Occurrence characteristics and amplitude-frequency relationship of the Pc5 ULF waves from 3 decades of GOES data

We investigate the occurrence characteristics and amplitude-frequency relationships of Pc5 ultra-low frequency (ULF) waves (1.67-6.7 mHz) using 30 years of GOES magnetic field data (1995-2025) from GOES-8 to GOES-18. An enhanced CLEAN algorithm, employing iterative Hanning peak model fitting and subtraction, identified 27,279 radial, 26,145 azimuthal, and 31,259 parallel wave events in the Mean Field-Aligned coordinate system. Radial and parallel waves exhibit peak amplitudes between 9-15 MLT, driven by solar wind dynamic pressure, while azimuthal and parallel components dominate in the 15-21 MLT sector, consistent with Kelvin-Helmholtz instability. Strong power-law relationships ([Formula: see text]) between amplitude and frequency are observed for radial and azimuthal components in dawn and dusk sectors, with weaker correlations for the parallel component ([Formula: see text]). These relationships vary with solar wind conditions, with radial components showing robust power-law fits under strong and moderate conditions ([Formula: see text]). ULF wave occurrence rates peak during solar maxima, correlating strongly with solar wind parameters ([Formula: see text]), and exhibit quasi-biennial oscillations (QBOs)-short-term (1.5-4 year) modulations linked to solar dynamo processes. High-pass filtered data show strong correlations with dynamic pressure ([Formula: see text]). These findings resolve discrepancies in prior studies, highlighting the interplay of solar cycle, QBOs, and MLT-dependent drivers in Pc5 ULF wave dynamics, with implications for radiation belt dynamics and space weather forecasting.