Observations and Analysis of the Occurrence Pattern of Large Ionospheric TEC Gradients Over the Brazilian Airspace

Rezy Pradipta, Patricia H. Doherty, Richard Cole, Navin Mathur

Peer Reviewed

Abstract:	We report the results from our recent investigations on the occurrence of large/steep gradient in GPS-derived total electron content (TEC) over the Brazilian airspace. The TEC gradients investigated in the present study are mostly associated with the naturally-occurring equatorial plasma bubbles (EPBs) that routinely develop in the nighttime ionosphere due to the Rayleigh-Taylor instability. This observational study had been conducted using GPS TEC data from the RBMC network, provided by Instituto Brasileiro de Geografia e Statistica (IBGE). Based on the data collected in 2014/2015, we have determined that the TEC gradients associated with EPBs could have magnitudes as large as 1000 mm/km at the GPS L1 frequency, and that the TEC gradient magnitude distribution follows a form of power law distribution function. In general, these EPB-related TEC gradients are associated with either the side wall(s) of the bubble, or the plasma density irregularities in the interior of the bubble. The TEC gradients associated with the side walls of bubbles can be very steep (sometimes with a magnitude exceeding 600 mm/km at the GPS L1 frequency). On the other hand, the TEC gradients associated with the plasma density irregularities in the interior of bubbles are usually not very large in magnitude (typically 200-300 mm/km at the GPS L1 frequency), but they are much more prevalent and extensive spatially than the side walls.
Published in:	Proceedings of the 2016 International Technical Meeting of The Institute of Navigation January 25 - 28, 2016 Hyatt Regency Monterey Monterey, California
Pages:	525 - 531
Cite this article:	Pradipta, Rezy, Doherty, Patricia H., Cole, Richard, Mathur, Navin, "Observations and Analysis of the Occurrence Pattern of Large Ionospheric TEC Gradients Over the Brazilian Airspace," Proceedings of the 2016 International Technical Meeting of The Institute of Navigation, Monterey, California, January 2016, pp. 525-531. https://doi.org/10.33012/2016.13431
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