Evaluating Total Electron Content (TEC) Detrending Techniques in Determining Ionospheric Disturbances during Lightning Events in A Low Latitude Region

Louis Osei-Poku,Long Tang,Wu Chen,Chen Mingli

doi:10.3390/rs13234753

Abstract

Total Electron Content (TEC) from Global Navigation Satellite Systems (GNSS) is used to ascertain the impact of space weather events on navigation and communication systems. TEC is detrended by several methods to show this impact. Information from the detrended TEC may or may not necessarily represent a geophysical parameter. In this study, two commonly used detrending methods, Savitzky–Golay filter and polynomial fitting, are evaluated during thunderstorm events in Hong Kong. A two-step approach of detection and distinguishing is introduced alongside linear correlation in order to determine the best detrending model. Savitzky–Golay filter on order six and with a time window length of 120 min performed the best in detecting lightning events, and had the highest moderate positive correlation of 0.4. That the best time frame was 120 min suggests that the observed disturbances could be travelling ionospheric disturbance (TID), with lightning as the potential source.

Highlights

Total electron content (TEC) obtained from Global Navigation Satellite Systems (GNSS)can be used to ascertain the impact of space weather events on communication and navigation systems
The filter falls into category of low-pass time domain filters that smooth out high data variability [16] and is used in many applications, such as electrocardiogram denoising [17], vegetation monitoring and GNSS-TEC changes
The polynomial of order 3 is represented as P3

Summary

Introduction

Total electron content (TEC) obtained from Global Navigation Satellite Systems (GNSS). Can be used to ascertain the impact of space weather events on communication and navigation systems. The difference obtained can determine amplitude, frequency, and other signal changes in case of a weather event. Different best fit models have been used. Each best fit method produces different results, which may or may not necessarily detect the impact a weather event makes on the signal or adequately show the occurrence of the event. In using GNSS for space weather event studies, extensive studies have been done on geomagnetic storms [2,3,4], earthquakes [5,6], and typhoons [7,8,9]. The fitting methods have been mostly used in these studies to detect travelling ionosphere disturbance (TID) and other ionosphere irregularities

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Discussion

Conclusion