Notice bibliographique
Résumé
A dual-frequency GPS receiver, GSV4004B, has been installed at Alert, Canada since May 2008 to study the ionospheric variability at a high-latitude location. This Ionospheric Scintillation and TEC Monitor (GISTM) receiver is able to measure amplitude and phase scintillation, and also Total Electron Content (TEC). In addition, a High Frequency (HF) link has been established from Qaanaaq to Svalbard since March 2009 to study the channel characteristics, including Doppler spreads. This study covers from end of May 2008 to February 2011 where it was mostly during the minimum state of solar activity. During the period of where both GISTM and HF data were available (i.e. March 2009-July 2010), data from both links are compared to see any relation between TEC variations and scintillation effects and also Doppler spreads. Data from the GISTM receivers at Svalbard were also utilised. \nWinter months expectedly show lower mean vertical TEC (VTEC) than in other months. Higher mean VTEC was observed in 2010 that could be related to the increase of solar activity. In 2010, both small and large patches of moderate-high intensity were found to be more than twice as common in February and March than in other months. The difference in the occurrences of small patches between months of the same year was about 1-2% (for low intensity patches) and 1-10% (moderate-high intensity). This difference increased to 1-4% (low intensity) and 1-12% (moderate-high intensity) for large patches. UT dependence can be seen where ~80 large and ~300 small patches were identified ~1000 to 2000 UT from June to \nOctober in both 2008 and 2009, and they doubled in 2010. Amplitude scintillations index, S4 were very low where at least ~99% were between 0 and 0.1, which is insignificant. Meanwhile, phase scintillations index, σφ were from 0 to 0.1 rad for at least 93% of the time. The relationship of TEC fluctuations/increase and phase scintillations is complex. There are few events where phase scintillations occurred simultaneously with slant TEC increases, but this is not frequent. The magnitude of the irregularities was generally independent of geomagnetic indices, Interplanetary Magnetic Field (IMF) components, and local magnetic fields at Eureka and Resolute Bay. \nMonthly upper decile of Doppler spreads generally varied from 1 to 5.5 Hz. High upper decile normally occurred from around September/October to March, from ~0000 to 1700 UT on 6.95 and 8.01 MHz. The hourly upper decile reached up to 7-8.5 Hz (6.95 MHz) and 7-9.5 Hz (8.01 MHz). Upper decile on these frequencies was mostly 0.5-4.5 Hz larger in October 2010-February 2011 than in the same months of the previous year which possibly related to the increase in solar activity. However, Doppler spreads were generally independent of independent of geomagnetic indices, IMF components, and local magnetic fields. The relation between the irregularities observed via transionospheric link and HF link is also complex. Large TEC fluctuations/increases and/or phase scintillations observed on satellite(s) close to HF midpoint may correspond to either small or large Doppler spreads.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,108 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; les deux têtes enseignantes s’accordent sur ce qui est montré ici.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».