Seasonal and solar activity variations of F₃ layer and quadruple stratification (StF‿) near the equatorial region

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• 作者：A. Tardelli ; P. R. Fagundes ; M. Pezzopane ; K. Venkatesh ; V. G. Pillat
• 刊名：Journal of Geophysical Research: Space Physics
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：121
• 期：12
• 页码：12,116-12,125
• 全文大小：1.1MB
• ISSN：2169-9402

文摘

The study of multiple stratification of the F layer has the initial records in the midtwentieth century. Since then, many studies were focused on F₃ layer. The diurnal, seasonal, and solar activity variations of the F₃ layer characteristics have been investigated by several researchers. Recently, investigations on multiple stratifications of F layer received an important boost after the quadruple stratification (StF-4) was observed at Palmas (10.3°S, 48.3°W; dip latitude 6.6°S—near-equatorial region), Brazil. The present study reports the latest findings related with the seasonal and solar activity characteristics of the F₃ layer and StF-4 near the equatorial region during the period from 2002 to 2006. A significant connection between StF-4 and F₃ layer has been noticed, since the StF-4 is always preceded and followed by a F₃ layer appearance. However, the F₃ layer and the StF-4 present different seasonal and solar cycle variations. At a near-equatorial station Palmas, the F₃ layer shows the maximum and minimum occurrences during summer and winter seasons, respectively. On the contrary, the StF-4 presents the maximum and minimum occurrences during winter and summer seasons, respectively. While the F₃ layer occurrence is not affected by solar cycle, the StF-4 appearance is instead more frequent during high solar activity.