Modeling of local ionospheric time varying characteristics based on singular value decomposition over low-latitude GPS stations
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Singular Value Decomposition (SVD) model is implemented to recognize the Total Electron Content (TEC) time series of daily, temporal as well as seasonal characteristics throughout the 24th solar cycle period of the year 2015 in the study. The Vertical (vTEC) analysis has been carried out with Global Positioning System (GPS) data sets collected from five stations from India namely GNT, Guntur (16.44∘ N, 80.62∘ E), and IISC, Bangalore (12.97∘ N, 77.59∘ E), LCK2, Lucknow (26.76∘ N, 80.88∘ E), one station from Thailand namely AITB, Bangkok (14.07∘ N, 100.61∘ E), and one station from South Andaman Island namely PBR, Port Blair (11.43∘ N, 92.43∘ E), located in low latitude region. The first five singular value modes constitute about 98% of the total variance, which are linearly transformed from the observed TEC data sets. So it is viable to decrease the number of modeling parameters. The Fourier Series Analysis (FSA) is carried out to characterize the solar-cycle, annual and semi-annual dependences through modulating the first three singular values by the solar (F10.7) and geomagnetic (Ap) indices. The positive correlation coefficient (0.75) of daily averaged GPS–TEC with daily averaged F10.7 strongly supports the temporal variations of the ionospheric features depends on the solar activity. Further, the significance and reliability of the SVD model is evaluated by comparing it with GPS–TEC data and the standard global model (Standard Plasma-Spherical Ionospheric Model, SPIM and International Reference Ionosphere, IRI 2016).
KeywordsIonosphere GPS SVD FSA TEC IRI SPIM
The present work has been carried out under the project titled ‘Development of Single Frequency Ionospheric correction & plasma bubble detection algorithms using GPS Aided GEO Augmented Navigation (GAGAN) & Navigation Indian Constellation (NavIC) TEC observations’ sponsored by NavIC–GAGAN Utilization Programme at Space Applications Centre, Ahmedabad, India, Project ID: NGP-10. The contribution is also supported by Department of Science and Technology (DST), New Delhi, India, SR/FST/ESI-130/2013(C) under DST–FIST Program. The authors thank the reviewers for their helpful comments.
- Bouya, Z., Terkildsen, M., Neudegg, D.: Regional GPS-based ionospheric TEC model over Australia using spherical cap harmonic analysis. In: Proceedings of 38th COSPAR Scientific Assembly, Bremen, Germany, vol. 38, p. 4 (2010) Google Scholar
- Chowdhary, V.R., Tripathi, N.K., Arunpold, S., Raju, D.K.: Characterization of GPS–TEC in a low-latitude region over Thailand during 2010–2012. Ann. Geophys. 58(5), 0553 (2015) Google Scholar
- Habarulema, J.B., McKinnell, L.A., Opperman, B.D.: Regional GPS TEC modeling; Attempted spatial and temporal extrapolation of TEC using neural networks. J. Geophys. Res., Space Phys. 116(A4) (2011) Google Scholar
- Jakowski, N., Wehrenpfennig, A., Heise, S., Schlueter, S., Noack, T.: Space weather effects in the ionosphere and their impact on positioning. In: ESA Workshop Paper, December (2001) Google Scholar
- Kaplan, E., Hegarty, C.: Understanding GPS, Principles and Applications. 2. Artech House, INC, Norwood (2006) Google Scholar
- Mao, T., Wan, W., Yue, X., Sun, L., Zhao, B., Guo, J.: An empirical orthogonal function model of total electron content over China. Radio Sci. 43(2) (2008) Google Scholar
- Preisendorfer, R., Mobley, C.D.: Principal Component Analysis in Meteorology and Oceanography. Elsevier, Amsterdam (1988) Google Scholar
- Skone, S.: Wide area ionosphere grid modelling in the auroral region. UCGE Reports, Number 20123, Department of Geomatics Engineering, The University of Calgary (1998) Google Scholar