Comparative study of the equatorial ionosphere over Jicamarca during recent two solar minima

摘要: It is a critical issue that whether or not the extremely deep solar minimum of cycle 23/24 brought serious influences on Earth's space environment. In this study, we collected and manually scaled ionograms recorded by DPS ionosonde at Jicamarca (12.0 degrees S, 283.2 E) to retrieve F layer parameters electron density (N-e) profiles. A comparative study performed evaluate equatorial ionosphere in minima 22/23 (1996-1997) (2008-2009). The seasonal median values frequency F-2 (f(o)F(2)) were remarkably reduced four seasons during minimum, compared those 1996-1997. first time find lower prevail most times 2008-2009 F2 peak height (h(m)F(2)) Chapman scale (H-m). bottomside profile thickness (B0) shows higher than 1996-1997 some daytime intervals, although it also becomes smaller rest times. Furthermore, contracted strongly altitudes above h(m)F(2) more perceptible afternoon hours. decrease N-e strongest September equinox weakest June solstice. ionospheric responses from are mainly caused reduction extreme ultraviolet intensity, contribution dynamical processes competes variable. Analysis reveals semiannual longer-scale components certainly while shorter (e. g., 4 month) may disrupt decline picture