250 MHz/GHz Scintillation Parameters in the Equatorial, Polar, and Auroral Environments

Basu, S.; MacKenzie, E.; Costa, Emanoel; Fougère, Paul F.; Carlson, H. C.; Whitney, H. E.

doi:10.1109/jsac.1987.1146533

Cited by 71 publications

(49 citation statements)

References 29 publications

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“…The dependence of total electron content (TEC) and scintillation intensity on these factors has been recognized and studied at VHF/UHF frequencies for many years (Aarons, 1982;Basu et al, 1987;Kersley et al, 1988;Gola et al, 1992). More recently, GPS receivers have improved coverage at high latitudes (Aarons, 1997;Aarons et al, 2000;Mitchell et al, 2005;Alfonsi et al, 2008;Jayachandran et al, 2009;Spogli et al, 2009;Yin et al, 2009;Li et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Climatology of GPS phase scintillation and HF radar backscatter for the high-latitude ionosphere under solar minimum conditions

et al. 2011

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Abstract. Maps of GPS phase scintillation at high latitudes have been constructed after the first two years of operation of the Canadian High Arctic Ionospheric Network (CHAIN) during the 2008-2009 solar minimum. CHAIN consists of ten dual-frequency receivers, configured to measure amplitude and phase scintillation from L1 GPS signals and ionospheric total electron content (TEC) from L1 and L2 GPS signals. Those ionospheric data have been mapped as a function of magnetic local time and geomagnetic latitude assuming ionospheric pierce points (IPPs) at 350 km. The mean TEC depletions are identified with the statistical high-latitude and mid-latitude troughs. Phase scintillation occurs predominantly in the nightside auroral oval and the ionospheric footprint of the cusp. The strongest phase scintillation is associated with auroral arc brightening and substorms or with perturbed cusp ionosphere. Auroral phase scintillation tends to be intermittent, localized and of short duration, while the dayside scintillation observed for individual satellites can stay continuously above a given threshold for several minutes and such scintillation patches persist over a large area of the cusp/cleft region sampled by different satellites for several hours. The seasonal variation of the phase scintillation occurrence also differs between the nightside auroral oval and the cusp. The auroral phase scintillation shows an expected semiannual oscillation with equinoctial maxima known to be associated with aurorae, while the cusp scintillation is dominated by an annual cycle maximizing in autumn-winter. These differences point to different irregularity production mechanisms: energetic electron precipitation into dynamic auroral arcs versus cusp ionospheric convection dynamics. Observations suggest anisotropy of scintillationcausing irregularities with stronger L-shell alignment of irregularities in the cusp while a significant component of Correspondence to: P. Prikryl (paul.prikryl@crc.gc.ca) field-aligned irregularities is found in the nightside auroral oval. Scintillation-causing irregularities can coexist with small-scale field-aligned irregularities resulting in HF radar backscatter. The statistical cusp and auroral oval are characterized by the occurrence of HF radar ionospheric backscatter and mean ground magnetic perturbations due to ionospheric currents.

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Section: Introductionmentioning

confidence: 99%

Climatology of GPS phase scintillation and HF radar backscatter for the high-latitude ionosphere under solar minimum conditions

et al. 2011

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“…Although scintillation is most intense at low latitudes (Aarons, 1982;Basu et al, 2002) it can be strong in high latitudes during disturbed conditions (Doherty et al, 2004). The high-latitude plasma structure associated with auroral and F-region polar cap patches and sun-aligned arcs is a source of scintillation that has been observed at UHF frequencies (Basu et al, 1987;MacDougall, 1990;Coker et al, 2004). Ionospheric scintillation also affects GPS receiver tracking performance (Skone, 2001).…”

Section: Introductionmentioning

confidence: 99%

GPS TEC, scintillation and cycle slips observed at high latitudes during solar minimum

et al. 2010

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Abstract. High-latitude irregularities can impair the operation of GPS-based devices by causing fluctuations of GPS signal amplitude and phase, also known as scintillation. Severe scintillation events lead to losses of phase lock, which result in cycle slips. We have used data from the Canadian High Arctic Ionospheric Network (CHAIN) to measure amplitude and phase scintillation from L1 GPS signals and total electron content (TEC) from L1 and L2 GPS signals to study the relative role that various high-latitude irregularity generation mechanisms have in producing scintillation. In the first year of operation during the current solar minimum the amplitude scintillation has remained very low but events of strong phase scintillation have been observed. We have found, as expected, that auroral arc and substorm intensifications as well as cusp region dynamics are strong sources of phase scintillation and potential cycle slips. In addition, we have found clear seasonal and universal time dependencies of TEC and phase scintillation over the polar cap region. A comparison with radio instruments from the Canadian GeoSpace Monitoring (CGSM) network strongly suggests that the polar cap scintillation and TEC variations are associated with polar cap patches which we therefore infer to be main contributors to scintillation-causing irregularities in the polar cap.

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“…The theoretical models generally depend upon an assumption about the shape of the power spectrum of electron density fluctuations along the path. Thus observations of power spectrum of electron density have been of interest to some scholars [3,[5][6][7][8][9], with many excellent reviews on this subject being published. Using VHF beaconing, Basu [10] found that the scintillation power spectra index is from 3 to 4.5 near the equatorial region, and the irregularity scale is less than 1 km.…”

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Spectra of L-band ionospheric scintillation over Nanjing

Fang

Yang

Sicheng³

2012

Chin. Sci. Bull.

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We report the spatiotemporal statistical characteristics of amplitude scintillation over Nanjing. A FFT method for computing scintillation intensity power spectra is briefly described. Using this method, the data with ISATM in Nanjing is analyzed. Spectra characteristic is presented and the irregularities property is discussed preliminarily. The results reveal that the power spectra obtained for Nanjing is consistent with theoretical modeling. At frequencies below the Fresnel frequency, the power density plotted on log-log scale is almost constant whereas above it asymptotes to a straight line. The spectral index ranges from 1.71 to 1.92, which has positive correlation with the S 4 index. Finally, the average drift velocity of irregularities is computed assumably and compared with that obtained for Xinxiang and Haikou. ionospheric scintillation, scintillation power spectra, electronic density irregularity, spectra index Citation:Fang H X, Yang S G, Wang S C. Spectra of L-band ionospheric scintillation over Nanjing. Chin Sci Bull, 2012, 57: 33753380, doi: 10.1007/s11434-012-5365-yThe ionosphere often features irregularities resulting from various unstable turbulence processes. When a radio wave from an extraterrestrial source, such as an artificial satellite, passes through the ionosphere, its wavefront will be distorted by the inhomogeneity present in the ionospheric plasma. As a result, the amplitude and phase of signals fluctuate, and the scintillation can be observed [1]. On propagating to the ground, these amplitude and phase variations cause interference to occur resulting in a diffraction pattern.Severe scintillations negatively affect trans-ionospheric radio communications and can interrupt or degrade GPS receiver operation by causing fading of the in-phase and quadrature signals, making the determination of phase by a tracking loop impossible. Degradation occurs when phase scintillations increase the frequency of cycle slips on the phase, and thus introduce ranging errors which in turn increase the dilution of precision and reduce the accuracy of GPS navigation. Since ionospheric scintillation originates from random electron density irregularities acting as wave scatterers, research on the formation and evolution of irregularities is closely related to scintillation studies [2]. A large number of theoretical investigations and statistical results have shown that the spectral analysis of scintillations from discrete radio sources and artificial satellites provides a new and valuable technique for investigating the continuous spectrum of small scale electron density irregularities in the ionosphere [3]. Information about irregularities in velocity, the equivalent thickness of the scattering layer, and irregularities in electron density can be deduced using conventional diffraction theory [4]. Also, knowledge of these irregularites is important in understanding the physical mechanisms underlying their formation and evolution; this is crucial in scintillation modeling [2]. During the past few decades, theor...

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250 MHz/GHz Scintillation Parameters in the Equatorial, Polar, and Auroral Environments

Cited by 71 publications

References 29 publications

Climatology of GPS phase scintillation and HF radar backscatter for the high-latitude ionosphere under solar minimum conditions

Climatology of GPS phase scintillation and HF radar backscatter for the high-latitude ionosphere under solar minimum conditions

GPS TEC, scintillation and cycle slips observed at high latitudes during solar minimum

Spectra of L-band ionospheric scintillation over Nanjing

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