F2-layer Maximum Research Articles

The Impact of Polar Vortex Strength on the Longitudinal Structure of the Noontime Mid-Latitude Ionosphere and Thermosphere

Ground-based ionospheric, CHAMP/STAR, and GOCE satellite neutral density ρ observations under deep solar minimum conditions were used to find whether there is a dependence of longitudinal variations on polar vortex strength. Ionospheric stations at fixed-dipole geomagnetic Φ ≈ 38° and geographic φ ≈ 40°N latitudes located in ‘near-pole’ and ‘far-from-pole’ longitudinal sectors were used in the analysis. No significant longitudinal NmF2 (electron concentration in the F2-layer maximum) dependence on the polar vortex strength was revealed. Geomagnetic control was shown to be responsible for the observed longitudinal NmF2 variations. Satellite-observed longitudinal variations in neutral density did not show any visible reaction to the polar vortex strength. However, the impact of sudden stratospheric warming (SSW) on the upper atmosphere is strong enough to change the neutral density longitudinal distribution. The impact of SSW shows a global occurrence and ‘works’ within 3–5 days in geographic coordinates in the vicinity of the SSW peak. Atomic oxygen values retrieved under ‘strong’ and ‘weak’ polar vortex strengths confirm the results obtained on longitudinal variations in NmF2 and ρ. In conclusion, no visible effects related to ‘strong’ or ‘weak’ polar vortex strengths have been revealed in either NmF2 or satellite neutral density longitudinal variations. Alternatively, such effects may be very small and therefore cannot be confirmed experimentally.

Ionospheric Perturbations after Stromboli Volcano Eruptions

Based on data from ground-based vertical sounding of the ionosphere, we analyze disturbances in the region of the maximum of the ionospheric F2-layer during the period of a strong eruption of the Stromboli volcano (Italy) in the form of two explosions in July and August 2019, as well as after the resumption of volcanic activity on October 9, 2022. As characteristics of the ionospheric response to these events, we research variations in the critical frequency of the F2-layer at the Giebilmann, Rome, and San Vito stations located near (no further than 450 km) the volcano. The measurement results indicate the influence on the ionosphere of atmospheric acoustic-gravity waves generated by volcanic activity and causing the appearance of long-lived disturbances in the ionosphere.

Response of the lower and upper ionosphere after the eruption of Shiveluch volcano on april 10, 2023

The disturbances in the lower ionosphere and in the region of the maximum of the ionospheric F2 layer during the Shiveluch volcanic eruption in April 2023 are analyzed based on data from ground-based magnetometers and GPS radio sounding of the ionosphere. The magnetic stations were located at distances of 455 km (Paratunka) and 752 km (Magadan) from the volcano. The variations in the magnetic field and total electron content of the ionosphere were studied as characteristics of the ionospheric response to this event. An analysis of the measurements showed that the impact on the ionosphere is carried out by seismic Rayleigh waves and atmospheric acoustic-gravity waves generated by volcanic explosions. The energy of several explosions was estimated from the amplitude of the ionospheric signal in the total electron content.

Dependence of annual asymmetry in <i>NmF2</i> on local time

Based on the global empirical model of the F2 layer critical frequency median (Satellite and Digisonde Data Model of the F2 layer, SDMF2), an analysis was made of the properties of diurnal variations in the annual asymmetry in the concentration of the F2 layer maximum NmF2 at different values of the solar activity index F. The AI index, which characterizes the relative difference in NmF2 averaged over all longitudes and latitudes between January and July at a given local time, was used as a parameter of this asymmetry. It was found that the diurnal variations of the AI index are dominated by a semidiurnal mode with maxima in the daytime and at night. The daytime maximum of the AI index is almost independent of the level of solar activity. The nighttime AI maximum decreases with increasing solar activity. For low solar activity, the daytime and nighttime AI maxima almost coincide in amplitude when AI = 16—17%. The difference in the solar radio flux between January and July due to the ellipticity of the Earth’s orbit relative to the Sun makes a significant contribution to the AI index at all hours of the day. On average, it is 3—4% and can reach 5% with low solar activity at night. The difference in the AI index for low and high activity according to the IRI model (with URSI and, especially, CCIR coefficients) is overestimated relative to the SDMF2 model at almost all hours of the day, apparently due to the limited number of experimental data when obtaining the CCIR and URSI coefficients especially over the oceans

Properties of the Variability of the Maximum Density of the F2-Layer over Almaty at Different Levels of Solar and Geomagnetic Activity

The properties of the variability of the maximum density of the F2-layer Nm at different levels ofsolar and geomagnetic activity have been analyzed based on hourly data of the Almaty station (43.2° N, 104° E)for 1958–1988. The standard deviation σ(x) of the fluctuations of Nm relative to the quiet level(x = (Nm/Nm0 – 1) × 100, %) and the average shift of these fluctuations xave are used to characterize thisvariability. In this path, an empirical model of the F2-layer maximum density Nm0 for low geomagnetic activityhas been created. It has been found that the variability of Nm depends weakly on the level of solar activity.The dependence of the variability of Nm on geomagnetic activity is one of the main ones, along with thedependences of this variability on time of day and season. In general, the variance σ2(x) is smaller for quietconditions than for periods of high geomagnetic activity. However, during periods of high geomagnetic activity,a further increase in geomagnetic activity does not lead to an increase in the variance σ2(x). The saturationin the increase in the variance σ2(x) against the background of a continuing increase in geomagnetic activityand the absence of this saturation for the average shift xave seems to be a stable property of the variability ofthe mid-latitude ionosphere during periods of geomagnetic storms. This conclusion is based on an additionalanalysis of ionospheric variability according to data from the Irkutsk and Yamagawa stations, which arelocated about 10 degrees north and south of Almaty station, respectively.

Dependence of the Annual Asymmetry Local Index for the NmF2 Median on Solar Activity

Based on the medians of the F2-layer maximum electron concentration NmF2 for two ionosphericstations, Boulder and Hobart, in 1963–2013, an analysis of the dependence of the annual asymmetry localindex R at noon on solar activity has been performed, where the R index is the January/July ratio of the summaryNmF2 concentration for this pair of stations. Solar activity indices averaged over 81 days are used: Fobs isthe solar radio emission flux at a wavelength of 10.7 cm measured by ground-based radio telescopes and Fadjis the value of Fobs reduced to a fixed distance from the Sun of one astronomical unit. It is found that theregression equations that manifest the NmF2 medians dependence on Fobs make it possible to obtain theannual asymmetry index R for a fixed value of Fobs with allowance for a substitution of Fobs by cFobs in theseregression equations, the c coefficient is equal to 1.03 and 0.97 for January and July, respectively. The c = 1case corresponds to neglecting the annual asymmetry in the Fobs index due to the ellipticity of the Earth’sorbit. For the c = 1 version, the R index increases with a solar activity increase from 1.2 under low activity upto almost 1.4 under high activity. An additional allowance for the annual asymmetry in Fobs leads to anincrease in the R index by approximately 0.1 almost independently of the solar activity level. Apparently, thisconclusion is being drawn for the first time. The Fadj index also makes it possible to obtain a correct estimateof the R index, because the annual asymmetry in the solar radiation flux is indirectly taken into account viathe experimental values of NmF2.

Possibilities of Estimating F2 Layer Peak Plasma Frequency Using HF Radiation from High Apogee Satellites over Arctic Region

Based on the results of mathematical modeling, we consider the possibility to estimate the plasma frequency F2 layer maximum of the polar ionosphere (critical frequency, foF2) using frequency-sweeping radiation from a highly elliptical spacecraft orbit in the Arctic zone. Our modeling concerning the energy problem of radio sensing consisted of analyzing wave field parameters, received field strength, and SNR on two radio paths with the distances 1900 and 2500 km along the earth’s surface, with the satellite height varying from 10,000 to 30,000 km. Radio path orientations were selected to be close to the classical limit cases of radio wave propagation in the anisotropic ionospheric plasma: quasi-longitudinal approximation and, to a large extent, the quasi-transversal one for the quiet midday and midnight conditions. As a result of these simulations and following specific spacecraft conditions, working with an optimal probing signal was proposed for the appropriate emission power for the onboard transmitter. In the inverse problem of radio sounding of an ionized media, common mathematical inaccuracy in foF2 calculated from the transionogram, frequency dependence of the probing signals magneto-ionic group delay, was estimated. Considering and founding a possible realization of the method, physical prerequisites are discussed based on the experimental data of radio waves passing the 16,000 km long radio path for Moscow–Antarctica (UAS Vernadsky).

Thermospheric parameters’ long-term variations over the period including the 24/25 solar cycle minimum. Whether the CO2 increase effects are seen?

The CO2 concentration has been increasing for more than five decades reaching ~29 % at present with respect to the pre-industrial era. The largest CO2 cooling effects in the thermosphere are predicted for solar minimum conditions. A comparison of solar minima in 1954/1964 to the recent one in 2019 was used to check at the quantitative level the theoretical predictions and the validity of the CO2 cooling hypothesis. June monthly median noontime ionospheric observations at Moscow, Rome, and Slough/Chilton were used to infer neutral gas density ρ, exospheric temperature Tex, height of the F2-layer maximum hmF2, and total solar EUV flux for the (1954–2020) period. Solar and geomagnetic activity was shown to explain ~99 % of the whole variability in the retrieved neutral gas density and Tex during the (1958–2020) period resulting in statistically insignificant residual linear trends. A comparison of 1954/1964 to 2019 solar minima does not confirm the theoretically predicted decrease of ~21 % in ρ, ~15 K in Tex, and ~7 km in hmF2 related to a 29 % increase of the CO2 abundance. The main conclusion: despite continuous CO2 increase in the Earth's atmosphere long-term variations of thermospheric parameters are controlled by solar and geomagnetic activity.

Planetary Variations in the Height of the F2-Layer Maximum during Ionospheric Disturbances

Planetary Variations in the Height of the F2-Layer Maximum during Ionospheric Disturbances

Multivariate Analysis on the Ionospheric Responses to Planetary Waves During the 2019 Antarctic SSW Event

AbstractA rare minor sudden stratospheric warming is observed in the Antarctic polar region during September 2019, which results in the enhancement of a westward wavenumber 1 quasi‐6‐day wave (Q6DW) in the mesopause region. The impacts of this Q6DW event to the ionosphere are then comparatively investigated with multiple data sets, including the ground‐based total electron content (TEC) from geostationary BeiDou satellite receivers and F2 layer maximum frequency (foF2) from ionosondes ranging from 20 to 40°N over eastern Asia. Besides, the global TEC maps from the International Global Navigation Satellite Systems Service (IGS) are also utilized to study the longitudinal variations. The ground‐based TEC and foF2 observations clearly shows planetary wave (PW) signals with a similar period as those in the mesosphere, which are further verified to be westward with zonal wavenumber 1 by IGS TEC maps. The ground‐based TEC and foF2 also show that the peak of the ionospheric response is at around 1,200–1,400 LT and 25°N over eastern Asia with maximum amplitudes of ∼9 TECU and ∼1.5 MHz, respectively, which are also well captured by IGS TEC maps. Nevertheless, the wave amplitudes exhibited by ground‐based TEC are 2–3 times larger than that in IGS TEC. Besides, the IGS TEC map shows that the ionospheric oscillations at different longitudes peak in the equatorial ionospheric anomaly crest region at similar solar local time, but with significant variabilities in their amplitude. Our analysis shows that the ground‐based ionospheric observations and IGS TEC maps generally exhibit consistent latitudinal structures on the neutral‐ion coupling through PWs.

Joint Analysis of Anomalies of Different Geophysical Fields, Recorded from Space before Strong Earthquakes in California

Results are presented from using satellite data to study anomalies of different geophysical fields due to the interaction of the lithosphere, atmosphere, and ionosphere. The anomalies are mid- and short-term precursors of strong earthquakes in California that occurred on July 4 and 5, 2019 (M = 6.4 and M = 7.1). Precursory changes in the lithosphere are analyzed using lineament system characteristics obtained by processing satellite imagery (Terra/Aqua satellites and MODIS instrument), along with variations in the Earth’s surface temperature (the Aqua satellite and the AIRS instrument). Fluctuations in the temperature of the near-surface atmospheric layer are studied to detect atmospheric anomalies during preparation of seismic events, as are fluctuations in the air temperature now at an altitude of 1000 hPa and changes in outgoing longwave radiation recorded by the AIRS instrument on the Aqua satellite. Variations in the ionospheric electron density in the F2-layer maximum are studied with GPS data to reveal ionospheric anomalies during the precursors and occurrence of earthquakes. Joint analysis of anomalies in different geophysical fields, identified via satellite monitoring, allow precursory changes in the lithosphere to be detected a month before strong earthquakes. Precursory changes in the atmosphere and ionosphere can be detected 3–6 days and 3–5 or 10 days before earthquakes, respectively.

INVERSION OF BACKSCATTER IONOGRAMS INTO QUASI-PARABOLIC IONOSPHERIC LAYER PARAMETERS

We present an inversion scheme of the backscatter signal leading edge into parameters of the quasi-parabolic electron density profile, which is based on the comparison of experimental and calculated minimum delays of scattered signals with corresponding distance to the skip zone border. Input parameters are frequency dependences of minimum group path of signal propagation, derived from processing and interpreting backscatter ionograms. For a fixed sounding frequency, the ionospheric parameter pair — the critical frequency and height of the F2-layer maximum — is defined as the intersection point of two curves representing solutions of minimization problems for discrepancy functionals of the minimum group path and the range to the skip zone border. Determining the ionospheric parameters by this inversion scheme on the sounding frequency grid allows us to construct a two-dimensional distribution of electron density in the direction of backscatter sounding.

Инверсия ионограмм возвратно-наклонного зондирования в параметры квази-параболического ионосферного слоя

We present an inversion scheme of the backscatter signal leading edge into parameters of the quasi-parabolic electron density profile, which is based on the comparison of experimental and calculated minimum delays of scattered signals with corresponding distance to the skip zone border. Input parameters are frequency dependences of minimum group path of signal propagation, derived from processing and interpreting backscatter ionograms. For a fixed sounding frequency, the ionospheric parameter pair — the critical frequency and height of the F2-layer maximum — is defined as the intersection point of two curves representing solutions of minimization problems for discrepancy functionals of the minimum group path and the range to the skip zone border. Determining the ionospheric parameters by this inversion scheme on the sounding frequency grid allows us to construct a two-dimensional distribution of electron density in the direction of backscatter sounding.

Excitation of Langmuir and Ion–Acoustic Turbulence in the High-Latitude Ionosphere by a High-Power HF Radio Wave Simultaneously Below and Above the F2-Layer Maximum

We present the results of experimental studies of the generation peculiarities and features of the Langmuir and ion–acoustic turbulence in the F region of the high-latitude ionosphere excited by high-power HF O-mode radio waves emitted by the EISCAT/Heating facility (Tromso, Norway) in the direction of the Earth’s magnetic field. The experiment was carried out at frequencies fH close to the fourth gyroharmonic, fH < 4fce, and the cutoff frequency of the F2 layer, foF2 , fH < foF2 < fH+fce/2, where fce is the electron gyrofrequency. By using the EISCAT incoherent scatter radar (930 MHz), a joint analysis of the plasma and ion line spectra simultaneously below and above the F2-layer maximum was performed. The excitation of the HF-induced plasma lines outshifted by 0.35–0.45 MHz from the pump-wave frequency and HF-enhanced ion lines simultaneously below and above the F2-layer maximum was found for the first time. The mechanisms of the pump-wave propagation to altitudes above the F2-layer maximum and a plausible mechanism for the excitation of the instability responsible for the generation of HF-enhanced ion lines and HF-induced plasma lines above the F2-layer maximum are discussed.

Improved IRI-2016 model based on BeiDou GEO TEC ingestion across China

Due to the quasi-invariant orbital locations of the BeiDou geostationary earth orbit (GEO) satellites, the BeiDou GEO total electron content (TEC) is not influenced by the contamination of ionospheric spatial and temporal gradient variations. We ingest BeiDou GEO TEC observations across China into the IRI-2016 model for the first time by developing effective hourly ionospheric global indices (IG), which were estimated based on the assumption that BeiDou GEO TEC is equal to the updated IRI TEC for the given location and time. When the retrieved hourly IG indices are used to drive the IRI-2016 model, the resulting near real-time ionospheric parameters are externally evaluated by other data sources, including (1) the Center for Orbit Determination of Europe (CODE) Global Ionosphere Maps (GIM) TEC products and extra BeiDou GEO TEC, (2) Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) electron density (Ne) profiles and F2 layer maximum electron density (NmF2) and (3) ionosonde Ne profiles and critical frequency (foF2) observations under both geomagnetic quiet and active conditions. The validation results show that the proposed ingestion technique successfully pushes the standard IRI model toward being usable for near real-time weather predictions. Moreover, a general improvement in accuracy of the updated IRI model regarding TEC, Ne, NmF2 and foF2 can be obtained during September 2–12, 2017, as expected: (1) updated TEC BIAS/RMS reduces from − 3.20/4.86 to − 0.10/1.86 TECU compared to CODE GIM, and from − 2.84/4.63 TECU to 0.75/1.05 TECU compared to external BeiDou GEO TEC. (2) Topside electron density from updated IRI matches better with that from the COSMIC than the standard IRI; the STD/RMS/BIAS versus COSMIC NmF2 decreases from 2.195/2.313/0.845 to 2.083/2.043/− 0.092 (unit: 105 cm−3). (3) Bottomside electron density from the updated IRI is much closer to the ionosonde measurement than the standard IRI; updated IRI foF2 also exhibits relatively minor improvements compared with ionosonde measurements, i.e., STD/RMS/BIAS reduces from 1.070/1.268/0.681 to 1.019/1.061/− 0.298 MHz.

Diurnal Variations in the Statistical Characteristics of the Variability of the Midlatitude NmF2 during Quiet Geomagnetic Conditions at Low Solar Activity

The work examines diurnal variations in the statistical characteristics of the variability of the electron number density NmF2 of the maximum of the ionspheric F2 layer during quiet geomagnetic conditions at low solar activity based on hourly ionosonde measurements of the critical frequency of the ionspheric F2 layer from 1957 to 2017 over Moscow. The statistical parameters of NmF2 are calculated for each month M of each year at the universal time UT = 0, 1, … 23 h: the mathematical expectation NmF2E; the most probable value NmF2MP; the average monthly median NmF2MED; the arithmetic mean NmF2A; the standard deviations of NmF2 from NmF2E, NmF2MP, and NmF2MED; and the coefficients of variation CVE, CVMP, and CVMED of NmF2 relative to NmF2E, NmF2MP, and NmF2MED, respectively. It follows from the calculations that the CVE, CVMED, and CVMP values vary within the intervals of 12–43%, 12–60%, and 13–75%, respectively, and, in the vast majority of cases, CVE(UT, M) < CVMED(UT, M) and CVE(UT, M) < CVMP(UT, M). If the coefficient CVE in each month of each year is compared for different time points, the lowest CVE value varies from 12% (July) to 19% (December) and occurs during daytime, while the highest CVE value lies in the interval from 26% (June) to 43% (December). For each UT, the lowest and highest values of this coefficient in the autumn, winter, and spring months are greater than those for the summer months. It was found that the difference of NmF2A(UT, M) from NmF2E(UT, M) does not exceed 0.2%.

Ingestion of GIM-derived TEC data for updating IRI-2016 driven by effective IG indices over the European region

In order to adapt the International Reference Ionosphere (IRI) model from ionospheric climatological model to near real-time weather predictions, total electron content (TEC) data from Global Ionosphere Maps are ingested into the IRI-2016 model through retrieving the optimal ionospheric index (IG) over Europe on an hourly basis. When the retrieved hourly effective IG indices are used to drive the IRI-2016 model, the resulting ionospheric parameters are externally evaluated with respect to multiple sources, including the COSMIC/ionosonde electron density (Ne) profiles, ionosonde F2 layer critical frequency (foF2), and individual GNSS-derived TEC for both quiet and storm conditions. Results show that: (1) The updated IG indices for different latitudinal zones tend to follow a similar trend under quiet conditions, but vary much more significantly during storm days. (2) The retrieved Ne profiles from the updated IRI-2016 agree better with those from the COSMIC Ne profiles, especially for the F2 layer maximum electron density (NmF2) values. Furthermore, the updated IRI-2016 Ne profiles show improved agreement with ionosonde measurements under quiet conditions, particularly for the bottom-side Ne profiles and NmF2 as well as for the storm-time Ne profiles. (3) Comparing the IRI-updated TEC with the GNSS-derived TEC, IRI-updated TEC improved approximately 19% for both quiet and storm days, and the nighttime TEC improvement is better than that during daytime. When compared to the ionosonde foF2 measurements, the daytime IRI-updated foF2 improvement during quiet time is better than that during storm condition, while the performance for nighttime foF2 drops during quiet time. Discussions about possible reasons for the nighttime foF2 degradation are included.

The possibility of estimating the height of the ionospheric inhomogeneities based on TEC variations maps obtained from dense GPS network

A state of the ionosphere can be effectively studied using electromagnetic signals received from global navigation satellite systems (GNSS). Utilization of the dual frequency observations allows estimating values of the total electron content (TEC). They can be used for a number of scientific studies such as detection and monitoring of traveling ionospheric disturbances or plasma bubbles. Moreover, maps of TEC variations allow to classify ionospheric heterogeneities and to evaluate their parameters. However, most of the research describes ionospheric parameters only in 2D space and time. In this paper, we focus on the determination of the height of the ionospheric inhomogeneities. We used a dense network of GPS receivers to obtain the sequences of TEC variation maps for different heights of the ionospheric layer. For each satellite observed above 70°, we constructed separate sets of maps. For each ionospheric height, the cross-correlation function between maps corresponding to different satellites was calculated. The biggest cross-correlation coefficient value determines the height of the ionospheric irregularities. This paper describes the methodology and the results obtained for a geomagnetic storm on St. Patrick’s Day in March 2013. We have found that in quiet geomagnetic conditions the ionospheric irregularities are localized predominantly within the interval 180–220 km close to the maximum of the ionospheric F2 layer. In disturbed conditions, the height of their localization was increased up to several hundreds of kilometers. These estimations correspond to the changes in the slab thickness of the ionosphere.

Local Time and Seasonal Variations in the Electron Density at the Ionospheric F2-Layer Maximum with Wave Disturbances under Low Solar Activity Conditions

Regular and quasi-periodic local time and seasonal variations in the electron density in the maximum of the ionospheric F2 layer during low solar activity in 2016 are analyzed. System spectral analysis of temporal variations in the electron density in the range of 30–180 min is based on windowed Fourier transform, adaptive Fourier transform, and wavelet transform. In all seasons, the ionospheric F2 layer is dominated by oscillation with a period of 70–120 min, an amplitude of ΔNa ≈ (2–10) × 1010 m–3, and a relative amplitude of $${{\Delta {{N}_{a}}} \mathord{\left/ {\vphantom {{\Delta {{N}_{a}}} {\bar {N}}}} \right. \kern-0em} {\bar {N}}}$$ ≈ 0.20–0.70. The duration of this oscillation varied from 6 to 17 h depending on the season. The amplitude of oscillations with other periods is significantly smaller. It has been confirmed that the regular local time and seasonal variations in the electron density in the F2-layer maximum are fully consistent with the existing views on physicochemical processes in the ionosphere. The main regularities in the behavior of quasi-periodic variations in the electron density have been revealed.

Validation results of maximum S4 index in F-layer derived from GNOS on FY3C satellite

The first Global Navigation Satellite System (GNSS) Occultation Sounder (GNOS) compatible with both BeiDou Navigation Satellite System (BDS) and Global Positioning System was successfully launched into orbit on September 23, 2013, which was mounted on the FengYun-3C (FY3C) satellite. FY3C/GNOS has produced a lot of ionospheric radio occultation (RO) scintillation data until now. This work was conducted to verify the accuracy of the scintillation data observed by FY3C/GNOS for monitoring of the GNSS signal attenuation and early warning of the possible GNSS signal interruption, thus laying the foundation for research on ionospheric space weather. In this work, the ionospheric F-layer maximum scintillation indexes S4 (\(S4_{{{\text{max}}}}^{{\text{F}}}\)) probed by FY3C/GNOS and Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) are matched into data pairs by data matching criterions during January 10, 2014 and January 9, 2015, which allow the comparison and error analysis of \(S4_{{{\text{max}}}}^{{\text{F}}}\) indexes between FY3C/GNOS and COSMIC. We find that FY3C/GNOS overestimates the \(S4_{{{\text{max}}}}^{{\text{F}}}\) data compared to that of COSMIC, and the biases and standard deviations (Stds) of the differences between the two \(S4_{{{\text{max}}}}^{{\text{F}}}\) indexes (FY3C/GNOS-COSMIC) in data pairs are 0.004 and 0.063 in the whole day, 0.007 and 0.080 at nighttime, 0.001 and 0.046 at daytime, respectively. The statistical error results verify the precision consistency of the ionospheric RO scintillation data between FY3C/GNOS and COSMIC. The errors at nighttime are larger than those in the whole day and daytime, which is probably due to time-varying ionospheric irregularities after midnight and disparity of the data matching criterions. Since the deployment of FY3 series satellites, GNOS can contribute more scintillation data to the international ionospheric research and forecasting of ionospheric space weather.