scholarly journals Simulated high frequency ray paths considering traveling ionospheric disturbances

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Mariano Fagre ◽  
Bruno S. Zossi ◽  
Jaroslav Chum ◽  
Ana G. Elias
Keyword(s):  
High Frequency ◽  
Ionospheric Disturbances ◽  
Traveling Ionospheric Disturbances ◽  
Ray Paths

scholarly journals Traveling ionospheric disturbances triggered by the 2009 North Korean underground nuclear explosion

2015 ◽  
Vol 33 (1) ◽  
pp. 137-142 ◽  
Author(s):  
X. Zhang ◽  
L. Tang
Keyword(s):  
Acoustic Waves ◽  
High Frequency ◽  
Ionospheric Disturbance ◽  
Low Frequency ◽  
Ionospheric Disturbances ◽  
Underground Nuclear Explosion ◽  
Dual Frequency ◽  
International Gnss Service ◽  
Acoustic Gravity Waves ◽  
Traveling Ionospheric Disturbances

Abstract. Underground nuclear explosions (UNEs) can induce acoustic-gravity waves, which disturb the ionosphere and initiate traveling ionospheric disturbances (TIDs). In this paper, we employ a multi-step and multi-order numerical difference method with dual-frequency GPS data to detect ionospheric disturbances triggered by the North Korean UNE on 25 May 2009. Several International GNSS Service (IGS) stations with different distances (400 to 1200 km) from the epicenter were chosen for the experiment. The results show that there are two types of disturbances in the ionospheric disturbance series: high-frequency TIDs with periods of approximately 1 to 2 min and low-frequency waves with period spectrums of 2 to 5 min. The observed TIDs are situated around the epicenter of the UNE, and show similar features, indicating the origin of the observed disturbances is the UNE event. According to the amplitudes, periods and average propagation velocities, the high-frequency and low-frequency TIDs can be attributed to the acoustic waves in the lower ionosphere and higher ionosphere, respectively.

scholarly journals Statistical study of medium-scale traveling ionospheric disturbances in low-latitude ionosphere using an automatic algorithm

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Pin-Hsuan Cheng ◽  
Charles Lin ◽  
Yuichi Otsuka ◽  
Hanli Liu ◽  
Panthalingal Krishanunni Rajesh ◽  
...  
Keyword(s):  
Climate Model ◽  
Geomagnetic Latitude ◽  
Detection Algorithm ◽  
Support Vector ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Low Latitude ◽  
Total Electron ◽  
Medium Scale ◽  
Traveling Ionospheric Disturbances

AbstractThis study investigates the medium-scale traveling ionospheric disturbances (MSTIDs) statistically at the low-latitude equatorial ionization anomaly (EIA) region in the northern hemisphere. We apply the automatic detection algorithm including the three-dimensional fast Fourier transform (3-D FFT) and support vector machine (SVM) on total electron content (TEC) observations, derived from a network of ground-based global navigation satellite system (GNSS) receivers in Taiwan (14.5° N geomagnetic latitude; 32.5° inclination), to identify MSTID from other waves or irregularity features. The obtained results are analyzed statistically to examine the behavior of low-latitude MSTIDs. Statistical results indicate the following characteristics. First, the southward (equatorward) MSTIDs are observed almost every day during 0800–2100 LT in Spring and Winter. At midnight, southward MSTIDs are more discernible in Summer and majority of them are propagating from Japan to Taiwan. Second, northward (poleward) MSTIDs are more frequently detected during 1200–2100 LT in Spring and Summer with the secondary peak of occurrence between day of year (DOY) 100–140 during 0000–0300 LT. The characteristics of the MSTIDs are interpreted with additional observations from radio occultation (RO) soundings of FORMOSAT-3/COSMIC as well as modeled atmospheric waves from the high-resolution Whole Atmosphere Community Climate Model (WACCM) suggesting that the nighttime MSTIDs in Summer is likely connected to the atmospheric gravity waves (AGWs).

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