Ionospheric Weather Observations of FORMOSAT-7/COSMIC-2

2020 ◽  
Author(s):  
Fu-Yuan Chang ◽  
Jann-Yenq Liu ◽  
Chi-Yen Lin ◽  
Shih-Ping Chen ◽  
Charles Lin
Keyword(s):  
Electron Content ◽  
Ion Temperature ◽  
Ion Density ◽  
Total Electron ◽  
Small Satellites ◽  
Weather Observations ◽  
Receiver System ◽  
Gnss Receivers ◽  
Ion Velocity ◽  
Electron Density Profiles

<p>FORMOSAT-7/COSMIC-2 (F7/C2), with the mission orbit of 550 km altitude, 24-deg inclination, and a period of 97 minutes, was launched on June 25, 2019.  Tri-GNSS Radio occultation (RO) receiver System (TGRS), Ion Velocity Meter (IVM), and RF Beacon (RFB) onboard F7/C2 six small satellites allow scientists to three-dimensionally observe the plasma structure and dynamics in the mid-latitude, low-latitude, and equatorial ionosphere.  Measurements of F7/C2 RO as well as the IVM ion density, ion temperature, and ion velocity have a better understanding on mechanisms of the plasma depletion bays, non-migrating tides, and scintillations.  Moreover, observations of ionospheric F7/C2 RO electron density profiles and the total electron content derived from global ground-based GNSS receivers are used to carry out ionospheric weather monitoring, nowcast, and forecast for positioning, navigation, and communication application.</p>

Seismo-ionospheric precursors of the 14 November 2019 M7.1 Indonesia Earthquake detected by FORMOSAT-7/COSMIC-2

2020 ◽  
Author(s):  
Jann-Yenq Liu ◽  
Chi-Yen Lin ◽  
Fu-Yuan Chang ◽  
Yuh-Ing Chen
Keyword(s):  
Electron Density ◽  
Electric Fields ◽  
Radio Occultation ◽  
Electron Content ◽  
Ion Temperature ◽  
Density Profiles ◽  
Ion Density ◽  
Total Electron ◽  
Ion Velocity ◽  
Electron Density Profiles

<p>FORMOSAT-7/COSMIC-2 (F7/C2), with the mission orbit of 550 km altitude, 24-deg inclination, and a period of 97 minutes, was launched on 25 June 2019.  Tri-GNSS Radio occultation System (TGRS), Ion Velocity Meter (IVM), and RF beacon onboard F7/C2 six small satellites allow scientists to observe the plasma structure and dynamics in the mid-latitude, low-latitude, and equatorial ionosphere in detail.  F7/C2 TGRS sounds ionospheric RO (radio occultation) electron density profiles, while F7/C2 IVM probes the ion density, ion temperature, and ion velocity at the satellite altitude.  The F7/C2 electron density profiles and the ion density, ion temperature, and ion velocity, as well as the global ionospheric map (GIM) of the total electron content (TEC) derived from global ground-based GPS receivers are used to detect seismo-ionospheric precursors (SIPs) of the 14 November 2019 M7.1 Indonesia Earthquake.  The GIM TEC and F7/C2 RO NmF2 significantly increase specifically over the epicenter on 25-26 October, which indicates SIPs of the 14 November 2019 M7.1 Indonesia Earthquake being detected.  The F7/C2 RO electron density profiles upward motions suggest that the eastward electric fields have been enhanced during the SIP days of the 2019 M7.1 Indonesia earthquake.  The seismo-generated electric fields of the 2019 M7.1 Indonesia earthquake are 0.34-0.64 mV/m eastward.  The results demonstrate that F7/C2 can be employed to detect SIPs in the ionospheric plasma, which shall shed some light on earthquake prediction/forecast.</p>

scholarly journals MODEL OF MID-AND LOW-LATITUDE F REGION IONOSPHERE AND PROTONOSPHERE

1981 ◽  
Vol 20 (1) ◽  
pp. 11-39
Author(s):  
A. Tan ◽  
S. T. Wu
Keyword(s):  
Drift Velocity ◽  
Loss Rate ◽  
Electron Content ◽  
Low Latitude ◽  
Ion Density ◽  
Total Electron ◽  
F Region ◽  
Latitude Station ◽  
Nocturnal Increase ◽  
Radio Beacon

The coupled continuity and momentum equations of O+ and H+ ions in the F region and the protonosphere are solved for a mid-latitude station (Arecibo) and a low-latitude station (Jicamarca) to investigate the diurnal behavior of the peak electron density NmF2, the height of the peak HmF2, the O+-H+ transition height Htr and the transition level ion density Ntr. The effects of the neutral wind on the NmF2, HmF2 Ntr and Htr curves above Arecibo are more important than and generally in the opposite direction of those of a sinusoidal elctromagnetic drift. the electromagnetic drift plays a fa-reaching role in shaping the ionospheric and protonospheric profiles at Jicamarca.  An upward drift that peaks during the day produces a 'valey' in the NmF2 curve, while an upward drift that stays constant during ost of the day produces a 'plateau'.  The nighttime decay in Nmf2 is due to the conbined effects of a slow downward drift and chemical recombination.  A nocturnal increase in NmF2 is due to a sufficiently large downward drift when the resultant 'squeezing' of the field tubes overcomes the O+ loss rate.  The diurnal variations of HmF2 and Htr tend to follow that of the upward drift velocity pattern, with gradients somewhat smoothed.  A downward reversal of the drift at sunset causes and enhancement in the post-sunset Ntr. Finally, the applicability of the model to the study of the total electron content measurements of the ATS-6 radio beacon experiments at Ootacamund is demonstrated.  By comparing with the observed values, the probable drift velocities over Ootacamund are determined for October and December, 1975.  The drift velocity patterns show broad similitarities with those observed over Jicamarca.

scholarly journals Spectral Asymmetry of Near-Concentric Traveling Ionospheric Disturbances Due to Doppler-Shifted Atmospheric Gravity Waves

2021 ◽  
Vol 8 ◽  
Author(s):  
Irfan Azeem
Keyword(s):  
Gravity Waves ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Neutral Wind ◽  
Atmospheric Gravity Waves ◽  
Total Electron ◽  
Traveling Ionospheric Disturbances ◽  
Gnss Receivers ◽  
Spectral Asymmetry ◽  
Atmospheric Gravity

Atmospheric Gravity Waves (AGWs) excited by meteorological sources are one of the prominent sources of variability in the ionosphere. Partially-concentric Traveling Ionospheric Disturbances (TIDs) associated with AGWs launched by convective storms have been reported in Total Electron Content (TEC) data from distributed networks of Global Navigation Satellite System (GNSS) receivers. In this paper, TEC data from GNSS receivers in the COntiguous United States (CONUS) are presented to examine AGWs in the ionosphere generated by a convective thunderstorm on April 28, 2014 over Mississippi (MS) and Tennessee (TN). Our analysis of the TID perturbations in the TEC data shows zonal asymmetry of the wave frequencies. This spectral asymmetry is examined to determine the effects of the background neutral wind on the intrinsic periods of the underlying AGWs. This work shows that if the relative motion of the TID wavefronts and the background neutral wind is in the opposite direction, the intrinsic periods will decrease and if they both travel in the same direction, the intrinsic periods will increase. Furthermore, our results show that the characteristics of the TIDs observed on April 28, 2014 in the TEC over CONUS are consistent with those of underlying AGWs being excited by a point source, such as a deep convection system.

FEATURES OF USING SURVEY RECEIVERS FOR REAL-TIME IONOSPHERE MONITORING

2021 ◽  
pp. 14-21
Author(s):  
P. А. Budnikov ◽  
◽  
V. V. Alpatov ◽  
Keyword(s):  
Real Time ◽  
Total Electron Content ◽  
Peak Height ◽  
Electron Content ◽  
Data Loss ◽  
Total Electron ◽  
Ionosphere Monitoring ◽  
Problems And Solutions ◽  
Gnss Receivers ◽  
Scintillation Indices

The features of using survey GNSS receivers for real-time ionosphere monitoring based on high orbital ionosphere tomography network are presented. The related problems and solutions methods are described. The algorithms for calculating total electron content and scintillation indices, that allow reducing errors and noise, are proposed. Special attention is given to the methods reducing data loss during processing. A model of the electron content peak height used for mapping ionospheric parameters is also introduced.

A New Approach to Monitoring the Interplanetary Shock Induced Pulse: TEC Measurements by the GNSS Receiver Network

2020 ◽  
Author(s):  
Xingran Chen ◽  
Quanhan Li ◽  
Qiugang Zong ◽  
Yongqiang Hao
Keyword(s):  
Propagation Speed ◽  
Interplanetary Shock ◽  
Satellite System ◽  
Wave Form ◽  
Electron Content ◽  
Shock Pulse ◽  
Total Electron ◽  
New Approach ◽  
Gnss Receivers ◽  
Global Navigation Satellite

<p>We revisit the typical interplanetary shock event on November 7, 2004, with high resolution total electron content (TEC) measurements obtained by the distributed Global Navigation Satellite System (GNSS) receivers. TEC impulses were observed after the IP shock impinged on the dayside agnetosphere at ~18:27 UT. In view of the similarity of the wave form and the time-delay characteristics, the TEC impulses were regarded as responses to the IP shock, despite the small amplitude (in the order of 0.4 TECU). Particularly, the peak of the TEC impulse was first observed by the receivers located around 120°W geographic longitude (corresponding to noon magnetic local time), while receivers at both sides recorded the impulse sequentially afterwards. From the timedelay of the TEC impulse, we derive the propagation velocity of the shock induced pulse. The angular velocity of the pulse is estimated to be ~2 degree per second, which is in the same order as the propagation speed of a typical shock pulse in the magnetosphere. Our results present global observational features of the shock pulse and provide new aspects to understand the ionospheric-magnetospheric dynamics in response to IP shocks.</p>

scholarly journals Correlation between Ionospheric TEC and the DCB Stability of GNSS Receivers from 2014 to 2016

2019 ◽  
Vol 11 (22) ◽  
pp. 2657 ◽  
Author(s):  
Choi ◽  
Sohn ◽  
Lee
Keyword(s):  
Estimation Method ◽  
Satellite System ◽  
Electron Content ◽  
Strong Positive Correlation ◽  
Low Latitude ◽  
Total Electron ◽  
Gnss Receiver ◽  
Gnss Receivers ◽  
Global Navigation Satellite ◽  
The Relationship

The Global Navigation Satellite System (GNSS) differential code biases (DCBs) are a major obstacle in estimating the ionospheric total electron content (TEC). The DCBs of the GNSS receiver (rDCBs) are affected by various factors such as data quality, estimation method, receiver type, hardware temperature, and antenna characteristics. This study investigates the relationship between TEC and rDCB, and TEC and rDCB stability during a three-year period from 2014 to 2016. Linear correlations between pairs of variables, measured with Pearson’s coefficient (), are considered. It is shown that the correlation between TEC and rDCB is the smallest in low-latitude regions. The mid-latitude regions exhibit the maximum value of. In contrast, the correlation between TEC and rDCB root mean square (RMS, stability) was greater in low-latitude regions. A strong positive correlation (R≥0.90) on average between TEC and rDCB RMS was also revealed at two additional GNSS stations in low-latitude regions, where the correlation shows clear latitudinal dependency. We found that the correlation between TEC and rDCB stability is still very strong even after replacing a GNSS receiver.

scholarly journals Error analysis of Abel retrieved electron density profiles from radio occultation measurements

2010 ◽  
Vol 28 (1) ◽  
pp. 217-222 ◽  
Author(s):  
X. Yue ◽  
W. S. Schreiner ◽  
J. Lei ◽  
S. V. Sokolovskiy ◽  
C. Rocken ◽  
...  
Keyword(s):  
Electron Density ◽  
Radio Occultation ◽  
Electron Content ◽  
Electron Densities ◽  
Density Profiles ◽  
Total Electron ◽  
The North ◽  
Spring Equinox ◽  
Electron Density Profiles ◽  
Artificial Plasma

Abstract. This letter reports for the first time the simulated error distribution of radio occultation (RO) electron density profiles (EDPs) from the Abel inversion in a systematic way. Occultation events observed by the COSMIC satellites are simulated during the spring equinox of 2008 by calculating the integrated total electron content (TEC) along the COSMIC occultation paths with the "true" electron density from an empirical model. The retrieval errors are computed by comparing the retrieved EDPs with the "true" EDPs. The results show that the retrieved NmF2 and hmF2 are generally in good agreement with the true values, but the reliability of the retrieved electron density degrades in low latitude regions and at low altitudes. Specifically, the Abel retrieval method overestimates electron density to the north and south of the crests of the equatorial ionization anomaly (EIA), and introduces artificial plasma caves underneath the EIA crests. At lower altitudes (E- and F1-regions), it results in three pseudo peaks in daytime electron densities along the magnetic latitude and a pseudo trough in nighttime equatorial electron densities.

scholarly journals Electron and ion density variations before strong earthquakes (<i>M</i>>6.0) using DEMETER and GPS data

2010 ◽  
Vol 10 (1) ◽  
pp. 7-18 ◽  
Author(s):  
M. Akhoondzadeh ◽  
M. Parrot ◽  
M. R. Saradjian
Keyword(s):  
Gps Data ◽  
Electron Content ◽  
Ion Density ◽  
Total Electron ◽  
Strong Earthquakes ◽  
Total Electron Content Data ◽  
Electromagnetic Emissions ◽  
Seismic Anomalies ◽  
Geomagnetic Activities ◽  
Large Earthquakes

Abstract. Using IAP (plasma analyzer) and ISL (Langmuir probe) experiments onboard DEMETER (Detection of Electromagnetic Emissions Transmitted from Earthquake Regions) satellite and GPS (Global Positioning System) measurements, we have statistically analyzed the variations of the electron and ion densities to search for disturbances in the vicinity of four large earthquakes prior to events. The indices Dst and Kp were used to distinguish pre-earthquake anomalies from the other anomalies related to the geomagnetic activities. For each studied case, a very good agreement was found between the different parameters estimated by DEMETER and GPS data in the detection of pre-seismic anomalies. Our statistics results show that the anomalous deviations prior to earthquakes have different sign from case to case, and that their amplitude depends on the magnitude of the earthquake. It has also been found that the electron density measured by the ISL experiment at night detects anomalous variations significantly before the earthquakes. The appearance of positive and negative anomalies in both of DEMETER and TEC (Total Electron Content) data during 1 to 5 days before all studied earthquakes during quiet geomagnetic conditions indicates that these anomalous behaviors are highly regarded as seismo-ionospheric precursors.

Sign in / Sign up

Export Citation Format

Share Document