Numerical Simulations on Day‐to‐Day Variations of Low‐Latitude Es Layers at Arecibo

Abstract

To reveal mechanisms of day‐to‐day variations of the low‐latitude sporadic E (Es) layers, Es layer simulations were performed and compared to plasma layers observed by the Arecibo radar. Many studies have been conducted about the Es layers till now. However, few studies investigated the day‐to‐day variations of the Es layers especially at the low‐latitudes. Herein, for the first time, our numerical model generally succeeded in reproducing features of the day‐to‐day variations of the low‐latitude Es layers. We found that the day‐to‐day variations of the Es layers are created by a combination of day‐to‐day variations of zonal/meridional‐wind shears driven by the tides and the downward phase velocity of the tides. The wind‐driven mechanism generally explains the day‐to‐day variations of the low‐latitude Es layers.

Occurrence features of intermediate descending layer and Sporadic E observed over the higher mid-latitude ionospheric station of Moscow

“…The first observations of IDLs were obtained from the Incoherent Scatter Radar (ISR) located at the Arecibo station (MacDougall 1974;Rowe 1974;Tong et al 1988;Mathews et al 1993;Morton et al 1993;Osterman et al 1994) which revealed the tidal motion and seasonal variations of IDLs over lowlatitudes. Numerical simulations by Andoh et al (2022) successfully reproduced for the first time day-to-day variations of the observed Es layers at Arecibo, while the same authors have also presented the first simulations of midlatitude Es day-to-day variability (Andoh et al 2020). Recently, Santos et al (2019Santos et al ( , 2020Santos et al ( & 2022 focused on the occurrence peculiarities, the response on solar activity and the climatology of IDL over several low-latitude stations in Brazil.…”

E‐Field Effects on Day‐To‐Day Variations of Geomagnetic Mid‐Latitude Sporadic E Layers

“…We utilized the same regional ionospheric model as in Andoh et al. (2022), which regarded Mg + as a proxy for metal ions. Detailed descriptions of the ionospheric model have been provided in Andoh et al.…”

“…They consist mainly of metal ions, such as Mg + , Fe + , Ca + , and Na + (Kopp, 1997). EsLs have been investigated through various observations (e.g., Arras et al., 2008; Cai, Yuan, Eccles, & Raizada, 2019; Delgado et al., 2012; Dou et al., 2010; Friedman et al., 2000; Haldoupis, 2012; Mathews, 1998; Whitehead, 1970, 1989; Yu et al., 2019) and simulations (e.g., Andoh et al., 2020, 2021, 2022; Cai, Yuan, Eccles, Pedatella, et al., 2019; Carter & Forbes, 1999; Huba et al., 2019) for decades. Many studies have focused on revealing the effects of winds on geomagnetic mid‐latitude EsL dynamics (Haldoupis, 2012; Mathews, 1998; Whitehead, 1970, 1989).…”

“…This can be because the model of Andoh et al. (2020, 2022) only included the winds and not the E‐fields. In this study, we aimed to elucidate dynamo E‐field roles in day‐to‐day EsL variations driven by winds at geomagnetic mid‐latitudes.…”

Quantifying day-to-day variability of O/N2 and its correlation with geomagnetic activity using GOLD

“…Strong agreement between the observed climatology of the IT region and the modeled climatology [from models like the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM), its predecessor the Thermosphere General Circulation Model (TGCM), and the Whole Atmosphere Community Climate Model with thermosphere and ionosphere eXtension (WACCM-X)] has been demonstrated since as early as 1981 (Dickinson et al, 1981;Richmond et al, 1992;Fesen et al, 2002;Qian et al, 2014;Liu et al, 2018), but the day-to-day variations are comparatively difficult to model/study and therefore less understood (Zhou et al, 2020, Zhou et al, 2021Andoh et al, 2022). Many details of the state of the IT system can be captured by parameters such as the ratio of atomic Oxygen (O) to molecular Nitrogen (N 2 ) (O/N 2 ).…”