Annales Geophysicae (Mar 2014)

Phase and coherence analysis of VHF scintillation over Christmas Island

  • E. B. Shume,
  • A. J. Mannucci,
  • R. Caton

DOI
https://doi.org/10.5194/angeo-32-293-2014
Journal volume & issue
Vol. 32
pp. 293 – 300

Abstract

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This short paper presents phase and coherence data from the cross-wavelet transform applied on longitudinally separated very high frequency (VHF) equatorial ionospheric scintillation observations over Christmas Island. The phase and coherence analyses were employed on a pair of scintillation observations, namely, the east-looking and west-looking VHF scintillation monitors at Christmas Island. Our analysis includes 3 years of peak season scintillation data from 2008, 2009 (low solar activity), and 2011 (moderate solar activity). In statistically significant and high spectral coherence regions of the cross-wavelet transform, scintillation observations from the east-looking monitor lead those from the west-looking monitor by about 20 to 60 (40 ± 20) min (most frequent lead times). Using several years (seasons and solar cycle) of lead (or lag) and coherence information of the cross-wavelet transform, we envisage construction of a probability model for forecasting scintillation in the nighttime equatorial ionosphere.