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Explore the use of Ground-Based GNSS for monitoring TEC variations, irregularities, geomagnetic storms, and pre-earthquake anomalies. Learn how it detects Space Seismometer signals and predicts events like Solar Flares. Discover the impact of solar eclipses and how GNSS helps in observing ionospheric signatures of earthquakes. Conclusion: GNSS sites globally offer continuous ionospheric monitoring.
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Chapter VI Space Environment Probing 6.2 Ground-based GNSS TEC and ionospheric applications
Content • Theory • Practical analyses TEC Variations Irregularity and Bubble Geomagnetic Storm Solar Eclipse and Solar Flare Pre-earthquake Anomalies Space Seismometer • Conclusion
Derive the TEC from GNSS signals • Pseudo Range • Phase range lf
Time Delay effect Pseudo range: Carry phase “f”
daytime dusk dawn nighttime
921 ChiChi Earthquake 1747 UT, Mw7.6
Hokkaiaido Earthquake 926 2003, 0450JST, M 8.0
Observing Ionospheric Signatures of the Indian Ocean Tsunami triggered bythe M9.3 Sumatra Earthquake00:58:53 UT 1226, 2004 Iononami - ionospheric tsunami signatures Space Tide-Gauge (STG)
Result • It is found that the tsunami waves triggered atmospheric waves near the sea surface, which then traveled upward with an average velocity of about 730m/s into the ionosphere and significantly disturbed the GPS TEC (or ionospheric electron density) within it. • The giant iononamis which have maximum heights of about 10 km, periods of 10-20 minutes, and horizontal wavelengths of about 100-200 km, travel away from the epicenter with an average horizontal speed of about 700 km/hr.
Conclusion • There are worldwide about thousands of ground-based GNSS sites, which provide an excellent chance to continuously monitor ionosphere.