Detection of ionospheric anomalies during intense space weather over a low-latitude GNSS station

Abstract

The operational availability of Global Navigation Satellite System is affected by large-scale irregularities of the ionosphere. The space weather events induce several intense irregularities and cause the non-linear distribution of ionospheric electron density. Monitoring of ionospheric responses due to extreme space weather events plays a key role in trans-ionospheric radio wave propagation. In the present analysis, a novel technique based on wavelet transform has been implemented for the analysis and detection of ionospheric anomalies during two intense space weather events that occurred in 2013. The investigations have been carried out using the ionospheric observable, Total Electron Content (TEC), derived from the Global Positioning System (GPS) receiver located at an Equatorial Ionisation Anomaly region, KL University, Guntur, India (Geographic Lat.16.37°N, Geographic Long. 80.37°E). The effects of geomagnetic storms (Sym-H B-100 nT) on the perturbations of ionospheric TEC have been investigated. The algorithm of Continuous wavelet transform has been used to study and characterise the presence of ionospheric anomalies in the local timescale plane. It can detect spatial and temporal details of ionospheric anomaly intensity during strong solar-terrestrial and geophysical events. It is observed that during the main phase of the geomagnetic storm that occurred during 17 March 2013, TEC enhanced by 7 TECU, while a suppression of 10 TECU in the GPS-TEC can be noticed during the main phase of the 29 June 2013 storm. The variation in the intensity of ionospheric TEC anomalies during storm time has been detected and compared to the intensity of the space weather events measured through solar and geomagnetic indices (F10.7, Sym-H, IMF Bz and IEF Ey).

Construction and Analysis of Urban Cultural Plane Space Mode considering Particle Swarm Cultural Scientific Computing Algorithm

“…e spatial structure of urban culture is also regarded as the cultural spiritual dimension of urban spatial structure, the highest form of urban spatial structure, and an important way of expressing the interaction between material and spiritual activities of urban people. It is mainly composed of three dimensions: the rich historical and cultural spatial structure of urban traditional historical culture, the diverse real spatial structure of urban reality and culture, and the extended spatial structure of urban social culture in the future [12]. At the same time, the urban cultural space is regarded as the existence form expressed by the material-social cultural form created by people, and it has the six characteristics of location, economy, humanity, symbolism, citizenship, and modernity [13].…”

“…From the initialization condition of (12), it can be known that the particle has been iterated at the initialization speed until the end of the algorithm. If an individual's current position, the individual's historical best predicted position, and the group's historical best predicted position are all the same, the individual will leave the best historical area because its previous speed and inertia weight are not zero.…”

Performance Evaluation of Global Ionospheric Models With Indian Regional Navigation Data Over Low Latitude Station During Low Solar Activity Year 2017

“…The ionospheric models can be classified as global, regional, and local for estimating ionospheric characteristics of a specific region at a specific time, latitude, longitude, altitude, and geomagnetic activity. In the recent past, several regional ionospheric models have been investigated over the Indian region with GPS data [3][4][5]. Significant fluctuations in TEC response have been observed by various investigations carried out during different geomagnetic storms and solar cycle phases over low-latitude and equatorial regions using GPS data [6][7][8][9][10][11][12][13].…”

“…[3][4][5][6][7][8][9][10] show the monthly and seasonal variations of VTEC and percentage of error deviation between models and NavIC data for quiet and disturbed days during the year 2017 over low latitude Hyderabad station. A gradual increase is observed in TEC from 00:00 UT to 09:00 UT, a peak value around 09:00 UT and a gradual decrease from 09:00 UT to 16:00 UT, minimum values with slight variations from 16:00 UT 23:00 UT for both quiet and disturbed days due to models and observed NavIC data.…”

Validation of the IRI‐2016 model with Indian NavIC data for future navigation applications

“…Hence, it is necessary for modelling of ionospheric time delay over low latitude regions. The variations of TEC over low latitude region have been investigated by many authors using GPS data from ground based measurements [6][7][8][9][10][11][12]. There are several ionospheric models like global, regional, and local for estimating TEC [13,14].…”