Effects of the ionosphere and solar activity on radio occultation signals: Application to CHAllenging Minisatellite Payload satellite observations

Liou, Yuei-An; Wickert, Jens; Schmidt, T.; Pavelyev, A. G.; Liu, Shuo-Fang

doi:10.1029/2006ja011625

Cited by 42 publications

(52 citation statements)

References 32 publications

(82 reference statements)

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“…The RO method delivers a great amount of data on the electron density distribution in the upper and lower ionosphere that are important sources for modernizing the current information over the morphology of the ionosphere and ionospheric processes [44,45]. The RO method has been actively used to study the global distribution of sporadic E-layers in dependence of latitude, longitude, altitude and local time [5,[27][28][29][30][31][32][39][40][41][45][46][47]. These investigations have produced useful data on climatology and the formation process of sporadic E-layers which depend mainly on the Earth's magnetic field and meteor impact according to the theory of the wind shear mechanism of plasma concentration [48][49][50][51].…”

Section: Application Of Gps Ro Methods To Study the Atmosphere And Ionmentioning

confidence: 99%

“…The radio occultation (RO) method employs the highly-stable radio waves transmitted at two GPS frequencies 1 f  1575.42 MHz and 2 f  1227.60 MHz by the GPS satellites and recorded at a GPS receiver onboard low Earth orbiting (LEO) satellite to remote sense the Earth's ionosphere and neutral atmosphere [4,5,10,11,17,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]46,47,[52][53][54][55][56][59][60][61]. When applied to ionospheric investigations the RO method may be considered as a global tool and can be compared with the global Earth-and space-based radio tomography [42,43].…”

Section: Application Of Gps Ro Methods To Study the Atmosphere And Ionmentioning

confidence: 99%

“…Thus, the RO data are the instantaneous one-dimensional radio-holograms of the ionosphere and atmosphere. In the case of global spherical symmetry of the ionosphere and atmosphere, the following relations between the phase-path increments () t  and the refractive attenuation () Xt of radio waves [4][5][6][7][8] Figure 3 (right panels). Smooth curve 2 corresponds to the total absorption  found by a least-squares method, its value nearly corresponds to the absorption in atmospheric oxygen in accordance with [21].…”

Section: Total Absorptionmentioning

confidence: 99%

“…Using the detected relationship, a possibility of determining the altitude, position, and inclination of plasma layers in the ionosphere from the RO data has been revealed [4][5][6][7][8]. The proposed calculation technique is simpler than the phase-screen [9] and back-propagation methods [10,11].…”

Section: Introductionmentioning

confidence: 99%

“…A new important relationship between the second-order time derivative (acceleration) of the phase path (eikonal), Doppler frequency, and intensity variations of the radio occultation (RO) signal was revealed by theoretical considerations and experimental analysis of the radio-holograms recorded onboard of the CHAMP and FORMOSAT-3 satellites [4][5][6]. Using the detected relationship, a possibility of determining the altitude, position, and inclination of plasma layers in the ionosphere from the RO data has been revealed [4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Radio Wave Propagation Phenomena from GPS Occultation Data Analysis

Pavelyev¹,

Matyugov²,

Yakovlev³

et al. 2013

Wave Propagation Theories and Applications

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Section: Application Of Gps Ro Methods To Study the Atmosphere And Ionmentioning

confidence: 99%

Section: Application Of Gps Ro Methods To Study the Atmosphere And Ionmentioning

confidence: 99%

Section: Total Absorptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Radio Wave Propagation Phenomena from GPS Occultation Data Analysis

Pavelyev¹,

Matyugov²,

Yakovlev³

et al. 2013

Wave Propagation Theories and Applications

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Explanation of the sporadic‐E layer formation by comparing FORMOSAT‐3/COSMIC data with meteor and wind shear information

et al. 2014

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The formation of the sporadic E (E s ) layer can be interpreted in several different ways, with wind shear theory and the meteor ionization mechanism being the most commonly used explanations. Nevertheless, neither the wind shear theory nor the meteor ionization mechanism alone can completely explain the formation of the E s layer. The meteor ionization mechanism cannot interpret the different activity in this layer between the Northern and Southern Hemispheres, while the wind shear theory cannot explain the source of the large amount of ionized particles in the E s layer. In this study, the activity in the E s layer is compared with information about meteors and the global vertical speed of ionized particles. The information about meteors is obtained from International Meteor Organization and Radio Meteor Observing Bulletin. The global vertical speed information for ionized particles is calculated using the International Geomagnetic Reference Field model, Horizontal Wind Model (HWM07), and Mass Spectrometer-Incoherent Scatter model. The activity in the E s layer is based on the value of the irregular degree index, which is derived from the signal-to-noise ratio obtained from Formosa Satellite Mission-3/Constellation Observing System for Meteorology, Ionosphere, and Climate (FORMOSAT-3/COSMIC) Global Positioning System radio occultation mission. Taking both wind shear theory and the meteor ionization mechanism together, the source of the ionized particles in the E s layer and the difference in the activity in the E s layer between Northern and Southern Hemispheres can thus be explained more completely.

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Autonomous identification and classification of ionospheric sporadicEin digital ionograms

Ghosh

Berkey

2015

Earth and Space Science

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This paper introduces a methodology to autonomously identify and classify ionospheric sporadic E layers (E s ) from digital ionograms acquired using a NOAA dynasonde operated at the Bear Lake Observatory (BLO) in northern Utah. This approach uses a windowed-fuzzy clustering technique to group ionospheric echoes present in digital ionograms, employing the transitive property of equivalence. The algorithm introduces a variance constraint to automatically determine the number and size of the clusters present in the data set. Principal component analysis (PCA) of the cluster shapes is employed for curvature estimation and to enable classification of the data into the four principal types of temperate latitude sporadic E. A visual evaluation of the autonomously classified ionograms suggests that the algorithm accurately identifies ∼95% of the sporadic E echoes present in the BLO data set. The paper also includes a "proof-of-concept" analysis of the methodology, deriving E s parameters for summer and winter intervals, that explicitly characterizes the diurnal and seasonal variations present in the E region at 42 ∘ N. This analysis was derived from approximately 34,000 digital ionograms acquired over 4 months. While the experimental data show lower peak E region heights than predicted by modeling studies, they are generally consistent with GPS satellite occultation measurements. Our analysis of the temporal variation of f o E during summer and winter intervals is inconsistent with previous results that suggest a seasonal E region density anomaly. The results confirm, however, the ionospheric effect of increased NO densities in both the summer and winter E region, as predicted by modeling studies. The identification of sporadic E using the approach outlined in this work markedly facilitates the analysis of E s parameters, as well as eliminating any human biases from the ionogram analysis process.

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Effects of the ionosphere and solar activity on radio occultation signals: Application to CHAllenging Minisatellite Payload satellite observations

Cited by 42 publications

References 32 publications

Radio Wave Propagation Phenomena from GPS Occultation Data Analysis

Radio Wave Propagation Phenomena from GPS Occultation Data Analysis

Explanation of the sporadic‐E layer formation by comparing FORMOSAT‐3/COSMIC data with meteor and wind shear information

Autonomous identification and classification of ionospheric sporadicEin digital ionograms

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