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University of Calgary
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- PublicationOpen AccessInterhemispheric comparison of GPS phase scintillation at high latitudes during the magnetic-cloud-induced geomagnetic storm of 5–7 April 2010(2011-12-21)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Prikryl, P.; Communications Research Centre Canada, Ottawa, ON, Canada ;Spogli, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Jayachandran, P. T.; Physics Department, University of New Brunswick, Fredericton, NB, Canada ;Kinrade, J.; Department of Electronic and Electrical Engineering, University of Bath, Bath, UK ;Mitchell, C. N.; Department of Electronic and Electrical Engineering, University of Bath, Bath, UK ;Ning, B.; Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China ;Li, G.; Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China ;Cilliers, P. J.; South African National Space Agency, Hermanus, South Africa ;Terkildsen, M.; IPS Radio and Space Services, Bureau of Meteorology, Haymarket, NSW, Australia ;Danskin, D. W.; Geomagnetic Laboratory, Natural Resources Canada, ON, Canada ;Spanswick, E.; Department of Physics and Astronomy, University of Calgary, AB, Canada ;Weatherwax, A. T.; Department of Physics and Astronomy, Siena College, Loudonville, NY, USA ;Bristow, W. A.; Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK, USA ;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 ;Ngwira, C. M.; South African National Space Agency, Hermanus, South Africa ;Opperman, B. D. L.; South African National Space Agency, Hermanus, South Africa; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Arrays of GPS Ionospheric Scintillation and TEC Monitors (GISTMs) are used in a comparative scintillation study focusing on quasi-conjugate pairs of GPS receivers in the Arctic and Antarctic. Intense GPS phase scintillation and rapid variations in ionospheric total electron content (TEC) that can result in cycle slips were observed at high latitudes with dual-frequency GPS receivers during the first significant geomagnetic storm of solar cycle 24 on 5–7 April 2010. The impact of a bipolar magnetic cloud of north-south (NS) type embedded in high speed solar wind from a coronal hole caused a geomagnetic storm with maximum 3-hourly Kp = 8- and hourly ring current Dst =−73 nT. The interhemispheric comparison of phase scintillation reveals similarities but also asymmetries of the ionospheric response in the northern and southern auroral zones, cusps and polar caps. In the nightside auroral oval and in the cusp/cleft sectors the phase scintillation was observed in both hemispheres at about the same times and was correlated with geomagnetic activity. The scintillation level was very similar in approximately conjugate locations in Qiqiktarjuaq (75.4° N; 23.4° E CGM lat. and lon.) and South Pole (74.1° S; 18.9° E), in Longyearbyen (75.3° N; 111.2° E) and Zhongshan (74.7° S; 96.7° E), while it was significantly higher in Cambridge Bay (77.0° N; 310.1° E) than at Mario Zucchelli (80.0° S; 307.7° E). In the polar cap, when the interplanetary magnetic field (IMF) was strongly northward, the ionization due to energetic particle precipitation was a likely cause of scintillation that was stronger at Concordia (88.8° S; 54.4° E) in the dark ionosphere than in the sunlit ionosphere over Eureka (88.1° N; 333.4° E), due to a difference in ionospheric conductivity. When the IMF tilted southward, weak or no significant scintillation was detected in the northern polar cap, while in the southern polar cap rapidly varying TEC and strong phase scintillation persisted for many hours. This interhemispheric asymmetry is explained by the difference in the location of solar terminator relative to the cusps in the Northern and Southern Hemisphere. Solar terminator was in the immediate proximity of the cusp in the Southern Hemisphere where sunlit ionospheric plasma was readily convected into the central polar cap and a long series of patches was observed. In contrast, solar terminator was far poleward of the northern cusp thus reducing the entry of sunlit plasma and formation of dense patches. This is consistent with the observed and modeled seasonal variation in occurrence of polar cap patches. The GPS scintillation and TEC data analysis is supported by data from ground-based networks of magnetometers, riometers, ionosondes, HF radars and all-sky imagers, as well as particle flux measurements by DMSP satellites.529 319 - PublicationOpen AccessAn interhemispheric comparison of GPS phase scintillation with auroral emission observed at the South Pole and from the DMSP satellite(2013)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Prikryl, P.; Communications Research Centre, Ottawa, ON, Canada ;Zhang, Y.; Johns Hopkins University Applied Physics Laboratory, Laurel, MD, United States ;Ebihara, Y.; Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto, Japan ;Ghoddousi-Fard, R.; Natural Resources Canada, Geodetic Survey Division, Ottawa, ON, Canada ;Jayachandran, P. T.; University of New Brunswick, Physics Department, Fredericton, NB, Canada ;Kinrade, J.; University of Bath, Electronic and Electrical Engineering, Bath, United Kingdom ;Mitchell, C. N.; University of Bath, Electronic and Electrical Engineering, Bath, United Kingdom ;Weatherwax, A. T.; Siena College, Physics and Astronomy, Loudonville, NY, United States ;Bust, G.; Johns Hopkins University Applied Physics Laboratory, Laurel, MD, United States ;Cilliers, P. J.; South African National Space Agency, Space Science Directorate, Hermanus, South Africa ;Spogli, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Alfonsi, Lu.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Romano, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Ning, B.; Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China ;Li, G.; Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China ;Jarvis, M. J.; British Antarctic Survey, Physical Sciences Division, Cambridge, United Kingdom ;Danskin, D. W.; Natural Resources Canada, Geomagnetic Laboratory, Ottawa, ON, Canada ;Spanswick, E.; University of Calgary, Department of Physics and Astronomy, AB, Canada ;Donovan, E.; University of Calgary, Department of Physics and Astronomy, AB, Canada ;Terkildsen, M.; IPS Radio and Space Services, Bureau of Meteorology, Haymarket, NSW, Australia; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; The global positioning system (GPS) phase scintillation caused by highlatitude ionospheric irregularities during an intense high-speed stream (HSS) of the solar wind from April 29 to May 5, 2011, was observed using arrays of GPS ionospheric scintillation and total electron content monitors in the Arctic and Antarctica. The one-minute phase-scintillation index derived from the data sampled at 50 Hz was complemented by a proxy index (delta phase rate) obtained from 1-Hz GPS data. The scintillation occurrence coincided with the aurora borealis and aurora australis observed by an all-sky imager at the South Pole, and by special sensor ultraviolet scanning imagers on board satellites of the Defense Meteorological Satellites Program. The South Pole (SP) station is approximately conjugate with two Canadian High Arctic Ionospheric Network stations on Baffin Island, Canada, which provided the opportunity to study magnetic conjugacy of scintillation with support of riometers and magnetometers. The GPS ionospheric pierce points were mapped at their actual or conjugate locations, along with the auroral emission over the South Pole, assuming an altitude of 120 km. As the aurora brightened and/or drifted across the field of view of the all-sky imager, sequences of scintillation events were observed that indicated conjugate auroras as a locator of simultaneous or delayed bipolar scintillation events. In spite of the greater scintillation intensity in the auroral oval, where phase scintillation sometimes exceeded 1 radian during the auroral break-up and substorms, the percentage occurrence of moderate scintillation was highest in the cusp. Interhemispheric comparisons of bipolar scintillation maps show that the scintillation occurrence is significantly higher in the southern cusp and polar cap.426 464 - PublicationOpen AccessFIRST COMPARATIVE SCINTILLATION STUDY USING ARCTIC AND ANTARCTIC GPS RECEIVER ARRAYS(2010-08-03)
; ; ; ; ; ; ; ; ; ;Prikryl, Paul; Communications Research Centre Canada ;Spogli, Luca; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Alfonsi, Lucilla; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Jayachandran, Thayyil; University of New Brunswick ;Mitchell, Cathryn N.; Department of Electronic and Electrical Engineering, University of Bath ;De Franceschi, Giorgiana; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Romano, Vincenzo; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Spanswick, Emma; University of Calgary ;Donovan, Eric; University of Calgary; ; ; ; ; ; ; ; Arrays of dual-frequency GPS receivers operating in the Arctic and Antarctic monitor scintillation and ionospheric total electron content at high latitudes. Even under solar minimum conditions, events of significant phase scintillation have been observed in both polar caps. Climatology studies in both hemispheres show that phase scintillation as a function of magnetic local time and geomagnetic latitude primarily occurs in the nightside auroral oval and ionospheric cusp, with the scintillation regions shifting in latitude in response to varying geomagnetic activity. Preliminary results from the first comparative scintillation study supported by ground-based instruments including HF radars, ionosondes and all-sky imagers are presented. In the future, in-situ measurements by the Enhanced Polar Outflow Probe (ePOP) will provide additional support to study the Arctic and Antarctic ionospheres.193 144