Characterization of High-m ULF Wave Signatures in GPS TEC Data

GPS total electron content (TEC) measurements were used to investigate high-m ultralow frequency (ULF) waves during the recovery phase of a geomagnetic storm. ULF wave signals in TEC data show high coherence and significant common power in the wavelet coherence and cross wavelet transform analyses with magnetic field radial component data from GOES-15. They did not cause significant ionospheric scintillation or ground magnetic signatures due to ionospheric screening effects. An automatic identification procedure is developed to identify ULF wave signature in TEC data from 10 GPS receivers on January 25, 2016. The waves were mainly distributed on the dayside and post dusk sector from ∼64° to ∼71° magnetic latitude. This is the first time that the large-scale 2D spatial structure and temporal evolution of high-m ULF waves are revealed, which demonstrates TEC measurements as an effective high-m ULF wave remote sensing tool.