Detrend effect on the scalograms of GPS power scintillation

• Published in: Advances in Space Research
• Main Authors: Materassi, M., Alfonsi, Lu., De Franceschi, G., Romano, V., Mitchell, C. N., Spalla, P.
• Other Authors: Materassi, M.; Istituto dei Sistemi Complessi del CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy, Alfonsi, Lu.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia, De Franceschi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia, Romano, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia, Mitchell, C. N.; Department of Electric and Electronic Engineering of the University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom, Spalla, P.; Istituto di Fisica Applicata ‘‘Carrara’’, IFAC-CNR, Via Madonna del Piano 10, 50019, Sesto Fiorentino, Italy, Istituto dei Sistemi Complessi del CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy, Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia, Department of Electric and Electronic Engineering of the University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom, Istituto di Fisica Applicata ‘‘Carrara’’, IFAC-CNR, Via Madonna del Piano 10, 50019, Sesto Fiorentino, Italy
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier Ltd. 2009
• Subjects: Ionospheric scintillation; Wavelet analysis; Turbolence remote sensing; 01. Atmosphere::01.02. Ionosphere::01.02.04. Plasma Physics; 01. Atmosphere::01.02. Ionosphere::01.02.06. Instruments and techniques; 01. Atmosphere::01.02. Ionosphere::01.02.07. Scintillations; Arctic
• Online Access: http://hdl.handle.net/2122/5050; https://doi.org/10.1016/j.asr.2008.01.023

The study of amplitude scintillation on GPS radio links is usually done after detrending the time series of the transmitted power so to define scintillations as the chaotic fluctuation around a unitary value. In a sense, the choice of how to detrend the time series is part of the definition of scintillation. Here we analyse how far the continuous wavelet analysis of the detrended signal is influenced by the choice of detrending. This study is done using amplitude raw data from the GPS receivers held by INGV and the University of Bath in the Northern polar region, with a sampling time of 0.02 s. Three detrending procedures are considered: a fifth degree polynomial detrending, a high-pass filter with detrending period as twice the length of the time series considered, and a high-pass filter with detrending period determined via some statistical criterion. We show that there exists a "threshold time scale" of about half minute under which the differences between the scalograms from the signals detrended in the three ways are very small. This is not changed by applying the same detrending procedures to the segment of length reduced to one-third. Consequences in terms of scintillation definition and practical applications are given. Published 1740-1748 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale JCR Journal reserved