scholarly journals Variations of the ionospheric TEC using simultaneous measurements from the China Crustal Movement Observation Network

2012 ◽  
Vol 30 (10) ◽  
pp. 1423-1433 ◽  
Author(s):  
Y. W. Wu ◽  
R. Y. Liu ◽  
B. C. Zhang ◽  
Z. S. Wu ◽  
J. S. Ping ◽  
...  
Keyword(s):  
Crustal Movement ◽  
Topside Ionosphere ◽  
Electron Content ◽  
Equatorial Anomaly ◽  
Total Electron ◽  
Movement Observation ◽  
The North ◽  
Ionospheric Total Electron Content ◽  
Observation Network ◽  
Two Peaks

Abstract. Variations of the ionospheric Total Electron Content (TEC) over China are investigated using the TEC data obtained from China Crustal Movement Observation Network in the year 2004. The results show a single-peak occurred in post-noon for the diurnal variation and two peaks exit around two equinox points, respectively, for the seasonal variation. Overall, the values of TEC increased from the north to the south of China. There were small but clear longitudinal differences in both sides of the longitudes with zero magnetic declination. The intensity of the day-to-day variation of TEC was not a monotonic change along the latitudes. It was usually weaker in the middle of China than that in the north or south. Comparing with the maximum F-layer electron density (NmF2) derived from the ionosonde stations in China, it is found that the day-to-day variation of TEC was less significant than that of NmF2, and that the northern crest of the equatorial anomaly identified from the NmF2 data can reach Guangzhou-region. While, the TEC crest was hardly observed in the same location. This is probably caused by the tilt of topside ionosphere near the northern anomaly crest region at lower latitudes.

scholarly journals Tsunami Detection by GPS-derived Ionospheric Total Electron Content

2020 ◽  
Author(s):  
Mahesh Shrivastava ◽  
Ajeet Maurya ◽  
Gabriel Gonzalez ◽  
P Sunil ◽  
Juan Gonzalez ◽  
...  
Keyword(s):  
Total Electron Content ◽  
Tide Gauge ◽  
Early Warning Systems ◽  
Electron Content ◽  
Tsunami Propagation ◽  
Total Electron ◽  
Tsunami Waves ◽  
The North ◽  
Ionospheric Total Electron Content ◽  
Illapel Earthquake

Abstract To unravel the relationship between earthquake and tsunami using ionospheric total electron content (TEC) changes, we analyzed two Chilean tsunamigenic subduction earthquakes: the 2014 Pisagua Mw 8.1 and the 2015 Illapel Mw 8.3. During the Pisagua earthquake, the TEC changes were detected at the GPS sites located to the north and south of the earthquake epicenter, whereas during the Illapel earthquake, we registered the changes only in the northward direction. Tide-gauge sites mimicked the propagation direction of tsunami waves similar to the TEC change pattern during both earthquakes. The TEC changes were represented by two signals. The initial weaker signal correlated well with seismic Rayleigh waves, while the following stronger perturbation was interpreted to be caused by acoustic and gravity waves induced by earthquakes and subsequent tsunamis. As a result, TEC changes can be utilized to evaluate earthquake occurrence and tsunami propagation within a framework of multi-parameter early warning systems.

scholarly journals Derivation of TEC and estimation of instrumental biases from GEONET in Japan

2003 ◽  
Vol 21 (10) ◽  
pp. 2083-2093 ◽  
Author(s):  
G. Ma ◽  
T. Maruyama
Keyword(s):  
Electron Content ◽  
Dual Frequency ◽  
Simple Method ◽  
Total Electron ◽  
Radio Science ◽  
Ionospheric Total Electron Content ◽  
Gps Satellites ◽  
Observation Network ◽  
Instruments And Techniques ◽  
High Degree

Abstract. This paper presents a method to derive the ionospheric total electron content (TEC) and to estimate the biases of GPS satellites and dual frequency receivers using the GPS Earth Observation Network (GEONET) in Japan. Based on the consideration that the TEC is uniform in a small area, the method divides the ionosphere over Japan into 32 meshes. The size of each mesh is 2° by 2° in latitude and longitude, respectively. By assuming that the TEC is identical at any point within a given mesh and the biases do not vary within a day, the method arranges unknown TECs and biases with dual GPS data from about 209 receivers in a day unit into a set of equations. Then the TECs and the biases of satellites and receivers were determined by using the least-squares fitting technique. The performance of the method is examined by applying it to geomagnetically quiet days in various seasons, and then comparing the GPS-derived TEC with ionospheric critical frequencies (foF2). It is found that the biases of GPS satellites and most receivers are very stable. The diurnal and seasonal variation in TEC and foF2 shows a high degree of conformity. The method using a highly dense receiver network like GEONET is not always applicable in other areas. Thus, the paper also proposes a simpler and faster method to estimate a single receiver’s bias by using the satellite biases determined from GEONET. The accuracy of the simple method is examined by comparing the receiver biases determined by the two methods. Larger deviation from GEONET derived bias tends to be found in the receivers at lower (<30° N) latitudes due to the effects of equatorial anomaly.Key words. Ionosphere (mid-latitude ionosphere; instruments and techniques) – Radio science (radio-wave propagation)

scholarly journals Seasonal variations of the ionospheric total electron content in Asian equatorial anomaly regions

2001 ◽  
Vol 106 (A12) ◽  
pp. 30363-30369 ◽  
Author(s):  
Ho-Fang Tsai ◽  
Jann-Yenq Liu ◽  
Wei-Hsiung Tsai ◽  
Chao-Han Liu ◽  
Ching-Liang Tseng ◽  
...  
Keyword(s):  
Total Electron Content ◽  
Seasonal Variations ◽  
Electron Content ◽  
Equatorial Anomaly ◽  
Total Electron ◽  
Ionospheric Total Electron Content
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