An empirical model of ionospheric foE over Wuhan

Abstract

Daytime half-hourly values of the critical frequency of the ionospheric E-layer, f oE, obtained at Wuhan Ionospheric Observatory (geographic 114.4• E, 30.6 • N; 45.2 • dip), China, during the whole interval of 1957-1991 and 1999-2004 have been used to develop an empirical model. The model, including variations with local time, day number and solar cycle, is in agreement with the observations. A comparison between our model and IRI and Titheridge's model has also been made. Statistically, our model gives a better performance than IRI and Titheridge's model because data set is obtained with our own station. Both the IRI and Titheridge's model overestimate f oE especially in May to September months. Combing with past investigations, we suggest that overestimation of ionospheric parameters by IRI may be a common feature in East Asia. This result is very helpful for both the correction of IRI in East Asia and the development of Chinese Reference Ionosphere (CRI) model.

TIME-IGGCAS model validation: Comparisons with empirical models and observations

“…Overestimation of IRI over Wuhan was discovered by Liu using foF2 data and by Chen using TEC data, respectively [16,17] . The same conclusion was also obtained by Yue using foE data [18] . Lack of Chinese data when IRI was constructed is a probable reason.…”

Dusk-to-nighttime enhancement of mid-latitude <i>Nm</i>F2 in local summer: inter-hemispheric asymmetry and solar activity dependence

“…Ionospheric electron density should have a diurnal variation characterized by higher electron densities at noontime, when solar zenith is lowest during a day, according to the Chapman photochemical theory (Rishbeth and Garriott, 1969). Photochemical processes are dominative at ionospheric E layer height; thus, diurnal variation feature of the E layer electron density is basically consistent with the diurnal trend of the Chapman theory (e.g., Yue et al, 2006). At the F layer height, ionospheric dynamics and electrodynamics processes as well as thermospheric compositions also significantly affect the electron density.…”

Solar activity effects of the ionosphere: A brief review

“…Besides various attempts to retrieve solar proxies directly from solar data, several ionospheric indices have been successively introduced since the 1950s [18,[24][25][26][27]. These indices are deduced from ionospheric data measured at single stations or over regions.…”