scholarly journals Variability of CODG TEC and IRI 2001 total electron content (TEC) during IHY campaign period (21 March to 16 April 2008) at Niamey under different geomagnetic activity conditions

2011 ◽  
Vol 6 (17) ◽  
pp. 3609-3622 ◽  
Author(s):  
Ouattara Freacute deacute ric ◽  
Roll ◽  
Fleury
Keyword(s):  
Total Electron Content ◽  
Geomagnetic Activity ◽  
Electron Content ◽  
Total Electron

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 VARIATIONS OF IONOSPHERIC PARAMETERS OVER ALMATY (KAZAKHSTAN) IN 1999–2013

2019 ◽  
Vol 5 (4) ◽  
pp. 110-116
Author(s):  
Saule Mukasheva ◽  
Vitaliy Kapytin ◽  
Andrey Malimbaev
Keyword(s):  
Solar Activity ◽  
Solar Radiation ◽  
Total Electron Content ◽  
Geomagnetic Activity ◽  
Radiation Flux ◽  
Electron Content ◽  
Nonlinear Relationship ◽  
Activity Levels ◽  
Total Electron ◽  
Solar Radiation Flux

The paper presents the results of a study of the behavior of ionospheric parameters of the total electron content, I(t), and electron density in the maximum F2 layer, Nm, over Almaty (Kazakhstan) [43.25° N; 76.92° E] in 1999–2013. The time interval under study covers different solar activity levels. We have shown that at F10.7>175 in summer and at F10.7>225 in winter there is a saturation effect, i.e. with increasing solar activity level values of I(t) do not increase. The observed nonlinear relationship between the total electron content of the ionosphere and the solar radiation flux F10.7 results from the nonlinear relationship between the solar ultraviolet radiation and the solar radiation flux. The study of the variability of the mid-latitude ionosphere parameters during different solar and geomagnetic activity levels has shown that the standard deviation ç(x) and average shift Xave of I(t) and Nm fluctuations relative to the quiet level weakly depend on solar activity, but greatly depend on geomagnetic activity when F10.7<100.

scholarly journals VARIATIONS OF IONOSPHERIC PARAMETERS OVER ALMATY (KAZAKHSTAN) IN 1999–2013

2019 ◽  
Vol 5 (4) ◽  
pp. 91-96
Author(s):  
Saule Mukasheva ◽  
Vitaliy Kapytin ◽  
Andrey Malimbaev
Keyword(s):  
Solar Activity ◽  
Solar Radiation ◽  
Total Electron Content ◽  
Geomagnetic Activity ◽  
Radiation Flux ◽  
Electron Content ◽  
Nonlinear Relationship ◽  
Activity Levels ◽  
Total Electron ◽  
Solar Radiation Flux

The paper presents the results of a study of the behavior of ionospheric parameters of the total electron content, I(t), and electron density in the maximum F2 layer, Nm, over Almaty (Kazakhstan) [43.25° N; 76.92° E] in 1999–2013. The time interval under study covers different solar activity levels. We have shown that at F10.7>175 in summer and at F10.7>225 in winter there is a saturation effect, i.e. with increasing solar activity level values of I(t) do not increase. The observed nonlinear relationship between the total electron content of the ionosphere and the solar radiation flux F10.7 results from the nonlinear relationship between the solar ultraviolet radiation and the solar radiation flux. The study of the variability of the mid-latitude ionosphere parameters during different solar and geomagnetic activity levels has shown that the standard deviation ç(x) and average shift Xave of I(t) and Nm fluctuations relative to the quiet level weakly depend on solar activity, but greatly depend on geomagnetic activity when F10.7<100.

scholarly journals Short-term relationship of total electron content with geomagnetic activity in equatorial regions

2008 ◽  
Vol 113 (A11) ◽  
pp. n/a-n/a ◽  
Author(s):  
X. Wang ◽  
Q. Sun ◽  
R. Eastes ◽  
B. Reinisch ◽  
C. E. Valladares
Keyword(s):  
Total Electron Content ◽  
Geomagnetic Activity ◽  
Electron Content ◽  
Short Term ◽  
Total Electron ◽  
Relationship Of

Low-latitude total electron content enhancement at low geomagnetic activity observed over Japan

2007 ◽  
Vol 112 (A7) ◽  
pp. n/a-n/a ◽  
Author(s):  
Ivan Kutiev ◽  
Yuichi Otsuka ◽  
Akinori Saito ◽  
Takuya Tsugawa
Keyword(s):  
Total Electron Content ◽  
Geomagnetic Activity ◽  
Electron Content ◽  
Low Latitude ◽  
Total Electron

scholarly journals Ionospheric total electron content anomaly possibly associated with the April 4, 2010 Mw7.2 Mexico earthquake

2020 ◽  
Author(s):  
Jing Liu ◽  
Wenbin Wang ◽  
Xuemin Zhang
Keyword(s):  
Total Electron Content ◽  
Geomagnetic Activity ◽  
Lower Atmosphere ◽  
Electron Content ◽  
Massachusetts Institute Of Technology ◽  
Total Electron ◽  
Nonlinear Fitting ◽  
Ionospheric Total Electron Content ◽  
Institute Of Technology ◽  
Mexico Earthquake

Abstract. Identifying ionospheric disturbances potentially related to an earthquake is a challenging work. Based on the ionospheric total electron content (TEC) data from the madrigal database at the Haystack Observatory, Massachusetts Institute of Technology, a new decomposition and nonlinear fitting method has been developed and applied in this work to extract the TEC disturbances that are potentially related to the Mw7.2 Mexico earthquake occurred on April 4 2010. By analyzing the TEC data for a long period of time (72 days) before and after the earthquake, we found that a unique TEC depletion occurred in the region around the epicenter on March 25. No other significant ionospheric TEC anomalies were identified in the 72-day period around the earthquake, except some TEC disturbances that appeared to be related to the geomagnetic activity between April 1 and 6, 2010. We further analyzed the TEC data from other magnetically quiet days, and no TEC anomaly like that occurred on March 25 was detected. The TEC data calculated from a first principles model SD-WACCM-X were also analyzed using the same method as that for the observational data. No TEC anomaly was found on March 25 from the model outputs either. Thus the source of the TEC anomaly on March 25 is unlikely from the lower atmosphere waves. In this study, we show the occurrence of TEC anomaly on March 25, 10 days before the Mw7.2 Mexico earthquake and this TEC anomaly may not be explained by lower atmosphere or geomagnetic activity forcing.

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