Intraseasonal Modulation of the Schumann Resonances by the MJO, CCEWs, and EWs

The Schumann resonances (SRs) are electromagnetic waves of zonal wavenumber one trapped in the cavity between the Earth and the Ionosphere and mainly caused by the excitation of terrestrial electromagnetic fields due to electric discharges that occur inside deep convective clouds. Füllekrug & Fraser-Smith (1996) found a periodicity of 20 to 30 days in SRs data that they associated with geomagnetic activity in the magnetosphere, and that could be related to the sunspot cycle. Anyamba, Williams, Susskind, Fraser-Smith, & Fullekrug (2000) explored the possibility of the influence of MJO in the modulation of SRs. However, works such as Beggan & Musur (2019) showed difficulty in detecting a relationship of MJO with SRs.

In the present study, we analyze data from the Sierra Nevada Extremely Low-Frequency Station in Spain. We explore the hypothesis that, due to the relationship between deep convection and SRs, it is expected that atmospheric phenomena associated with intra-seasonal modulation of deep convection like the MJO have an inherent effect on the modulation of SR. We also explore the possibility of SRs modulation by other intra-seasonal modes like the Convectively Coupled Equatorial Waves (CCEWs) and the Easterly Waves (EWs).

REFERENCES

Anyamba, E., Williams, E., Susskind, J., Fraser-Smith, A., & Fullekrug, M. (2000). The Manifestation of the Madden–Julian Oscillation in Global Deep Convection and in the Schumann Resonance Intensity. Journal of the Atmospheric Sciences, 57(8), 1029–1044.

Beggan, C. D., & Musur, M. A. (2019). Is the Madden-Julian Oscillation reliably detectable in Schumann Resonances? Journal of Atmospheric and Solar-Terrestrial Physics. https://doi.org/10.1016/J.JASTP.2019.05.009

Füllekrug, M., & Fraser-Smith, A. C. (1996). Further evidence for a global correlation of the Earth-ionosphere cavity resonances. Geophysical Research Letters, 23(20), 2773–2776. https://doi.org/10.1029/96GL02612