@article{oai:nipr.repo.nii.ac.jp:00002193, author = {Mendes da Costa, Aracy and Rizzo Piazza,Liliana}, journal = {Memoirs of National Institute of Polar Research. Special issue}, month = {Aug}, note = {P(論文), 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