scholarly journals Global Distribution of Persistence of Total Electron Content Anomaly

Atmosphere ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 297 ◽  
Author(s):  
Yang-Yi Sun ◽  
Jann-Yenq Liu ◽  
Tsung-Yu Wu ◽  
Chieh-Hong Chen
Keyword(s):  
Total Electron Content ◽  
Orbit Determination ◽  
Electron Content ◽  
Neutral Wind ◽  
Eastern Asia ◽  
Total Electron ◽  
The Pacific ◽  
Longitudinal Sector ◽  
Low Latitudes ◽  
The Pacific Ocean

To better understand the ionospheric morphology response to lithospheric activities, we study the global location preference of the positive and negative total electron content (TEC) anomalies persisting continuously for longer than 24 h at middle and low latitudes (within ±60° N geomagnetic latitudes). The TEC is obtained from the global ionospheric map (GIM) of Center for Orbit Determination in Europe (CODE) under the geomagnetic quiet condition of Kp ≤ 3o during the period of 2005 to 2018. There are a few (less than 4%) TEC anomalies that can persist over 24 h. The conjugate phenomenon is most significant in the eastern Asia to Australia longitudinal sector. The result shows the persistence of the positive TEC anomaly along the ring of fire on the western edge of the Pacific Ocean. The high persistence of the TEC anomalies at midlatitudes suggests that thermospheric neutral wind contributes to the anomaly formation.

scholarly journals Emergence of a localized total electron content enhancement during the severe geomagnetic storm of 8 September 2017

2019 ◽  
Vol 37 (2) ◽  
pp. 153-161 ◽  
Author(s):  
Carlos Sotomayor-Beltran ◽  
Laberiano Andrade-Arenas
Keyword(s):  
Statistical Method ◽  
Total Electron Content ◽  
Geomagnetic Storm ◽  
Orbit Determination ◽  
Geomagnetic Storms ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Total Electron ◽  
Equatorial Ionization Anomaly ◽  
The Pacific

Abstract. In this work, the results of the analysis on total electron content (TEC) data before, during and after the geomagnetic storm of 8 September 2017 are reported. One of the responses to geomagnetic storms due to the southern vertical interplanetary magnetic field (Bz) is the enhancement of the electron density in the ionosphere. Vertical TEC (VTEC) from the Center for Orbit determination in Europe (CODE) along with a statistical method were used to identify positive and/or negative ionospheric storms in response to the geomagnetic storm of 8 September 2017. When analyzing the response to the storm of 8 September 2017 it was indeed possible to observe an enhancement of the equatorial ionization anomaly (EIA); however, what was unexpected was the identification of a local TEC enhancement (LTE) to the south of the EIA (∼40∘ S, right over New Zealand and extending towards the southeastern coast of Australia and also eastward towards the Pacific). This was a very transitory LTE that lasted approximately 4 h, starting at ∼ 02:00 UT on 8 September where its maximum VTEC increase was of 241.2 %. Using the same statistical method, comparable LTEs in a similar category geomagnetic storm, the 2015 St. Patrick's Day storm, were looked for. However, for the aforementioned storm no LTEs were identified. As also indicated in a past recent study for a LTE detected during the 15 August 2015 geomagnetic storm, an association between the LTE and the excursion of Bz seen during the 8 September 2017 storm was observed as well. Furthermore, it is very likely that a direct impact of the super-fountain effect along with traveling ionospheric disturbances may be playing an important role in the production of this LTE. Finally, it is indicated that the 8 September 2017 LTE is the second one to be detected since the year 2016.

scholarly journals Case study on total electron content enhancements at low latitudes during low geomagnetic activities before the storms

2008 ◽  
Vol 26 (4) ◽  
pp. 893-903 ◽  
Author(s):  
◽  
◽  
◽  
Keyword(s):  
Total Electron Content ◽  
Geomagnetic Activity ◽  
Electron Content ◽  
Low Latitude ◽  
Total Electron ◽  
Defense Meteorological Satellite Program ◽  
Low Latitudes ◽  
Global Ionospheric Maps ◽  
Geomagnetic Activities

Abstract. Sometimes the ionospheric total electron content (TEC) is significantly enhanced during low geomagnetic activities before storms. In this article, we investigate the characteristics of those interesting TEC enhancements using regional and global TEC data. We analyzed the low-latitude TEC enhancement events that occurred around longitude 120° E on 10 February 2004, 21 January 2004, and 4 March 2001, respectively. The TEC data are derived from regional Global Positioning System (GPS) observations in the Asia/Australia sector as well as global ionospheric maps (GIMs) produced by Jet Propulsion Laboratory (JPL). Strong enhancements under low geomagnetic activity before the storms are simultaneously presented at low latitudes in the Asia/Australia sector in regional TEC and JPL GIMs. These TEC enhancements are shown to be regional events with longitudinal and latitudinal extent. The regions of TEC enhancements during these events are confined at narrow longitude ranges around longitude 120° E. The latitudinal belts of maxima of enhancements locate around the northern and southern equatorial ionization anomaly (EIA) crests, which are consistent with those low-latitude events presented by Liu et al. (2008). During the 4 March 2001 event, the total plasma density Ni observed by the Defense Meteorological Satellite Program (DMSP) spacecraft F13 at 840 km altitude are of considerably higher values on 4 March than on the previous day in the TEC enhanced regions. Some TEC enhancement events are possibly due to contributions from auroral/magnetospheric origins; while there are also quasi-periodic enhancement events not related to geomagnetic activity and associated probably with planetary wave type oscillations (e.g. the 6 January 1998 event). Further investigation is warrented to identify/separate contributions from possible sources.

scholarly journals Response of the total electron content at Brazilian low latitudes to corotating interaction region and high-speed streams during solar minimum 2008

2018 ◽  
Vol 70 (1) ◽  
Author(s):  
Claudia M. N. Candido ◽  
Inez S. Batista ◽  
Virginia Klausner ◽  
Patricia M. de Siqueira Negreti ◽  
Fabio Becker-Guedes ◽  
...  
Keyword(s):  
Total Electron Content ◽  
Solar Minimum ◽  
High Speed ◽  
Interaction Region ◽  
Electron Content ◽  
Corotating Interaction Region ◽  
Total Electron ◽  
Low Latitudes

Total electron content at low latitudes and its comparison with the IRI90

1994 ◽  
Vol 14 (12) ◽  
pp. 87-90 ◽  
Author(s):  
I.S. Batista ◽  
J.R. de Souza ◽  
M.A. Abdu ◽  
E.R. de Paula
Keyword(s):  
Total Electron Content ◽  
Electron Content ◽  
Total Electron ◽  
Low Latitudes

Anomaly effects of 6–10 September 2017 solar flares on ionospheric total electron content over Saudi Arabian low latitudes

2020 ◽  
Vol 177 ◽  
pp. 332-340
Author(s):  
Kanaka Durga Reddybattula ◽  
Sampad Kumar Panda ◽  
Sunil Kumar Sharma ◽  
Arun Kumar Singh ◽  
Kasmira Kurnala ◽  
...  
Keyword(s):  
Total Electron Content ◽  
Solar Flares ◽  
Saudi Arabian ◽  
Electron Content ◽  
Total Electron ◽  
Ionospheric Total Electron Content ◽  
Low Latitudes

Modulation of total electron content by global Pc5 waves at low latitudes

2016 ◽  
Vol 57 (1) ◽  
pp. 309-319 ◽  
Author(s):  
E. Vorontsova ◽  
V. Pilipenko ◽  
E. Fedorov ◽  
A.K. Sinha ◽  
G. Vichare
Keyword(s):  
Total Electron Content ◽  
Electron Content ◽  
Total Electron ◽  
Low Latitudes

Total electron content at low latitudes

1978 ◽  
Vol 87 (1) ◽  
pp. 47-55
Author(s):  
Malkiat Singh ◽  
H S Gurm ◽  
M R Deshpande ◽  
R G Rastogi ◽  
G Sethia ◽  
...  
Keyword(s):  
Total Electron Content ◽  
Electron Content ◽  
Total Electron ◽  
Low Latitudes

Global distribution of persistence of total electron content anomaly

2020 ◽  
Author(s):  
Yang-Yi Sun ◽  
Chieh-Hong Chen ◽  
Jann-Yenq Liu ◽  
Tsung-Yu Wu
Keyword(s):  
Electric Field ◽  
Total Electron Content ◽  
Electron Content ◽  
Neutral Wind ◽  
Large Area ◽  
Atmospheric Gravity Wave ◽  
Total Electron ◽  
Ionospheric Plasma Density ◽  
Gps Products ◽  
Ionospheric Electric Field

<p>Solar activities can disturb the ionosphere globally and induce ionospheric weather phenomena that transit rapidly through a large area. By contrast, sometimes the ionospheric plasma density can remain high or low over a certain location for a few days, which are difficult to be attributed to solar activities. This study shows the location preference of the positive and negative total electron content (TEC) anomalies persisting continuously longer than 24 hours (cross the two terminators) at middle and low latitudes (within ±60ºN geomagnetic latitudes). The TEC is obtained from the global ionospheric map (GIM) of the Center for Orbit Determination in Europe (CODE) (ftp://cddis.gsfc.nasa.gov/pub/gps/products/ionex) under the geomagnetic quiet condition of Kp ≤ 3o during the period of 2005–2018. There are a few (less than 4%) TEC anomalies that can persist over 24 hours. The persistence of the positive TEC anomaly along the ring of fire on the western edge of the Pacific Ocean. The high persistence of the TEC anomalies at midlatitudes suggests that thermospheric neutral wind contributes to the anomaly formation. The temporal and spatial anomalies of the ionospheric electric field, atmospheric electric field (flash), atmospheric gravity wave, and neutral wind over the ring of fire should be further examined for explaining whether the persistence of the TEC anomalies associates with lithospheric activities.</p>

scholarly journals Annual and semiannual variations of vertical total electron content during high solar activity based on GPS observations

2011 ◽  
Vol 29 (5) ◽  
pp. 865-873 ◽  
Author(s):  
M. P. Natali ◽  
A. Meza
Keyword(s):  
Solar Activity ◽  
Total Electron Content ◽  
Principal Component ◽  
High Solar Activity ◽  
Electron Content ◽  
Vertical Total Electron Content ◽  
Total Electron ◽  
Ionospheric Variability ◽  
Low Latitudes ◽  
Sudden Decrease

Abstract. Annual, semiannual and seasonal variations of the Vertical Total Electron Content (VTEC) have been investigated during high solar activity in 2000. In this work we use Global IGS VTEC maps and Principal Component Analysis to study spatial and temporal ionospheric variability. The behavior of VTEC variations at two-hour periods, at noon and at night is analyzed. Particular characteristics associated with each period and the geomagnetic regions are highlighted. The variations at night are smaller than those obtained at noon. At noon it is possible to see patterns of the seasonal variation at high latitude, and patterns of the semiannual anomaly at low latitudes with a slow decrease towards mid latitudes. At night there is no evidence of seasonal or annual anomaly for any region, but it was possible to see the semiannual anomaly at low latitudes with a sudden decrease towards mid latitudes. In general, the semiannual behavior shows March–April equinox at least 40 % higher than September one. Similarities and differences are analyzed also with regard to the same analysis done for a period of low solar activity.

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