PCA effects on a VLF transantarctic propagation path

• Main Authors: Mendes da Costa, Aracy, Rizzo Piazza,Liliana
• Format: Report
• Language: English
• Published: INPE: Instituto de Pesquisas Espaciais/INPE: Instituto de Pesquisas Espaciais 1987
• Subjects: Antarctic; The Antarctic; Antarc*; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2193; http://id.nii.ac.jp/1291/00002193/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2193&item_no=1&attribute_id=18&file_no=1

We present a study of polar cap absorption events occurred from September 1967 to November 1974 and their effects on phase records of very low frequency (VLF) signals on NWC (Australia)-Sao Paulo (Brazil) propagation path, crossing the Antarctic continent. Nearly 50 PCAs from that period, of different intensities, were studied and the most relevant ones were analyzed in more detail. A good correlation between nighttime VLF signal phase advances and total proton flux content of energy 10MeV<E<30MeV measured by satellites (Explorer 34 and 41,NOAA 2 and 3 and ATS-1) was obtained for strong PCA events. Geomagnetic storms with sudden commencement, associated or not with proton precipitation, also produces well defined VLF signal phase advances. Comparison of these results with those obtained in the northern hemisphere during PCA events may provide relevant information on the behavior of the ionospheric D-layer over the Antarctic region. Simultaneous analysis of VLF on non-polar propagation paths were also included for the major PCA discussed. Well defined phase deviations were detected showing the significant contribution of the South Atlantic Geomagnetic Anomaly to the ionization of the lower part of the ionospheric D-region.