For this purpose, electron density profiles derived from ionospheric GPS radio occultation measurements of the satellite missions FORMOSAT-3/COSMIC, GRACE and CHAMP have been successfully exploited. Profiles contain electron density observations at discrete spots, in contrast to the commonly used integrated total electron content from GNSS, and therefore are highly sensitive to obtaining the required information of the vertical electron density structure. The spatio-temporal availability of profiles is indeed rather sparse, but the model approach meets all requirements to combine observation techniques implicating the mutual support of the measurements concerning accuracy, sensitivity and data resolution. For the model initialization and to bridge observation gaps, the International Reference Ionosphere 2007 is applied. Validations by means of simulations and selected real data scenarios show that this model approach has significant potential and the ability to yield reliable results.

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Thickness parameters in the empirical modeling of bottomside electron density profiles

Advances in Space Research ◽

10.1016/j.asr.2020.12.037 ◽

2021 ◽

Author(s):

S.M. Radicella ◽

K. Alazo-Cuartas ◽

Y. Migoya-Orué ◽

A. Kashcheyev

Keyword(s):

Electron Density ◽

Empirical Modeling ◽

Density Profiles ◽

Electron Density Profiles

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Different long-term trends of the oxygen red 630.0 nm line nightglow intensity as the result of lowering the ionosphere F2 layer

Annales Geophysicae ◽

10.5194/angeo-26-2069-2008 ◽

2008 ◽

Vol 26 (8) ◽

pp. 2069-2080 ◽

Cited By ~ 5

Author(s):

N. B. Gudadze ◽

G. G. Didebulidze ◽

L. N. Lomidze ◽

G. Sh. Javakhishvili ◽

M. A. Marsagishvili ◽

...

Keyword(s):

Electron Density ◽

Line Intensity ◽

Peak Height ◽

Height Distribution ◽

Theoretical Simulation ◽

Type Layer ◽

Long Term Trends ◽

The Mean ◽

Long Term Trend

Abstract. Long-term observations of total nightglow intensity of the atomic oxygen red 630.0 nm line at Abastumani (41.75° N, 42.82° E) in 1957–1993 and measurements of the ionosphere F2 layer parameters from the Tbilisi ionosphere station (41.65° N, 44.75° E) in 1963–1986 have been analyzed. It is shown that a decrease in the long-term trend of the mean annual red 630.0 nm line intensity from the pre-midnight value (+0.770±1.045 R/year) to its minimum negative value (−1.080±0.670 R/year) at the midnight/after midnight is a possible result of the observed lowering of the peak height of the ionosphere F2 layer electron density hmF2 (−0.455±0.343 km/year). A theoretical simulation is carried out using a simple Chapman-type layer (damping in time) for the height distribution of the F2 layer electron density. The estimated values of the lowering in the hmF2, the increase in the red line intensity at pre-midnight and its decrease at midnight/after midnight are close to their observational ones, when a negative trend in the total neutral density of the upper atmosphere and an increase in the mean northward wind (or its possible consequence – a decrease in the southward one) are assumed.

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