The devastating Hunga Tonga-Hunga Ha’apai underwater volcano erupted at ~04:15 UT on 15 January 2022. We captured the waves that erupted from the volcano propagating in the ionosphere by monitoring total electron content (TEC) perturbations utilizing ground-based global navigation satellite system (GNSS) receivers that receive electromagnetic signals transmitted from the geostationary satellites operated by the BeiDou Navigation Satellite System (BDS). Meanwhile, ground barometers detected unusual enhancements of air pressure traveling in the troposphere. A novel phenomenon shows that the waves can individually propagate with a speed of ~335 m/s in the ionosphere, which is faster than its’ ~305 m/s in the troposphere. We further examined multiple geophysical data at the particular site of the novel instrumental array. Analytical results show that the pressure enhancements traveling in the troposphere not only downward trigger ground vibrations mainly in the horizontal components without obvious time difference, but also upward, leading the secondary TEC perturbations with a ~12-min delay.

Seismic waves can be detected in the Earth's atmosphere and ionosphere; however, their impacts on ionospheric electron density (Ne) structures near the altitude of peak Ne (h_mF₂) have not yet been fully determined due to the lack of sufficient observations sampled in the vertical direction. Here we apply a ground‐based Global Positioning System (GPS) receiving network in Asia as well as the space‐based GPS occultation experiment on board the FORMOSAT‐3/COSMIC (F3/C) satellite to vertically scan the ionospheric Ne structures, which were perturbed by the magnitude M_w7.8 Nepal earthquake that occurred on 25 April 2015. The F3/C altitudinal Ne profiles show that the Nepal earthquake‐induced air perturbations penetrate into the ionosphere at supersonic speeds of approximately 800 m/s and change the Ne structure by 10% near h_mF₂. The vertical scale of the Ne perturbation is 150 km, while the h_mF₂ is uplifted by more than 30 km within 1 min. Those results reveal that the earthquake‐induced ground displacement should be considered as a significant force that perturbs the vertical Ne structure of the ionosphere.

A moon shadow of annular solar eclipse passed through East Asia in the afternoon on June 21, 2020, which was a good opportunity to study the rapid ionospheric response to the solar radiation variations. In the study, the high‐frequency echoes recorded by the ionosondes at Wuhan (82.4% obscuration), Xiamen (97.8% obscuration), and Nanning (81.1% obscuration) are analyzed to examine the variations in sporadic‐E (E_s) during the obscuration over the East China area. The echoes show not only the variations in the typical signal E_s layer below 130 km, but for the first time also the multilayered E_s at much higher altitudes (130–190 km) during the eclipse. Specifically, the multilayered E_s is only observed over Nanning, while different E_s behaviors are observed in the other two stations. The relationship between the formation of the multilayered E_s and the uplifted E_s near the center path of the moon shadow are examined in the study. The small‐scale atmospheric gravity waves play a key role in modulating the E_s behaviors during the eclipse.

Sporadic E (Es) layers are known for their layered structures with enhanced electron density. Recently, some scientists have studied the relationship between the occurrence rate and intensity of the Es layer in the global distribution. However, the relationship between the Es layer parameters (Es layer occurrence rate, Es layer intensity, Es layer thickness) in the vertical direction seems to be ignored to date. This paper highlights the vertical profiles of the occurrence rate, intensity, and thickness of the Es layers by using scintillation index (S4) from FORMOSAT‐3/COSMIC satellites from July 2007 to March 2015. The results show that there are some persistent differences between the occurrence rate, intensity, and thickness of the Es layers in the vertical profiles, which is different from their general similarity in the latitude distribution. It is found that the Es layer occurrence rate has a maximum value at ∼102 km altitude, but the Es layer intensity and Es layer thickness reach their maximum at an altitude of ∼110 km. Besides, the intensity and thickness of the Es layer exhibit a high linear relationship, which suggests that the larger electron density of the Es layer, the thicker its thickness. The Horizontal Wind Model (HWM14) indicates that the latitudinal variations in Es layers parameters are highly coincident with the zonal wind shear. However, the altitudinal variations in Es layers parameters do not agree well with the zonal wind shear.