L-band scintillation and TEC variations on St. Patrick’s Day storm of 17 March 2015 over Indian longitudes using GPS and GLONASS observations

Abstract

The aim of the present study is to investigate the response of ionospheric total electron content (TEC), Global Positioning System (GPS) and Global Navigation Satellite System (GLONASS) scintillations during 17 March 2015 St. Patrick's Day geomagnetic storm over Visakhapatnam, which is popularly known as Waltair (WALT) in the literature. GPS TEC observations obtained from five IGS stations (SGOC, IISC, HYDE, LCK4 and LHAZ) and WALT during the storm have been compared. The TEC derived from GPS, GLONASS constellations and CODE global ionosphere TEC map (GIM) over WALT has also been compared. Positive storm effect during the main phase of the storm and negative storm effect during the recovery phase of the storm were observed over the said stations. The variation of northern equatorial ionisation anomaly TEC (CODE GIM TEC maps) in response to the St. Patrick's Day storm over four Indian longitudes (75 • E, 80 • E, 85 • E and 90 • E) has also been presented. Strong amplitude and phase scintillations were observed in the L-band signals of GPS and GLONASS constellations over WALT. Twelve satellite (Pseudo Random Noise) PRNs of GPS L1 and nine PRNs of each GLONASS L1 and L2-band signals were affected by strong amplitude and phase scintillation. The peak amplitude scintillation index (S4) obtained from the effected PRNs of GPS L1 signal and GLONASS L1-band signals over WALT range from 0.36 to 0.74 and 0.36 to 0.76, respectively. Strong fluctuations in rate of TEC index are noted over the said stations. This enhanced scintillation activity is mainly due to the main phase of the storm falls in the evening sector over the Indian region.

Spatio‐Temporal Evolution of Global Ionospheric Storm Drivers and Hemispherical Asymmetry During 17–18 March 2015 Geomagnetic Storm

“…As apparently seen in Figure 9 (second and third columns) during this period the PPEF point in the east ward direction, for example in the European (CLF) and Asian (AAA) region in the NH and also CZT in SH. The East ward PPEF enhance the global scale eastward electric field, intensifying the upward drift and thereby transport plasma to higher altitudes where electrons loss rate is minimum, and thus an increase in Ne and TEC leading to positive ionospheric storm effect (Srinivasu et al., 2019; Tsurutani et al., 2013; Venkatesh et al., 2017). Additionally, the positive ionospheric storm effect seen in these times and sectors was partly due to the enhanced (O)/(N 2 ) ratio, as marked in Figure 8d.…”

Signatures of Equatorial Plasma Bubbles and Ionospheric Scintillations from Magnetometer and GNSS Observations in the Indian Longitudes during the Space Weather Events of Early September 2017

“…The scintillation characteristics were presented in the past by using the extracted ROTI from the GPS aided geo augmented system (GAGAN) and other data over the Indian low latitude region [42]. Furthermore, the observations at a low latitude location in Visakhapatnam in India reported strong fluctuations in ROTI during the St. Patrick's day (17 March 2015) geomagnetic storm [43].…”

Irregularities in the African ionosphere associated with total electron content anomalies observed during high solar activity levels

“…Total electron content (TEC) is an integrated value of electron density that exists between the satellite that emits the signal and the ground receiver (Okoh et al, 2019). Several researchers (Fagundes et al, 2016;Venkatesh et al, 2017;Srinivasu et al, 2019) have employed TEC data to study ionospheric variability since it is a suitable parameter to study the different phases of ionospheric disturbances globally and locally (Jakowski et al, 2002;Xiong et al, 2019). Unfortunately, the complex mechanisms and processes in the ionosphere are difficult to model, and the practical applications that use the existing models are still far away to provide the required accuracy (Borries et al, 2015;Nava et al, 2016).…”