Abstract In this study, multiple data sets from Beidou geostationary orbit satellites total electron contents (TECs), ionosonde, meteor radar, magnetometer, and model simulations have been used to investigate the ionospheric responses in Asian‐Australian sector during September 2017 geomagnetic storm. It was found that long‐duration daytime TEC enhancements lasted 7 12 were observed by satellite constellation. This is a unique event as prominent persisted storm recovery phase when activity...

Abstract An unseasonal equatorial plasma bubble (EPB) event occurred in the East/Southeast Asian sector during geomagnetic storm on 1 December 2023, causing strong amplitude scintillations from to middle latitudes. Based observations multiple instruments over a large latitudinal and longitudinal region, spatial features of super EPB were investigated. The developed vertically at fast rising speed ∼470 m/s magnetic equator extended very high latitude more than 40°N, despite that intensity was...

Abstract Plasma blob is generally a low‐latitude phenomenon occurring at the poleward edge of equatorial plasma bubble (EPB) during post‐sunset periods. Here we report case midlatitude ionospheric blob‐like structures along with super EPBs over East Asia around sunrise May 2024 great geomagnetic storm. Interestingly, appeared both and westward edges EPBs, reached up to 40°N magnetic latitudes, migrated several thousand kilometers together bubble. The total electron content (TEC) inside was...

Abstract This article proposes a technique to map the tidal winds in mesosphere and lower thermosphere (MLT) region from observations of four‐station meteor radar chain located at middle‐ low‐latitudes along 120°E meridian Northern Hemisphere. A 1 month dataset horizontal altitude range 80–100 km is observed during December 2011. We first decompose into mean, diurnal, semidiurnal, terdiurnal components for each station. It found that diurnal/semidiurnal dominate low‐latitude/midlatitude...

[1] Postmidnight equatorial F region irregularities (EFIs) are known to develop mainly during the solstitial months. However, it is not well understood whether they occur at all longitudes and what process causes their occurrence different longitude sectors. In this study, we use GPS total electron content (TEC) fluctuations obtained from a global network spread in ionograms Jicamarca (283°E, 12°S, Dip 1°N) American sector Kwajalein (167°E, 9°N, 4°N), Bac Lieu (106°E, 2°N), Chumphon (99°E,...

Recent case studies on the precursor signatures of equatorial spread‐F (ESF) have shown a one‐to‐one correspondence between large‐scale wave structures (LSWS) and ESF development at latitude. In this study, LSWS onset are investigated over Sanya (18°N, 109°E), station located 13° north magnetic equator, during both geomagnetic quiet disturbed conditions in September–October 2011. High‐time‐resolution ionograms from Digisonde Portable Sounder (DPS‐4D) provided satellite trace measurements...

Abstract The 2015 St. Patrick's Day geomagnetic storm with SYM‐H value of −233 nT is an extreme space weather event in the current 24th solar cycle. In this work, we investigated main mechanisms profound ionospheric disturbances over equatorial and low latitudes Asian‐Australian sector American during super event. results reveal that disturbed electric fields, which comprise penetration fields (PEFs) disturbance dynamo (DDEFs), play a decisive role effects latitude regions. PEFs occur on 17...

Abstract. On the basis of S4max data retrieved from COSMIC GPS radio occultation measurements, long-term climatology intensity Es layers is investigated for period December 2006 to January 2014. Global maps show high-spatial-resolution geographical distribution and strong seasonal dependence layers. The maximum occurs over mid-latitudes, its value in summer 2–3 times larger than that winter. A relatively layer observed at North Pole South Pole, with a distinct boundary dividing mid-latitudes...

Abstract The Low lAtitude long Range Ionospheric raDar (LARID), which consists of two high frequency (HF) radars looking toward the east and west Hainan Island, respectively, has been developed installed at Dongfang (19.2°N, 108.8°E, dip lat. 13.8°N), China. This paper describes system design LARID its first observational results equatorial plasma bubble (EPB) irregularities. antenna array is composed a west‐looking an east‐looking array. Each 20 log‐periodic antennas for transmission...

During the period 22–28 July 2004, three geomagnetic storms occurred due to a sequence of coronal mass ejections. In this paper we present and discuss ionospheric observations from set in situ satellites ground‐based GPS total electron content scintillation receivers, VHF radar, two chains ionosondes (∼300°E ∼120°E, respectively) that provide evolutionary characteristics equatorial low‐latitude irregularities versus longitude during these storm periods. It is found over wide longitudinal...

The longest total solar eclipse of this century occurred in East and South Asia on 22 July 2009. was accompanied with a medium magnetic storm, whose main phase onset ∼27 min after the passage Moon's umbral shadow. Using TEC data from 60 GPS stations, we construct differential maps to investigate ionosphere response central China range 26°N–36°N, 108°E–118°E (i.e., latitude 15°N–25°N). During eclipse's totality, “shadow” shown as depletion area formed ∼100 km south path maximum decrease 5...

The electron density in the ionospheric F region occasionally stops its decay and rises pronouncedly during night hours, which are termed nighttime enhancements. In this case study, we analyzed manually scaled ionogram records measured by a Lowell DPS‐4D ionosonde operated at Sanya (18.3°N, 109.6°E), China, to explore postmidnight enhancement events occurred 2012, year of moderate solar activities. Common features these cases illustrate that, accompanying peak F2 layer (NmF2), height is...

Abstract In this paper, an ionospheric electron density reanalysis algorithm was used to generate global optimized during the 17–18 March 2013 geomagnetic storm by assimilating ~10 low Earth orbit satellites based and ~450 ground navigation satellite system receiver‐based total content into a background model. The reanalyzed could identify large‐scale features quite well time, including storm‐enhanced density, positive effect initial main phases, negative recovery phase. simulations from...

Abstract An Ionospheric Observational Network for Irregularity and Scintillation in East Southeast Asia (IONISE) is developed to identify study the short‐term fine‐scale ionospheric variations over China. The IONISE network mainly includes three crossed chains of Beidou geostationary satellite total electron content (TEC)/scintillation receivers along 110°E, 23°N, 40°N respectively, multistatic portable digital ionosondes bistatic very high‐frequency radars. Based on observations, we report...

The Hunga–Tonga volcano eruption at 04:14:45 UT on 15 January 2022 produced various waves propagating globally, disturbing the background atmosphere and ionosphere. Coinciding with arrival of perturbation waves, several equatorial plasma bubbles (EPBs) were consecutively generated post-sunset hours over East/Southeast Asian region, largest extension to middle latitudes. These EPBs caused intense L -band amplitude scintillations middle-to-low latitudes, signal fading depths up ~16 dB....

Abstract Seasonal variations of different tides in the mesosphere and lower thermosphere are investigated from wind observations a meteor radar chain on basis Hough mode decomposition. First, observed winds decomposed into (diurnal, semidiurnal, terdiurnal) tidal components. Different seasonal patterns revealed for each component. Pronounced semiannual oscillation (SAO) is presented diurnal component, while latitude‐dependent variation found semidiurnal terdiurnal At low/midlatitude...

Abstract An Ionospheric Observation Network for Irregularity and Scintillation in East/Southeast Asia was recently deployed. Using ionospheric total electron content (TEC) from the two crossed Beidou geostationary satellite receiver chains of network along 110°E 23°N Doppler velocity measurements Sanya (18.3°N, 109.6°E) portable digital ionosonde, we report first observations low latitude TEC oscillations synchronized over a wide longitude range Asia, which occur at nighttime, after main...

Abstract The Global Navigation Satellite System (GNSS) beacon has been widely used in ionospheric monitoring. Chinese Beidou (BDS) started to operate 2012, with three kinds of constellations: the medium Earth orbit, inclined geosynchronous satellite and orbit. A compact, portable, low‐power GNSS observation instrument which is named BG2 monitor was developed at Institute Geology Geophysics, Academy Sciences. It capable tracking BDS, Positing System, signals a sampling rate up 5 Hz. To use...

Abstract The Meteor and ionospheric Irregularity Observation System (MIOS), which consists of multi‐station optical subsystem at Ledong (18.4°N, 109°E) Sanya (18.3°N, 109.6°E), radar including a 38.9 MHz all‐sky interferometric 47.5 coherent phased array Ledong, has been in full operational since December 2021. This paper describes the system design first results meteor plasma density irregularities corresponding meteoroids. MIOS few tens video cameras for observing trail spectrum. is...

Abstract Equatorial plasma bubble (EPB) irregularities can significantly impact satellite‐based communication and navigation systems. Accurate prediction of EPB occurrence is essential for mitigating these impacts. Using the GNSS receiver network ionosonde data from East Southeast Asia during 2010–2021, rate TEC change index to characterize irregularities, we developed a novel Spatio‐Temporal deep learning model regional short‐term Prediction (STEP). The integrates convolutional neural long...

Abstract Previous studies suggest that the planetary waves in mesosphere and low thermosphere (MLT) could modulate occurrence of equatorial plasma bubbles (EPBs) via altering post‐sunset F layer height. Using simultaneous observations by Global Navigation Satellite System receiver networks, two ionosondes separated about 10° longitude, high frequency very radars, we investigated day‐to‐day variations height EPB southeast Asia during quasi‐2‐day wave (QTDW) event July 2023. The results showed...

Abstract Ionospheric plasma bubbles refer to density depletion structures in the ionosphere, which are usually seen electron profiles observed by radar, and have never been of metallic ions. In this letter, we report first observation bubble signatures captured lidar, manifested as bifurcation profile a Ca + patch appearing at F‐region height over low latitude. Different from majority radar mainly altitude, visualized lidar latitude could be down below F layer bottom, that is, valley‐region...