Phase and coherence analysis of VHF scintillation over Christmas Island

• Main Authors: E. B. Shume, A. J. Mannucci, R. Caton
• Format: Article
• Language: English
• Published: Copernicus Publications 2014-03-01
• Series: Annales Geophysicae
• Online Access: https://www.ann-geophys.net/32/293/2014/angeo-32-293-2014.pdf

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.