Observations of ionospheric F layer quadruple stratification near equatorial region

摘要

This paper presents and discusses the occurrence of F layer quadruple stratification (StF-1, StF-2, StF-3, and StF-4) during southern hemisphere winter season (June, July, and August 2002) and high solar activity condition, which was observed at Palmas (10.3°S, 48.3°W; dip latitude 5.5°S-near equatorial region), Brazilian sector. This is the first time that the formation of F layer quadruple stratification (StF-1, StF-2, StF-3, and StF-4) has been reported in the South American sector. The StF-4 has a short lifetime compared with triple stratification/F_3 layer, and it is antecedent and followed by triple/F_3 layer stratification.