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Extraction of the geomagnetic activity effect from TEC data: A comparison between the spectral whitening method and 28 day running median
Author(s) -
Chen Zhou,
Wang JingSong,
Deng Yue,
Huang ChunMing
Publication year - 2017
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2016ja023412
Subject(s) - tec , earth's magnetic field , geomagnetic storm , quiet , ionosphere , atmospheric sciences , environmental science , total electron content , ionospheric dynamo region , geophysics , geology , magnetic field , physics , quantum mechanics
The spectral whitening method (SWM) has been previously proved to be very effective at identifying ionospheric disturbances on f o F 2 (the critical frequency of ionospheric F 2 layer). To continuously investigate the strength of the new method, in this paper SWM has been used to extract the effect of geomagnetic activity on total electron content (TEC) and has been compared with the traditional 28 day running median centered (RMC) method. First, ionospheric variations during quiet and disturbed conditions are analyzed by both SWM and RMC. The results from RMC, compared with those from SWM, overestimate the disturbance occurrence by about 5–20% during the geomagnetic storms and up to 35% during the quiet time. The possible reason is that the results can be contaminated by the residuals of periodic components in the RMC identified disturbances. Meanwhile, the power spectral analysis of the disturbance field shows that the annual and diurnal variations are still significant in RMC results but very weak in SWM results, which indicates that SWM has some advantage to clean up the background variation. Finally, the analysis of the spatial correlation of the disturbance field with F 10.7 and Ap illustrates that the effects of solar and geomagnetic activities from SWM are significantly reduced and enhanced, respectively. It suggests that the SWM is more effective in extracting the effect of geomagnetic activity from TEC than RMC. The relative deviation of TEC derived by SWM is more sensitive to geomagnetic activity than solar activity.