First simulations of day-to-day variability of mid-latitude sporadic E layer structures

<jats:title>Abstract</jats:title><jats:p>We present the first simulations that successfully reproduce the day-to-day variability of the mid-latitude sporadic E (<jats:inline-formula><jats:alternatives><jats:tex-math>$$E_s$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>E</mml:mi><mml:mi>s</mml:mi></mml:msub></mml:math></jats:alternatives></jats:inline-formula>) layers.<jats:inline-formula><jats:alternatives><jats:tex-math>$$E_s$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>E</mml:mi><mml:mi>s</mml:mi></mml:msub></mml:math></jats:alternatives></jats:inline-formula>layers appearing in the lower ionosphere have been extensively investigated to monitor and forecast their effects on long-distance communication by radio waves. Although it is widely accepted that the atmospheric tides are important in generating the<jats:inline-formula><jats:alternatives><jats:tex-math>$$E_s$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>E</mml:mi><mml:mi>s</mml:mi></mml:msub></mml:math></jats:alternatives></jats:inline-formula>layers, no simulations to date have reproduced the<jats:inline-formula><jats:alternatives><jats:tex-math>$$E_s$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>E</mml:mi><mml:mi>s</mml:mi></mml:msub></mml:math></jats:alternatives></jats:inline-formula>layers observed on a certain day. This is due to the lack of the combination of realistic information on the atmospheric tides in the lower ionosphere and a three-dimensional numerical ionospheric model that can simulate the precise transport of metallic ions. We developed a numerical ionospheric model coupled with the neutral winds from the GAIA (Ground-to-topside model of Atmosphere and Ionosphere for Aeronomy). The fundamental structures and the day-to-day variations of the<jats:inline-formula><jats:alternatives><jats:tex-math>$$E_s$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>E</mml:mi><mml:mi>s</mml:mi></mml:msub></mml:math></jats:alternatives></jats:inline-formula>layers observed by a<jats:inline-formula><jats:alternatives><jats:tex-math>$$\hbox {Ca}^+$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mtext>Ca</mml:mtext><mml:mo>+</mml:mo></mml:msup></mml:math></jats:alternatives></jats:inline-formula>lidar are well-reproduced in the simulations.</jats:p>