scholarly journals Global distribution of GPS losses of phase lock and total electron content slips during the 2005 May 15 and the 2003 November 20 magnetic storms

2015 ◽  
Vol 1 (4) ◽  
pp. 58-65 ◽  
Author(s):  
Юрий Ясюкевич ◽  
Yury Yasyukevich ◽  
Эльвира Астафьева ◽  
Elvira Astafyeva ◽  
Илья Живетьев ◽  
...  
Keyword(s):  
Total Electron Content ◽  
Background Level ◽  
Auroral Oval ◽  
Magnetic Storms ◽  
Electron Content ◽  
High Latitudes ◽  
Total Electron ◽  
Phase Lock ◽  
Using Data ◽  
Worldwide Network

Using data of worldwide network of GPS receivers we investigated losses of GPS phase lock (LoL) during two strong magnetic storms. At fundamental L1 frequency, LoL density is found to increase up to 0.25 % and at L2 frequency the increase is up to 3 %. This is several times as much compared with the background level. During the 2003 November 20 magnetic storm, the number of total electron content (TEC) slips exceeded the background level ~50 times. During superstorms, the most number of GPS LoL is observed at low and high latitudes. At the same time, the area of numerous TEC slips correspond to auroral oval boundaries.

Localized enhancements of total electron content in Southern Hemisphere

2020 ◽  
Author(s):  
Ilya Edemskiy ◽  
Ilya Edemskiy
Keyword(s):  
Southern Hemisphere ◽  
Total Electron Content ◽  
Magnetic Storms ◽  
Occurrence Rate ◽  
Electron Content ◽  
Quiet Time ◽  
Total Electron ◽  
Middle Latitudes ◽  
Near Space ◽  
Global Ionospheric Maps

<p>Localized enhancements of total electron content (TEC) are usually registered during magnetic storms and are often believed to be connected with storm enhanced density (SED) events. Investigating global ionospheric maps we found that such localized TEC enhancements (LTE) could be observed in Southern Hemisphere during both disturbed and quiet time with no clear dependence on parameters of near space. Analysis of occurrence of LTEs in the regions of Indian and Southern Atlantic Oceans showed that part of them (observed during magnetic storms and localized in subpolar latitudes) can be connected with SEDs. Since another part of subpolar LTEs is detected during relatively quiet conditions its generation mechanism should be different despite they have similar spatial distribution. Most of the enhancements are observed in middle latitudes and is detected during all the investigated years. The occurrence rate of LTEs hardly depends on solar activity and the most probable season for LTE detection is April-September (autumn-winter).</p><p>Here we investigate reasons of generation both midlatitudinal and subpolar LTEs trying to define the mechanisms of their generation in details.</p>

scholarly journals Regional reference total electron content model over Japan based on neural network mapping techniques

2007 ◽  
Vol 25 (12) ◽  
pp. 2609-2614 ◽  
Author(s):  
T. Maruyama
Keyword(s):  
Neural Network ◽  
Solar Activity ◽  
Total Electron Content ◽  
Reference Model ◽  
Activity Period ◽  
Electron Content ◽  
Total Electron ◽  
Grid Points ◽  
Using Data ◽  
Regional Reference

Abstract. A regional reference model of total electron content (TEC) was constructed using data from the GPS Earth Observation Network (GEONET), which consists of more than 1000 Global Positioning System (GPS) satellite receivers distributed over Japan. The data covered almost one solar activity period from April 1997 to June 2007. First, TECs were determined for 32 grid points, expanding from 27 to 45° N in latitude and from 127 to 145° E in longitude at 15-min intervals. Secondly, the time-latitude variation averaged over three days was determined by using the surface harmonic functional expansion. The coefficients of the expansion were then modeled by using a neural network technique with input parameters of the season (day of the year) and solar activity (F10.7 index and sunspot number). Thus, two-dimensional TEC maps (time vs. latitude) can be obtained for any given set of solar activity and day of the year.

Determining receiver biases in GPS-derived total electron content in the auroral oval and polar cap region using ionosonde measurements

GPS Solutions ◽  
2012 ◽  
Vol 17 (3) ◽  
pp. 357-369 ◽  
Author(s):  
David R. Themens ◽  
P. T. Jayachandran ◽  
R. B. Langley ◽  
J. W. MacDougall ◽  
M. J. Nicolls
Keyword(s):  
Total Electron Content ◽  
Auroral Oval ◽  
Electron Content ◽  
Polar Cap ◽  
Total Electron

scholarly journals SCINDA-GPS derived TEC depletions and amplitude scintillations over Kisumu, Kenya during selected quiet and storm days of 2013 and 2014

2020 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Uluma Edward ◽  
Ndinya Boniface ◽  
Omondi George
Keyword(s):  
Total Electron Content ◽  
Equatorial Region ◽  
Activity Period ◽  
High Solar Activity ◽  
Electron Content ◽  
Vertical Total Electron Content ◽  
Gps Receiver ◽  
Total Electron ◽  
Solar Intensity ◽  
Using Data

Total Electron Content (TEC) depletion and amplitude scintillation (S4) can be derived from, SCINDA-GPS receivers situated in various parts of the equatorial region. In this paper we present results of characterization of TEC depletions and amplitude scintillations over Kisumu, Kenya (Geomagnetic coordinates: 9.64o S, 108.59o E; Geographic coordinates: 0.02o S, 34.6o E) for both selected geomagnetically quiet and geomagnetically disturbed conditions between 1st January 2013 and 31st December 2014 using data derived from the Kisumu NovAtel GSV4004B SCINDA-GPS receiver situated at Maseno University. TEC depletions and amplitude scintillations affect Global Positioning System (GPS) signals in the ionosphere as they propagate from the satellite to the receiver. This study aims to investigate day to day variability of TEC depletions and amplitude scintillations over Kisumu, Kenya during both geomagnetically quiet and geomagnetically disturbed days of 2013 and 2014 which was a high solar activity period for Solar Cycle 24. Seasonal variability of TEC depletions and S4 index is also presented. The Receiver Independent Exchange (RINEX) data for the years 2013 and 2014 was retrieved from the Kisumu SCINDA-GPS receiver, processed to obtain Vertical Total Electron Content (VTEC), S4 and Universal Time (UT) and fed into MATLAB to generate VTEC and S4 plots against UT for each selected quiet and storm day within the 2013 and 2014 period. The obtained results showed a diurnal variation of TEC where TEC was minimum at pre-sunrise, maximum during daytime and minimum during nighttime. The minimum TEC during pre-sunrise and nighttime was attributed to reduced solar intensity while maximum TEC during daytime is attributed to increased solar intensity. Most of the selected quiet and storm days of the years 2013 and 2014 showed TEC depletions and TEC enhancements corresponding with enhanced amplitude scintillations between 1800UT and 20:00UT. This might be attributed to the rapid rise of the F-layer and the increase in the vertical E x B plasma drift due to the Pre-reversal Enhancement (PRE) of the eastward electric field. Post-midnight TEC depletions and amplitude scintillations were observed for some days and this was attributed to the effect of zonal winds which brought post-midnight enhancement of the E x B drift. The percentage occurrence of amplitude scintillations for the selected quiet and storm days exhibited a seasonal dependence with equinoctial months having higher occurrences than the solstitial months. The higher average S4 index during equinoctial months might be attributed to increased solar intensity resulting from the close alignment of the solar terminator and the geomagnetic meridian.  

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