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Seasonal and solar activity variations of F 3 layer and quadruple stratification (StF‐4) near the equatorial region
Author(s) -
Tardelli A.,
Fagundes P. R.,
Pezzopane M.,
Venkatesh K.,
Pillat V. G.
Publication year - 2016
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2016ja023580
Subject(s) - stratification (seeds) , low latitude , atmospheric sciences , latitude , solar cycle , environmental science , seasonality , climatology , geology , physics , plasma , mathematics , solar wind , geodesy , biology , seed dormancy , statistics , botany , germination , quantum mechanics , dormancy
The study of multiple stratification of the F layer has the initial records in the midtwentieth century. Since then, many studies were focused on F 3 layer. The diurnal, seasonal, and solar activity variations of the F 3 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 F 3 layer and StF‐4 near the equatorial region during the period from 2002 to 2006. A significant connection between StF‐4 and F 3 layer has been noticed, since the StF‐4 is always preceded and followed by a F 3 layer appearance. However, the F 3 layer and the StF‐4 present different seasonal and solar cycle variations. At a near‐equatorial station Palmas, the F 3 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 F 3 layer occurrence is not affected by solar cycle, the StF‐4 appearance is instead more frequent during high solar activity.