Occurrence Pattern of Lightning Whistler Waves Observed at the Great Wall Station in Antarctica

Abstract

Lightning whistler waves are critical for the evolution and dynamics of the radiation belts and play an important role in coupling the Earth's atmosphere with the magnetosphere. Ground‐based very‐low‐frequency (VLF) measurements in Peninsula Antarctica have been historically utilized to analyze the lightning whistler waves from the geomagnetic conjugate region in North America. However, statistical study of lightning whistler waves in Antarctica still remains insufficient, especially for the Solar Cycle 25. Therefore, in this study, we have developed a method to automatically pick out whistler waves from an enormous amount of VLF data based on the You Only Look Once model. This method achieves an accuracy of 95% and we have identified 51,236 whistler waves with clear dispersion structures from the VLF data collected at the Great Wall Station in Antarctica during 2023–2024. These whistler events originated from the geomagnetic conjugate region, and the majority were recorded during the summer season of the northern hemisphere, as well as local nighttime conditions, because of the reduced ionospheric electron density. The temporal dispersion parameter was found to be higher during nighttime conditions and the variation in different seasons was insignificant. However, this parameter decreased by 5% during geomagnetic storms, corresponding to an approximate 9.8% decrease in the density of cold plasma along the propagation path of whistler waves, likely related to storm‐time redistribution or depletion of cold plasma in the inner magnetosphere.