On the diurnal variability in F2-region plasma density above the EISCAT Svalbard radar

Moen, J.; Li, Xiaoping; Carlson, H. C.; Fujii, Ryoichi; McCrea, I. W.

doi:10.5194/angeo-26-2427-2008

Cited by 67 publications

(102 citation statements)

References 21 publications

(27 reference statements)

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“…The enhancement around noon is visible mainly in the NYA map as an expected cusp effect due to the field of view of the station. To this enhancement contributes also the polar cap patches that form in the cusp and enters the polar cap in cusp inflow region (Moen et al, 2008). During midnight the enhancement and the asymmetry are evident also in the auroral stations (HAM and BRO), while NOT data contribute weakly to the midnight enhancement, maybe due to the equatorward boundary of the very disturbed oval.…”

Section: Phase Scintillationmentioning

confidence: 95%

Climatology of GPS ionospheric scintillations over high and mid-latitude European regions

et al. 2009

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Abstract. We analyze data of ionospheric scintillation in the geographic latitudinal range 44 • -88 • N during the period of October, November and December 2003 as a first step to develop a "scintillation climatology" over Northern Europe. The behavior of the scintillation occurrence as a function of the magnetic local time and of the corrected magnetic latitude is investigated to characterize the external conditions leading to scintillation scenarios. The results shown herein, obtained merging observations from four GISTM (GPS Ionospheric Scintillation and TEC Monitor), highlight also the possibility to investigate the dynamics of irregularities causing scintillation by combining the information coming from a wide range of latitudes. Our findings associate the occurrences of the ionospheric irregularities with the expected position of the auroral oval and ionospheric troughs and show similarities with the distribution in magnetic local time of the polar cap patches. The results show also the effect of ionospheric disturbances on the phase and the amplitude of the GPS signals, evidencing the different contributions of the auroral and the cusp/cap ionosphere.

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Section: Phase Scintillationmentioning

confidence: 95%

Climatology of GPS ionospheric scintillations over high and mid-latitude European regions

et al. 2009

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“…Patches become particularly large during geomagnetic storms (called tongue of ionization) and form a channel of enhanced density from the dayside and nightside auroral oval across the polar cap (Foster et al 2005). The IMF By also controls dawn-dusk motion of patches (Moen et al 2008a;Hosokawa et al 2009). Convection within the polar cap is often assumed to consist of relatively uniform anti-sunward flow with a typical speed of several hundreds of m/s (e.g., MacDougall and Jayachandran 2001).…”

Section: Introductionmentioning

confidence: 99%

Analysis of close conjunctions between dayside polar cap airglow patches and flow channels by all-sky imager and DMSP

et al. 2016

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Recent imager and radar observations in the nightside polar cap have shown evidence that polar cap patches are associated with localized flow channels. To understand how flow channels propagate from the dayside auroral oval into the polar cap, we use an all-sky imager in Antarctica and DMSP (F13, F15, F16, F17 and F18) to determine properties of density and flows associated with dayside polar cap patches. We identified 50 conjunction events during the southern winter seasons of 2007-2011. In a majority (45) of events, longitudinally narrow flow enhancements directed anti-sunward are found to be collocated with the patches, have velocities (up to a few km/s) substantially larger than the large-scale background flows (~500 m/s) and have widths comparable to patch widths (~400 km). While the patches start with poleward moving auroral forms (PMAFs) as expected, many PMAFs propagate azimuthally away from the noon over a few hours of MLT, resulting in formation of polar cap patches quite far away from the noon, as early as ~6 MLT. The MLT separation from the noon is found to be proportional to the IMF |By|. Fast polar cap flows of >~1500 m/s are predominantly seen during large IMF |By| and small |Bz|. The presence of fast, anti-sunward flow channels associated with the polar cap patches suggests that the flow channels form in the dayside auroral oval through transient reconnection and can be the source of flow channels propagating into the polar cap.

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“…There is a possibility that patches formed in the cusp and convected towards the night-time auroral oval also contribute to scintillation and cycle slips. The asymmetry of the polar cap patches distribution around magnetic midnight has been recently discussed by Moen et al (2008). Regions of most frequent occurrence of scintillation as a function of magnetic latitude and magnetic local time (MLT) are subject of ongoing investigation to be presented in the future publication.…”

Section: Gps Scintillation In the Auroral And Cusp Regionsmentioning

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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On the diurnal variability in F2-region plasma density above the EISCAT Svalbard radar

Cited by 67 publications

References 21 publications

Climatology of GPS ionospheric scintillations over high and mid-latitude European regions

Climatology of GPS ionospheric scintillations over high and mid-latitude European regions

Analysis of close conjunctions between dayside polar cap airglow patches and flow channels by all-sky imager and DMSP

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

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