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

Abstract

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.

GPS phase scintillation and proxy index at high latitudes during a moderate geomagnetic storm

“…The assumption that IPPs are at the E region altitudes results in better alignment or co-location with strong auroral emission (Fig. 8a) (Prikryl et al, 2011), and where the assumption of IPP altitude of 350 km is more appropriate. At sub-auroral latitudes, scintillation indices are usually not expected to reach high values.…”

“…S 4 scintillation index proxies have been used at low latitudes (Du et al, 2001;Dandekar and Groves, 2004). In this paper, a proxy for σ is obtained from GPS receivers recording 1-Hz data to complement availability of σ that is often enhanced at high latitudes (Prikryl et al, 2011(Prikryl et al, , 2013.…”

“…Scintillation indices, S 4 and σ , are widely used as a measure of amplitude and phase scintillation, respectively (Basu et al, 1985;Du et al, 2001;Kintner et al, 2007;Béniguel et al, 2009;Spogli et al, 2009;Prikryl et al, 2011). The S 4 -index is the standard deviation of the received power normalised by its mean value, and the phase scintillation index σ is the standard deviation of the detrended L1 phase using a filter in the receiver with a cutoff frequency.…”

GPS scintillation effects associated with polar cap patches and substorm auroral activity: direct comparison

“…It is well known that both polar cap patches and auroral particle precipitations can develop small scale ionospheric irregularities (Tsunoda 1988;Basu et al 1990); these irregularities can scatter radio signals and give rise to scintillations. In recent years, more GPS scintillation monitors have been deployed at high latitudes, and several statistical and case studies of high latitude GPS scintillations have been conducted (De Franceschi et al 2008;Spogli et al 2009;Li et al 2010;Alfonsi et al 2011;Prikryl et al 2010Prikryl et al , 2011Prikryl et al , 2013Moen et al 2013;Jiao et al 2013). Mitchell et al (2005) found phase and amplitude scintillations to be colocated with strong gradients in the Total Electron Content (TEC) at the edges of the high electron density streams.…”

The Behaviors of Ionospheric Scintillations Around Different Types of Nightside Auroral Boundaries Seen at the Chinese Yellow River Station, Svalbard

“…Cusp region ionospheric irregularity dynamics which gives rise to pre-noon hour scintillation and cycle slips have been found to be associated with the polar cap patches during the solar minimum (Prikryl et al, 2010). However, the nightside auroral oval is known to have predominant phase scintillations (Prikryl et al, 2011). Certainly, cusp scintillation and nighttime auroral scintillation are different because of different ionospheric irregularity production dynamics (van der Meeren et al, 2016).…”