Generalization of ionospheric tomography on diverse data sources: Reconstruction of the three-dimensional ionosphere from simultaneous vertical ionograms, backscatter ionograms, and total electron content data

Radio Science ◽  
2001 ◽  
Vol 36 (5) ◽  
pp. 1129-1139 ◽  
Author(s):  
S. V. Fridman ◽  
L. J. Nickisch
Keyword(s):  
Total Electron Content ◽  
Three Dimensional ◽  
Data Sources ◽  
Electron Content ◽  
Total Electron ◽  
Total Electron Content Data ◽  
Ionospheric Tomography ◽  
Diverse Data

scholarly journals Reconstruction of Storm‐Time Total Electron Content Using Ionospheric Tomography and Artificial Neural Networks: A Comparative Study Over the African Region

Radio Science ◽  
2018 ◽  
Vol 53 (11) ◽  
pp. 1328-1345 ◽  
Author(s):  
Jean Claude Uwamahoro ◽  
Nigussie M. Giday ◽  
John Bosco Habarulema ◽  
Zama T. Katamzi‐Joseph ◽  
Gopi Krishna Seemala
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Comparative Study ◽  
Total Electron Content ◽  
Electron Content ◽  
African Region ◽  
Total Electron ◽  
Ionospheric Tomography ◽  
Artificial Neural

scholarly journals Assessing the performance of a Northeast Asia Japan-cantered 3-D ionosphere specification technique during the 2015 St. Patrick’s day solar storm

2021 ◽  
Author(s):  
Nicholas Ssessanga ◽  
Mamoru Yamamoto ◽  
Susumu Saito
Keyword(s):  
Northeast Asia ◽  
Three Dimensional ◽  
Satellite System ◽  
Electron Content ◽  
Potential Candidate ◽  
Storm Events ◽  
Total Electron ◽  
Total Electron Content Data ◽  
Swarm Satellites ◽  
Solar Storm

Abstract This paper demonstrates and assesses the capability of the advanced three- dimensional (3-D) ionosphere tomography technique, during severe conditions. The study area is northeast Asia and quasi-Japan-centred. Reconstructions are based on Total electron content data from a dense ground-based global navigation satellite system receiver network and parameters from operational ionosondes. We used observations from ionosondes, Swarm satellites and radio occultation (RO) to assess the 3-D picture. Specifically, we focus on St. Patrick’s day solar storm (17–19 March 2015), the most intense in solar cycle 24. During this event, the energy ingested into the ionosphere resulted in Dst and Kp and reaching values ~-223 nT and 8, respectively, and the region of interest, the East Asian sector, was characterized by a ~ 60% reduction in electron densities. Results show that the reconstructed densities follow the physical dynamics previously discussed in earlier publications about storm events. Moreover, even when ionosonde data were not available, the technique could still provide a consistent picture of the ionosphere vertical structure. Furthermore, analyses show that there is a profound agreement between the RO profiles/in-situ densities and the reconstructions. Therefore, the technique is a potential candidate for applications that are sensitive to ionospheric corrections.

scholarly journals Ionospheric response to total solar eclipse of 22 July 2009 in different Indian regions

2013 ◽  
Vol 31 (9) ◽  
pp. 1549-1558 ◽  
Author(s):  
S. Kumar ◽  
A. K. Singh ◽  
R. P. Singh
Keyword(s):  
Total Electron Content ◽  
Solar Eclipse ◽  
Total Solar Eclipse ◽  
Lower Atmosphere ◽  
Electron Content ◽  
Vertical Total Electron Content ◽  
Total Electron ◽  
Ionospheric Response ◽  
Total Electron Content Data ◽  
Photoionization Process

Abstract. The variability of ionospheric response to the total solar eclipse of 22 July 2009 has been studied analyzing the GPS data recorded at the four Indian low-latitude stations Varanasi (100% obscuration), Kanpur (95% obscuration), Hyderabad (84% obscuration) and Bangalore (72% obscuration). The retrieved ionospheric vertical total electron content (VTEC) shows a significant reduction (reflected by all PRNs (satellites) at all stations) with a maximum of 48% at Varanasi (PRN 14), which decreases to 30% at Bangalore (PRN 14). Data from PRN 31 show a maximum of 54% at Kanpur and 26% at Hyderabad. The maximum decrement in VTEC occurs some time (2–15 min) after the maximum obscuration. The reduction in VTEC compared to the quiet mean VTEC depends on latitude as well as longitude, which also depends on the location of the satellite with respect to the solar eclipse path. The amount of reduction in VTEC decreases as the present obscuration decreases, which is directly related to the electron production by the photoionization process. The analysis of electron density height profile derived from the COSMIC (Constellation Observing System for Meteorology, Ionosphere & Climate) satellite over the Indian region shows significant reduction from 100 km altitude up to 800 km altitude with a maximum of 48% at 360 km altitude. The oscillatory nature in total electron content data at all stations is observed with different wave periods lying between 40 and 120 min, which are attributed to gravity wave effects generated in the lower atmosphere during the total solar eclipse.

The ionospheric response to perturbation electric fields during the onset phase of geomagnetic storms

1992 ◽  
Vol 70 (7) ◽  
pp. 575-581 ◽  
Author(s):  
N. Jakowski ◽  
A. Jungstand ◽  
K. Schlegel ◽  
H. Kohl ◽  
K. Rinnert
Keyword(s):  
Total Electron Content ◽  
Electric Fields ◽  
Geomagnetic Storms ◽  
Slab Thickness ◽  
Electron Content ◽  
Total Electron ◽  
Total Electron Content Data ◽  
Critical Frequency Fof2 ◽  
Eiscat Radar ◽  
Onset Phase

The generation and propagation of ionospheric storms are studied by analyzing EISCAT radar, and vertical-sounding and total-electron-content data obtained under different geophysical conditions. Both, case studies as well as the average storm pattern of percentage deviations of different ionospheric parameters from their corresponding reference values such as total electron content, F2-layer critical frequency foF2, F2-layer height hmF2, and slab thickness τ indicate the action of a perturbation electric field during the first few hours during the onset phase of geomagnetic storms. Considering the onset phase of the storm on July 28–29, 1987 evidence has been found that high-latitude electric fields may penetrate to lower latitudes before the ring current has developed. In most cases this process is accompanied by a positive phase in the upper ionosphere and F2-layer ionization. Different mechanisms are assumed to be responsible for the daytime and nighttime behaviour, respectively. The negative phase propagates equatorward with velocities in the order of 70–350 m s−1 following a strong heating of the thermosphere and ionosphere due to the auroral electrojet.

scholarly journals DETECTION OF EQUATORIAL PLASMA BUBBLES USING GPS IONOSPHERIC TOMOGRAPHY OVER PENINSULAR MALAYSIA

2021 ◽  
Vol 6 (24) ◽  
pp. 152-160
Author(s):  
Siti Syukriah Khamdan ◽  
Tajul Ariffin Musa ◽  
Suhaila M. Buhari
Keyword(s):  
Three Dimensional ◽  
Peninsular Malaysia ◽  
Rate Of Change ◽  
Electron Content ◽  
Total Electron ◽  
Ionospheric Tomography ◽  
Plasma Bubbles ◽  
Equatorial Plasma Bubbles ◽  
Tomography Method

This paper presents the detection of the equatorial plasma bubbles (EPB) using the Global Positioning System (GPS) ionospheric tomography method over Peninsular Malaysia. This paper aims to investigate the capability of the GPS ionospheric tomography method in detecting the variations of the EPB over the study area. In doing so, a previous case study during post-sunset 5th April 2011 has been selected as a reference for the detection of the EPBs over the study area. It has been observed that at least three structures of the EPBs have been captured based on the rate of change total electron content (TEC) index (ROTI) from 12 UT until 19 UT. Therefore, the three-dimensional ionospheric profiles have been reconstructed over Peninsular Malaysia using the tomography method during the study period in order to capture the signature of the EPBs. In this study, the detection of the EPBs using the tomography method is based on the rate of change of electron density (ROTNe). The results from three-dimensional ionospheric tomography show only two structures of EPBs are detected during the study period. It has been observed that the ROTNe depleted up to ~-12x109el/cm. Overall, the results in this study show that the GPS ionospheric tomography capable to be utilized in detecting the variations of EPBs in support of ionospheric studies and monitoring in the Malaysian region.

scholarly journals Sodankylä ionospheric tomography dataset 2003–2014

2015 ◽  
Vol 5 (2) ◽  
pp. 385-404
Author(s):  
J. Norberg ◽  
L. Roininen ◽  
A. Kero ◽  
T. Raita ◽  
T. Ulich ◽  
...  
Keyword(s):  
Total Electron Content ◽  
Low Earth Orbit ◽  
Electron Content ◽  
Vertical Total Electron Content ◽  
Dual Frequency ◽  
Total Electron ◽  
Ionospheric Tomography ◽  
Maximum Elevation ◽  
Long Term Performance ◽  
Term Performance

Abstract. Sodankylä Geophysical Observatory has been operating a tomographic receiver network and collecting the produced data since 2003. The collected dataset consists of phase difference curves measured from Russian COSMOS dual-frequency (150/400 MHz) low-Earth-orbit satellite signals, and tomographic electron density reconstructions obtained from these measurements. In this study vertical total electron content (VTEC) values are integrated from the reconstructed electron densities to make a qualitative and quantitative analysis to validate the long-term performance of the tomographic system. During the observation period, 2003–2014, there were three-to-five operational stations at the Fenno-Scandinavian sector. Altogether the analysis consists of around 66 000 overflights, but to ensure the quality of the reconstructions, the examination is limited to cases with descending (north to south) overflights and maximum elevation over 60°. These constraints limit the number of overflights to around 10 000. Based on this dataset, one solar cycle of ionospheric vertical total electron content estimates is constructed. The measurements are compared against International Reference Ionosphere IRI-2012 model, F10.7 solar flux index and sunspot number data. Qualitatively the tomographic VTEC estimate corresponds to reference data very well, but the IRI-2012 model are on average 40 % higher of that of the tomographic results.

Toward ionospheric tomography in Antarctica: first steps and comparison with dynasonde observations

1996 ◽  
Vol 8 (3) ◽  
pp. 297-302 ◽  
Author(s):  
J.A.T. Heaton ◽  
G.O.L. Jones ◽  
L. Kersley
Keyword(s):  
Electron Density ◽  
Total Electron Content ◽  
Satellite System ◽  
Electron Density Profile ◽  
Electron Content ◽  
Total Electron ◽  
Ionospheric Tomography ◽  
Contour Maps ◽  
Tomographic Method ◽  
Independent Observations

Total electron content (TEC) measurements obtained at two Antarctic stations over nine months beginning early in 1994 have been analysed as a first step to performing ionospheric tomography. Two receiving systems were deployed at the Faraday and Halley research stations operated by the British Antarctic Survey to monitor signals from a random selection of passes of satellites in the Navy Navigational Satellite System. The resultant measurements of total electron content have been inverted and combined with ionosonde measurements of true height and foF2 to yield two-dimensional contour maps of ionospheric electron density. In spite of the poor geometry of the observations, some 130 satellite passes were found to be suitable for reconstruction using the techniques developed for ionospheric tomography. The contour maps of plasma density have been compared with independent observations of the vertical electron density profile measured by the dynasonde ionospheric sounder located at Halley. An example is presented of a deep trough investigated by the technique, illustrating the potential of the tomographic method for study of an extended spatial region of the ionosphere over inhospitable terrain.

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