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Annales Geophysicae An interactive open-access journal of the European Geosciences Union
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Volume 29, issue 12
Ann. Geophys., 29, 2287–2304, 2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
Ann. Geophys., 29, 2287–2304, 2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.

Regular paper 21 Dec 2011

Regular paper | 21 Dec 2011

Interhemispheric comparison of GPS phase scintillation at high latitudes during the magnetic-cloud-induced geomagnetic storm of 5–7 April 2010

P. Prikryl1, L. Spogli2, P. T. Jayachandran3, J. Kinrade4, C. N. Mitchell4, B. Ning5, G. Li5, P. J. Cilliers6, M. Terkildsen7, D. W. Danskin8, E. Spanswick9, E. Donovan9, A. T. Weatherwax10, W. A. Bristow11, L. Alfonsi2, G. De Franceschi2, V. Romano2, C. M. Ngwira6, and B. D. L. Opperman6 P. Prikryl et al.
  • 1Communications Research Centre Canada, Ottawa, ON, Canada
  • 2Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy
  • 3Physics Department, University of New Brunswick, Fredericton, NB, Canada
  • 4Department of Electronic and Electrical Engineering, University of Bath, Bath, UK
  • 5Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
  • 6South African National Space Agency, Hermanus, South Africa
  • 7IPS Radio and Space Services, Bureau of Meteorology, Haymarket, NSW, Australia
  • 8Geomagnetic Laboratory, Natural Resources Canada, ON, Canada
  • 9Department of Physics and Astronomy, University of Calgary, AB, Canada
  • 10Department of Physics and Astronomy, Siena College, Loudonville, NY, USA
  • 11Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK, USA

Abstract. 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.

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